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Artículos SCI



2023


Química de Superficies y Catálisis

Are Ni/ and Ni5Fe1/biochar catalysts suitable for synthetic natural gas production? A comparison with g-Al2O3 supported catalysts

González-Castaño, M; Morales, C; de Miguel, JCN; Boelte, JH; Klepel, O; Flege, JI; Arellano-Garcia, H
Green Energy & Environment, 8 (2023) 744-756

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Among challenges implicit in the transition to the post-fossil fuel energetic model, the finite amount of resources available for the technological implementation of CO2 revalorizing processes arises as a central issue. The development of fully renewable catalytic systems with easier metal recovery strategies would promote the viability and sustainability of synthetic natural gas production circular routes. Taking Ni and NiFe catalysts supported over g-Al2O3 oxide as reference materials, this work evaluates the potentiality of Ni and NiFe supported biochar catalysts for CO2 methanation. The development of competitive biochar catalysts was found dependent on the creation of basic sites on the catalyst surface. Displaying lower Turn Over Frequencies than Ni/Al catalyst, the absence of basic sites achieved over Ni/C catalyst was related to the depleted catalyst performances. For NiFe catalysts, analogous Ni5Fe1 alloys were constituted over both alumina and biochar supports. The highest specific activity of the catalyst series, exhibited by the NiFe/C catalyst, was related to the development of surface basic sites along with weaker NiFe-C interactions, which resulted in increased Ni0:NiO surface populations under reaction conditions. In summary, the present work establishes biochar supports as a competitive material to consider within the future low-carbon energetic panorama.


Junio, 2023 | DOI: 10.1016/j.gee.2021.05.007 | Digital CSIC: http://hdl.handle.net/10261/246312

Química de Superficies y Catálisis

Review and Perspectives of CO2 Absorption by Water- and Amine-Based Nanofluids

Yuan, CT; Wang, Y; Baena-Moreno, FM; Pan, Z; Zhang, R; Zhou, H; Zhang, Z
Energy & Fuels, 37 (2023) 8883-8901

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The emission of greenhouse gases, especially CO2, hasbecome a major cause of environmental degradation, and carbon capture,utilization, and storage (CCUS) is a proposed solution to mitigateits impact. Nanofluids, a relatively new method for CO2 absorption, have gained attention in recent years. This review focuseson conventional methods for preparing nanofluids along with techniquesto improve their stability and enhance the CO2 absorptionand desorption mechanisms. Additionally, the influences of factors,i.e., nanoparticle and base solution types as well as nanoparticleconcentration, on the CO2 absorption process are summarized.Furthermore, models that can predict the absorption of CO2 accurately are outlined. It is found that the types of both baseliquids and nanoparticles have an important impact on the absorptionby nanofluids. In-depth studies on the predictive capabilities ofartificial intelligence (AI) models hold immense potential in thisregard. This review also puts forth effective strategies to addressprevailing challenges. This will provide a solid theoretical basisfor this field and underscore the promising potential of nanofluidsas CO2 solvents. There are still many unexplored aspectsto be considered, such as the economic viability and energy consumptionof this technology.


Junio, 2023 | DOI: 10.1021/acs.energyfuels.3c00874

Química de Superficies y Catálisis

Toluene combustion on MnOx, CeO2, and Mn-Ce-O solids prepared via citrate complexation, and citrate and urea combustion methods

Rahou, S; Benadda-Kordjani, A; Ivanova, S; Odriozola, JA; Chebout, R; Mahzoul, H; Zouaoui, N
Journal of Nanoparticle Research, 25 (2023) 114

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MnOx, CeO2, and MnCe-O (Mn/Ce = 1) solids have been prepared via the citrate complexation and combustion method using citrate and urea precursors. The solids have been characterized by XRD, SEM-EDX, N-2-adsorption-desorption, UV-Vis spectroscopy, TPR, O-2-TPD, and XPS techniques. The catalytic reactivity of the manganese oxides was not affected by the preparation protocol. In the case of ceria and mixed oxides, the synthesis method greatly affected the structural and chemical properties, ultimately altering their reactivity. The citrate complexation method produced the most homogeneous and active mixed oxide, whereas the urea combustion method resulted in less active solids. The mixed oxide prepared via urea combustion was less active than the manganese single oxide; the decrease in activity was attributed to phase separation and the formation of Mn3O4 domains on the surface of ceria. In contrast, citrate complexation resulted in solids with the lowest particle size (similar to 3 nm), the highest oxidation state for manganese, and the highest proportion of oxygen vacancies, which promote the oxidation reaction.


Junio, 2023 | DOI: 10.1007/s11051-023-05759-6

Química de Superficies y Catálisis

Formic Acid Dehydrogenation over a Monometallic Pd and Bimetallic Pd:Co Catalyst Supported on Activated Carbon

Pelaez, MR; Ruiz-Lopez, E; Dominguez, MI; Ivanova, S; Centeno, MA
Catalysts, 13 (2023) 977

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In this study, palladium is proposed as an active site for formic acid dehydrogenation reaction. Pd activity was modulated with Co metal with the final aim of finding a synergistic effect that makes possible efficient hydrogen production for a low noble metal content. For the monometallic catalysts, the metal loadings were optimized, and the increase in the reaction temperature and presence of additives were carefully considered. The present study aimed, to a great extent, to enlighten the possible routes for decreasing noble metal loading in view of the better sustainability of hydrogen production from liquid organic carrier molecules, such as formic acid.


Junio, 2023 | DOI: 10.3390/catal13060977

Nanotecnología en Superficies y Plasma

Structure and Void Connectivity in Nanocolumnar Thin Films Grown by Magnetron Sputtering at Oblique Angles

Alvarez, R; Regodon, G; Acosta-Rivera, H; Rico, V; Alcala, G; Gonzalez-Elipe, AR; Palmero, A
Coatings, 13 (2023) 991

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The morphology and void connectivity of thin films grown by a magnetron sputtering deposition technique at oblique geometries were studied in this paper. A well-tested thin film growth model was employed to assess the features of these layers along with experimental data taken from the literature. A strong variation in the film morphology and pore topology was found as a function of the growth conditions, which have been linked to the different collisional transport of sputtered species in the plasma gas. Four different characteristic film morphologies were identified, such as (i) highly dense and compact, (ii) compact with large, tilted mesopores, (iii) nanocolumns separated by large mesopores, and (iv) vertically aligned sponge-like coalescent nanostructures. Attending to the topology and connectivity of the voids in the film, the nanocolumnar morphology was shown to present a high pore volume and area connected with the outside by means of mesopores, with a diameter above 2 nm, while the sponge-like nanostructure presented a high pore volume and area, as well as a dense network connectivity by means of micropores, with a diameter below 2 nm. The obtained results describe the different features of the porous network in these films and explain the different performances as gas or liquid sensors in electrochromic applications or for infiltration with nanoparticles or large molecules.


Junio, 2023 | DOI: 10.3390/coatings13060991

 

 

 

 

 

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