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Scientific Papers in SCI


Materiales de Diseño para la Energía y Medioambiente

Revealing the Impact of Different Iron-Based Precursors on the 'Catalytic' Graphitization for Synthesis of Anode Materials for Lithium Ion Batteries

Frankenstein, L; Glomb, P; Ramirez-Rico, J; Winter, M; Placke, T; Gomez-Martin, A
Chemelectrochem, (2023) e202201073

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Low cost and environmentally friendly production of graphite anodes from naturally available biomass resources is of great importance to satisfy the increasing material demand for lithium ion batteries. Herein, graphitization of coffee ground was performed using four different iron-based activating additives, including iron (III) chloride, iron (III) nitrate, iron (III) oxide and pure iron, following either a wet or a dry mixing approach. The structural development regarding the type of activator used and the impact on the corresponding electrochemical performance are systematically investigated. A maximum degree of graphitization between 55 and 74 % (as determined by Raman spectroscopy) is attained using iron (III) chloride and iron powder, respectively. The graphitic anode material synthesized using iron powder reached a maximum reversible capacity of approximate to 320 mAh g(-1) at a rate of 0.1 C. This study provides significant insights into the impact of activators on the design of synthetic graphite from renewable sources.

January, 2023 | DOI: 10.1002/celc.202201073

Materiales Coloidales

Carboxylate functionalized NaDy(MoO4)(2) nanoparticles with tunable size and shape as high magnetic field MRI contrast agents

Gomez-Gonzalez, E; Nuñez, NO; Caro, C; Garcia-Martin, ML; Ocaña, M
Journal of Colloid and Interface Science, 629 (2023) 310-321

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Uniform sodium-dysprosium double molybdate (NaDy(MoO4)(2)) nanoparticles having different morphologies (spheres and ellipsoids) and tunable size have been synthesized for the first time in literature. The procedure is based on a homogeneous precipitation process at moderated temperatures (<= 220 ?) from solutions containing appropriated precursors dissolved in ethylene glycol-water mixtures, in the absence (spheres) or the presence (ellipsoids) of tartrate anions. The effects of the morphological characteristics (size and shape) of the nanoparticles on the magnetic relaxivity at high field (9.4 T) have been evaluated finding that the latter magnitude was higher for the spheres than for the ellipsoids, indicating their better suitability as contrast agents for high-field magnetic resonance imaging. Such nanoparticles have been successfully coated with polymers bearing carboxylate functional groups through a layer-by -layer process, which improves the colloidal stability of the nanoparticles in physiological media. It has been also found that the coating layer had no significant effects on the nanoparticles relaxivity and that such coated nanoparticles exhibited a high biocompatibility and a high chemical stability. In summary, we have developed NaDy(MoO4)(2 )based bioprobes which meet the required criteria for their use as contrast agents for high-field magnetic resonance imaging. 

January, 2023 | DOI: 10.1016/j.jcis.2022.08.130

Reactividad de Sólidos

Nanocrystalline Skinnerite (Cu3SbS3) Prepared by High-Energy Milling in a Laboratory and an Industrial Mill and Its Optical and Optoelectrical Properties

Dutkova, E; Sayagues, MJ; Fabian, M; Balaz, M; Kovac, J; Kovac, J; Stahorsky, M; Achimovicova, M; Bujnakova, ZL
Molecules, 28 (2023)

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Copper, antimony and sulfur in elemental form were applied for one-pot solid-state mechanochemical synthesis of skinnerite (Cu3SbS3) in a laboratory mill and an industrial mill. This synthesis was completed after 30 min of milling in the laboratory mill and 120 min in the industrial mill, as corroborated by X-ray diffraction. XRD analysis confirmed the presence of pure monoclinic skinnerite prepared in the laboratory mill and around 76% monoclinic skinnerite, with the secondary phases famatinite (Cu3SbS4; 15%), and tetrahedrite (Cu11.4Sb4S13; 8%), synthesized in the industrial mill. The nanocrystals were agglomerated into micrometer-sized grains in both cases. Both samples were nanocrystalline, as was confirmed with HRTEM. The optical band gap of the Cu3SbS3 prepared in the laboratory mill was determined to be 1.7 eV with UV-Vis spectroscopy. Photocurrent responses verified with I-V measurements under dark and light illumination and Cu3SbS3 nanocrystals showed similar to 45% enhancement of the photoresponsive current at a forward voltage of 0.6 V. The optical and optoelectrical properties of the skinnerite (Cu3SbS3) prepared via laboratory milling are interesting for photovoltaic applications.

January, 2023 | DOI: 10.3390/molecules28010326

Química de Superficies y Catálisis

Formic Acid Dehydrogenation over Ru- and Pd-Based Catalysts: Gas- vs. Liquid-Phase Reactions

Ruiz-Lopez, E; Pelaez, MR; Ruz, MB; Leal, MID; Tejada, MM; Ivanova, S; Centeno, MA
Materials, 16 (2023) 472

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Formic acid has recently been revealed to be an excellent hydrogen carrier, and interest in the development of efficient and selective catalysts towards its dehydrogenation has grown. This reaction has been widely explored using homogeneous catalysts; however, from a practical and scalable point of view, heterogeneous catalysts are usually preferred in industry. In this work, formic acid dehydrogenation reactions in both liquid- and vapor-phase conditions have been investigated using heterogeneous catalysts based on mono- or bimetallic Pd/Ru. In all of the explored conditions, the catalysts showed good catalytic activity and selectivity towards the dehydrogenation reaction, avoiding the formation of undesired CO.

January, 2023 | DOI: 10.3390/ma16020472

Materiales y Procesos Catalíticos de Interés Ambiental y Energético

Methanation of CO2 over High Surface Nickel/Aluminates Compounds Prepared by a Self-Generated Carbon Template

Roudane, S; Bettahar, N; Caballero, A; Holgado, JP
Catalysts, 13 (2023) 142

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Catalytic gas-phase hydrogenation of CO2 into CH4 was tested under three different nickel/aluminate catalysts obtained from precursors of hexaaluminate composition (MAl16O19, M = Mg, Ca, Ba). These catalysts were prepared using a carbon template method, where carbon is self-generated from a sol-gel that contains an excess of citric acid and the Al and M salts (Ba2+, Ca2+, Mg2+) by two-step calcination in an inert/oxidizing atmosphere. This procedure yielded Ni particles decorating the surface of a porous high surface area matrix, which presents a typical XRD pattern of aluminate structure. Ni particles are obtained with a homogeneous distribution over the surface and an average diameter of ca 25-30 nm. Obtained materials exhibit a high conversion of CO2 below 500 degrees C, yielding CH4 as a final product with selectivity >95%. The observed trend with the alkaline earth cation follows the order NiBaAlO-PRx > NiCaAlO-PRx > NiMgAlO-PRx. We propose that the high performance of the NiBaAlO sample is derived from both an appropriate distribution of Ni particle size and the presence of BaCO3, acting as a CO2 buffer in the process.

January, 2023 | DOI: 10.3390/catal13010142