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Scientific Papers in SCI



2024


Materiales Ópticos Multifuncionales

Scattering Spheres Boost Afterglow: A Mie Glass Approach to Go Beyond the Limits Set by Persistent Phosphor Composition

Castaing, V; Romero, M; Torres, J; Lozano, G; Míguez, H
Advanced Optical Materials, 12 (2024) 2301565

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Persistent luminescence phosphor nanoparticles (PersLNPs) offer exciting opportunities for anticounterfeiting, data storage, imaging displays, or AC-driven lighting applications owing to the possibility to process them as shapable thin coatings. However, despite unique delayed and long-lasting luminescence, the relatively low storage capacity of persistent phosphor nanoparticles combined with the difficulty of harvesting photons from transparent thin layers drastically hinder the perceived afterglow. In order to enhance persistent luminescence (PersL) of thin coatings, herein a novel approach is proposed based on resonant optical nanostructures. In particular, it is demonstrated that the integration of TiO2 scattering spheres in films (with thickness comprised between 1 and 10 mu m) made of ZnGa2O4:Cr3+ PersLNPs enables a significant increase in afterglow intensity due to the combination of effective charging and enhanced outcoupling. As a result, a approximate to 3.5-fold enhancement of the PersL is observed in 2 mu m-thick films stuffed with scattering centers using low-light illumination conditions. Furthermore, inclusion of scattering centers leads to an unprecedented acceleration of the PersL charging speed. These results constitute the first example of photonic engineering applied to enhance the properties of PersL materials coatings.


January, 2024 | DOI: 10.1002/adom.202301565

Química de Superficies y Catálisis

Subnanometric Pt clusters dispersed over Cs-doped TiO2 for CO2 upgrading via low-temperature RWGS: operando mechanistic insights to guide an optimal catalyst design

Torres-Sempere, G; Blay-Roger, R; Luque-Alvarez, LA; Santos, JL; Bobadilla, LF; Pastor-Pérez, L; Centeno, MA; Hernández, WY; Yousef, I; Odriozola, JA; Reina, TR
Journal of Matertials Chemistry A, 12 (2024) 1779-1792

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The RWGS reaction is gathering momentum as an effective route for CO2 valorisation and given its endothermic nature the challenge lies in the design of active low-temperature catalysts. Herein we have designed two catalysts based on subnanometric Pt clusters providing effective CO2 conversion and, more importantly, high CO selectivity in the low-temperature range. The impact of Cs as a dopant in the catalyst's formulation is crucial leading to full selectivity at 300 °C. The reaction mechanisms for the studied systems namely Pt/TiO2 and PtCs/TiO2 are significantly different due to the presence of the alkali promoter. The presence of Cs neutralises the hydroxide groups of the TiO2 surface, changing the reaction pathway. The Pt/TiO2 catalyst follows a redox mechanism where CO2 dissociates to CO in the oxygen vacancies, and then these vacancies are recovered by the migration of H2 by spill over phenomena. On the other hand, the Cs doped catalyst has two possible mechanism pathways: the (ii) formyl/acyl pathway, where –CHO species are formed and, depending on the reaction conditions, evolve to CO gas or oxygenated compounds, and (ii) frustrated Lewis pair (FLP) assisted CO2 reduction route, in which the FLP induces the heterolytic dissociation of H2 and the subsequent hydrogenation of CO2 to CO. The latter route enabled by Cs-doping combined with the subnanometric Pt domains seems to be responsible for the excellent catalytic behaviour leading to fully selective low-temperature RWGS systems and thus unlocking new possibilities for less energy demanding CO2 valorisation units based on RWGS.


January, 2024 | DOI: 10.1039/D3TA05482A

Química de Superficies y Catálisis

Mechanistic insights into methanol carbonylation to methyl acetate over an efficient organic template-free Cu-exchanged mordenite

Luque-Alvarez, LA; Gonzalez-Arias, J; Romero-Sarria, F; Reina, TR; Bobadilla, LF; Odriozola, JA
Catalysis Science & Technology, 14 (2024) 128-136

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Currently, acetic acid is produced via the carbonylation reaction of methanol with the main route entailing the use of homogeneous noble metal-based catalysts, which has certain limitations, including the use of polluting alkyl halide promoters and difficulty in catalyst recovery. To overcome these challenges, the exploration of alternative methods utilizing heterogeneous catalysts, particularly zeolites with copper as a redox center, has gained attention. Nonetheless, the conversion and selectivity obtained are sought after to compete against the homogeneous route. Therefore, a deeper understanding of the reaction and mechanism is needed to determine the weak points and overcome them. In this study, we propose the use of time-resolved operando DRIFTS-MS to study the methanol carbonylation reaction over a Cu–H-MOR catalyst. The study aimed to propose a reaction mechanism through an investigation of the behavior of the catalyst, including potential identification of the location of the copper redox center in the zeolite. The catalytic performance of the Cu–H-MOR catalyst was also evaluated, demonstrating its activity and stability in the methanol carbonylation reaction. The operando DRIFTS-MS results provide insights into the reaction mechanism and the involvement of the acid and redox centers in the process. Based on the findings, we propose a reaction mechanism for methanol carbonylation on Cu–H-MOR zeolite: (i) methanol dehydration, (ii) CO insertion into methoxide groups, (iii) reaction between dimethyl ether and acetyl groups, and (iv) hydrolysis of methyl acetate. Overall, we believe that this work contributes to a deeper understanding of the heterogeneous route for acetic acid production and offers potential avenues for optimizing the process.


January, 2024 | DOI: 10.1039/d3cy01271a



2023


Nanotecnología en Superficies y Plasma

Spherosilicate-modified epoxy coatings with enhanced icephobic properties for wind turbines applications

Kozera, R; Zietkowska, K; Przybyszewski, B; Boczkowska, A; Sztorch, B; Paku, D; Przekop, RE; Trzcinski, J; Borras, A
Colloids and Surfaces A-Physicochemical and Engineering Aspects, 679 (2023) 132475

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Industries around the world use active methods, which include thermal, mechanical and chemical approaches, to reduce icing on aerodynamic surfaces such as wind turbines and aircraft. However, they are often inefficient, costly, and pollute the environment. For years, new coatings with anti-icing properties (so-called icephobic coatings) have been developed to either replace or work in tandem with active systems. In this study, coatings were designed based on an epoxy gelcoat commonly used for wind turbines through chemical modification with spherosilicate derivatives. Di- and tri-functional spherosilicates have both groups that increase the degree of hydro-/icephobicity of composites , groups capable of interacting with epoxy resin and amine hardener. The icephobicity of the surface was determined using ice adhesion. The lowest value of this parameter reached a value of 186 kPa, a 30 % reduction compared to the unmodified coating. In addition, the hydrophobicity of the surface was determined (the highest water contact angle was equal to 103 degrees). A correlation was observed, proven in many works, that as the surface roughness increases, the anti-icing properties deteriorate. For individual modifications, it was also shown that hydrophobicity has a positive effect on ice adhesion. The work also examined the surface zeta potential and determined the durability of the properties after 100 icing/deicing cycles.


December, 2023 | DOI: 10.1016/j.colsurfa.2023.132475

Química de Superficies y Catálisis

Alkane metathesis over immobilized pincer-ligated iridium complexes: Effect of support nature

Megías-Sayago, C; Centeno-Vega, I; Bobadilla, LF; Ivanova, S; Rendon, N; Suarez, A
Applied Catalysis B-Environmental, 338 (2023) 123002

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In this work, catalytic alkane metathesis has been evaluated as a suitable approach to upcycle hydrocarbons (polyolefins) at moderate temperatures. To this end, a pincer-ligated iridium complex (dehydrogenation catalyst) has been combined with a rhenium-based (metathesis) catalyst, being the effect of immobilizing the Ir complex over different supports deeply investigated. FTIR spectroscopy has been used to confirm the complex grafting and to elucidate the anchoring site to the support. Additionally, the supports have been dehydroxylated at different conditions to evaluate its possible impact in both the complex grafting and the catalytic activity. The influence of the support nature and its participation in the catalytic reaction have been clearly evidenced.


December, 2023 | DOI: 10.1016/j.apcatb.2023.123002

 

 

 

 

 

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