Scientific Papers in SCI

Abstract

The thermal memory effect, TME, has been studied in Ni₅₅Fe₁₉Ga₂₆ shape memory alloys, fabricated as ribbons via melt-spinning and as pellets via arc-melting, to evaluate its dependence on the martensitic structure and the macrostructure of the samples. When the reverse martensitic transformation is interrupted, a kinetic delay in the subsequent complete transformation is only evident in the ribbon samples, where the 14M modulated structure is the dominant phase. In contrast, degradation of the modulated structure or the presence of the γ phase significantly reduces the observed TME. In such cases, the magnitude of the TME approaches the detection limits of commercial calorimeters, and only high-resolution calorimeter at very low heating rate (40 mK h⁻¹) can show the effect. Following the kinetic arrest and subsequent cooling, the reverse martensitic transformation was completed at several heating rates to confirm the athermal nature of the phenomenon.

Abstract

Access to clean water is crucial for human health, yet microbial contamination poses significant challenges. This study investigates the effectiveness of novel photocatalytic catalysts: heterostructured TiO₂/AgBr and faceted titanium dioxide, for microbial inactivation under ultraviolet and visible light. Both catalysts were synthesized and characterized. Performance was evaluated using real wastewater samples and saline solutions, targeting gram-positive and gram-negative bacteria. The experimental approach included testing the photocatalysts with and without the addition of peroxydisulfate to assess its impact on inactivation effectiveness. Results indicated that the TiO₂/AgBr catalyst outperformed the faceted titanium dioxide one due to its superior visible light absorption and enhanced charge separation, achieving complete inactivation of environmental strains of Escherichia coli and significant inactivation for Enterococcus faecalis in real wastewater. The inclusion of peroxodisulfate with TiO₂/AgBr significantly improved inactivation rates, demonstrating a synergistic effect. Regarding wastewater composition, the treatment achieves a significant COD removal while the rest of studied parameters remain stable. Both catalysts effectively prevented bacterial regrowth for up to 48 hours, underscoring its long-term efficacy. Overall, these findings highlight the potential application of TiO₂/AgBr combined with peroxodisulfate as an effective strategy for microbial inactivation, contributing to the advancement in water treatment technologies across real environmental contexts.

Abstract

The influence of the characteristic features and firing temperature on the ceramic properties of raw kaolin samples were examined studying a wide range of firing temperatures (1000–1500 ºC). The techniques of investigation have been particle size analysis, Transmission Electron Microscopy (TEM), X-ray powder Diffraction (XRD), X-ray Fluorescence analysis (XRF), and Thermal Analysis using Termodilatometry (TD), Thermalgravimetric analysis (TGA) and Differential Thermal Analysis (DTA). Uniaxial pressed cylindric bodies were obtained and fired from 1000 to 1500 °C/2 h. TEM allowed investigate morphological differences and identification of kaolinite and halloysite. The mineralogical analysis indicated that the kaolinite content is high (80–90 wt%). The contents of oxide impurities are relatively low although in a sample is 7.6 wt% on a calcined basis. The characteristic sharp DTA exothermic effect of kaolinite was observed in the range 900–1000 °C. The ceramic properties of the group of kaolin samples has been determined: linear firing shrinkage, water absorption capacity, apparent density and open porosity. Sintering diagrams allowed investigate the progressive decrease of water absorption and the increase of firing shrinkage. In some kaolin samples the water absorption reached zero at 1450–1500 ^ᵒC. High sintering temperatures have been observed when kaolinite is present in high contents and the fluxes content is low. The maximum values of apparent density were determined, with a sample with the highest value (2.75 ± 0.10 g/cm³). The open porosity changes from ∼ 34–38 % at 1000 ᵒC up to zero or minimum values (< 3 %) at 1500 ^ᵒC. This behaviour is associated to the progressive sintering of the particles and filling of pores by glassy phase originated by the presence of fluxes and the influence of a low particle size. The formation of mullite and cristobalite by firing have been studied by XRD. Mullite has been detected from 1000 to 1100 ᵒC and the crystals developed as increasing firing temperatures. Cristobalite (α-cristobalite) has been identified at 1200–1300 ºC. The presence of an alkaline melt could impede the crystallization of cristobalite. This study presents a comparative research because all these commercial kaolin samples have been examined under the same experimental conditions. Consequently, the results have allowed to provide new data about raw kaolin powders with high kaolinite content in the range 80–90 wt%.

Abstract

Magnetron sputtering (MS) is an emerging technique to prepare electrocatalysts for oxygen and hydrogen evolution reactions that take place in alkaline water electrolysis. It is a physical vapour deposition method that provides a strict control over the composition, chemical state, and microstructure. It permits to adjust complex stoichiometries and guarantees reproducibility. This technology allows to deposit electrocatalysts on suitable current collectors to get anode and cathode electrodes in a one-step process. Furthermore, MS is an environment friendly technology with easy scalability for industrial electrode production. Additionally, when operated in an oblique angle deposition configuration, it allows precise control of the microstructure of the deposits that can be tuned from compact to mesoporous. On this brief review we discuss recent studies on the field showing the possibility of using MS for the preparation of catalyst layers with complex compositions, bi-layer structure configurations, and bimetallic, trimetallic, and multicomponent alloys.

Abstract

In this paper, we investigate the Casimir-Lifshitz free energy mechanism that governs both ice growth and melting near metal surfaces, with a particular focus on the role of oxidation. Our study reveals that metals such as gold, iron, and aluminum induce incomplete premelting, resulting in micron-sized liquid water layers when in contact with ice. These layers could have significant implications for the defrosting of metallic surfaces. When exposed to water vapor at the triple point, aluminum and other metals can induce the formation of notably thick layers of either liquid water or ice, which can theoretically become infinitely thick if other interactions are disregarded. However, when aluminum undergoes oxidation to form alumina, its behavior changes dramatically. Alumina surfaces cause complete melting when in direct contact with bulk ice and result in only micron-sized layers of water or ice in vapor conditions. In contrast, magnetite, the oxidized form of iron, retains metalliclike behavior due to its high dielectric constant, similar to other metals, and continues to support thick layers of water or ice. This distinction highlights the significant influence of oxidation on the dynamics of ice growth and melting near different metal surfaces.

Abstract

Metal-Organic frameworks (MOFs) are promising candidates for advanced photocatalytically active materials. These porous crystalline compounds have large active surface areas and structural tunability and are thus highly competitive with oxides, the well-established material class for photocatalysis. However, due to their complex organic and coordination chemistry composition, photophysical mechanisms involved in the photocatalytic processes in MOFs are still not well understood. Employing electron paramagnetic resonance (EPR) spectroscopy and time-resolved photoluminescence spectroscopy (trPL), the fundamental processes of electron and hole generation are investigated, as well as capture events that lead to the formation of various radical species in UiO-66, an archetypical MOF photocatalyst. A manifold of photoinduced electron spin centers is detected, which is subsequently analyzed and identified with the help of density-functional theory (DFT) calculations. Under UV illumination, the symmetry, g-tensors, and lifetimes of three distinct contributions are revealed: a surface O2-radical, a light-induced electron-hole pair, and a triplet exciton. Notably, the latter is found to emit (delayed) fluorescence. The findings provide new insights into the photoinduced charge transfer processes, which are the basis of photocatalytic activity in UiO-66. This sets the stage for further studies on photogenerated spin centers in this and similar MOF materials.

Abstract

One of the biggest players in the world economy is the naval industry, which mainly controls the merchandise transportation sector. Any issue with ships could represent millions of USD of loss and increases in the cost of goods for the population worldwide. Two main problems which this industry has fought are corrosion and biofouling. Lastly, the pollution of the sea has gained importance, and more strict policies have been applied regarding the use of certain products by this industry. One of these is paintings, which represented this industry's definitive solution to avoid the mentioned problems for a long time. This situation allowed to explore other solutions like PVD coatings through multifunctional coatings. Zirconium nitride has been demonstrated to be useful in resisting corrosion with reliable mechanical properties. However, this material does not possess antimicrobial action. The present study presents a nanostructured coating combining ZrN with Cu, which works as a biocide, contributing to the desired multifunctionality. The developed coating was obtained using a hybrid magnetron co-sputtering employing High-power impulse (HiPIMS) and direct current (DCMS) power sources under a reactive atmosphere. SEM, EDX, XRD and Raman spectroscopy were used to assess the physico-chemical properties of the coatings. Besides, depth-sensing nano-indentation explored the mechanical properties. The tribological performance was tested by a reciprocating tribometer under dry and wet (with 3.5 % w/w NaCl solution) contact conditions and employing a soda lime glass ball as a counterbody. The results showed that adding Cu to ZrN through this technology resulted in a limited hardness reduction from 19 (pure ZrN) to 14 GPa. Also, the chemical activation with NaOCl solution softens the obtained coating and, together with the saline solution, influences the wear resistance. However, the nanostructured coating has been demonstrated to be suitable for use under real conditions, without loss of its protection over the used substrate. It opens a new possibility of a solution for the naval industry.

Abstract

This study investigates the impact of cerium promotion on NiMgAl catalysts for methane dry reforming (DRM) at 750 degrees C. A series of NiMgAl-Ce oxides with varying cerium content NiMgAlCe-x (x: rate of substitution of aluminium by cerium) were synthesized via co-precipitation method, aiming to enhance catalytic activity through the incorporation of nickel into hydrotalcite structures and cerium promotion. The obtained systems calcined at 800 degrees C, reduced at 750 degrees C and used catalysts were characterized by ICP, BET, XRD, SEM, H2-TPR, TPO and O2-TG analysis. The results demonstrate that cerium content influences specific surface area, with higher cerium promoting increased surface area but hindering catalytic activity and improved carbon resistance of the catalysts.. Activity improved with reaction temperature, with NiMgAl achieving the highest conversion, with CH4 conversion dropping from 16% at 450 degrees C to 95.0% at 750 degrees C. Stability tests at 750 degrees C, revealed decreased activity in cerium-containing catalysts. On the other hand in the case of catalysts without prior reduction, the catalytic activity of NiMgAlCe-1 and NiMgAlCe-2 catalysts are better, however, the NiMgCe solid presents a total catalytic inertia. This result suggests that the presence of aluminium is bringing a Lewis acidity favours this reducibility suggesting an influence on redox behaviour. Carbon fibers formation was observed, but it did not significantly affect reactor performance.

Abstract

The first demonstration of plasma-flash sintering (PFS) is presented in this work. PFS is performed under a low-pressure atmosphere that consecutively generates plasma and flash events. It is shown, by using several combined characterization techniques, that PFS stabilizes metastable phases on the surface of the material, which may be partially, but not solely, attributed to the generation of oxygen vacancies, and induces the absorption of ionized species, if a reactive atmosphere is employed. Even though additional research is required to understand the fundamentals of PFS, it is evidenced its potential to be used as a material surface engineering tool, which may widen the technological capabilities of flash sintering.

Cover Photograph: Plasma-Flash Sintering (PFS) is performed under low-pressure atmosphere that consecutively generates plasma and flash events. This study shows that PFS stabilizes metastable phases on the surface of the material and enables absorption of ionized species generated in the plasma, giving this technique potential to be used as a surface engineering tool. Read more in the rapid communication in this issue,

Abstract

Doped-PrBaMn2-xTMxO5+delta samples with TM = Co and/or Ni were synthesized by a mechanochemical route from stoichiometric oxide precursor mixtures (Pr6O11, BaO2, MnO, NiO and CoO) using a planetary mill at 600 rpm for 150 min. A disordered ABO(3) pseudocubic perovskite phase was obtained after the milling process that was transformed, as established by XRD, into the double layered AA'B2O5+delta perovskite phase after annealing at 900 degrees C in a reducing atmosphere (10%H-2/Ar). The microstructural characterization by SEM, TEM, and HRTEM ascertained that this reducing treatment induced the exsolution of Ni and Co metallic nanoparticles from the doped samples. Ni-Co alloys were even exsolved when the layered manganite phase was co-doped with both transition metals. It was confirmed that the exsolution process was reversible by switching the working atmosphere from reducing to oxidizing. Polarization resistance values of the doped samples determined in symmetrical cells in air and H-2, as well as the electrochemical performance of electrolyte LSGM-supported planar cells suggested that these samples can be used as symmetrical electrodes in SOFCs.

Abstract

Dredged material is a common environmental and economic issue worldwide. Tons of highly contaminated material, derived from cleaning the bottoms of bays and harbours, are stored until depuration. These volumes occupy huge extensions and require costly treatments. The Ria of Huelva (southwest Spain) receives additionally high metal contamination inputs from the Odiel and Tinto Rivers which are strongly affected by acid mine drainage (acid lixiviates with high metal content and sulphates). These two circumstances convert the port of Huelva into an acceptor/accumulator of contamination. The current study proposes an alternative active treatment of dredged material and mining residues using ASEC (Adiabatic Sonic Evaporation and Crystallization) technology to obtain distilled water and valuable solid conglomerates. Different samples were depurated and the efficiency of the technology was tested. The results show a complete recovery of the treated volumes with high-quality water (pH similar to 7, EC < 56 mu S/cm, complete removal of dissolved elements). Also, the characterization of the dried solids enable the calculation of approximate revenues from the valorization of some potentially exploitable elements (Rio Tinto: 4 M, Tharsis: 3.7 M, dredged material: 2.5 M USD/yr). The avoidance of residue discharge plus the aggregated value would promote a circular economy in sectors such as mining and dredging activities.

Abstract

Smart textiles represent a revolutionary approach to wearable technology with applications ranging from healthcare to energy harvesting. This review paper explores the importance of textile technologies and highlights their potential to revolutionize consumer electronics. Conventional technologies are sometimes heavy, and lack comfort and flexibility, but smart textiles seamlessly integrate into everyday clothing, improving wearability and user experience. The article emphasizes the need for sustainable sourcing and environmentally friendly production methods, as well as responsible manufacturing and disposal practices. Manufacturing techniques such as wet spinning, melt spinning, electrostatic spinning, weaving, knitting, and printing are detailed and shed light on their role in incorporating electronics into textiles. Several applications of textile-based devices are being explored, including biochemical sensing, temperature monitoring, energy harvesting, energy storage, and smart displays. Each application demonstrates the versatility and potential of smart textiles in different areas. Despite optimistic progress, challenges remain, from improving energy efficiency to protecting user privacy and data security. The review analyzes these problems and suggests future improvements, including interdisciplinary collaboration to find new solutions. Finally, an overview of the current state of smart textiles provides the future of this technology. It serves as an in-depth reference for academics and readers interested in understanding recent advances and discoveries in textile technologies, highlighting the importance of this rapidly growing industry.

Abstract

The instability and limited scalability of halide perovskites hinder their long-term viability in applications as X-ray detectors. Here, we introduce a sol-gel ship-in-bottle approach to produce a monolithic perovskite@metal-organic framework (MOF) composite, combining the properties of the individual building blocks and enhancing density, robustness, and stability. By tuning seed particles below 100 nm, we achieve highly crystalline, dense composites with up to 40% perovskite loading. Structural and optical characterization unveils perovskite nanocrystals forming within MOF mesopores, maximizing stability and preventing degradation, maintaining over 90% photoluminescence and structural integrity after weeks of exposure to humidity, heat, and solvents. Proposed as an innovative class of scintillator, these monolithic perovskite@MOFs attenuate X-rays efficiently and exhibit outstanding stability under high radiation doses equivalent to 110,000 typical chest X-rays, with a radioluminescence lifetime of 10 ns, outperforming commercial scintillators. This approach offers vast potential for developing high-performance, cost-effective, and stable devices for radiation detection and other optoelectronic applications.

Abstract

Ethylene, as an important chemical raw material, could be produced through the coal-based acetylene hydrogenation route. Nickel-based catalysts demonstrate significant activity in the semihydrogenation reaction of acetylene, but they encounter challenges related to catalyst deactivation and overhydrogenation. Herein, the effect of Sn promoter on Ni/CeO2 catalysts has been comprehensively explored for acetylene semihydrogenation. The optimized Ni/8%Sn-CeO2 catalytic performance was significantly improved, with 100% acetylene conversion and 82.5% ethylene selectivity at 250 degrees C, and the catalyst maintained high catalyst performance within a 1000 min stability test. A series of characterization tests show that CeO2 modified by moderate Sn4+ doping is more conducive to modulating the charge structure and geometry of the Ni active center. Additionally, the in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy and density functional theory results indicated that catalysts doped with Sn4+ facilitated more efficient desorption of ethylene from the catalyst surface compared to Ni/CeO2 catalysts, thus improving ethylene selectivity and yield. This study highlights an effective strategy for improving the catalytic performance of rare-earth-based catalysts through the incorporation of effective metal promoters.

Abstract

Plant biomass is an attractive precursor to prepare activated carbons with high surface area for CO2 adsorption due to its low-cost and easy regeneration. Despite this interest, there are still remaining questions regarding the optimal processing conditions and the choice of activating agent. Moreover, since plant biomass shows a highly variable proportion of different biopolymers (cellulose, hemicellulose, lignin), it is important to understand the activation effect on each constituent. In this work, carbons obtained from pyrolysis of cellulose were activated using two potassium salts, using two different activation temperatures. The samples were characterized to elucidate the influence of the activation conditions on their CO2 adsorption capacity. In general, all the carbons activated at higher temperature showed higher adsorption capacity. These results are comparable with other carbons derived from biomass described in the bibliography. Among the activated carbons studied, the carbon activated only with KOH exhibits the highest CO2 adsorption capacity at 1 bar meanwhile the highest adsorption capacity at saturation pressure belongs to the carbon activated with larger ratio of KNO3.

Abstract

The direct conversion of carbon dioxide into hydrocarbons is a very desirable but difficult approach for achieving lower value-added olefins with minimal CO selectivity. In this effort, we report the direct conversion of CO2 into light olefins on a Cu/CeO2 hybrid catalyst mixed with SAPO-34 zeolite. The samples are characterized by N-2 sorption, XRD, TEM, SEM, NH3-TPD and H-2 -TPR. The results showed that the acidity of modified zeolite had decreased. The response surface methodology has been used to optimize the operating parameters (temperature and space velocity (SV)) of process. A high olefin selectivity of 70.4% has been obtained on CuCe/SAPO-34 at H-2/CO2 =3, 10 h, 382.46 degrees C, 17.33 L/g.h and 20 bar. The optimum operating conditions for multiple responses have also been achieved. The optimal values are T = 396.26 degrees C and SV = 5.80 L/g.h. Under these conditions, the predicted olefin and CO selectivity and CO2 conversion are 61.83%, 57.11% and 13.15%, respectively. Multiple optimization outputs are outstanding for obtaining the suitable operating conditions.

Abstract

In this study, the feasibility of preparing quinary equimolar high-entropy oxides within the Co–Cu–Fe–Mg–Mn–Ni–O system was explored using the reactive flash sintering (RFS) technique. Various compositions were tested using this technique under atmosphere pressure, leading to the formation of two primary phases: rock-salt and spinel. Conversely, a new high-entropy oxide was produced as a single-phase material with the composition (Co_0.2,Cu_0.2,Mg_0.2,Mn_0.2,Ni_0.2)O when RFS experiments were conducted in nitrogen atmosphere. The reducing conditions achieved in nitrogen enabled the incorporation of cations with oxidation states different from +2 into the rock-salt lattice, emphasizing the critical role of the processing atmosphere, whether inert or oxidizing, in the formation of high-entropy oxides. The electrical characterization of this material was obtained via impedance spectroscopy, exhibiting a homogeneous response attributed to electronic conduction with a temperature dependence characteristic of disordered systems. 

Abstract

Gel polymer electrolytes (GPEs) are regarded as a promising alternative to conventional electrolytes, combining the advantages of solid and liquid electrolytes. Leveraging the abundance and eco-friendliness of cellulose-based materials, GPEs were produced using methyl cellulose and incorporating various doping agents, either an ionic liquid (1-Butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide [Pyr14][TFSI]), its polymeric ionic liquid analogue (Poly(diallyldimethylammonium bis(trifluoromethylsulfonyl)imide) [PDADMA][TFSI]), or an anionically charged backbone polymeric ionic liquid (lithium poly[(4-styrenesulfonyl)(trifluoromethyl(S-trifluoromethylsulfonylimino) sulfonyl) imide] LiP[STFSI]). The ion dynamics and molecular interactions within the GPEs were thoroughly analyzed using Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Heteronuclear Overhauser Enhancement Spectroscopy (HOESY), and Pulsed-Field Gradient Nuclear Magnetic Resonance Diffusion (PFG-NMR). Li+ transference numbers (tLi+) were successfully calculated. Our study found that by combining slow-diffusing polymeric ionic liquids (PILs) with fast-diffusing lithium salt, we were able to achieve transference numbers comparable to those of liquid electrolytes, especially with the anionic PIL, LiP[STFSI]. This research highlights the influence of the polymer ' s nature on lithium-ion transport within GPEs. Additionally, micro supercapacitor (MSC) devices assembled with these GPEs exhibited capacitive behavior. These findings suggest that further optimization of GPE composition could significantly improve their performance, thereby positioning them for application in sustainable and efficient energy storage systems.

Abstract

Herein, it is reported the concomitant synthesis and sintering in a single step of (Mn0.2Co0.2Ni0.2Cu0.2X0.2)Fe2O4 (X=Fe, Mg), a spinel-structured high-entropy oxides, by the reactive flash sintering technique. A single phase, identified with a spinel crystal structure Fd3m, was obtained in just 30 min at a furnace temperature of 1173 K. The structural and magnetic properties of the prepared compounds were assessed by the combined use of various techniques, aiming to understand the correlations between functional properties and crystal structure. Characteristic features of the Mossbauer spectra prove the existence of different nonequivalent Fe environments . Both compositions display soft magnetic behavior, characterized by low coercive fields and saturation magnetization reached at low fields. Thus, the substitution of nonmagnetic Mg2+ for magnetic Fe2+ results in a decrease in magnetic parameters due to the weakening of the super-exchange interaction among the magnetic moments.

Abstract

This work shows the synthesis and characterization of the Zn2-xGeO4-GeO2:(x)Mn2+ (x = 0.10, 0.25, and 0.50 at.%) films using the Ultrasonic Spray Pyrolysis (USP) technique. These films were deposited at 500 degrees C and heat treated at 800 degrees C for 13 h. X-ray diffraction (XRD) measurements showed the rhombohedral and hexagonal phases of Zn2-xGeO4 (78.8 %) and GeO2 (21.2 %), respectively. SEM micrographs exhibited the surface morphology of these films. The STEM and HAADF show Ge, Zn, and O atomic layers. In addition, XPS was carried out to observe the oxidation states of Mn2+ (75.4 %) and Mn3+ (24.6 %) for the films doped with Mn ions (0.10 at.%). Incorporating manganese ions into the Zn2-xGeO4-GeO2 host lattice generated an extremely green emission, exciting at 250 nm. The photoluminescence and persistence luminescence properties were studied in accordance with the manganese doping concentration. For photoluminescence, it was found that the optimal doping percentage was 0.25 at.%, and for persistence luminescence, it was 0.10 at.% Mn with lambda(ex) = 250 nm. Quantum efficiency measurements gave a result of 100 %. In addition, preliminary CL measurements were exhibited.

Abstract

Novel zinc-doped Metal-Organic Framework based on MIL53(Fe) (Zn-MIL53(Fe)) has been successfully synthesised in one-step, exhibiting dual applications as adsorbent and catalyst. Initially, the adsorption capacity of MIL53(Fe) and Zn-MIL53(Fe) for removing Rhodamine B was assessed through kinetic and isotherm studies. The bimetallic variant exhibited superior performance, showcasing enhanced adsorption capabilities, particularly in the context of its physical interaction under natural pH. After that, the catalytic activity of both synthesised materials was evaluated to generate sulphate radicals by activating PeroxyMonoSulphate (PMS). It was also demonstrated that Zn-MIL53(Fe) exhibited the best catalytic activity being optimised using response surface methodology for Rhodamine B degradation (0.11 mM PMS and 43.2 mg Zn-MIL53(Fe)). Under optimal conditions, favourable outcomes were attained, facilitating the degradation of Rhodamine B, Fluoxetine, and Sulfamethoxazole by 93, 99, and 75 %, respectively. Furthermore, the operational stability of the Zn-MIL53(Fe) was verified, as it remains structurally and catalytically intact after different cycles.

Abstract

Triboelectric nanogenerators (TENGs) are the most promising technology for harvesting energy from low-frequency liquid flows and impacts such as rain droplets. However, current drop energy harvester technologies suffer from low output power due to limitations in triboelectric materials, suboptimal device designs, and the inability to fully capture the kinetic energy of falling drops. This article introduces a microscale TENG capable of efficiently converting drop impact energy into electrical power in a single, rapid step. The device features a capacitive structure that enhances energy conversion through instantaneous capacitance changes when the drops contact the submillimetric top electrodes. This compact design establishes a path toward the development of dense arrays and rain panels and is adaptable to various liquids, scales, triboelectric surfaces, and thin-film configurations, including flexible and transparent materials. 

Abstract

With the rapid advancement of industry and the continuous growth of population, there has been a noteworthy surge in greenhouse gas (GHG) emissions, thereby exacerbating the impact of climate change. Carbon Capture and Storage (CCS) is widely recognized as a pivotal technology in addressing global climate change. This is attributed to its alignment with existing energy infrastructure and its substantial potential for significant reduction in CO₂ emissions. Among the alternatives for carbon capture, chemical absorption stands out due to its robust processing capacity, adaptability, and high reliability, making it the most mature technology for capturing CO₂ in contemporary power plants. Life cycle assessment (LCA) can assist decision-makers in determining whether the use of the technology to mitigate GHG emissions will result in elevated environmental impacts. This work offers an overview of the problems and present status associated with different chemical solvents in CO₂ capture and emphasizes the merits and drawbacks in the use of different solvents within the absorption process. Although the integration of chemical absorption systems in power plants leads to a substantial reduction in direct CO₂ emissions, there are varying degrees of impacts on other environmental impact categories (e.g., acidification, eutrophication, ecological and human toxicity, etc.) in addition to global warming. This paper analyzes the potential environmental impacts associated with carbon capture using different solvents and suggests directions for improvement. Finally, it is reviewed in the aspects of combination with new technology and interdisciplinary evaluation. This work aims to deepen our comprehension of the environmental impacts linked to diverse post-combustion CO₂ capture systems relying on chemical absorption, facilitating decision-makers in developing optimal solutions that provide both economic and environmental benefits.

Abstract

Embracing a circular economy in the textile industry represents a crucial step toward sustainability, where fashion and textile sectors contribute significantly to CO2 emissions. However, transitioning from a linear “take-make-waste” model to circularity, poses multifaceted challenges, that highlight the staggering volume of annual textile waste surpassing industry predictions, thus emphasizing the urgent need for comprehensive strategies. Despite advancements in recycling technologies, challenges persist in collecting and sorting textile waste, where fragmentation in waste management and recycling processes hinders effective management of post-consumer waste. Addressing these challenges demands elevated efforts in collection, sorting, and pre-processing, alongside regulatory interventions to drive enhanced waste collection and circular business models. Efforts are underway to promote sustainable textile recycling, with initiatives like the EU’s Sustainable and Circular Textiles Strategy aiming to reduce reliance on virgin resources. However, achieving a circular textile market in the near future requires collaborative action and innovative solutions. Though challenges in scaling and technological limitations still remain, recent breakthroughs in textile-recycling technologies offer promise, signaling a shift toward scalable and sustainable alternatives to virgin fibers, where bio-based chemical processes, and thermochemical recycling processes present transformative opportunities. Where, bold scaling targets, collaborative efforts, and short-term funding support narrated in this perspective article are imperative to accelerate the transition to a circular textile economy, thus delving into the pivotal role of textile recycling, tracing the evolution of recycling technologies, and addressing critical challenges hindering widespread adoption.

Abstract

Dry reforming of methane (DRM) represents an alluring approach to the direct conversion of CO2 and CH4, gases with the highest global warming potential, into syngas, a value-added intermediate used in chemical industry. In this study, mixed oxide structures of cerium and zirconium doped with 10 wt% Ni were used due to the high thermal stability. This study showcased the importance of choosing suitable conditions and explored the impact of calcination temperature on Ce-Zr mixed oxides with Ni. XRD analysis confirmed the existence of different crystalline phases according to the calcination temperature. Redox characterisation showed a trade-off among calcination temperature, the dispersion of Ni clusters and its interaction with the support structure. Calcined catalysts at 900 and 1000 degrees C underwent harsh, long-term DRM conditions. Despite the low surface area of the designed catalysts, the stability experiments proved a relation between dispersion of Ni active phase and catalytic performance, showing an optimum calcination temperature of 1000 degrees C.

Abstract

NiFe electrocatalysts are among the most active phases for water splitting with regard to the alkaline oxygen evolution reaction (OER). The interplay between Ni and Fe, both at the surface and in the subsurface of the catalyst, is crucial to understanding such outstanding properties and remains a subject of debate. Various phenomena, ranging from the formation of oxides/(oxy)hydroxides to the associated segregation of certain species, occur during the electrochemical reactions and add another dimension of complexity that hinders the rational design of electrodes for water splitting. In this work, we have developed the procedure for the quantification of chemical depth profiling by XPS/HAXPES measurements and applied it to two NiFe electrodes with different porosities. The main outcome of this study is related to the surface reconstruction of the electrodes during the OER, followed at two different depths by means of X-ray photoelectron spectroscopy. We find that Fe initially segregates at the surface when exposed to ambient conditions, resulting in the formation of an inactive FeOx phase. In addition, the porosity of the catalyst plays a significant role in the segregation process and thus in the performance of the electrode. In particular, the higher porosity of the nanostructured sample is responsible for a more pronounced diffusion of Fe from the subsurface to the surface with a more effective suppression of the activity of the Ni1–xFexOOH phase. These results highlight the importance of the fact that the chemical state of the surface of a multielement system is a snapshot in time, dependent on both external parameters, such as the applied potential and the adjacent electrolyte, and the underlying bulk properties accessible with HAXPES.

Abstract

The world needs more environmentally friendly materials every time, especially when the application demands constant interaction with fragile habitats. The naval industry is a crucial player in a globalised economy, and the ambient impact of ships on the seas is well-known. Biofouling is one of the significant issues in this industry, and paints with biocides are used as the principal coating solution. However, those are mechanically poor, releasing heavy pollutants into the oceans. Multifunctional coatings obtained by PVD technology could help overcome this situation. The present study proposes a solution to create an advanced coating composed of zirconium nitride and copper in a specific nano-architecture. The developed coating was obtained in a hybrid magnetron co-sputtering system, employing high-power impulse and direct current power sources in a reactive atmosphere. SEM and TEM expose the morphology and the structure of the coatings. EDX, RBS, and XPS were used to assess the chemical insights of the coating. Halo and biofilm tests (with Cobetia marina) were employed to evaluate the antibiofouling action of the coating. The results showed that the activation of the coating, regardless of the used method, provoked the copper migration to the surface, being crucial to obtaining the antibacterial action (reduced bacteria adhesion and > 3 log reduction in CFU on the surface) without affecting the coating integrity (assessed by SEM), and not releasing heavy metals in a significant manner (< 2 log reduction CFU on supernatant). This opens the option of this kind of material, which is environmentally friendly, to be applied in real applications.

Abstract

Early results on the plasma deposition of dielectric thin films on acoustic wave (AW) activated substrates revealed a densification pattern arisen from the focusing of plasma ions and their impact on specific areas of the piezoelectric substrate. Herein, we extend this methodology to tailor the plasma deposition of metals onto AW-activated LiNbO₃ piezoelectric substrates. Our investigation reveals the tracking of the initial stages of nanoparticle (NP) formation and growth during the submonolayer deposition of silver. We elucidate the specific role of AW activation in reducing particle size, enhancing particle circularity, and retarding NP agglomeration and account for the physical phenomena making these processes differ from those occurring on non-activated substrates. We provide a comparative analysis of the results obtained under two representative plasma conditions: diode DC sputtering and magnetron sputtering. In the latter case, the AW activation gives rise to a 2D pattern of domains with different amounts of silver and a distinct size and circularity for the silver NPs. This difference was attributed to the specific characteristics of the plasma sheath formed onto the substrate in each case. The possibilities of tuning the plasmon resonance absorption of silver NPs by AW activation of the sputtering deposition process are discussed.