BUSCADOR RECOLECTA

Bacterial infections are a public health threat of increasing concern in medical care systems; hence, the search for novel strategies to lower the use of antibiotics and their harmful effects becomes imperative. Herein, the antimicrobial performance of four polyoxometalate (POM)-stabilized gold nanoparticles (Au@POM) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as Gram-negative and Gram-positive bacteria models, respectively, is studied. The bactericidal studies performed, both in planktonic and sessile forms, evidence the antimicrobial potential of these hybrid nanostructures with selectivity toward Gram-negative species. In particular, the Au@GeMoTi composite with the novel [Ti2 (HGeMo7 O28 )2 ]10- POM capping ligand exhibits outstanding bactericidal efficiency with a minimum inhibitory concentration of just 3.12 µm for the E. coli strain, thus outperforming the other three Au@POM counterparts. GeMoTi represents the fourth example of a water-soluble TiIV -containing polyoxomolybdate, and among them, the first sandwich-type structure having heteroatoms in high-oxidation state. The evaluation of the bactericidal mechanisms of action points to the cell membrane hyperpolarization, disruption, and subsequent nucleotide leakage and the low cytotoxicity exerted on five different cell lines at antimicrobial doses demonstrates the antibiotic-like character. These studies highlight the successful design and development of a new POM-based nanomaterial able to eradicate Gram-negative bacteria without damaging mammalian cells., The authors thank the following institutions for the financial support to carry out this research: Spanish Ministerio de Ciencia e Innovación, Spanish Agencia Estatal de Investigación, and FEDER “una manera de hacer Europa” (grant numbers PID2020-113987RB-I00, PDC2021-121405-I00, PID2019-106687RJ-I00, and PID2021-127265OB-C21); Gobierno de Navarra (grant number PC091-092 FOREST2+). CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008–2011 financed by the Instituto de Salud Carlos III with the assistance of the European Regional Development Fund. M.P. acknowledges the support from Gobierno de Aragón (Orden CUS/581/2020). G.M. gratefully acknowledges the support from the Miguel Servet Program (MS19/00092; Instituto de Salud Carlos III)., Peer reviewed

This article belongs to the Special Issue Heterogeneous Catalysis — A Themed Issue in Honor of Prof. Dr. Avelino Corma., The use of metal–organic frameworks (MOFs) as templates or precursors in the manufacture of heterogeneous catalysts is highly attractive due to the transfer of MOFs’ inherent porosity and homogeneous metallic distribution to the derived structure. Herein, we report on the preparation of MOF-derived Ru@ZrO2 catalysts by controlled thermal treatment of zirconium-based MOF UiO-66 with ruthenium moieties. Ru3+ (3 or 10 mol%) precursor was added to UiO-66 synthesis and, subsequently, the as-synthesized hybrid structure was calcined in flowing air at different temperatures (400–600 °C) to obtain ZrO2-derived oxides doped with highly dispersed Ru metallic clusters. The materials were tested for the catalytic photo-thermal conversion of CO2 to CH4. Methanation experiments were conducted in a continuous flow (feed flow rate of 5 sccm and 1:4 CO2 to H2 molar ratio) reactor at temperatures from 80 to 300 °C. Ru0.10@ZrO2 catalyst calcined at 600 °C was able to hydrogenate CO2 to CH4 with production rates up to 65 mmolCH4·gcat.–1·h–1, CH4 yield of 80% and nearly 100% selectivity at 300 °C. The effect of the illumination was investigated with this catalyst using a high-power visible LED. A CO2 conversion enhancement from 18% to 38% was measured when 24 sun of visible LED radiation was applied, mainly due to the increase in the temperature as a result of the efficient absorption of the radiation received. MOF-derived Ru@ZrO2 catalysts have resulted to be noticeably active materials for the photo-thermal hydrogenation of CO2 for the purpose of the production of carbon-neutral methane. A remarkable effect of the ZrO2 crystalline phase on the CH4 selectivity has been found, with monoclinic zirconia being much more selective to CH4 than its cubic allotrope., Financial support was obtained from Spanish Agencia Estatal de Investigación and Spanish Ministerio de Ciencia e Innovación MCIN/AEI/10.13039/501100011033/ and FEDER “Una manera de hacer Europa” (grants PID2019-106687RJ-I00/AEI/ 10.13039/501100011033 and PID2021-127265OB-C21), as well as from Plan de Recuperación, Transformación y Resiliencia and NextGenerationEU (grants PLEC2022-009221 and TED2021-130846B-100), which is gratefully acknowledged. M.L. and M.I. thank Spanish Ministerio de Universidades and Unión Europea-NextGenerationEU for the postdoctoral ¨Margarita Salas¨ and FPU 18/01877 grants, respectively. A.E. thanks Universidad Pública de Navarra for the predoctoral fellowship. L.M.G. thanks the Banco de Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative., Peer reviewed

Renewed interest in CO2 methanation is due to its role within the framework of the Power-to-Methane processes. While the use of nickel-based catalysts for CO2 methanation is well stablished, the support is being subjected to thorough research due to its complex effects. The objective of this work was the study of the influence of the support with a series of catalysts supported on alumina, ceria, ceria–zirconia, and titania. Catalysts’ performance has been kinetically and spectroscopically evaluated over a wide range of temperatures (150–500 °C). The main results have shown remarkable differences among the catalysts as concerns Ni dispersion, metallic precursor reducibility, basic properties, and catalytic activity. Operando infrared spectroscopy measurements have evidenced the presence of almost the same type of adsorbed species during the course of the reaction, but with different relative intensities. The results indicate that using as support of Ni a reducible metal oxide that is capable of developing the basicity associated with medium-strength basic sites and a suitable balance between metallic sites and centers linked to the support leads to high CO2 methanation activity. In addition, the results obtained by operando FTIR spectroscopy suggest that CO2 methanation follows the formate pathway over the catalysts under consideration., Financial support from Spanish Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación MCIN/AEI/10.13039/501100011033/ and FEDER “Una manera de hacer Europa” (grant PID2021-127265OB-C21), as well as from Plan de Recuperación, Transformación y Resiliencia and NextGenerationEU (grants PLEC2022-009221 and TED2021-130846B-100) is gratefully acknowledged. Financial support from Universidad Pública de Navarra is also thanked for the PhD grant awarded to V.V. González-Rangulan. V.V. González-Rangulan also acknowledges the CNRS for the financial support, the guidance, and assistance provided during the 3-month research sojourn in ENSICAEN. L.M. Gandía also thanks Banco de Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative., Peer reviewed

In the present study, new ceria-based high-entropy oxides (HEOs) were investigated as CO2 hydrogenation catalysts. The nominal composition was (Ce0.5Ni0.1Co0.1Cu0.1Zn0.1Mg0.1)Ox and the synthesis was accomplished through the citrate complexing sol–gel method. Characterization techniques utilized including ICP-AES, in situ XRD and in situ XPS, SEM-EDS, HR-TEM and HAADF-STEM, Raman spectroscopy, H2-TPR, CO2-TPD and N2 physical adsorption. The physicochemical characterization and the catalytic results revealed that the conditions of the thermal treatments at which the oxides were subjected critically determined the catalytic performance, especially the CO2 hydrogenation products selectivities. Calcination in air and/or reduction in hydrogen conducted at temperatures below 500 °C led to active but poorly selective catalysts that produced both methane and CO with significant yields. This was mainly attributed to the presence of metallic Cu, Ni and Co on the catalysts that appeared to be supported on ceria doped with the rest of the formulation elements. In contrast, thermal treatments at 750 °C favored the formation of a rocksalt entropy-stabilized (NiCoCuZnMg)Ox HEO supported on ceria that has stood out for showing an excellent selectivity towards the reverse water–gas shift (RWGS) reaction. This catalyst led to CO selectivities of almost 100 % over a very wide range of reaction temperatures (300–700 °C). Long-term stability tests (100 h) showed only a slight decrease in CO2 conversion, while CO selectivity remained stable at nearly 100 % at 400 °C. XRD characterization of the used catalysts evidenced that, whereas the basic catalyst structure remained, some metallic copper exsolved during reduction and reaction period. These results are relevant and very promising, opening a door to the development of new catalysts for the valorization of CO2 through the RWGS reaction, thus expanding the low-temperature limit at which this process can be carried out selectively., Authors wish to thank the Spanish Agencia Estatal de Investigación (AEI) and Ministerio de Ciencia e Innovación (MCIN), the European Regional Development Fund (ERDF/FEDER), the European Union’s NextGenerationEU funds for their financial support. In particular, this work was partially funded by the following research projects: TED2021-130846B-I00 (MULTIeFUEL project), PID2021-127265OB-C21 (SOLFUEL project), PLEC2022-009221 (Panel-to-Fuel project), PID2021-124572OB-C31, and CEX2023-001300-M. M. Cortazar and M. Lafuente also thank Ministerio de Universidades (Spain) and NextGenerationEU funds for their ¨Margarita Salas¨ postdoctoral grants. JL is a Serra Húnter Fellow and is grateful to ICREA Academia program., With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (CEX2023-001300-M)., Open access funding provided by Universidad Pública de Navarra., Peer reviewed

Renewed interest in CO2 methanation is due to its role within the framework of the Power-to-Methane processes. While the use of nickel-based catalysts for CO2 methanation is well stablished, the support is being subjected to thorough research due to its complex effects. The objective of this work was the study of the influence of the support with a series of catalysts supported on alumina, ceria, ceria–zirconia, and titania. Catalysts’ performance has been kinetically and spectroscopically evaluated over a wide range of temperatures (150–500 °C). The main results have shown remarkable differences among the catalysts as concerns Ni dispersion, metallic precursor reducibility, basic properties, and catalytic activity. Operando infrared spectroscopy measurements have evidenced the presence of almost the same type of adsorbed species during the course of the reaction, but with different relative intensities. The results indicate that using as support of Ni a reducible metal oxide that is capable of developing the basicity associated with medium-strength basic sites and a suitable balance between metallic sites and centers linked to the support leads to high CO2 methanation activity. In addition, the results obtained by operando FTIR spectroscopy suggest that CO2 methanation follows the formate pathway over the catalysts under consideration., Financial support from Spanish Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación MCIN/AEI/10.13039/501100011033/ and FEDER “Una manera de hacer Europa” (grant PID2021-127265OB-C21), as well as from Plan de Recuperación, Transformación y Resiliencia and NextGenerationEU (grants PLEC2022-009221 and TED2021-130846B-100) is gratefully acknowledged. Financial support from Universidad Pública de Navarra is also thanked for the PhD grant awarded to V.V. González-Rangulan. V.V. González-Rangulan also acknowledges the CNRS for the financial support, the guidance, and assistance provided during the 3-month research sojourn in ENSICAEN. L.M. Gandía also thanks Banco de Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative.

Dry and combined (with O2) reforming of synthetic biogas were studied at 700 °C using 0.5 % Rh catalysts prepared by impregnation on different supports: γ-Al2O3, SiO2, TiO2, ZrO2 and CeO2. Gas hourly space velocity (GHSV) was varied between 150 and 700 N L CH4/(gcat·h), and two O2/CH4 molar ratios of 0 and 0.12 were studied. Rh/Al2O3 catalysts (prepared using two different commercial supports here denoted as Sph and AA) presented the highest biogas conversion and syngas yields under both dry and combined reforming conditions. Catalytic activities were as follows: Rh/AA ≈ Rh/Sph > Rh/SiO2 > Rh/ZrO2 ≈ Rh/CeO2 > Rh/TiO2. The effect of catalysts’ calcination pre-treatment at relatively low (200 °C) and high temperatures (750 °C) was also studied. Calcination at high temperatures had a detrimental effect on both dry and combined reforming activities. However, a positive effect on the reforming activities and syngas yields was observed when the catalysts were calcined at 200 °C, especially under biogas combined reforming conditions: higher CH4 conversions and syngas yields could be achieved, as well as increasing CO2 conversions, though at the expense of lower H2/CO molar ratios., The financial support of the Spanish Agencia Estatal de Investigación (AEI) and Ministerio de Ciencia e Innovación (MCIN), the European Regional Development Fund (ERDF/FEDER), the European Union´s NextGenerationEU funds. In particular, this work was partially funded by the following research projects: TED2021-130846B-I00 (MULTIeFUEL project), PID2021-127265OB-C21 (SOLFUEL project) and PLEC2022-009221 (Panel-to-Fuel project). Open access funding provided by Universidad Pública de Navarra.

In the study of photocatalytic and photoactivated processes and devices a tight control on the illumination conditions is mandatory. The practical challenges in the determination of the necessary photonic quantities pose serious difficulties in the characterization of catalytic performance and reactor designs and configurations, compromising an effective comparison between different experiments. To overcome these limitations, we have designed and constructed a new illumination system based in the concept of the integrating sphere (IS). The system provides uniform and isotropic illumination on the sample, either in batch or continuous flow modes, being these characteristics independent of the sample geometry. It allows direct, non-contact and real time determination of the photonic quantities as well as versatile control on the irradiance values and its spectral characteristics. It can be also scaled up to admit samples of different sizes without affecting its operational behaviour. The performance of the IS system has been determined in comparison with a second illumination system, mounted on an optical bench, that provides quasi-parallel beam (QPB) nearly uniform illumination in tightly controlled conditions. System performance is studied using three sample geometries: a standard quartz cuvette, a thin straight tube and a microreactor by means of potassium ferrioxalate actinometry. Results indicate that the illumination geometry and the angular distribution of the incoming light greatly affect the absorption at the sample. The sample light absorption efficiency can be obtained with statistical uncertainties of about 3% and in very good agreement with theoretical estimations., Authors thank the financial support from the Spanish Agencia Estatal de Investigación and Spanish Ministerio de Ciencia e Innovación, MCIN/AEI/ 10.13039/501100011033/ and FEDER 'Una manera de hacer Europa', grants PID2019-106687RJ-I00 and PID2021-127265OB-C21, and Gobierno de Navarra, grant PC091-092 FOREST2+. L.M.G. thanks Banco de Santander and UPNA for their financial support under 'Programa de Intensificación de la Investigación 2018' initiative.

En el contexto actual de crisis climática producida por las elevadas emisiones de CO2 antropogénico, la vía de la catálisis fototérmica explorada en este trabajo posibilita la producción limpia de metano neutro en emisiones de carbono, por medio de la reacción de Sabatier, utilizando la luz solar como fuente de energía e hidrógeno de origen renovable. De este modo, hemos preparado materiales consistentes en nanopartículas de rutenio y níquel (metales activos para la metanación de CO2 por vía térmica) soportadas sobre diferentes óxidos metálicos, los hemos caracterizado por diferentes técnicas y hemos evaluado su actividad foto-termocatalítica bajo iluminación con luz artificial. Una parte fundamental del trabajo la hemos centrado en tratar de estudiar de manera diferenciada los procesos fotoquímicos y termoquímicos producidos en los catalizadores iluminados durante la reacción, lo cual es fundamental para futuros desarrollos orientados a aprovechar al máximo el espectro de la radiación solar. Así mismo, hemos llevado a cabo la validación de estos catalizadores en condiciones relevantes de reacción con luz solar real concentrada mediante la adaptación del reactor empleado en el laboratorio. Por último, hemos explorado nuevas vías para la preparación de catalizadores multimetálicos en un solo paso a partir de la pirólisis/calcinación de MOFs, así como el diseño y fabricación de microrreactores como posible tecnología para la intensificación de la producción de metano solar a una escala superior a la de laboratorio. En el capítulo 1 ofrecemos una introducción general sobre las estrategias de actuación para paliar la crisis climática actual, las tecnologías de captura, almacenamiento y utilización de CO2 y la reacción de Sabatier como proceso clave en la obtención de combustibles solares. En el capítulo 2 se describen los principales objetivos del trabajo. En el capítulo 3 abordamos la preparación y caracterización de catalizadores de rutenio soportado sobre óxidos metálicos y comparamos los efectos del método de preparación y del soporte empleado en la actividad catalítica de los materiales para la reacción de Sabatier asistida por luz solar simulada. En el capítulo 4 incluimos una serie de estudios sobre la actividad fototermocatalítica de los mismos catalizadores a los que se refiere el capítulo III, que tiene como objetivo último analizar de forma desacoplada los procesos fotoquímicos y termoquímicos que tienen lugar al iluminar los materiales durante la reacción. En el capítulo 5 recogemos el estudio de los mismos catalizadores a los que se refiere en el capítulo III en condiciones relevantes de reacción, empleando la luz como única fuente de energía. En este capítulo incluimos el estudio realizado bajo luz solar real concentrada. En el capítulo 6 mostramos la preparación y caracterización de catalizadores de níquel soportado sobre TiO2 y estudiamos el efecto del método de preparación asistida con borohidruro sódico en la actividad catalítica de los materiales para la reacción de Sabatier por las vías termocatalítica y foto-termocatalítica. En el capítulo 7 exploramos el empleo de MOFs como soportes de nanopartículas de rutenio y como precursores para la preparación de catalizadores a partir de tratamientos térmicos de pirólisis o calcinación. En el capítulo 8 mostramos el trabajo realizado en la puesta a punto del sistema de reacción y el reactor catalítico y exploramos el diseño y fabricación de microrreactores. En el capítulo 9 recogemos las conclusiones generales de esta tesis y las líneas de trabajo futuro propuestas., Ayuda para la Formación de Profesorado Universitario (FPU) (Ref. FPU18/01877) del Ministerio de Ciencia, Innovación y Universidades y Ayuda de Movilidad Predoctoral Internacional del Gobierno de Navarra (Res. 84E/2022). Financiación parcial de las investigaciones a través de los siguientes proyectos de investigación: AEI –Ministerio de Ciencia e Innovación (PID2021-127265OB-C21); AEI – Ministerio de Ciencia e Innovación (PLEC2022-009221); Gobierno de Navarra – Departamento de Universidad, Innovación y Transformación Digital (PC091-092 FOREST2+); AEI – Ministerio de Ciencia e Innovación (PID2019-106687RJ-I00)., Programa de Doctorado en Ciencias y Tecnologías Industriales (RD 99/2011), Industria Zientzietako eta Teknologietako Doktoretza Programa (ED 99/2011)

In the present work, methane, carbon monoxide, hydrogen and the binary mixtures 20 % CH4–80 % H2, 80 %
CH4–20 % H2, 25 % CO–75 % H2 (by volume) were considered as fuels of a naturally aspirated port-fuel injection
four-cylinder Volkswagen 1.4 L spark-ignition (SI) engine. The interest in these fuels lies in the fact that they can
be obtained from renewable resources such as the fermentation or gasification of residual biomasses as well as
the electrolysis of water with electricity of renewable origin in the case of hydrogen. In addition, they can be used
upon relatively easy modifications of the engines, including the retrofitting of existing internal combustion
engines. It has been found that the engine gives similar performance regardless the gaseous fuel nature if the
air–fuel equivalence ratio (λ) is the same. Maximum brake torque and mean effective pressure values within
45–89 N⋅m and 4.0–8.0 bar, respectively, have been obtained at values of λ between 1 and 2 at full load, engine
speed of 2000 rpm and optimum spark-advance. In contrast, the nature of the gaseous fuel had great influence
upon the range of λ values at which a fuel (either pure or blend) could be used. Methane and methane-rich
mixtures with hydrogen or carbon monoxide allowed operating the engine at close to stoichiometric conditions (i.e. 1 < λ < 1.5) yielding the highest brake torque and mean effective pressure values. On the contrary,
hydrogen and hydrogen-rich mixtures with methane or carbon monoxide could be employed only in the very
fuel-lean region (i.e. 1.5 < λ < 2). The behavior of carbon monoxide was intermediate between that of methane
and hydrogen.
The present study extends and complements previous works in which the aforementioned fuels were compared
only under stoichiometric conditions in air (λ = 1). In addition, a simple zero-dimensional thermodynamic
combustion model has been developed that allows describing qualitatively the trends set by the several fuels.
Although the model is useful to understand the influence of the fuels properties on the engine performance, its
predictive capability is limited by the simplifications made., Financial support from Spanish Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación MCIN/AEI/10.13039/501100011033/ and FEDER “Una manera de hacer Europa” (grant PID2021-127265OB-C21), as well as from Plan de Recuperación, Transformación y Resiliencia and NextGenerationEU (grants PLEC2022-009221 and TED2021-130846B-100) is gratefully acknowledged. L.M. Gandía also thanks Banco de Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative. Authors also acknowledge Open Access Funding provided by Universidad Pública de Navarra.

In the present study, new ceria-based high-entropy oxides (HEOs) were investigated as CO2 hydrogenation catalysts. The nominal composition was (Ce0.5Ni0.1Co0.1Cu0.1Zn0.1Mg0.1)Ox and the synthesis was accomplished through the citrate complexing sol-gel method. Characterization techniques utilized including ICP-AES, in situ XRD and in situ XPS, SEM-EDS, HR-TEM and HAADF-STEM, Raman spectroscopy, H2-TPR, CO2-TPD and N2 physical adsorption. The physicochemical characterization and the catalytic results revealed that the conditions of the thermal treatments at which the oxides were subjected critically determined the catalytic performance, especially the CO2 hydrogenation products selectivities. Calcination in air and/or reduction in hydrogen conducted at temperatures below 500 °C led to active but poorly selective catalysts that produced both methane and CO with significant yields. This was mainly attributed to the presence of metallic Cu, Ni and Co on the catalysts that appeared to be supported on ceria doped with the rest of the formulation elements. In contrast, thermal treatments at 750 °C favored the formation of a rocksalt entropy-stabilized (NiCoCuZnMg)Ox HEO supported on ceria that has stood out for showing an excellent selectivity towards the reverse water¿gas shift (RWGS) reaction. This catalyst led to CO selectivities of almost 100 % over a very wide range of reaction temperatures (300-700 °C). Long-term stability tests (100 h) showed only a slight decrease in CO2 conversion, while CO selectivity remained stable at nearly 100 % at 400 °C. XRD characterization of the used catalysts evidenced that, whereas the basic catalyst structure remained, some metallic copper exsolved during reduction and reaction period. These results are relevant and very promising, opening a door to the development of new catalysts for the valorization of CO2 through the RWGS reaction, thus expanding the low-temperature limit at which this process can be carried out selectively., Authors wish to thank the Spanish Agencia Estatal de Investigaci´on
(AEI) and Ministerio de Ciencia e Innovaci´on (MCIN), the European
Regional Development Fund (ERDF/FEDER), the European Union¿s
NextGenerationEU funds for their financial support. In particular, this
work was partially funded by the following research projects: TED2021-
130846B-I00 (MULTIeFUEL project), PID2021-127265OB-C21 (SOLFUEL
project), PLEC2022-009221 (Panel-to-Fuel project), PID2021-
124572OB-C31, and CEX2023-001300-M. M. Cortazar and M.
Lafuente also thank Ministerio de Universidades (Spain) and NextGenerationEU
funds for their ¨Margarita Salas¨postdoctoral grants. JL is a
Serra Húnter Fellow and is grateful to ICREA Academia program. Open
access funding provided by Universidad Pública de Navarra.

Photothermal catalysis offers a promising approach for the clean production of carbon-neutral chemicals from CO2 through reactions with hydrogen as a renewable energy carrier. While the combined action of photons and heat from solar radiation can drive catalytic reactions, the interactions involved are very complex, depend on the catalyst composition, and often remain uncertain. Herein, we assessed the thermal and nonthermal contributions to the overall activities of a series of Ru catalysts during the photothermal hydrogenation of CO2. TiO2 (anatase/rutile mixture), anatase, ZrO2, CeO2, and SiO2 were used as supports for Ru nanoparticles (2 wt%) that were deposited using an amino-acid-assisted method. Ru@TiO2 and Ru@ZrO2 presented the best catalytic performance at relatively low reaction temperatures (220-250 °C), whereas Ru@CeO2 was the most active catalyst above 300 °C. The catalysts were tested under direct and indirect illumination conditions to assess their thermal and nonthermal contributions to the overall production of methane, with a nonthermal contribution of 60-75 % observed at the highest applied irradiance (2.2 W·cm-²). Ru@ZrO2 registered the highest nonthermal CH4 production, which is tentatively ascribable to the participation of photo-generated electrons in the catalytic reaction and the light-induced formation of oxygen vacancies. The selected catalysts were also tested under concentrated-sunlight conditions in outdoor experiments, with a maximum methane production of 200 mmolCH4·gcat-¹·h-¹ achieved over Ru@ZrO2, which resulted in 31 % CO2 conversion and 92 % selectivity for methane in a continuous flow reactor at a space velocity of 1500 mLSTP·g-¹·min-¹., Financial support from the Spanish Ministerio de Ciencia e Innovación and Spanish Agencia Estatal de Investigación (grants PID2019-106687RJ-I00, PID2021-127265OB-C21, PLEC2022-009221 and Beca FPU 18/01877) and from Gobierno de Navarra (PC091-092 FOREST2+) is gratefully acknowledged. Open access funding provided by Universidad Pública de Navarra.

CO elimination is an important step for the proper management of gaseous effluents from various processes, thus
avoiding adverse impacts on the environment and human health. In this study, different bimetallic Al2O3-supported CoMo catalysts have been developed, characterized, and tested in the CO oxidation reaction, based on
their respective oxides, carbides, and nitrides phases. The parent CoMo-oxide catalyst (CoMo) was prepared by
impregnation and then transformed to its carburized (CoMoC) and nitrided (CoMoN) forms using temperatureprogrammed reaction methods under controlled atmospheres of CH4/H2 and NH3, respectively. The catalytic
results demonstrate that the CoMoC catalyst exhibits higher activity compared to its CoMoN counterpart, and
both are more active than the parent CoMo catalyst. Furthermore, the reduction temperature and space velocity
were key process factors, which notably influenced activity and kinetic parameters, while the increase of
reduction time does not seem to improve catalytic behavior. These results were associated with a better metal
dispersion, and relatively higher reduction grade and metallic surface area on the carbides and nitrides, opening
the possibility that new adsorption sites may be created. The catalytic results compare favorably with other nonnoble metal catalysts, such as Cr-, Cu-, Fe-, and Ni-based samples, and highlight the potential of using carbides
and nitrides as alternative formulations to enhance the performance of CO oxidation., All authors would like to express our sincere appreciation to the Agencia Española de Cooperación Internacional para el Desarrollo (AECID) through the Ikiam-UE-AECID 2018/SPE/0000400194 agreement for funding the research. F.J. Méndez also thanks SIP-IPN for partially supporting the research through the SIP-IPN-20230056 project, while J.A. Garcia-Macedo and H.A. Lara-Garcia thank DGAPA-UNAM through the PAPIIT-IN112622 and PAPIIT-IA107023 projects, respectively. L.M. Gandía, F. Bimbela and the rest of UPNA co-authors would also like to thank the Spanish Agencia Estatal de Investigación (AEI) and Ministerio de Ciencia e Innovación (MICINN), as well as the European Union’s NextGenerationEU Funds and the European Regional Development Fund (ERDF/FEDER), for granting additional financial support (Project Refs. PID2021-127265OB-C21 and TED2021-130846B-I00) and for the funding provided to hire A. Navarro-Puyuelo as postdoctoral researcher (Project Ref. PLEC2022-009221). M. Boujnah and J. Muñiz also would like to acknowledge the Supercomputing Department (UNAM) for the computing resources under Projects Ref. LANCAD-UNAM-DGTIC-425 project. Likewise, M. Boujnah (CVU number 1018873) wants to acknowledge CONAHCYT-México for his postdoctoral fellowship.

Microstructured reactors (MSRs) are especially indicated for highly demanding heterogeneous catalysis due to the small channel dimensions that minimize diffusional limitations and enhance mass and heat transport between the fluid and the catalyst. Herein, we present the fabrication protocol of the fused filament 3D printing of silicone monolithic microreactors based on a multichannel design. Microchannels of 200 to 800 µm in width and up to 20 mm in length were developed following the scaffold-removal procedure using acrylonitrile butadiene styrene (ABS) as the material for the 3D-printed scaffold fabrication, polydimethylsiloxane (PDMS) as the building material, and acetone as the ABS removing agent. The main printing parameters such as temperature and printing velocity were optimized in order to minimize the bridging effect and filament collapsing and intercrossing. Heterogeneous catalysts were incorporated into the microchannel walls during fabrication, thus avoiding further post-processing steps. The nanoparticulated catalyst was deposited on ABS scaffolds through dip coating and transferred to the microchannel walls during the PDMS pouring step and subsequent scaffold removal. Two different designs of the silicone monolithic microreactors were tested for four catalytic applications, namely liquid-phase 2-nitrophenol photohydrogenation and methylene blue photodegradation in aqueous media, lignin depolymerization in ethanol, and gas-phase CO2 hydrogenation, in order to investigate the microreactor performance under different reaction conditions (temperature and solvent) and establish the possible range of applications., Financial support was received from Spanish Agencia Estatal de Investigación and Spanish Ministerio de Ciencia e Innovación MCIN/AEI/10.13039/501100011033/ and FEDER “Una manera de hacer Europa” (grants PID2019-106687RJ-I00/AEI/10.13039/501100011033 and PID2021-127265OB-C21) as well as from Plan de Recuperación, Transformación y Resiliencia and NextGenerationEU (grants PLEC2022-009221 and TED2021-130846B-100), and Gobierno de Navarra grant PC091-092 FOREST2+ which are gratefully acknowledged. The Spanish Ministerio de Universidades fellowship FPU 18/01877 was granted to M.I. The Universidad Pública de Navarra predoctoral fellowship was granted to M.M. L.M. Gandía thanks Banco de Santander and Universidad Pública de Navarra for their financial support under the “Programa de Intensificación de la Investigación 2018” initiative.

The use of metal–organic frameworks (MOFs) as templates or precursors in the manufacture
of heterogeneous catalysts is highly attractive due to the transfer of MOFs’ inherent porosity and
homogeneous metallic distribution to the derived structure. Herein, we report on the preparation
of MOF-derived Ru@ZrO2 catalysts by controlled thermal treatment of zirconium-based MOF UiO66 with ruthenium moieties. Ru3+ (3 or 10 mol%) precursor was added to UiO-66 synthesis and,
subsequently, the as-synthesized hybrid structure was calcined in flowing air at different temperatures
(400–600 ◦C) to obtain ZrO2
-derived oxides doped with highly dispersed Ru metallic clusters. The
materials were tested for the catalytic photo-thermal conversion of CO2
to CH4
. Methanation
experiments were conducted in a continuous flow (feed flow rate of 5 sccm and 1:4 CO2
to H2 molar
ratio) reactor at temperatures from 80 to 300 ◦C. Ru0.10@ZrO2 catalyst calcined at 600 ◦C was able to
hydrogenate CO2
to CH4 with production rates up to 65 mmolCH4·gcat.
–1
·h
–1, CH4 yield of 80% and
nearly 100% selectivity at 300 ◦C. The effect of the illumination was investigated with this catalyst
using a high-power visible LED. A CO2 conversion enhancement from 18% to 38% was measured
when 24 sun of visible LED radiation was applied, mainly due to the increase in the temperature
as a result of the efficient absorption of the radiation received. MOF-derived Ru@ZrO2 catalysts
have resulted to be noticeably active materials for the photo-thermal hydrogenation of CO2
for the
purpose of the production of carbon-neutral methane. A remarkable effect of the ZrO2 crystalline
phase on the CH4 selectivity has been found, with monoclinic zirconia being much more selective to
CH4
than its cubic allotrope., Financial support was obtained from Spanish Agencia Estatal de Investigación and Spanish Ministerio de Ciencia e Innovación MCIN/AEI/10.13039/501100011033/ and FEDER “Una manera de hacer Europa” (grants PID2019-106687RJ-I00/AEI/ 10.13039/501100011033 and PID2021-127265OB-C21), as well as from Plan de Recuperación, Transformación y Resiliencia and NextGenerationEU (grants PLEC2022-009221 and TED2021-130846B-100), which is gratefully acknowledged. M.L. and M.I. thank Spanish Ministerio de Universidades and Unión Europea-NextGenerationEU for the postdoctoral ¨Margarita Salas¨ and FPU 18/01877 grants, respectively. A.E. thanks Universidad Pública de Navarra for the predoctoral fellowship. L.M.G. thanks the Banco de Santander and Universidad Pública de Navarra for their financial support under “Programa de Intensificación de la Investigación 2018” initiative.

Bacterial infections are a public health threat of increasing concern in medical care systems; hence, the search for novel strategies to lower the use of antibiotics and their harmful effects becomes imperative. Herein, the antimicrobial performance of four polyoxometalate (POM)-stabilized gold nanoparticles (Au@POM) against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as Gram-negative and Gram-positive bacteria models, respectively, is studied. The bactericidal studies performed, both in planktonic and sessile forms, evidence the antimicrobial potential of these hybrid nanostructures with selectivity toward Gram-negative species. In particular, the Au@GeMoTi composite with the novel [Ti2(HGeMo7O28)2]10¿ POM capping ligand exhibits outstanding bactericidal efficiency with a minimum inhibitory concentration of just 3.12 µm for the E. coli strain, thus outperforming the other three Au@POM counterparts. GeMoTi represents the fourth example of a water-soluble TiIV-containing polyoxomolybdate, and among them, the first sandwich-type structure having heteroatoms in high-oxidation state. The evaluation of the bactericidal mechanisms of action points to the cell membrane hyperpolarization, disruption, and subsequent nucleotide leakage and the low cytotoxicity exerted on five different cell lines at antimicrobial doses demonstrates the antibiotic-like character. These studies highlight the successful design and development of a new POM-based nanomaterial able to eradicate Gram-negative bacteria without damaging mammalian cells., The authors thank the following institutions for the financial support to carry out this research: Spanish Ministerio de Ciencia e Innovación,Spanish Agencia Estatal de Investigación, and FEDER “una manera dehacer Europa” (grant numbers PID2020-113987RB-I00, PDC2021-121405-I00, PID2019-106687RJ-I00, and PID2021-127265OB-C21); Gobierno de Navarra (grant number PC091-092 FOREST2+). CIBER-BBN is an initia-tive funded by the VI National R&D&i Plan 2008–2011 financed by the In-stituto de Salud Carlos III with the assistance of the European Regional Development Fund. M.P. acknowledges the support from Gobierno de Aragón (Orden CUS/581/2020). G.M. gratefully acknowledges the sup-port from the Miguel Servet Program (MS19/00092; Instituto de SaludCarlos III). Open access funding is provided by Universidad Pública de Navarra.

Two series of Ni and Co catalysts supported onto La-Al2O3 were prepared and the CO2 hydrogenation reactions investigated. The catalytic performance was evaluated in terms of the evolution with the reaction temperature of the CO2 conversion and product (CH4 and CO) yields, as well as specific activities (TOF) and apparent activation energies. CH4 was the favored product over both metals while the TOF for CH4 formation was about three times higher for Ni than Co at 240–265 °C. Metallic particle size effects were found, with the TOF for CH4 formation decreasing over both Ni and Co as the mean metallic size decreased. In contrast, the TOF for CO formation tended to increase at a decreasing particle size for the catalysts with the smallest Ni particle sizes. The apparent activation energies for Ni and Co were very similar and significantly decreased to values of 73–79 kJ/mol when the metallic dispersion increased. The catalysts were prepared using the all-in-one method, resulting in (poly)vinyl alcohol (PVA) being a key additive that allowed us to enhance the dispersion of Ni and Co to give very effective catalysts. This comparative study joins the few existing ones in the literature in which catalysts based on these metals operated under strictly the same reaction conditions., This research was funded by the Spanish Agencia Estatal de Investigación (AEI) and Ministerio de Ciencia e Innovación (MICINN), the European Union’s NextGenerationEU funds, the European Regional Development Fund (ERDF/FEDER) “Una manera de hacer Europa” and Plan de Recuperación, Transformación y Resiliencia, grant numbers PID2021-127265OB-C21, TED2021-130846B-I00 and PLEC2022-009221. This research was funded also by the University of the Basque Country, grant numbers COLLAB22/05 and GIU21/033.