Artículos SCI
2024
2024
Química de Superficies y Catálisis
Reforming of biomass-derived producer gas using toluene as model tar: Deactivation and regeneration studies in Ni and K-Ni catalysts
Azancot, L; González-Castaño, M; Bobadilla, LF; Centeno, MA; Odriozola, JAEnvironmental Research, 247 (2024) 118210 DOI: 10.1016/j.envres.2024.118210
Abstract
Within the syngas production from biomass gasification, tar removal constitutes a chief issue to overcome for advanced catalytic systems. This work investigates the performance of Ni and Ni-K catalysts for reforming of derived-biomass producer gas using toluene as model tar. At 750 degrees C and 60Lg(-1)h(-1), the stability test (70 h) revealed stable performances (CO2, CH4 and C7H8 conversions of 60, 95 and 100%, correspondingly) uniquely for the Ni-K catalyst. Although the efficient protection towards coking let by K was demonstrated, TPO studies over the post-reacted systems still evidenced the presence of carbon deposits for both samples. Conducting three successive reaction/regeneration cycles with different gasifying agents (air, steam and CO2) at 800 C for 1h, the capability towards regeneration of both catalytic systems was assessed and the spent catalysts were characterized by XRD, SEM and TEM. While none of the regeneration treatments recovered the performance of the unpromoted catalyst, the Ni-K catalysts demonstrated the capability of being fully regenerated by air and CO2 and exhibited analogous catalytic performances after a series of reaction/regeneration cycles. Hence, it is proved that the addition of K into Ni catalysts not only enhances the resistance against deactivation but enables rather facile regenerative procedures under certain atmospheres (air and CO2).
Abril, 2024 | DOI: 10.1016/j.envres.2024.118210
Materiales Nanoestructurados y Microestructura
Synergistic Effect of He for the Fabrication of Ne and Ar Gas-Charged Silicon Thin Films as Solid Targets for Spectroscopic Studies
Fernández, A; Godinho, V; Ávila, J; Jiménez de Haro, MC; Hufschmidt, D; López-Viejobueno, J; Almanza-Vergara, GE; Ferrer, FJ; Colaux, JL; Lucas, S; Asensio, MCNanomaterials, 14(8) (2024) 727 DOI: 10.3390/nano14080727
Abstract
Sputtering of silicon in a He magnetron discharge (MS) has been reported as a bottom-up procedure to obtain He-charged silicon films (i.e., He nanobubbles encapsulated in a silicon matrix). The incorporation of heavier noble gases is demonstrated in this work with a synergistic effect, producing increased Ne and Ar incorporations when using He–Ne and He–Ar gas mixtures in the MS process. Microstructural and chemical characterizations are reported using ion beam analysis (IBA) and scanning and transmission electron microscopies (SEM and TEM). In addition to gas incorporation, He promotes the formation of larger nanobubbles. In the case of Ne, high-resolution X-ray photoelectron and absorption spectroscopies (XPS and XAS) are reported, with remarkable dependence of the Ne 1s photoemission and the Ne K-edge absorption on the nanobubble’s size and composition. The gas (He, Ne and Ar)-charged thin films are proposed as “solid” targets for the characterization of spectroscopic properties of noble gases in a confined state without the need for cryogenics or high-pressure anvils devices. Also, their use as targets for nuclear reaction studies is foreseen.
Abril, 2024 | DOI: 10.3390/nano14080727
Materiales y Procesos Catalíticos de Interés Ambiental y Energético
H2 production based on a ternary mixture of commercial CuO-NiO-TiO2 in a solar pilot plant
Villachica-Llamosas, JG; Ruiz-Aguirre, A; Colón, G; Peral, J; Malato, SCatalysis Today, 431 (2024) 114608 DOI: 10.1016/j.cattod.2024.114608
Abstract
Glycerol is a by-product in biodiesel production (in the range of g·L−1), so its photoreforming by photocatalysis is a way of valorising it. TiO2 in photocatalysis has been widely studied, although its efficiency is limited by the high energy band gap, and the electron-hole recombination. Its combination with different semiconductors should improve charge separation, extending also the absorption from UV to visible light. Cu and Ni oxides are two of the most efficient low-cost transition metal oxide catalysts. Experiments were carried out in a 25 L pilot plant connected to a compound parabolic solar collector. Different combinations of the three semiconductors, based on the concentration of each metal on TiO2 (Me, 5%, 7.2% and 10%) were evaluated. Evonik P25-TiO2, CuO and NiO were combined by mechanical mixing. Hydrogen was quantified by a micro gas chromatograph, and copper and nickel leaching by ICP-MS. The best hydrogen production (0.060 mMol kJ−1) was attained with a proportion of 10:1 of TiO2:MeO, that corresponds to a total metal concentration of 7.2 wt%, being Cu and Ni in the same proportion. Metal content in solution increased as the reaction progressed, but Ni lixiviation of <0.012 mg L−1 was not significant. Significant Cu leaching (>1 mg L−1) was observed. This article presents novel results, in a solar pilot plant, for determining which ternary mixture can give better results, as well as metal leaching into water. Handling relevant volume of water in anoxic conditions can help to understand the application of this technology for the production of hydrogen.
Abril, 2024 | DOI: 10.1016/j.cattod.2024.114608
Reactividad de Sólidos
Magnesium calcites for CO2 capture and thermochemical energy storage using the calcium-looping process
Perejón, A; Arcenegui-Troya, J; Sánchez-Jiménez, PE; Diánez, MJ; Pérez-Maqueda, LAEnvironmental Research, 246 (2024) 118119 DOI: 10.1016/j.envres.2024.118119
Abstract
In this study, a precipitation-based synthesis method has been employed to prepare magnesium calcites with the general formula Ca1-xMgxCO3, with the objective of use them in the calcium looping (CaL) process for CO2 capture (CaL-CCS) and thermochemical energy storage (CaL-CSP). The structure and microstructure of the samples have been characterized. It has been found by X-ray diffraction that the samples with a Ca:Mg molar ratio of 0.5:0.5 and 0.55:0.45 are phase pure, while the samples with molar ratios of 0.7:0.3 and 0.8:0.2 are composed by two phases with different stoichiometry. In addition, the sample prepared with calcium alone shows the aragonite phase. The microstructure of the magnesium-containing samples is composed of nanocrystals, which are aggregated in spherical particles whereas the aragonite sample presents a typical rod-like morphology. The multicycle tests carried out under CaL-CCS conditions show that an increase on the MgO content in the calcined samples results in a reduced value of effective conversion when compared to aragonite. On the other hand, under CaL-CSP conditions, the samples with the higher MgO content exhibit nearly stable effective conversion values around 0.5 after 20 cycles, which improve the results obtained for aragonite and those reported for natural dolomite tested under the same conditions.
Abril, 2024 | DOI: 10.1016/j.envres.2024.118119
Materiales y Procesos Catalíticos de Interés Ambiental y Energético
MoS2 2D materials induce spinal cord neuroinflammation and neurotoxicity affecting locomotor performance in zebrafish
Di Mauro, G; González, VJ; Bambini, F; Camarda, S; Prado, E; Holgado, JP, Vázquez, E; Ballerini, L; Cellot, GNanoscale Horizons, 9(5)(2024) 785-798 DOI: 10.1039/d4nh00041b
Abstract
MoS2 nanosheets belong to an emerging family of nanomaterials named bidimensional transition metal dichalcogenides (2D TMDCs). The use of such promising materials, featuring outstanding chemical and physical properties, is expected to increase in several fields of science and technology, with an enhanced risk of environmental dispersion and associated wildlife and human exposures. In this framework, the assessment of MoS2 nanosheets toxicity is instrumental to safe industrial developments. Currently, the impact of the nanomaterial on the nervous tissue is unexplored. In this work, we use as in vivo experimental model the early-stage zebrafish, to investigate whether mechano-chemically exfoliated MoS2 nanosheets reach and affect, when added in the behavioral ambient, the nervous system. By high throughput screening of zebrafish larvae locomotor behavioral changes upon exposure to MoS2 nanosheets and whole organism live imaging of spinal neuronal and glial cell calcium activity, we report that sub-acute and prolonged ambient exposures to MoS2 nanosheets elicit locomotor abnormalities, dependent on dose and observation time. While 25 μg mL−1 concentration treatments exerted transient effects, 50 μg mL−1 ones induced long-lasting changes, correlated to neuroinflammation-driven alterations in the spinal cord, such as astrogliosis, glial intracellular calcium dysregulation, neuronal hyperactivity and motor axons retraction. By combining integrated technological approaches to zebrafish, we described that MoS2 2D nanomaterials can reach, upon water (i.e. ambient) exposure, the nervous system of larvae, resulting in a direct neurological damage.
Abril, 2024 | DOI: 10.1039/d4nh00041b
Materiales Avanzados
Preparation of Geopolymeric Materials from Industrial Kaolins, with Variable Kaolinite Content and Alkali Silicates Precursors
Martínez-Martínez, S; Bouguermouh, K; Bouzidi, N; Mahtout, L; Sánchez-Soto, PJ; Pérez-Villarejo, LMaterials, 17 (2024) 1839 DOI: 10.3390/ma17081839
Abstract
In the present work, the development of geopolymeric materials with Na or K based on industrial kaolin samples, with variable kaolinite content and alkaline silicates, is studied. XRF, XRD, FTIR and SEM-EDS have been used as characterization techniques. Three ceramic kaolin samples, two from Algeria and one from Charente (France), have been considered. In particular, chemical and mineralogical characterization revealed elements distinct of Si and Al, and the content of pure kaolinite and secondary minerals. Metakaolinite was obtained by grinding and sieving raw kaolin at 80 mu m and then by thermal activation at 750 degrees C for 1 h. This metakaolinite has been used as a base raw material to obtain geopolymers, using for this purpose different formulations of alkaline silicates with NaOH or KOH and variable Si/K molar ratios. The formation of geopolymeric materials by hydroxylation and polycondensation characterized with different Si/Al molar ratios, depending on the original metakaolinite content, has been demonstrated. Sodium carbonates have been detected by XRD and FTIR, and confirmed by SEM-EDS, in two of these geopolymer materials being products of NaOH carbonation.
Abril, 2024 | DOI: 10.3390/ma17081839
Reactividad de Sólidos
A generalized interface reaction kinetic model for describing heterogeneous processes driven by contracting mechanisms
Arcenegui-Troya, J; Sánchez-Jiménez, PE; Rodríguez-Laguna, MR; Perejón, AJournal of Thermal Analysis and Calorimetry, 149(6) (2024) 2653-2663 DOI: 10.1007/s10973-023-12835-5
Abstract
The correct determination of the kinetic model and the kinetic parameters that describe a heterogeneous process is key to accurately predicting its progress within a wide range of conditions, which is one of the main purposes of kinetic analysis. Albeit ideal kinetic models continue to be used to gain insight about the process mechanism, they are constrained by certain assumptions that are rarely met in real experiments and limit their applicability. This is the case of contracting (or interface) kinetic models, which are one of the most commonly used. Thus, the ideal kinetic model R2 is derived by assuming a cylindrical contraction in the radial direction but not contemplating the possibility of a contraction in the direction of the axis of the cylinder. Moreover, in the case of the ideal model R3, it is assumed that contraction takes place simultaneously in particles of identical dimensions in all three directions of space (spheres or cubes). Here, it is revisited this type of model, and it is considered the contraction of particles with different geometries, namely cylinders with different aspect ratios and rectangular cuboids. Besides, a novel generalized interface reaction model is proposed, which covers all the studied cases and broadens the range of applicability to more complex situations involving different geometries and inhomogeneous particle sizes. Finally, the proposed model is applied to the analysis of the experimental thermal dissociation of ammonium nitrate, previously described in the literature as a sublimation process. It is proved that the novel kinetic model provides a more accurate description of the kinetics of the reaction and better prediction capabilities.
Marzo, 2024 | DOI: 10.1007/s10973-023-12835-5
Materiales y Procesos Catalíticos de Interés Ambiental y Energético
Surface Defect Engineered Nano-Cu/TiO2 Photocatalysts for Hydrogen Production
Liccardo, L; Moras, P; Shewerdyaeva, PM; Vomiero, A; Caballero, A; Colón, G; Moretti, EAdvanced Sustainable Systems, 8(3) (2024) 2300418 DOI: 10.1002/adsu.202300418
Abstract
Surface defects engineered nano-Cu/TiO2 photocatalysts are synthesized through an easy and cost-effective microwave-assisted hydrothermal synthesis, mixing commercial P25 titania (TiO2) and oxalic acid (Ox), followed by 2.0 wt% Cu co-catalyst (labeled as Cu2.0) loading through in situ photodeposition during reaction. The hydrothermal treatment does not affect the catalyst crystalline structure, morphology, nor the surface area. However, depending on the Ox/TiO2 molar ratio used an influence on the optical properties and on the reactivity of the system is detected. The presence of surface defects leads to intraband states formation between valence band and conduction band of bare titania, inducing an important enhancement in the photoactivity. Thus, Cu2.0/gOx/P25 200 (where g is the weight of Ox and 200 the temperature in Celsius degrees used during the synthesis) have been successfully tested as efficient photocatalysts for hydrogen production through methanol (MeOH) reforming under UV light in a MeOH/ H2O solution (10% v/v) by fluxing the system with N2, showing an increased reactivity compared to the bare Cu2.0/P25 system.
Marzo, 2024 | DOI: 10.1002/adsu.202300418
Materiales y Procesos Catalíticos de Interés Ambiental y Energético
Developing and understanding Leaching-Resistant cobalt nanoparticles via N/P incorporation for liquid phase hydroformylation
Galdeano-Ruano, C; Gutiérrez-Tarriño, S; Lopes, CW; Mazarío, J; Chinchilla, LE; Agostini, G; Calvino, JJ; Holgado, JP; Rodriguez-Castellón, E; Roldan, A; Oña-Burgos, PJournal of Catalysis, 431 (2024) 115374 DOI: 10.1016/j.jcat.2024.115374
Abstract
The ultimate target in heterogeneous catalysis is the achievement of robust, resilient and highly efficient materials capable of resisting industrial reaction conditions. Pursuing that goal in liquid -phase hydroformylation poses a unique challenge due to carbon monoxide -induced metal carbonyl species formation, which is directly related to the formation of active homogeneous catalysts by metal leaching. Herein, supported heteroatomincorporated (P and N) Co nanoparticles were developed to enhance the resistance compared with bare Co nanoparticles. The samples underwent characterization using operando XPS, XAS and HR electron microscopy. Overall, P- and N -doped catalysts increased reusability and suppressed leaching. Among the studied catalysts, the one with N as a dopant, CoNx@NC, presents excellent catalytic results for a Co -based catalyst, with a 94% conversion and a selectivity to aldehydes of 80% in only 7.5 h. Even under milder conditions, this catalyst outperformed existing benchmarks in Turnover Numbers (TON) and productivity. In addition, computational simulations provided atomistic insights, shedding light on the remarkable resistance of small Co clusters interacting with N -doped carbon patches.
Marzo, 2024 | DOI: 10.1016/j.jcat.2024.115374
Materiales Avanzados
Effect of olive-pruning fibres as reinforcements of alkali-activated cements based on electric arc furnace slag and biomass bottom ash
Gómez-Casero, MA; Sánchez-Soto, PJ; Castro, E; Eliche-Quesada, DArchives of Civil and Mechanical Engineering, 24(2) (2024) 84 DOI: 10.1007/s43452-024-00882-0
Abstract
In this work, alkali-activated composites using electric arc furnace slag (50 wt%) and biomass bottom ash (50 wt%) were manufactured, adding olive-pruning fibres as reinforcement. The objective of adding fibres is to improve the flexural strength of composites, as well as to prevent the expansion of cracks as a result of shrinkage. For this reason, composites reinforced with olive-pruning fibres (0.5-2 wt%) untreated and treated with three different solutions to improve matrix-fibre adhesion were manufactured. Treatments developed over fibres were a 10 wt% Na2SiO3 solution, 3 wt% CaCl2 solution and 5 wt% NaOH solution. Mechanical properties, physical properties, thermal properties and the microstructure of composites by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) were studied to demonstrate the improvement. Alkaline treatment degraded fibre surface, increasing the matrix-fibre adhesion, and as a consequence, flexural strength increased up to 20% at 90 days of curing. Optimal results were obtained with composites reinforced with 1 wt% of olive-pruning fibre treated by a 10 wt% Na2SiO3 solution. Higher quantity of olive-pruning fibre leads to local agglomeration, which weakens the matrix-fibre adhesion. The effect on the compressive strength is less evident, since the addition of fibres produces an admissible decrease (between 0 and 9% using 0.5 or 1 wt% of fibres), except in composites that use olive pruning treated with 10 wt% Na2SiO3 solution, where values remain stable, similar or better to control paste. A greater ductility of the matrix in all composites was observed. Furthermore, the alkali-activated cement matrix was bonded to olive-pruning fibre better than untreated fibre, as it is shown in SEM images. Thus, the results showed that olive-pruning fibres could be used as reinforcement in the manufacturing of alkali-activated materials when they are treated with alkali solutions.
Marzo, 2024 | DOI: 10.1007/s43452-024-00882-0
Materiales Nanoestructurados y Microestructura
Long-lasting low fluorinated stainless steel hierarchical surfaces for omniphobic, anti-fouling and anti-icing applications
Montes, L; Rico, V; Nuñez-Galvez, F; Arenas, MA; del Campo, AC; Lopez-Flores, V; Espinós, JP; Borrás, A; González-Elipe, AR; López-Santos, CSurfaces and Interfaces, 46 (2024) 104167 DOI: 10.1016/j.surfin.2024.104167
Abstract
Stainless steel (SS) alloys are prevalent in many industries, household appliances or other commodities, where a strict control of surface properties is required to tailor their interaction with the environment. In this work we report a new procedure of stainless steel surface processing that provides a multifunctional response including superhydrophobicity, omniphobicity, self-cleaning, anti-fouling and effective anti-icing capacity, while still preserving a corrosion resistance similar to that of this material in compact form. The method consists of a first nanostructuration step followed by a low fluorination. The nanostructured surfaces presented a dual scale roughness of hierarchical character. The liquid free approach developed in this work to get this singular surface nanostructuration entails a first laser treatment of stainless steel flat substrates, followed by the deposition of a nanostructured thin layer of this material by electron beam evaporation in an oblique angle configuration. The resulting hierarchical surfaces were subjected to fluorination by: (i) the plasma-assisted deposition of a thin Teflon-like coating or (ii) the grafting of fluorinated molecules. The self-cleanable, anti-adherent and ice repellent character of the resulting low fluorinated surfaces outperformed the behaviour of classical slippery surfaces obtained by the infusion of high amounts of fluorinated liquids. These hierarchical SS surfaces withstood mild abrasion tests and the effect of water jets. Moreover, the corrosion behaviour of the fluorinated surfaces determined through their potentiodynamic analysis revealed a similar corrosion resistance than the flat SS substrates. Outstandingly, after these corrosion tests, the fluorinated samples obtained by grafting preserved their surface functionalities without significant degradation. The high mechanical and chemical stability of these low fluorinated samples support their usage for a large variety of applications.
Marzo, 2024 | DOI: 10.1016/j.surfin.2024.104167
Materiales de Diseño para la Energía y Medioambiente
Optimising anode supported BaZr1-xYxO3-δ electrolytes for solid oxide fuel cells: Microstructure, phase evolution and residual stresses analysis
Fernández Muñoz, S; Chacartegui, R; Alba, MD; Ramírez Rico, JJournal of Power Sources, 596 (2024) 234070 DOI: 10.1016/j.jpowsour.2024.234070
Abstract
Yttrium-doped BaZrO3 is a promising electrolyte for intermediate-temperature protonic ceramic fuel cells. In the anode-supported configuration, a slurry containing the electrolyte is deposited on the surface of a calcined porous anode and sintered. Differences in sintering behaviour and thermal expansion coefficients for the anode and electrolyte result in elastic residual stresses that can impact the long-term stability of the cell during cyclic operation. Half-cells using BaZr0.8Y0.2O3-δ as the electrolyte were fabricated using the solid-state reaction sintering method under various sintering conditions. Comprehensive microstructure and residual stress analyses as a function of processing parameters were performed using two-dimensional X-ray diffraction, Rietveld refinement, and scanning electron microscopy, before and after the half-cells were reduced under hydrogen, giving a complete picture of phase, microstructure, and stress evolution under thermal and reduction cycles like the actual operation of the cell. Our results reveal that a temperature of 1400 °C and shorter soaking times might be advantageous for obtaining phase-pure and thin yttrium-doped BaZrO3 electrolytes with improved microstructure and the presence of compressive residual stress. These findings offer valuable insights into optimising the fabrication process of BaZrO3-based electrolytes, leading to enhanced performance and long-term stability of anode-supported protonic ceramic fuel cells operating at intermediate temperatures.
Marzo, 2024 | DOI: 10.1016/j.jpowsour.2024.234070
Química de Superficies y Catálisis
Highly Effective Non-Noble MnO2 Catalysts for 5-Hydroxymethylfurfural Oxidation to 2,5-Furandicarboxylic Acid
Alvarez-Hernández, D; Megías-Sayago, C; Penkova, A; Centeno, MA; Ivanova, SChemsuschem, 17 (2024) e202400115 DOI: 10.1002/cssc.202400115
Abstract
Noble metal-free catalyst or catalytic oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid are proposed in this study as a proposal to solve one of the great disadvantages of this reaction of using preferably noble metal-based catalysts. The catalytic activity of six MnO2 crystal structures is studied as alternative. The obtained results showed a strong connection between catalytic activity the type of MnO2 structure organization and redox behavior. Among all tested catalysts, epsilon-MnO2 showed the best performance with an excellent yield of 74 % of 2,5-furandicarboxylic acid at full -hydroxymethylfurfural conversion.
Marzo, 2024 | DOI: 10.1002/cssc.202400115
Química de Superficies y Catálisis
A profitability study for catalytic ammonia production from renewable landfill biogas: Charting a route for the next generation of green ammonia
González-Arias, J; Nawaz, MA; Vidal-Barrero, F; Reina, TRFuel, 360 (2024) 130584 DOI: 10.1016/j.fuel.2023.130584
Abstract
This study introduces a novel techno-economic approach to renewable ammonia production using landfill biogas. The proposed process involves bio-hydrogen generation from landfill biogas, nitrogen production via air separation, and the Haber-Bosch process. Building on our prior research, which demonstrated the economic competitiveness of renewable hydrogen production from landfill gas, we extend our investigation to analyze the feasibility of producing renewable ammonia from biogas-derived bio-hydrogen. However, the economic analysis for the baseline scenario reveals the current lack of profitability (net present value of −18.3 M€), with ammonia prices needing to quadruple to achieve profitability. Major costs, including investment, maintenance, overhead expenses, and electricity, collectively account for over 70%, suggesting the potential efficacy of investment subsidies as a political tool. Only cases with subsidies exceeding 50% of total investment costs, under current ammonia market prices, would render the green ammonia route profitable. Our findings underscore the significant techno-economic challenges in realizing renewable ammonia production, emphasizing the need for innovation in process engineering and catalytic technologies to enable competitive and scalable green ammonia production.
Marzo, 2024 | DOI: 10.1016/j.fuel.2023.130584
Materiales de Diseño para la Energía y Medioambiente
Revalorization of Yerba Mate Residues: Biopolymers-Based Films of Dual Wettability as Potential Mulching Materials
Sánchez, LM; De Haro, J; Domínguez, E; Rodríguez, A; Heredia, A; Benítez, JJPolymers, 16 (2024) 815 DOI: 10.3390/polym16060815
Abstract
Biodegradable mulching films are a very attractive solution to agronomical practices intended to achieve more successful crop results. And, in this context, the employment of agricultural and industrial food residues as starting material for their production is an alternative with economic and environmental advantages. This work reports the preparation of bilayer films having two different wettability characteristics from three bio-derived biopolymers: TEMPO-oxidized cellulose nanofibers isolated from infused Yerba Mate residues, Chitosan and Polylactic acid. The infused Yerba Mate residues, the isolated and oxidized cellulose nanofibers, and the films were characterized. Nanofibrillation yield, optical transmittance, cationic demand, carboxyl content, intrinsic viscosity, degree of polymerization, specific surface area and length were studied for the (ligno)cellulose nanofibers. Textural and chemical analysis, thermal and mechanical properties studies, as well as water and light interactions were included in the characterization of the films. The bilayer films are promising materials to be used as mulching films.
Marzo, 2024 | DOI: 10.3390/polym16060815
Nanotecnología en Superficies y Plasma
Growth dynamics of nanocolumnar thin films deposited by magnetron sputtering at oblique angles
Alvarez, R; Garcia-Valenzuela, A; Regodon, G; Ferrer, FJ; Rico, V; Garcia-Martin, JM; Gonzalez-Elipe, AR; Palmero, ANanotechnology, 35 (2024) 095705 DOI: 10.1088/1361-6528/ad113d
Abstract
The morphology of numerous nanocolumnar thin films deposited by the magnetron sputtering technique at oblique geometries and at relatively low temperatures has been analyzed for materials as different as Au, Pt, Ti, Cr, TiO2, Al, HfN, Mo, V, WO3 and W. Despite similar deposition conditions, two characteristic nanostructures have been identified depending on the material: a first one defined by highly tilted and symmetric nanocolumnar structures with a relatively high film density, and a second one characterized by rather vertical and asymmetric nanocolumns, with a much lower film density. With the help of a model, the two characteristic nanostructures have been linked to different growth dynamics and, specifically, to different surface relaxation mechanisms upon the incorporation of gaseous species with kinetic energies above the surface binding energy. Moreover, in the case of Ti, a smooth structural transition between the two types of growths has been found when varying the value of the power used to maintain the plasma discharge. Based on these results, the existence of different surface relaxation mechanisms is proposed, which quantitatively explains numerous experimental results under the same conceptual framework.
Febrero, 2024 | DOI: 10.1088/1361-6528/ad113d
Materiales Ópticos Multifuncionales - Materiales Semiconductores para la Sostenibilidad
Casimir-Lifshitz Optical Resonators: A New Platform for Exploring Physics at the Nanoscale
Esteso, V; Frustaglia, D; Carretero-Palacios, S; Míguez, HAdvanced Physics Research, 3 (2024) 2300065. DOI: 10.1002/apxr.202300065
Abstract
The Casimir-Lifshitz force, FC − L, has become a subject of great interest to both theoretical and applied physics communities due to its fundamental properties and potential technological implications in emerging nano-scale devices. Recent cutting-edge experiments have demonstrated the potential of quantum trapping at the nano-scale assisted by FC − L in metallic planar plates immersed in fluids through appropriate stratification of the inner dielectric media, opening up new avenues for exploring physics at the nano-scale. This review article provides an overview of the latest results in Casimir-Lifshitz based-optical resonator schemes and their potential applications in fields such as microfluidic devices, bio-nano and micro electromechanical systems (NEMS and MEMS), strong coupling, polaritonic chemistry, photo-chemistry, sensing, and metrology. The use of these optical resonators provides a versatile platform for fundamental studies and technological applications at the nano-scale, with the potential to revolutionize various fields and create new opportunities for research.
Febrero, 2024 | DOI: 10.1002/apxr.202300065
Materiales Ópticos Multifuncionales
Strong Light-Matter Coupling in Lead Halide Perovskite Quantum Dot Solids
Bujalance, C; Caliò, Dirin, DN; Tiede, DO; Gaisteo-López, JF; Feist, J; García-Vidal, FJ; Kovalenko, MV; Míguez, HACS Nano, 18(6) (2024) 4922-4931 DOI: 10.1021/acsnano.3c10358
Abstract
Strong coupling between lead halide perovskite materials and optical resonators enables both polaritonic control of the photophysical properties of these emerging semiconductors and the observation of fundamental physical phenomena. However, the difficulty in achieving optical-quality perovskite quantum dot (PQD) films showing well-defined excitonic transitions has prevented the study of strong light-matter coupling in these materials, central to the field of optoelectronics. Herein we demonstrate the formation at room temperature of multiple cavity exciton-polaritons in metallic resonators embedding highly transparent Cesium Lead Bromide quantum dot (CsPbBr3-QD) solids, revealed by a significant reconfiguration of the absorption and emission properties of the system. Our results indicate that the effects of biexciton interaction or large polaron formation, frequently invoked to explain the properties of PQDs, are seemingly absent or compensated by other more conspicuous effects in the CsPbBr3-QD optical cavity. We observe that strong coupling enables a significant reduction of the photoemission line width, as well as the ultrafast modulation of the optical absorption, controllable by means of the excitation fluence. We find that the interplay of the polariton states with the large dark state reservoir plays a decisive role in determining the dynamics of the emission and transient absorption properties of the hybridized light-quantum dot solid system. Our results should serve as the basis for future investigations of PQD solids as polaritonic materials.
Febrero, 2024 | DOI: 10.1021/acsnano.3c10358
Nanotecnología en Superficies y Plasma
Harnessing a Vibroacoustic Mode for Enabling Smart Functions on Surface Acoustic Wave Devices - Application to Icing Monitoring and Deicing
Karimzadeh, A; Weissker, U; del Moral, J; Winkler, A; Borrás, A; González-Elipe, AR; Jacob, SAdvanced Materials Technologies, (2024) 2301749 DOI: 10.1002/admt.202301749
Abstract
Microacoustic wave devices are essential components in the radio frequency (RF) electronics and microelectromechanical systems (MEMS) industry with increasing impact in various sensing and actuation applications. Reliable and smart operation of acoustic wave devices at low costs will cause a crucial advancement. Herein, this study presents the enablement of temperature and mechanical sensing capabilities in a Rayleigh-mode standing surface acoustic wave (sSAW) chip device by harnessing an acoustic shear-thickness dominant wave (SD) using the same set of electrodes. Most importantly, this mode is excited by switching the polarity of the sSAW transducer electrodes by simple electronics, allowing for direct and inexpensive compatibility with an existing setup. The method in the emergent topic of surface de-icing is validated by continuously monitoring temperature and liquid–solid water phase changes using the SD mode, and on-demand Rayleigh-wave deicing with a negligible energy cost. The flexibility for adapting the system to different scenarios, and loads and the potential for scalability opens the path to impact in lab-on-a-chip, internet of things (IoT) technology, and sectors requiring autonomous acoustic wave actuators.
Febrero, 2024 | DOI: 10.1002/admt.202301749
Química de Superficies y Catálisis
Optimizing biogas methanation over nickel supported on ceria-alumina catalyst: Towards CO2-rich biomass utilization for a negative emissions society
González-Arias, J; Torres-Sempere, G; Arroyo-Torralvo, F; Reina, TR; Odriozola, JAEnrironmental Research, 242 (2024) 117735 DOI: 10.1016/j.envres.2023.117735
Abstract
Biogas methanation emerges as a prominent technology for converting biogas into biomethane in a single step. Furthermore, this technology can be implemented at biogas plant locations, supporting local economies and reducing dependence on large energy producers. However, there is a lack of comprehensive studies on biogas methanation, particularly regarding the technical optimization of operational parameters and the profitability analysis of the overall process. To address this gap, our study represents a seminal work on the technical optimization of biogas methanation obtaining an empirical model to predict the performance of biogas methanation. We investigate the influence of operational parameters, such as reaction temperature, H2/CO2 ratio, space velocity, and CO2 share in the biogas stream through an experimental design. Based on previous research we selected a nickel supported on ceria-alumina catalyst; being nickel a benchmark system for methanation process such selection permits a reliable data extrapolation to commercial units. We showcase the remarkable impact of studied key operation parameters, being the temperature, the most critical factor affecting the reaction performance (ca. 2 to 5 times higher than the second most influencing parameter). The impact of the H2/CO2 ratio is also noticeable. The response surfaces and contour maps suggest that a temperature between 350 and 450 degrees C and an H2/CO2 ratio between 2.5 and 3.2 optimize the reaction performance. Further experimental tests were performed for model validation and optimization leading to a reliable predictive model. Overall, this study provides validated equations for technology scaling-up and techno-economic analysis, thus representing a step ahead towards real-world applications for bio-methane production.
Febrero, 2024 | DOI: 10.1016/j.envres.2023.117735
Fotocatálisis Heterogénea: Aplicaciones
Insights into the physicochemical properties of Sugar Scum as a sustainable biosorbent derived from sugar refinery waste for efficient cationic dye removal
F. Atmani, M.M. Kaci, N. Yeddou-Mezenner, A. Soukeur, I. Akkari, J.A. NavíoBiomass Conversion and Biorefinery, 14 (2024) 4843-4857 DOI: 10.1007/s13399-022-02646-3
Abstract
The objective of this study was to determine the ability of sugar scum (SS), an industrial waste, as a novel biosorbent for the removal of Basic Blue 41 (BB 41) from aqueous solutions. The biosorbent was characterized by SEM/EDS, BET, FTIR, and pHpzc measurements, respectively. To reach a maximum adsorption capacity of 26.45 mg.g–1, impacting operational factors such as pH, biosorbent dose, contact duration, starting dye concentration, and temperature were adjusted, when the removal efficiency reached 84% during 60 min at pH 10, 1.5 g.L–1 of biosorbent and Co = 10 mg.L–1. The experimental data were modeled by various isotherm models, whereas the best fit was found for Freundlich with a high correlation coefficient (R2 = 0.991). Other kinetic models including pseudo-first, pseudo-second order, and intra-particle diffusion models were tested to fit the kinetic data. The biosorption of BB 41 onto SS was spontaneous (∆G° < 0) and exothermic (∆H° < 0), while the biosoprtion mechanism of BB41 over SS was proposed with repeated reuse showing that SS could be regenerated after four successive runs. Furthermore, this study revealed that sugar scum is an underutilized bioresource in Algeria, with the potential to provide low-cost environmental removal of additional contaminants in the wastewater treatment domain.
Febrero, 2024 | DOI: 10.1007/s13399-022-02646-3
Tribología y Protección de Superficies
Synthesis and Characterization of Multilayered CrAlN/Al2O3 Tandem Coating Using HiPIMS for Solar Selective Applications at High Temperature
Sánchez-Pérez, M; Rojas, TR; Reyes, DF; Ferrer, FJ; Farchado, M; Morales, A; Escobar-Galindo, R; Sánchez-López, JCACS Applied Energy Materials, 7 (2024) 438-449 DOI: 10.1021/acsaem.3c02310
Abstract
The effect of applying a negative bias during deposition of a previously designed multilayer solar selective absorber coating was studied on two types of substrates (316L stainless steel and Inconel 625). The solar selective coating is composed of different chromium aluminum nitride layers deposited using a combination of radiofrequency (RF), direct current (DC), and high-power impulse magnetron sputtering (HiPIMS) technologies. The chemical composition is varied to generate an infrared reflective/absorber layer (with low Al addition and N vacancies) and two CrAlN intermediate layers with medium and high aluminum content (Al/Cr = 0.6 and 1.2). A top aluminum oxide layer (Al2O3) is deposited as an antireflective layer. In this work, a simultaneous DC-pulsed bias (−100 V, 250 kHz) was applied to the substrates in order to increase the film density. The optical performance, thermal stability, and oxidation resistance was evaluated and compared with the performance obtained with similar unbiased coating and a commercial Pyromark paint reference at 600, 700, and 800 °C. The coating remained stable after 200 h of annealing at 600 °C, with solar absorptance (α) values of 93% and 92% for samples deposited on stainless steel and Inconel, respectively, and a thermal emittance ε25°C of 18%. The introduction of additional ion bombardment during film growth through bias assistance resulted in increased durability, thermal stability, and working temperature limits compared with unbiased coatings. The solar-to-mechanical energy conversion efficiency at 800 °C was found to be up to 2 times higher than Pyromark at C = 100 and comparable at C = 1000.
Febrero, 2024 | DOI: 10.1021/acsaem.3c02310
Materiales Avanzados
Synthesis and characterization of porous and photocatalytic geopolymers based on natural clay: Enhanced properties and efficient Rhodamine B decomposition
Ettahiri, Y; Bouna, L: Brahim, A; Benlhachemi, A; Bakiz, B; Sánchez-Soto, PJ; Eliche-Quesada, D; Pérez-Villarejo, LApplied Materials Today, 36 (2024) 102048 DOI: 10.1016/j.apmt.2023.102048
Abstract
In this work, the incorporation of anatase TiO2 semiconductor in the geopolymer matrix as catalytic materials has been studied. The most noteworthy results obtained from the synthesis of a novel TiO2/geopolymer nanocomposite as an effective ecological catalyst with high thermal stability and significant porosity is presented. The porous and photocatalytic geopolymers based natural clay rich in pyrophyllite and kaolinite minerals were prepared by simple method, the geopolymerization reaction was able to successfully load TiO2 nanoparticles into the geopolymer surface. Furthermore, the results indicate that the prepared catalyst achieved the best performance to degrade Rhodamine B (RhB) molecules present in aqueous solution under UV light irradiation. The geopolymer matrix proved to be a reusable support for TiO2 nanoparticles during the photocatalytic process, efficiently facilitating the separation of photogenerated charges. Finally, the physicochemical and morphological properties of the samples was characterized by several techniques, namely X-ray Fluorescence (XRF), X-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), Thermogravimetric and Differential Thermal Analysis (TGA/DTA), N2 adsorption/desorption isotherm analysis (BET and BJH methods), UV–Vis Diffuse Reflectance Spectroscopy (DRS), Scanning Electron Microscopy (SEM) coupled to an Energy Dispersive X-ray Spectroscopy (EDS) analyzer and Transmission Electron Microscopy (TEM).
Febrero, 2024 | DOI: 10.1016/j.apmt.2023.102048
Materiales Semiconductores para la Sostenibilidad
Synergetic Near- and Far-Field Plasmonic Effects for Optimal All-Perovskite Tandem Solar Cells with Maximized Infrared Absorption
Bueno, J; Carretero Palacios, S; Anaya, MJournal of Physical Chemistry Letters, 15(9) (2024) 2632-2638 DOI: 10.1021/acs.jpclett.4c00194
Abstract
The efficiency and reliability of perovskite solar cells have rapidly increased in conjunction with the proposition of advanced single-junction and multi-junction designs that allow light harvesting to be maximized. However, Sn-based compositions required for optimized all-perovskite tandem devices have reduced absorption coefficients, as opposed to pure Pb perovskites. To overcome this, we investigate near- and far-field plasmonic effects to locally enhance the light absorption of infrared photons. Through optimization of the metal type, particle size, and volume concentration, we maximize effective light harvesting while minimizing parasitic absorption in all-perovskite tandem devices. Interestingly, incorporating 240 nm silver particles into the Pb-Sn perovskite layer with a volume concentration of 3.1% indicates an absolute power conversion efficiency enhancement of 2% in the tandem system. We present a promising avenue for experimentalists to realize ultrathin all-perovskite tandem devices with optimized charge carrier collection, diminishing the weight and the use of Pb.
Febrero, 2024 | DOI: 10.1021/acs.jpclett.4c00194
Materiales para Bioingeniería y Regeneración Tisular
New Nano-Crystalline Hydroxyapatite-Polycarboxy/Sulfo Betaine Hybrid Materials: Synthesis and Characterization
Díaz-Cuenca, A; Sezanova, K; Gergulova, R; Rabadjieva, D; Ruseva, KMolecules, 29(5) (2024) 930 DOI: 10.3390/molecules29050930
Abstract
Hybrid materials based on calcium phosphates and synthetic polymers can potentially be used for caries protection due to their similarity to hard tissues in terms of composition, structure and a number of properties. This study is focused on the biomimetic synthesis of hybrid materials consisting of hydroxiapatite and the zwitterionic polymers polysulfobetaine (PSB) and polycarboxybetaine (PCB) using controlled media conditions with a constant pH of 8.0–8.2 and Ca/P = 1.67. The results show that pH control is a dominant factor in the crystal phase formation, so nano-crystalline hydroxyapatite with a Ca/P ratio of 1.63–1.71 was observed as the mineral phase in all the materials prepared. The final polymer content measured for the synthesized hybrid materials was 48–52%. The polymer type affects the final microstructure, and the mineral particle size is thinner and smaller in the synthesis performed using PCB than using PSB. The final intermolecular interaction of the nano-crystallized hydroxyapatite was demonstrated to be stronger with PCB than with PSB as shown by our IR and Raman spectroscopy analyses. The higher remineralization potential of the PCB-containing synthesized material was demonstrated by in vitro testing using artificial saliva.
Febrero, 2024 | DOI: 10.3390/molecules29050930
Química de Superficies y Catálisis
Renewable Carbonaceous Materials from Biomass in Catalytic Processes: A Review
Villora-Picó, JJ; González-Arias, J; Baena-Moreno, FM; Reina, TRMaterials, 17 (2024) 565 DOI: 10.3390/ma17030565
Abstract
This review paper delves into the diverse ways in which carbonaceous resources, sourced from renewable and sustainable origins, can be used in catalytic processes. Renewable carbonaceous materials that come from biomass-derived and waste feedstocks are key to developing more sustainable processes by replacing traditional carbon-based materials. By examining the potential of these renewable carbonaceous materials, this review aims to shed light on their significance in fostering environmentally conscious and sustainable practices within the realm of catalysis. The more important applications identified are biofuel production, tar removal, chemical production, photocatalytic systems, microbial fuel cell electrodes, and oxidation applications. Regarding biofuel production, biochar-supported catalysts have proved to be able to achieve biodiesel production with yields exceeding 70%. Furthermore, hydrochars and activated carbons derived from diverse biomass sources have demonstrated significant tar removal efficiency. For instance, rice husk char exhibited an increased BET surface area from 2.2 m2/g to 141 m2/g after pyrolysis at 600 °C, showcasing its effectiveness in adsorbing phenol and light aromatic hydrocarbons. Concerning chemical production and the oxidation of alcohols, the influence of biochar quantity and pre-calcination temperature on catalytic performance has been proven, achieving selectivity toward benzaldehyde exceeding 70%.
Febrero, 2024 | DOI: 10.3390/ma17030565
Nanotecnología en Superficies y Plasma
Green hydrogen production using doped Fe2O3 foams
Damizia, M; Lloreda-Jurado, PJ; De Filippis, P; de Caprariis, B; Chicardi, E; Sepúlveda, RInternational Journal of Hydrogen Energy, 51 (2024) 834-845 DOI: 10.1016/j.ijhydene.2023.09.008
Abstract
Hydrogen is the ideal energy vector to reduce our fossil-fuels dependency and diminish the climate change consequence. However, current production is still methane based. It is possible to produce hydrogen using bioethanol from the alcoholic fermentation of organic waste by chemical looping processes, but unfortunately current redox systems generate hydrogen with significant traces of CO. In the case of proton exchange membrane fuel cells (PEMFC), hydrogen must be highly purified to produce electricity. Here, high porosity inter-connected Fe2O3 foams doped with 2 wt% Al2O3 were manufactured by the freeze-casting method, obtaining around 5.1 mmol H2$g?1 sample of highly pure hydrogen (<10 ppm of CO) consuming only 3.42 mmol of ethanol on each redox cycles, with no deactivation. This result shows the possibility of using an abundant and inexpensive raw material as the iron oxide to scale-up the direct pure H2 production and facilitates its use in the automotive sector.
Enero, 2024 | DOI: 10.1016/j.ijhydene.2023.09.008
Química de Superficies y Catálisis
Natural hydrogen in the energy transition: Fundamentals, promise, and enigmas
Blay-Roger, R; Bach, W; Bobadilla, LF; Reina, TR; Odriozola, JA; Amils, R; Blay, VRenewable & Sustainable Energy Reviews, 189 (2024) 113888 DOI: 10.1016/j.rser.2023.113888
Abstract
Beyond its role as an energy vector, a growing number of natural hydrogen sources and reservoirs are being discovered all over the globe, which could represent a clean energy source. Although the hydrogen amounts in reservoirs are uncertain, they could be vast, and they could help decarbonize energy-intensive economic sectors and facilitate the energy transition. Natural hydrogen is mainly produced through a geochemical process known as serpentinization, which involves the reaction of water with low-silica, ferrous minerals. In favorable locations, the hydrogen produced can become trapped by impermeable rocks on its way to the atmosphere, forming a reservoir. The safe exploitation of numerous natural hydrogen reservoirs seems feasible with current technology, and several demonstration plants are being commissioned. Natural hydrogen may show variable composition and require custom separation, purification, storage, and distribution facilities, depending on the location and intended use. By investing in research, in the mid-term, more hydrogen sources could become exploitable and geochemical processes could be artificially stimulated in new locations. In the long term, it may be possible to leverage or engineer the interplay between microorganisms and geological substrates to obtain hydrogen and other chemicals in a sustainable manner.
Enero, 2024 | DOI: 10.1016/j.rser.2023.113888
Fotocatálisis Heterogénea: Aplicaciones
Ba3(PO4)2 Photocatalyst for Efficient Photocatalytic Application
Naciri, Y; Ahdour, A; Benhsina, E; Hamza, MA; Bouziani, A; Hsini, A; Bakiz, B; Navio, JA; Ghazzal, MNGlobal Challenges, 8(1) (2024) 2300257 DOI: 10.1002/gch2.202300257
Abstract
Barium phosphate (Ba-3(PO4)(2)) is a class of material that has attracted significant attention thanks to its chemical stability and versatility. However, the use of Ba-3(PO4)(2) as a photocatalyst is scarcely reported, and its use as a photocatalyst has yet to be reported. Herein, Ba-3(PO4)(2) nanoflakes synthesis is optimized using sol-gel and hydrothermal methods. The as-prepared Ba-3(PO4)(2) powders are investigated using physicochemical characterizations, including XRD, SEM, EDX, FTIR, DRS, J-t, LSV, Mott-Schottky, and EIS. In addition, DFT calculations are performed to investigate the band structure. The oxidation capability of the photocatalysts is investigated depending on the synthesis method using rhodamine B (RhB) as a pollutant model. Both Ba-3(PO4)(2) samples prepared by the sol-gel and hydrothermal methods display high RhB photodegradation of 79% and 68%, respectively. The Ba-3(PO4)(2) obtained using the sol-gel process exhibits much higher stability under light excitation after four regeneration cycles. The photocatalytic oxidation mechanism is proposed based on the active species trapping experiments where O-2(center dot-) is the most reactive species. The finding shows the promising potential of Ba-3(PO4)(2) photocatalysts and opens the door for further investigation and application in various photocatalytic applications.
Enero, 2024 | DOI: 10.1002/gch2.202300257
Nanotecnología en Superficies y Plasma
Towards efficient strain engineering of 2D materials: A four-points bending approach for compressive strain
Li, H; Carrascoso, F; Borrás, A; Moreno, GP; Aparicio, FJ; Barranco, A; Gómez, ACNano Research, 17 (2024) 5317-5325 DOI: 10.1007/s12274-023-6402-7
Abstract
Strain engineering, as a powerful strategy to tune the optical and electrical properties of two-dimensional (2D) materials by deforming their crystal lattice, has attracted significant interest in recent years. 2D materials can sustain ultra-high strains, even up to 10%, due to the lack of dangling bonds on their surface, making them ideal brittle solids. This remarkable mechanical resilience, together with a strong strain-tunable band structure, endows 2D materials with a broad optical and electrical response upon strain. However, strain engineering based on 2D materials is restricted by their nanoscale and strain quantification troubles. In this study, we have modified a homebuilt three-points bending apparatus to transform it into a four-points bending apparatus that allows for the application of both compressive and tensile strains on 2D materials. This approach allows for the efficient and reproducible construction of a strain system and minimizes the buckling effect caused by the van der Waals interaction by adamantane encapsulation strategy. Our results demonstrate the feasibility of introducing compressive strain on 2D materials and the potential for tuning their optical and physical properties through this approach.
Enero, 2024 | DOI: 10.1007/s12274-023-6402-7
Química de Superficies y Catálisis
Optimized electrocatalytic degradation of ciprofloxacin using Co3O4 coated stainless steel electrodes
Saleem, MU; Jawad, M; Azad, F; Nawaz, MA; Zaman, WQ; Miran, WColloids and Surfaces A-Physicochemical and Engineering Aspects, 681 (2024) 132738 DOI: 10.1016/j.colsurfa.2023.132738
Abstract
Ciprofloxacin (CIP) is a fluoroquinolone antibiotic that is widely used across the globe and its release is a serious concern due to its persistent nature, partial degradation, and simple transport through different environmental matrices. Pharmaceuticals have been degraded effectively by electrochemical oxidation. Exploring ways to in-crease the mineralization of these compounds while maintaining low power consumption is important. In this study, the treatability and degradation of CIP were investigated by using cobalt oxide-coated stainless steel (SS) electrodes in a lab-scale electrochemical (EC) reactor. The performance of the electrochemical reactor was determined under various operational conditions. The feed wastewater was synthetically prepared in the laboratory with varying concentrations of CIP ranging from 8 to 41 mg/L and the EC reactor was operated with an applied voltage and airflow rate of 2.6-9.3 volts and 1.6-3.5 L/min, respectively. A 3-factor central composite experimental design (CCD) was developed by using response surface methodology (RSM) in Design-Expert software. At a residence time of 27 min, initial concentration of 25 mg/L, airflow rate of 2.5 L/min, and applied voltage of 6 volts, the EC reactor achieved a removal efficiency of 70.8% for CIP with SS electrodes. On the contrary, the removal efficiency was increased to 91.5% at a reduced residence time of 21 min with cobalt oxide (Co3O4) coated over SS plates. The results indicated that Co3O4@SS electrodes resulted in better removal efficiency of CIP at a lower residence time. This system can be used as a robust benchmark for a single or consortium of antibiotics present in domestic and hospital wastewater.
Enero, 2024 | DOI: 10.1016/j.colsurfa.2023.132738
Materiales Ópticos Multifuncionales
Scattering Spheres Boost Afterglow: A Mie Glass Approach to Go Beyond the Limits Set by Persistent Phosphor Composition
Castaing, V; Romero, M; Torres, J; Lozano, G; Míguez, HAdvanced Optical Materials, 12 (2024) 2301565 DOI: 10.1002/adom.202301565
Abstract
Persistent luminescence phosphor nanoparticles (PersLNPs) offer exciting opportunities for anticounterfeiting, data storage, imaging displays, or AC-driven lighting applications owing to the possibility to process them as shapable thin coatings. However, despite unique delayed and long-lasting luminescence, the relatively low storage capacity of persistent phosphor nanoparticles combined with the difficulty of harvesting photons from transparent thin layers drastically hinder the perceived afterglow. In order to enhance persistent luminescence (PersL) of thin coatings, herein a novel approach is proposed based on resonant optical nanostructures. In particular, it is demonstrated that the integration of TiO2 scattering spheres in films (with thickness comprised between 1 and 10 mu m) made of ZnGa2O4:Cr3+ PersLNPs enables a significant increase in afterglow intensity due to the combination of effective charging and enhanced outcoupling. As a result, a approximate to 3.5-fold enhancement of the PersL is observed in 2 mu m-thick films stuffed with scattering centers using low-light illumination conditions. Furthermore, inclusion of scattering centers leads to an unprecedented acceleration of the PersL charging speed. These results constitute the first example of photonic engineering applied to enhance the properties of PersL materials coatings.
Enero, 2024 | DOI: 10.1002/adom.202301565
Química de Superficies y Catálisis
Subnanometric Pt clusters dispersed over Cs-doped TiO2 for CO2 upgrading via low-temperature RWGS: operando mechanistic insights to guide an optimal catalyst design
Torres-Sempere, G; Blay-Roger, R; Luque-Alvarez, LA; Santos, JL; Bobadilla, LF; Pastor-Pérez, L; Centeno, MA; Hernández, WY; Yousef, I; Odriozola, JA; Reina, TRJournal of Matertials Chemistry A, 12 (2024) 1779-1792 DOI: 10.1039/D3TA05482A
Abstract
The RWGS reaction is gathering momentum as an effective route for CO2 valorisation and given its endothermic nature the challenge lies in the design of active low-temperature catalysts. Herein we have designed two catalysts based on subnanometric Pt clusters providing effective CO2 conversion and, more importantly, high CO selectivity in the low-temperature range. The impact of Cs as a dopant in the catalyst's formulation is crucial leading to full selectivity at 300 °C. The reaction mechanisms for the studied systems namely Pt/TiO2 and PtCs/TiO2 are significantly different due to the presence of the alkali promoter. The presence of Cs neutralises the hydroxide groups of the TiO2 surface, changing the reaction pathway. The Pt/TiO2 catalyst follows a redox mechanism where CO2 dissociates to CO in the oxygen vacancies, and then these vacancies are recovered by the migration of H2 by spill over phenomena. On the other hand, the Cs doped catalyst has two possible mechanism pathways: the (ii) formyl/acyl pathway, where –CHO species are formed and, depending on the reaction conditions, evolve to CO gas or oxygenated compounds, and (ii) frustrated Lewis pair (FLP) assisted CO2 reduction route, in which the FLP induces the heterolytic dissociation of H2 and the subsequent hydrogenation of CO2 to CO. The latter route enabled by Cs-doping combined with the subnanometric Pt domains seems to be responsible for the excellent catalytic behaviour leading to fully selective low-temperature RWGS systems and thus unlocking new possibilities for less energy demanding CO2 valorisation units based on RWGS.
Enero, 2024 | DOI: 10.1039/D3TA05482A
Química de Superficies y Catálisis
Mechanistic insights into methanol carbonylation to methyl acetate over an efficient organic template-free Cu-exchanged mordenite
Luque-Alvarez, LA; Gonzalez-Arias, J; Romero-Sarria, F; Reina, TR; Bobadilla, LF; Odriozola, JACatalysis Science & Technology, 14 (2024) 128-136 DOI: 10.1039/d3cy01271a
Abstract
Currently, acetic acid is produced via the carbonylation reaction of methanol with the main route entailing the use of homogeneous noble metal-based catalysts, which has certain limitations, including the use of polluting alkyl halide promoters and difficulty in catalyst recovery. To overcome these challenges, the exploration of alternative methods utilizing heterogeneous catalysts, particularly zeolites with copper as a redox center, has gained attention. Nonetheless, the conversion and selectivity obtained are sought after to compete against the homogeneous route. Therefore, a deeper understanding of the reaction and mechanism is needed to determine the weak points and overcome them. In this study, we propose the use of time-resolved operando DRIFTS-MS to study the methanol carbonylation reaction over a Cu–H-MOR catalyst. The study aimed to propose a reaction mechanism through an investigation of the behavior of the catalyst, including potential identification of the location of the copper redox center in the zeolite. The catalytic performance of the Cu–H-MOR catalyst was also evaluated, demonstrating its activity and stability in the methanol carbonylation reaction. The operando DRIFTS-MS results provide insights into the reaction mechanism and the involvement of the acid and redox centers in the process. Based on the findings, we propose a reaction mechanism for methanol carbonylation on Cu–H-MOR zeolite: (i) methanol dehydration, (ii) CO insertion into methoxide groups, (iii) reaction between dimethyl ether and acetyl groups, and (iv) hydrolysis of methyl acetate. Overall, we believe that this work contributes to a deeper understanding of the heterogeneous route for acetic acid production and offers potential avenues for optimizing the process.
Enero, 2024 | DOI: 10.1039/d3cy01271a
Fotocatálisis Heterogénea: Aplicaciones - Reactividad de Sólidos
Investigating the room- and cryo-milling impact in lignocellulosic biomass and its consequence over pyrolysis and oxidative treatments
Pérez, CR; González, MDA; Sarria, FR; López, MDH; Gallego, JMCJournal of Cleaner Production, 437 (2024) 140761 DOI: 10.1016/j.jclepro.2024.140761
Abstract
The lignocellulosic biomass recalcitrance is the uppermost factor for the utilization of this renewable resource. The development of new pre -treatments, addressed to enhance performance in lignocellulosic biomass conversion into biofuels, fine chemicals, and as potential sources of building blocks for materials, must be focus in two main areas: effectiveness (cost-effective and chemical effective) and green chemistry. In this research, a set of different biomass sources (farmer, harvested wild trees and secondary products) were studied to evaluate the high efficiency of the non -liquid nitrogen (LN) and LN-treated biomass samples' planetary ball milling performance. The samples have been characterized by particle size distribution, thermogravimetric, FT-IR, statistical chemometric and chemical oxidation analysis. The results have shown a high level on the rupture of the crystallinity and depolymerization degrees of the cellulose and the lignin, for both, non-LN and LN-treated samples. The thermogravimetric analysis showed a clear diminishing in temperature degradation, and a larger amount of biomass degraded at lower temperature, as well as, a high chemical oxidation degree than not milled samples. Finally, the LN-treated samples even exhibited a lower degradation temperature, a larger amount of biomass degraded at lower temperature and a higher oxidation degree, than those non-LN milled.
Enero, 2024 | DOI: 10.1016/j.jclepro.2024.140761
Química de Superficies y Catálisis
Synthetic natural gas production using CO2-rich waste stream from hydrothermal carbonization of biomass: Effect of impurities on the catalytic activity
González-Arias, J; Torres-Sempere, G; Villora-Picó, JJ; Reina, TR; Odriozola, JAJournal of CO2 Utilization, 79 (2024) 102653 DOI: 10.1016/j.jcou.2023.102653
Abstract
The utilization of biomass and bio-waste, particularly through hydrothermal processes, has shown promise as a technology for converting these materials into valuable products. While most research has traditionally focused on the solid and liquid byproducts of these hydrothermal treatments, the gaseous phase has often been over-looked. This study specifically investigates the conversion of off-gases produced during hydrothermal carbonation (HTC) into synthetic natural gas, offering a readily marketable product with economic potential. Although the methanation of conventional flue gases has been extensively studied, dealing with non-standard off-gases from processes like HTC presents challenges due to the presence of minor impurities like CO and CH4. This novel research seeks to experimentally evaluate the methanation of HTC off-gases using nickel-based catalysts and analyze how these impurities affect the catalytic performance. The studied catalysts include nickel supported by ceria and alumina, as well as alumina supported nickel-cobalt systems. The results demonstrate that these catalysts exhibit high CO2 conversion and CH4 selectivity under ideal gas conditions. However, when real gas compositions with impurities are considered, CO2 conversion decreases at lower temperatures (ca. 20% lower conversion for real gas vs. ideal), probably due to side reactions such as CH4 cracking. This difference becomes less pronounced at higher temperatures. Nevertheless, the catalysts perform satisfactorily, especially at temperatures exceeding 350 degrees C. In conclusion, this study sheds light on the methanation of HTC off-gases and underscores the significance of understanding how impurities in real gases impact the process, providing potential directions for future research.
Enero, 2024 | DOI: 10.1016/j.jcou.2023.102653
Química de Superficies y Catálisis
Boosting Low-Temperature CO2 Hydrogenation over Ni-based Catalysts by Tuning Strong Metal-Support Interactions
Ye, RP; Ma, LX; Hong, XL; Reina, TR; Luo, WH; Kang, LQ; Feng, G; Zhang, RB; Fan, MH, Zhang, RGAngewandte Chemie-International Edition, 63 (2024) e202317669 DOI: 10.1002/anie.202317669
Abstract
Rational design of low-cost and efficient transition-metal catalysts for low-temperature CO2 activation is significant and poses great challenges. Herein, a strategy via regulating the local electron density of active sites is developed to boost CO2 methanation that normally requires >350 °C for commercial Ni catalysts. An optimal Ni/ZrO2 catalyst affords an excellent low-temperature performance hitherto, with a CO2 conversion of 84.0 %, CH4 selectivity of 98.6 % even at 230 °C and GHSV of 12,000 mL g−1 h−1 for 106 h, reflecting one of the best CO2 methanation performance to date on Ni-based catalysts. Combined a series of in situ spectroscopic characterization studies reveal that re-constructing monoclinic-ZrO2 supported Ni species with abundant oxygen vacancies can facilitate CO2 activation, owing to the enhanced local electron density of Ni induced by the strong metal-support interactions. These findings might be of great aid for construction of robust catalysts with an enhanced performance for CO2 emission abatement and beyond.
Enero, 2024 | DOI: 10.1002/anie.202317669
Materiales y Procesos Catalíticos de Interés Ambiental y Energético
CuO-TiO2 pilot-plant system performance for solar photocatalytic hydrogen production
Villachica-Llamosas, JG; Ruiz-Aguirre, A; Colón, G; Peral, J; Malato, SInternational Journal of Hydrogen Energy, 51 (2024) 1069-1077 DOI: 10.1016/j.ijhydene.2023.07.149
Abstract
The main goal of the present study was to explore photocatalytic performance of the TiO2 -CuO mixture, for solar to hydrogen conversion at pilot plant scale under two different irradiation conditions (sunny and partly cloudy), focusing on high-temperature pretreat-ment of the catalyst mixture to try to improve TiO2 doping with copper. P25-TiO2 and commercial CuO were used with different amounts of Cu (2 wt% or 7 wt% Cu) calcined at 200-400 degrees C during several hours. Catalysts were tested at pilot plant scale using solar compound parabolic collectors, with glycerol as the sacrificial agent. The photocatalyst prepared after heating at 200 degrees C for 3 h and with 7 wt% Cu, resulted in higher hydrogen production than under the other heating conditions, and results were slightly better (5 -10%) than the reference values with the untreated catalysts. Photocatalytic efficiency was slightly lower at the higher calcination temperature (400 degrees C). CO2 production and formation of formate and glycolate clearly demonstrated glycerol photoreforming. The Cu from the calcined catalyst remaining on the solid was significantly less (2.5%) than on the non -calcined catalyst (4.2%), with an important fraction of lixiviated copper and copper deposition on the reactor walls. This is a critical drawback that must be considered for large-scale applications.
Enero, 2024 | DOI: 10.1016/j.ijhydene.2023.07.149
Química de Superficies y Catálisis
Switchable catalysis for methanol and synthetic natural gas synthesis from CO2: A techno-economic investigation
Merkouri, LP; Mathew, J; Jacob, J; Reina, TR; Duyar, MSJournal of CO2 Utilization, 79 (2024) 102652 DOI: 10.1016/j.jcou.2023.102652
Abstract
The oil and gas sector produces a considerable volume of greenhouse gas emissions, mainly generated from flaring and venting natural gas. Herein, a techno-economic analysis has been performed of a switchable catalytic process to convert the CH4 and CO2 in flared/vented natural gas into syngas or methanol. Specifically, it was shown that depending on greenhouse gas composition, dry methane reforming (DRM), reverse water-gas shift (RWGS), and CO2 methanation could be chosen to valorise emissions in an overall profitable and flexible operation scenario. The switchable process produced methanol and synthetic natural gas as its products, resulting in an annual income of €687m and annual operating expenses of €452m. The pre-tax profit was calculated at €234m, and at the end of the project, the net present value was calculated as €1.9b with a profitability index of 4.7€/€. The expected payback time of this process was ca. 4 years, and with a 35% internal rate of return (IRR). Most importantly, this process consumed 42.8m tonnes of CO2 annually. The sensitivity analysis revealed that variations in operation time, green hydrogen price, and products' prices significantly impacted the profitability of the process. Overall, this techno-economic analysis demonstrated that switchable catalysis in greenhouse gas utilisation processes is profitable, and thus it could play an important role in achieving net zero emissions.
Enero, 2024 | DOI: 10.1016/j.jcou.2023.102652
Química de Superficies y Catálisis
A review on high-pressure heterogeneous catalytic processes for gas-phase CO2 valorization
Villora-Picó, J.J; González-Arias, J; Pastor-Pérez, L; Odriozola, JA; Reina, TREnvironmental Research, 240 (2024) 117520 DOI: 10.1016/j.envres.2023.117520
Abstract
This review discusses the importance of mitigating CO2 emissions by valorizing CO2 through high-pressure catalytic processes. It focuses on various key processes, including CO2 methanation, reverse water-gas shift, methane dry reforming, methanol, and dimethyl ether synthesis, emphasizing pros and cons of high-pressure operation. CO2 methanation, methanol synthesis, and dimethyl ether synthesis reactions are thermodynami-cally favored under high-pressure conditions. However, in the case of methane dry reforming and reverse water -gas shift, applying high pressure, results in decreased selectivity toward desired products and an increase in coke production, which can be detrimental to both the catalyst and the reaction system. Nevertheless, high-pressure utilization proves industrially advantageous for cost reduction when these processes are integrated with Fischer-Tropsch or methanol synthesis units. This review also compiles recent advances in heterogeneous catalysts design for high-pressure applications. By examining the impact of pressure on CO2 valorization and the state of the art, this work contributes to improving scientific understanding and optimizing these processes for sustainable CO2 management, as well as addressing challenges in high-pressure CO2 valorization that are crucial for industrial scaling-up. This includes the development of cost-effective and robust reactor materials and the development of low-cost catalysts that yield improved selectivity and long-term stability under realistic working environments.
Enero, 2024 | DOI: 10.1016/j.envres.2023.117520
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