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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.

Noviembre, 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.

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

Química de Superficies y Catálisis

Impact of topology framework of microporous solids on methanol carbonylation: An operando DRIFTS-MS study

Luque-Alvarez, LA; Serrano-Cruz, M; Gonzalez-Castano, M; Bobadilla, LF; Odriozola, JA
Microporous and mesoporous materials, 360 (2023) 112725

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Methanol carbonylation was evaluated over heterogeneous catalysts based on Cu-exchanged zeolitic materials with different topology: Cu@MOR, Cu@FER, and Cu@ZSM-5. Despite the similar Si/Al ratios, it is crucial to acknowledge that the acid strength is influenced by the framework topology, as supported by the NH3-TPD results. This, along with other characterization techniques allowed us to estimate the impact of pore size and pore distribution in these microporous materials on catalytic performance. The channel structure influenced catalytic parameters such as conversion and selectivity. The higher methanol conversion achieved on Cu@FER shows the importance of Bronsted acid sites and redox centres location regarding the topology of the material. Concerning the selectivity, the production of acetic acid was endorsed by the 12-MR (MOR) channels, methyl acetate's production by the 10-MR (FER) channels. Finally, the presence of 6-MR (ZSM-5) channels led to a complete selectivity towards DME production. The reaction mechanism was elucidated via operando DRIFTS-MS and results revealed a bifunctional mechanism in which methanol adsorbs and dehydrates on acidic Bronsted sites and CO is activated over Cu+ species.

Octubre, 2023 | DOI: 10.1016/j.micromeso.2023.112725

Química de Superficies y Catálisis

Water-assisted HDO of biomass model compounds enabled by Ru-based catalysts

Carrasco-Ruiz, S; Parrilla-Lahoz, S; Santos, JL; Penkova, A; Odriozola, JA; Reina, TR; Pastor-Pérez, L
Fuel Processing Technology, 249 (2023) 107860

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Biofuels upgrading gathering momentum in view of the gradual depletion of fossil fuels and the pursuit of renewable energy sources to mitigate global warming. Hydrodeoxygenation (HDO) is a key reaction in the upgrading of bio-oil to produce hydrocarbon fuels or high-value chemicals. Oxygen removal in bio-oil increases its calorific value, improve thermal and chemical stability, reduce corrosiveness, etc., making the upgraded biooil suitable as a fuel or blending fuel. However, the dependence on high-pressure hydrogen is a serious disadvantage, as it is an expensive resource whose use also poses safety concerns. In this scenario, we propose a pioneering route for model biomass compounds upgrading via H2-free HDO. Herein we have developed multifunctional catalysts based on Ru and ceria supported on carbon able conduct the hydrodeoxygenation reaction using water as hydrogen source. We found that cerium oxide improves ruthenium metallic dispersion and the overall redox properties of the multicomponent system leading to enhanced catalytic performance. Along with the successful catalytic formulation we identify 300 degrees C as an optimal temperature validating the H2-free HDO route for bio-compounds upgrading.

Octubre, 2023 | DOI: 10.1016/j.fuproc.2023.107860

Materiales de Diseño para la Energía y Medioambiente

Mechanical treatments on design powder ceramic materials: Insight into the textural and structural changes

Osuna, FJ; Fernández, M; Pavón, E; Sánchez, RMT; Alba, MD
Advanced Powder Technology, 34 (2023) 104189

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Mechanical treatment of porous ceramics, such as porous clay minerals, is a crucial step in ceramic processing. Among clay minerals, design swelling brittle micas have shown exceptional properties for further applications, although they exhibit low surface area and porosity. But, their mechanical activation could improve their textural properties and deserves to be investigated. Thus, the aim of this work was to evaluate the effects of gradual grinding in their surface and framework. At short grinding times, the surface area increases and mesoporous and microporous are generated. Long grinding time provokes particle agglomeration with the consequent change in their colloidal stability. At bulk level, framework defects are observed in both tetrahedral and octahedral sheets and increase with the total layer charge.

Octubre, 2023 | DOI: 10.1016/j.apt.2023.104189