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Scientific Papers in SCI



2023


Materiales Coloidales

Mn2+-doped MgGeO3 nanophosphors with controlled shape and optimized persistent luminescence

González-Mancebo, D; Arroyo, E; Becerro, AI; Ocaña, M
Ceramics International, 49 (2023) 36791-36799

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Mn2+-doped MgGeO3 (MgGeO3:Mn2+) is an efficient persistent phosphor that emits red luminescence for long time after stopping excitation with UV light. For optical and biotechnological uses a precise control of particle size and shape is highly desired since these parameters may have a strong influence on the properties and suitability of phosphor materials for the intended applications. To the best of our knowledge, MgGeO3:Mn2+ has been synthesized by conventional solid-state-reaction, which yields particles of heterogeneous size and shape. Here, we report for the first time in the literature a salt-assisted method for the synthesis of MgGeO3:Mn2+ nanoparticles with uniform shape (nanorods) and a mean size of 350 nm x 99 nm. The rigorous study of the luminescence properties of the MgGeO3:Mn2+ nanorods revealed that whereas the optimum doping level for photoluminescence was 2.0 mol% Mn2+, the best persistent luminescence was attained with just 0.5 mol% Mn2+, which is ascribed to the different mechanisms of both luminescence processes. The optimum persistent nano-phosphor showed an intense red emission, which persisted at least 17 h after stopping the excitation. Such excellent properties make the developed nanophosphor an attractive candidate for use in optical and biotech-nological applications.


November, 2023 | DOI: 10.1016/j.ceramint.2023.09.008

Química de Superficies y Catálisis

Glucose dehydration reaction over metal halides supported on activated charcoal catalysts

Martin, Gabriel Delgado; Lara, Beatriz; Bounoukta, Charf Eddine; Domínguez, María Isabel; Ammari, Fatima; Ivanova, Svetlana; Centeno, Miguel Ángel
Catalysis Today, 423 (2023) 114012

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Different metal halide catalysts supported on a commercial active charcoal have been synthesized, activated, characterized and tested in glucose dehydration to 5-hydroxymethylfurfural using a biphasic water/methyl isobutyl ketone media. The influence of the cation nature (K+, Ca2+, Sr2+, Mg2+) and anion nature (F-, Cl-, Br-) on the catalytic performance of the solid is discussed in terms of glucose conversion, HMF yield and products selectivity. The activation of the impregnated catalysts results in a great diversity of active sites, such as Bronsted sites (carboxylic groups), basic sites (metal oxide), and Lewis acid site (Mn+). Their distribution within the samples determinates the resulting products and the final HMF yield. 


November, 2023 | DOI: 10.1016/j.cattod.2023.01.019

Química de Superficies y Catálisis

Coal Chemistry Industry: From Production of Liquid Fuels to Fine Chemicals to Carbon Materials

Zhang, YY; Li, HT; Reina, TR; Liu, J
Energy & Fuels, (2023)

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Coal resources are one of the key energy sources and essential for modern economic development. Despite the traditional coal industries having made considerable contributions to chemical production and energy storage, the accompanying environmental pollution and high energy consumption have also arisen that cause significant influence of the ecological balance. Hence, there is an urgent need to exploit feasible approaches to the sustainable utilization of coal resources. This review begins with a comprehensive summary of the representative coal chemistry technologies with critical discussions. Subsequently, a novel strategy coupled with green hydrogen is discussed for sustainable conversion of coal and highly efficient manufacture of downstream products. Moreover, the unique role of coal in terms of high-value-added carbon material production is highlighted as a low-cost resource for distinct applications. Finally, we propose several future directions for advanced coal chemistry development.


November, 2023 | DOI: 10.1021/acs.energyfuels.3c02661

Química de Superficies y Catálisis

Multicomponent graphene based catalysts for guaiacol upgrading in hydrothermal conditions: Exploring "H2-free" alternatives for bio-compounds hydrodeoxygenation

Parrilla-Lahoz, S; Jin, W; Pastor-Perez, L; Duyar, MS; Martinez-Quintana, L; Dongil, AB; Reina, TR
Catalysis Today, 422 (2023) 114235

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Catalytic hydrodeoxygenation (HDO) is a critical technique for upgrading biomass derivatives to deoxygenated fuels or other high-value compounds. Phenol, guaiacol, anisole, p-cresol, m-cresol and vanillin are all monomeric phenolics produced from lignin. Guaiacol is often utilised as a model lignin compound to deduce mechanistic information about the bio-oil upgrading process. Typically, a source of H2 is supplied as reactant for the HDO reaction. However, the H2 supply, due to the high cost of production and additional safety precautions needed for storage and transportation, imposes significant economic infeasibilities on the HDO process's scaling up. We investigated a novel H2-free hydrodeoxygenation (HDO) reaction of guaiacol at low temperatures and pressures, using water as both a reaction medium and hydrogen source. A variety of Ni catalysts supported on zirconia/ graphene/with/without nitrogen doping were synthesised and evaluated at 250 degrees C and 300 degrees C in a batch reactor, with the goal of performing a multi-step tandem reaction including water splitting followed by HDO. The catalysts were characterised using H2-TPR, XRD, TEM and XPS to better understand the physicochemical properties and their correlation with catalytic performance of the samples in the HDO process. Indeed, our NiZr2O/Gr-n present the best activity/selectivity balance and it is deemed as a promising catalyst to conduct the H2-free HDO reaction. The catalyst reached commendable conversion levels and selectivity to mono-oxygenated compounds considering the very challenging reaction conditions. This innovative HDO approach provides a new avenue for cost-effective biomass upgrading.


November, 2023 | DOI: 10.1016/j.cattod.2023.01.027

Materiales Ópticos Multifuncionales

Enhancement of upconversion photoluminescence in phosphor nanoparticle thin films using metallic nanoantennas fabricated by colloidal lithography

Ngo, TT; Viaña, JM; Romero, M; Calvo, ME; Lozano, G; Miguez, H
Materials Advances, 4 (2023) 6381-6388

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Lanthanide-doped upconversion nanoparticles (UCNPs), as multifunctional light sources, are finding utility in diverse applications ranging from biotechnology to light harvesting. However, the main challenge in realizing their full potential lies in achieving bright and efficient photon upconversion (UC). In this study, we present a novel approach to fabricate an array of gold nanoantennas arranged in a hexagonal lattice using a simple and inexpensive colloidal lithography technique, and demonstrate a significant enhancement of UC photoluminescence (UCPL) by up to 35-fold through plasmon-enhanced photoexcitation and emission. To elucidate the underlying physical mechanisms responsible for the observed UCPL enhancement, we provide a comprehensive theoretical and experimental characterization, including a detailed photophysical description and numerical simulations of the spatial electric field distribution. Our results shed light on the fundamental principles governing the enhanced UCNPs and pave the way for their potential applications in photonic devices.


November, 2023 | DOI: 10.1039/D3MA00775H

 

 

 

 

 

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