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Scientific Papers in SCI



2024


Materiales de Diseño para la Energía y Medioambiente

Optimising anode supported BaZr1-xYxO3-δ electrolytes for solid oxide fuel cells: Microstructure, phase evolution and residual stresses analysis

Fernández Muñoz, S; Chacartegui, R; Alba, MD; Ramírez Rico, J
Journal of Power Sources, 596 (2024) 234070

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Yttrium-doped BaZrO3 is a promising electrolyte for intermediate-temperature protonic ceramic fuel cells. In the anode-supported configuration, a slurry containing the electrolyte is deposited on the surface of a calcined porous anode and sintered. Differences in sintering behaviour and thermal expansion coefficients for the anode and electrolyte result in elastic residual stresses that can impact the long-term stability of the cell during cyclic operation. Half-cells using BaZr0.8Y0.2O3-δ as the electrolyte were fabricated using the solid-state reaction sintering method under various sintering conditions. Comprehensive microstructure and residual stress analyses as a function of processing parameters were performed using two-dimensional X-ray diffraction, Rietveld refinement, and scanning electron microscopy, before and after the half-cells were reduced under hydrogen, giving a complete picture of phase, microstructure, and stress evolution under thermal and reduction cycles like the actual operation of the cell. Our results reveal that a temperature of 1400 °C and shorter soaking times might be advantageous for obtaining phase-pure and thin yttrium-doped BaZrO3 electrolytes with improved microstructure and the presence of compressive residual stress. These findings offer valuable insights into optimising the fabrication process of BaZrO3-based electrolytes, leading to enhanced performance and long-term stability of anode-supported protonic ceramic fuel cells operating at intermediate temperatures. 


March, 2024 | DOI: 10.1016/j.jpowsour.2024.234070

Química de Superficies y Catálisis

Highly Effective Non-Noble MnO2 Catalysts for 5-Hydroxymethylfurfural Oxidation to 2,5-Furandicarboxylic Acid

Alvarez-Hernández, D; Megías-Sayago, C; Penkova, A; Centeno, MA; Ivanova, S
Chemsuschem, 17 (2024) e202400115

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Noble metal-free catalyst or catalytic oxidation of 5-hydroxymethylfurfural into 2,5-furandicarboxylic acid are proposed in this study as a proposal to solve one of the great disadvantages of this reaction of using preferably noble metal-based catalysts. The catalytic activity of six MnO2 crystal structures is studied as alternative. The obtained results showed a strong connection between catalytic activity the type of MnO2 structure organization and redox behavior. Among all tested catalysts, epsilon-MnO2 showed the best performance with an excellent yield of 74 % of 2,5-furandicarboxylic acid at full -hydroxymethylfurfural conversion.


March, 2024 | DOI: 10.1002/cssc.202400115

Química de Superficies y Catálisis

A profitability study for catalytic ammonia production from renewable landfill biogas: Charting a route for the next generation of green ammonia

González-Arias, J; Nawaz, MA; Vidal-Barrero, F; Reina, TR
Fuel, 360 (2024) 130584

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This study introduces a novel techno-economic approach to renewable ammonia production using landfill biogas. The proposed process involves bio-hydrogen generation from landfill biogas, nitrogen production via air separation, and the Haber-Bosch process. Building on our prior research, which demonstrated the economic competitiveness of renewable hydrogen production from landfill gas, we extend our investigation to analyze the feasibility of producing renewable ammonia from biogas-derived bio-hydrogen. However, the economic analysis for the baseline scenario reveals the current lack of profitability (net present value of −18.3 M€), with ammonia prices needing to quadruple to achieve profitability. Major costs, including investment, maintenance, overhead expenses, and electricity, collectively account for over 70%, suggesting the potential efficacy of investment subsidies as a political tool. Only cases with subsidies exceeding 50% of total investment costs, under current ammonia market prices, would render the green ammonia route profitable. Our findings underscore the significant techno-economic challenges in realizing renewable ammonia production, emphasizing the need for innovation in process engineering and catalytic technologies to enable competitive and scalable green ammonia production.


March, 2024 | DOI: 10.1016/j.fuel.2023.130584

Materiales de Diseño para la Energía y Medioambiente

Revalorization of Yerba Mate Residues: Biopolymers-Based Films of Dual Wettability as Potential Mulching Materials

Sánchez, LM; De Haro, J; Domínguez, E; Rodríguez, A; Heredia, A; Benítez, JJ
Polymers, 16 (2024) 815

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Biodegradable mulching films are a very attractive solution to agronomical practices intended to achieve more successful crop results. And, in this context, the employment of agricultural and industrial food residues as starting material for their production is an alternative with economic and environmental advantages. This work reports the preparation of bilayer films having two different wettability characteristics from three bio-derived biopolymers: TEMPO-oxidized cellulose nanofibers isolated from infused Yerba Mate residues, Chitosan and Polylactic acid. The infused Yerba Mate residues, the isolated and oxidized cellulose nanofibers, and the films were characterized. Nanofibrillation yield, optical transmittance, cationic demand, carboxyl content, intrinsic viscosity, degree of polymerization, specific surface area and length were studied for the (ligno)cellulose nanofibers. Textural and chemical analysis, thermal and mechanical properties studies, as well as water and light interactions were included in the characterization of the films. The bilayer films are promising materials to be used as mulching films.


March, 2024 | DOI: 10.3390/polym16060815

Reactividad de Sólidos

A generalized interface reaction kinetic model for describing heterogeneous processes driven by contracting mechanisms

Arcenegui-Troya, J; Sánchez-Jiménez, PE; Rodríguez-Laguna, MR; Perejón, A
Journal of Thermal Analysis and Calorimetry, 149(6) (2024) 2653-2663

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The correct determination of the kinetic model and the kinetic parameters that describe a heterogeneous process is key to accurately predicting its progress within a wide range of conditions, which is one of the main purposes of kinetic analysis. Albeit ideal kinetic models continue to be used to gain insight about the process mechanism, they are constrained by certain assumptions that are rarely met in real experiments and limit their applicability. This is the case of contracting (or interface) kinetic models, which are one of the most commonly used. Thus, the ideal kinetic model R2 is derived by assuming a cylindrical contraction in the radial direction but not contemplating the possibility of a contraction in the direction of the axis of the cylinder. Moreover, in the case of the ideal model R3, it is assumed that contraction takes place simultaneously in particles of identical dimensions in all three directions of space (spheres or cubes). Here, it is revisited this type of model, and it is considered the contraction of particles with different geometries, namely cylinders with different aspect ratios and rectangular cuboids. Besides, a novel generalized interface reaction model is proposed, which covers all the studied cases and broadens the range of applicability to more complex situations involving different geometries and inhomogeneous particle sizes. Finally, the proposed model is applied to the analysis of the experimental thermal dissociation of ammonium nitrate, previously described in the literature as a sublimation process. It is proved that the novel kinetic model provides a more accurate description of the kinetics of the reaction and better prediction capabilities.


March, 2024 | DOI: 10.1007/s10973-023-12835-5

 

 

 

 

 

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