Aplicación catalítica de nuevos nanosistemas obtenidos a partir de la aproximación organometálica

[ES] La presente tesis doctoral se desarrolla en el ámbito de la catálisis, la cual está enmarcada dentro del concepto de Química Sostenible. En concreto, la investigación se ha centrado en el desarrollo y aplicación de nuevos catalizadores basados en nanopartículas metálicas coloidales y soportadas para llevar a cabo reacciones de interés. Todas las MNPs sintetizadas en esta tesis doctoral se llevaron a cabo a partir de la aproximación organometálica, donde generalmente se descompone un precursor organometálico bajo condiciones suaves de reacción y en presencia de un agente estabilizador (molécula orgánica o soporte). En el Capítulo 4 de la tesis, se ha descrito el primer ejemplo de estabilización de Ru NPs con una nueva familia de ligandos policíclicos aromáticos no planos, denominados nanografenos (hept-HBC). Específicamente, se han utilizado dos tipos distintos de nanografeno distorsionado: i) uno funcionalizado con un grupo carbonilo, y ii) otro funcionalizado con una grupo metileno en la misma posición (Ru@1 y Ru@2, respectivamente). Gracias a la similitud con los sistemas basados en MNPs soportadas en grafeno o derivados, este material puede utilizarse como referencia para estudiar los modos de coordinación y las dinámicas de estos con la superficie de la nanopartícula. A partir de un estudio combinado teórico/experimental se ha demostrado que la curvatura de los nanografenos hept-HBC es crucial para la estabilización de las Ru NPs. Por último, se ha evaluado la actividad catalítica de estas Ru NPs en la hidrogenación de multitud de sustratos aromáticos, observándose diferencias significativas en función del ligando estabilizador utilizado. En el Capítulo 5 se ha investigado la formación de MNPs a través de la aproximación organometálica utilizando el óxido de grafeno reducido dopado con átomos de nitrógeno (NH2-rGO) como soporte. En la primera parte del capítulo, sintetizamos Ru NPs soportadas sobre NH2-rGO (Ru@NH2-rGO) y rGO (Ru@rGO), con la intención de investigar el rol de los átomos de N en la estabilización de las MNPs, así como en su actividad catalítica. Para ello, se estudió la hidrogenación del ácido palmítico a 1-hexadecanol, siendo el Ru@NH2-rGO el catalizador heterogéneo monometálico de Ru más activo y selectivo reportado hasta la fecha (99% conversión y 93 % selectivo). En la segunda parte del capítulo, generamos PtRu NPs con distintas composiciones atómicas (5:1, 1:1 y 1:5) sobre NH2-rGO, siguiendo la aproximación organometálica. La misma velocidad de descomposición de los precursores Pt(NBE)3 y Ru(COD)(COT) nos permitió generar las NPs de tipo aleación. Estos sistemas bimetálicos (PtxRuy@NH2-rGO) se estudiaron en la hidrogenación de multitud de compuestos con grupos polares (C=O), observándose diferencias significativas en función del soporte utilizado y la composición atómica de las MNPs. Por último, en el Capítulo 6 se investigó el uso de nanopartículas magnéticas (MagNPs) para emitir calor por pérdidas de histéresis en presencia de un campo magnético oscilante de alta frecuencia. En primer lugar, se generaron nuevos agentes calefactores basados en MagNPs bimetálicas de tipo "core-shell" de CoNi encapsuladas en carbono (Co@Ni@C), con el objetivo de hidrogenar selectivamente el CO2 a CO (RWGS) obteniéndose excelentes resultados catalíticos. Por último, también presentamos la síntesis de una nueva MagNP de tipo "core-shell" (FeCo@Ni) para su aplicación en catálisis inducida magnéticamente en disolución, siendo capaz de modular su selectividad al producto de la hidrogenación o de la hidrodesoxigenación del HMF en función del campo magnético aplicado. Además, después de su encapsulación en carbono (FeCo@Ni@C) han demostrado ser activas, selectivas y estables en la reducción de multitud de sustratos oxigenados derivados de la biomasa en medio acuoso, siendo el primer ejemplo reportado hasta la fecha de catálisis magnética realizada en agua.[CAT] La present Tesi Doctoral es desenvolupa en l'àmbit de la catàlisi, la qual està emmarcada dins del concepte de Química Sostenible. Concretament, la investigació s'ha centrat en el desenvolupament i aplicació de nous catalitzadors basats en nanopartícules metàl·liques col·loïdals i suportades per dur a terme reaccions d'interès. Totes les MNPs sintetitzades en aquesta tesi doctoral es van dur a terme a partir de l'aproximació organometàl·lica, on generalment es descompon un precursor organometàl·lic sota condicions suaus de reacció i en presència d'un agent estabilitzador (molècula orgànica o suport). En el Capítol 4 de la Tesi, s'ha descrit el primer exemple d'estabilització de Ru NPs amb una nova família de lligands policíclics aromàtics no plans, denominats nanografens (hept-HBC). Específicament, s'han utilitzat dos tipus diferents de nanografen distorsionat: i) un funcionalitzat amb un grup carbonil, i un altre ii) funcionalitzat amb un grup metilè en la mateixa posició (Ru@1 i Ru@2, respectivament). Gràcies a la similitud amb els sistemes basats en MNPs suportades en grafè o derivats, aquest material pot utilitzar-se com a referència per a estudiar els modes de coordinació i dinàmiques d'aquests amb la superfície de la nanopartícula. A partir d'un estudi combinat teòric/experimental s'ha demostrat que la curvatura dels nanografens hept-HBC és crucial per a l'estabilització de les Ru NPs. Finalment, s'ha avaluat l'activitat catalítica d'aquestes Ru NPs en la hidrogenació de multitud de substrats aromàtics, observant diferències significatives en funció del lligand estabilitzador utilitzat. En el Capítol 5 s'ha investigat la formació de MNPs a través de l'aproximació organometàl·lica utilitzant l'òxid de grafè reduït dopat amb àtoms de nitrogen (NH2-rGO) com a suport. En la primera part del capítol, vam sintetitzar Ru NPs suportades sobre NH2-rGO (Ru@NH2-rGO) i rGO (Ru@rGO), amb l'intenció d'investigar el paper dels àtoms de N en l'estabilització de les MNPs, així com en la seua activitat catalítica. Per a això, es va estudiar la hidrogenació de l'àcid palmític a 1-hexadecanol, sent el Ru@NH2-rGO el catalitzador heterogeni monometàl·lic de Ru més actiu i selectiu reportat fins a la data (99% conversió i 93 % selectiu). En la segona part del capítol, es van generar PtRu NPs amb diferents composicions atòmiques (5:1, 1:1 i 1:5) sobre NH2-rGO, seguint l'aproximació organometàl·lica. La mateixa velocitat de descomposició dels precursores Pt(NBE)3 i Ru(COD)(COT) ens va permetre generar les NPs de tipus aliatge. Aquests sistemes bimetàl·lics (PtxRuy@NH2-rGO) es van estudiar en la hidrogenació de multitud de compostos amb grups polars (C=O), observant-se diferències significatives en funció del suport utilitzat i la composició atòmica de les MNPs. Finalment, en el Capítol 6 es va investigar l'ús de nanopartícules magnètiques (MagNPs) per emetre calor per pèrdues d'histèresi en presència d'un camp magnètic oscil·lant d'alta freqüència. En primer lloc, es van generar nous agents calefactores basats en generar MagNPs bimetàl·liques de tipus "core-shell" de CoNi encapsulades en carbó (Co@Ni@C), amb l'objectiu d'hidrogenar selectivament el CO2 a CO (RWGS) obtenint excel·lents resultats catalítics. Finalment, també presentem la síntesi d'una nova MagNP de tipus "core-shell" (FeCo@Ni) per a la seva aplicació en catàlisi induïda magnèticament en solució, demostrant ser capaç de modular la seva selectivitat al producte de l'hidrogenació o de l'hidrodesoxigenació del HMF en funció del camp magnètic aplicat. A més, després de la seva encapsulació en carbó (FeCo@Ni@C) han demostrat ser actives, selectives i estables en la reducció de multitud de substrats oxigenats derivats de la biomassa en medi aquós, sent el primer exemple reportat fins a la data de catàlisi magnètica realitzada en aigua.[EN] This Doctoral Thesis is developed in the field of catalysis, which is framed within the concept of Sustainable Chemistry. Specifically, the research has focused on the development and application of new catalysts based on colloidal and supported metallic nanoparticles to carry out relevant catalytic reactions. All the MNPs synthesized in this doctoral thesis were carried out from the organometallic approach, where an organometallic precursor is generally decomposed under mild conditions, room temperature and 3 bar H2, in the presence of a stabilizing agent (organic molecule, polymer, or support). The catalytic properties of MNPs are greatly influenced by the stabilizing agents used, which are capable of modifying their electronic and steric properties. Therefore, the search for new ligands capable of modulating these properties is of great scientific interest. In Chapter 4 of the Thesis, we describe the first example of Ru NPs stabilized with a new family of non-planar polycyclic aromatic ligands, called nanographenes (hept-HBC). Specifically, two different types of distorted nanographene have been used: i) one functionalized with a carbonyl group, and another ii) functionalized with a methylene group in the same position (Ru@1 and Ru@2, respectively). Thanks to the resemblance with systems based on supported-MNPs on graphene or derivatives, this material can be used as a reference to study the coordination modes and dynamics of these with the surface of the nanoparticle. A combined theoretical/experimental study revealed that the curvature of hept-HBC nanographenes is crucial for the stabilization of Ru NPs. Finally, the catalytic activity of these Ru NPs has been evaluated in the hydrogenation of multitude of arenes, observing significant differences depending on the stabilizing ligand used. In Chapter 5, the formation of MNPs through the organometallic approach was investigated using reduced graphene oxide N-doped (NH2-rGO) as support. In the first part of the chapter, Ru NPs supported on NH2-rGO (Ru@NH2-rGO) and rGO (Ru@rGO) were synthesized, with the aim of investigating the role of N atoms in the stabilization of the MNPs, as well as their catalytic activity. For this purpose, the hydrogenation of palmitic acid to 1-hexadecanol was studied, and Ru@NH2-rGO was found to be the most active and selective monometallic Ru-based heterogeneous catalyst reported to date (99% conversion and 93% selectivity). In the second part of the chapter, PtRu NPs with different atomic compositions (5:1, 1:1, and 1:5) were generated on NH2-rGO using the organometallic approach. The same decomposition rate of Pt(NBE)3 and Ru(COD)(COT) precursors allowed us to generate alloy-type NPs. These bimetallic systems (PtxRuy@NH2-rGO) were studied in the hydrogenation of a variety of compounds with polar groups (C=O), and significant differences were observed depending on the support used and the atomic composition of the MNPs. Finally, in Chapter 6 the use of magnetic nanoparticles (MagNPs) for heat generation through hysteresis losses in the presence of a high-frequency oscillating magnetic field was investigated. Firstly, new heat-generating agents based on bimetallic core-shell type CoNi MagNPs encapsulated in carbon (Co@Ni@C) were synthesized with the aim of selectively hydrogenate CO2 to CO (RWGS), obtaining excellent catalytic results. Finally, a new core-shell type MagNP (FeCo@Ni@C), the MagNPs proved to be active, selective, and stable in the reduction of several oxygenated substrates derived from biomass in aqueous media, being the first reported example of magnetic catalysis performed in water to date. In Chapter 6, the crucial role of MagNP encapsulation was demonstrated, where carbon not only limits the total oxidation of MagNPs but also prevents their sintering at high temperatures (~ 700 °C) in gas phase and avoids their aggregation in liquid phase.Cerezo Navarrete, C. (2023). Aplicación catalítica de nuevos nanosistemas obtenidos a partir de la aproximación organometálica [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/19636

Organometallic Nanoparticles Ligated by NHCs: Synthesis, Surface Chemistry and Ligand Effects

[EN] Over the last 20 years, the use of metallic nanoparticles (MNPs) in catalysis has awakened a great interest in the scientific community, mainly due to the many advantages of this kind of nanostructures in catalytic applications. MNPs exhibit the characteristic stability of heterogeneous catalysts, but with a higher active surface area than conventional metallic materials. However, despite their higher activity, MNPs present a wide variety of active sites, which makes it difficult to control their selectivity in catalytic processes. An efficient way to modulate the activity/selectivity of MNPs is the use of coordinating ligands, which transforms the MNP surface, subsequently modifying the nanoparticle catalytic properties. In relation to this, the use of N-heterocyclic carbenes (NHC) as stabilizing ligands has demonstrated to be an effective tool to modify the size, stability, solubility and catalytic reactivity of MNPs. Although NHC-stabilized MNPs can be prepared by different synthetic methods, this review is centered on those prepared by an organometallic approach. Here, an organometallic precursor is decomposed under H-2 in the presence of non-stoichiometric amounts of the corresponding NHC-ligand. The resulting organometallic nanoparticles present a clean surface, which makes them perfect candidates for catalytic applications and surface studies. In short, this revision study emphasizes the great versatility of NHC ligands as MNP stabilizers, as well as their influence on catalysis.This research was funded by: Proyectos Intramurales Especiales (201880E079), Primero Proyectos de Investigacion PAID-06-18 (SP20180088), Agencia Estatal de Investigacion (PID2019-104159GB-I00/AEI/10.13039/501100011033) and Junta de Andalucia (PY18-3208). The authors thank Instituto de Tecnología Química (ITQ), Consejo Superior de Investigaciones Científicas (CSIC), Universitat Politècnica de València (UPV), Departamento de Química Inorgánica (University of Seville), Institute for Chemical Research (IIQ) for the facilities and Severo Ochoa excellence programme, C.C.-N. thanks Generalitat Valenciana for the predoctoral GVA fellowship (ACIF/2019/076). We gratefully acknowledge B. Chaudret for his invaluable contribution to this research area and his sincere friendship.Cerezo-Navarrete, C.; Lara, P.; Martínez-Prieto, LM. (2020). Organometallic Nanoparticles Ligated by NHCs: Synthesis, Surface Chemistry and Ligand Effects. Catalysts. 10(10):1-30. https://doi.org/10.3390/catal10101144S1301010Hopkinson, M. N., Richter, C., Schedler, M., & Glorius, F. (2014). An overview of N-heterocyclic carbenes. Nature, 510(7506), 485-496. doi:10.1038/nature13384Smith, C. A., Narouz, M. R., Lummis, P. A., Singh, I., Nazemi, A., Li, C.-H., & Crudden, C. M. 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Nuclear Magne

Uniform Ru nanoparticles on N-doped graphene for selective hydrogenation of fatty acids to alcohols

[EN] Ruthenium nanoparticles (Ru NPs) supported on reduced-graphene oxide doped with N (NH2-rGO) was synthesized and used for the selective hydrogenation of fatty acids to alcohols, being the hydrogenation of palmitic acid selected as model. Ru was stabilized forming uniform nanometer size particles on N-doped graphene (Ru/NH2-rGO). The resultant catalyst was very selective for the carbonyl reduction giving 93% of the aliphatic alcohol at 99% conversion. The Ru/NH2-rGO catalysts was more active and selective than the corresponding Ru on non-doped graphene (Ru/rGO) or Ru on carbon (Ru/C). Mechanistic studies points to a dual mechanism for H-2 dissociation, i.e. homolytic and heterolytic cleavage exists on the Ru/NH2-rGO, while only the homolytic H-2 dissociation occurs on Ru/rGO. This heterolytic splitting, which activates the carbonyl groups and facilitates the hydrogenation of aliphatic acids, is due to the presence of basic centres next to the Ru atoms. The presence of N atoms also increases the stability of the catalyst, allowing a reuse up to four times. (C) 2019 Elsevier Inc. All rights reserved.The authors thank Institute de Tecnologia Quimica (ITQ), Consejo Superior de Investigaciones Cientificas (CSIC) and Universitat Politecnica de Valencia (UPV) for the facilities and Severo Ochoa excellence programme, "Juan de la Cierva" programme and Primeros Proyectos de Investigacion (PAID-06-18) for financial support. We gratefully acknowledge Prof. A. Corma for his invaluable contribution to this research. We also thank the Electron Microscopy Service of the UPV for TEM facilities, Jose A. Vidal-Moya (ITQ CSIC-UPV) for NMR measurements and J. Gaona and C. Morales for their assistance in catalytic reactions.Martínez-Prieto, LM.; Puche Panadero, M.; Cerezo-Navarrete, C.; Chaudret, B. (2019). Uniform Ru nanoparticles on N-doped graphene for selective hydrogenation of fatty acids to alcohols. Journal of Catalysis. 377:429-437. https://doi.org/10.1016/j.jcat.2019.07.040S42943737

Controlling the selectivity of bimetallic platinum¿ruthenium nanoparticles supported on N-doped graphene by adjusting their metal composition

[EN] Mono and bimetallic platinum-ruthenium nanoparticles have been generated on N-doped graphene (NH2-rGO) following an organometallic approach. Surface and structural studies confirmed the formation of bimetallic MNPs with controlled metal compositions. To evaluate the activity/selectivity of the different materials prepared we used the hydrogenation of acetophenone as a model reaction. We found that both the activity and selectivity of the supported-bimetallic NPs are highly dependent on the support and the atomic composition. The higher the Pt/Ru ratio, the higher the selectivity towards 1-phenylethanol. Indeed, a remarkable activity and selectivity in the hydrogenation of acetophenone was observed for Pt5Ru1@NH2-rGO. The reactivity of these catalysts was also investigated in the hydrogenation of other substrates such as functionalized arenes (i.e. nitrobenzene and benzaldehyde) or hydroxymethylfurfural (HMF), demonstrating that it is possible to control the activity and selectivity of bimetallic Pt-Ru MNPs supported on N-doped graphene by adjusting their metal composition.The authors thank Instituto de Tecnologia Quimica (ITQ), Consejo Superior de Investigaciones Cientificas (CSIC), and Universitat Politecnica de Valencia (UPV) for the facilities, and Severo Ochoa excellence programme (SEV-2016-0683), "Juan de la Cierva" programme (IJCI-2016-27966) and Primero Proyectos de Investigacion (PAID-06-18) for financial support. C. C.-N. gratefully thanks Generalitat Valenciana predoctoral fellowship (GVA: ACIF/2019/076). We also thank the Electron Microscopy Service of the UPV for TEM facilities and A. Garcia Zaragoza for his assistance in catalytic reactions.Cerezo-Navarrete, C.; Mathieu, Y.; Puche Panadero, M.; Morales, C.; Concepción Heydorn, P.; Martínez-Prieto, LM.; Corma Canós, A. (2021). Controlling the selectivity of bimetallic platinum¿ruthenium nanoparticles supported on N-doped graphene by adjusting their metal composition. Catalysis Science & Technology. 11(2):494-505. https://doi.org/10.1039/D0CY02379E49450511

Ultrastable Magnetic Nanoparticles Encapsulated in Carbon for Magnetically Induced Catalysis

[EN] Magnetically induced catalysis using magnetic nanoparticles (MagNPs) as heating agents is a new efficient method to perform reactions at high temperatures. However, the main limitation is the lack of stability of the catalysts operating in such harsh conditions. Normally, above 500 degrees C, significant sintering of MagNPs takes place. Here we present encapsulated magnetic FeCo and Co NPs in carbon (Co@C and FeCo@C) as an ultrastable heating material suitable for high-temperature magnetic catalysis. Indeed, FeCo@C or a mixture of FeCo@C:Co@C (2:1) decorated with Ni or Pt-Sn showed good stability in terms of temperature and catalytic performances. In addition, consistent conversions and selectivities regarding conventional heating were observed for CO2 methanation (Sabatier reaction), propane dehydrogenation (PDH), and propane dry reforming (PDR). Thus, the encapsulation of MagNPs in carbon constitutes a major advance in the development of stable catalysts for high-temperature magnetically induced catalysis.The authors thank the Instituto de Tecnologia Quimica (ITQ), Consejo Superior de Investigaciones Cientificas (CSIC), Universitat Politecnica de València (UPV) for the facilities and Severo Ochoa programe (SEV-2016-0683), "Juan de la Cierva" by MINECO (IJCI-2016-27966), and Primero Proyectos de Investigación PAID-06-18 (SP20180088) for financial support. The authors acknowledge ERC Advanced Grants (MONACAT-2015-694159 and SynCatMatch-2014671093). We also thank the Electron Microscopy Service of the UPV for TEM facilities.Martínez-Prieto, LM.; Marbaix, J.; Asensio, JM.; Cerezo-Navarrete, C.; Fazzini, P.; Soulantica, K.; Chaudret, B.... (2020). Ultrastable Magnetic Nanoparticles Encapsulated in Carbon for Magnetically Induced Catalysis. 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The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts

Biodiversity continues to decline in the face of increasing anthropogenic pressures such as habitat destruction, exploitation, pollution and introduction of alien species. Existing global databases of species’ threat status or population time series are dominated by charismatic species. The collation of datasets with broad taxonomic and biogeographic extents, and that support computation of a range of biodiversity indicators, is necessary to enable better understanding of historical declines and to project – and avert – future declines. We describe and assess a new database of more than 1.6 million samples from 78 countries representing over 28,000 species, collated from existing spatial comparisons of local-scale biodiversity exposed to different intensities and types of anthropogenic pressures, from terrestrial sites around the world. The database contains measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35) biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains more than 1% of the total number of all species described, and more than 1% of the described species within many taxonomic groups – including flowering plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans and hymenopterans. The dataset, which is still being added to, is therefore already considerably larger and more representative than those used by previous quantitative models of biodiversity trends and responses. The database is being assembled as part of the PREDICTS project (Projecting Responses of Ecological Diversity In Changing Terrestrial Systems – www.predicts.org.uk). We make site-level summary data available alongside this article. The full database will be publicly available in 2015

Ruthenium nanoparticles canopied by heptagon-containing saddle-shaped nanographenes as efficient aromatic hydrogenation catalysts

The search for new ligands capable of modifying the metal nanoparticle (MNP) catalytic behavior is of increasing interest. Herein we present the first example of RuNPs stabilized with non-planar heptagoncontaining saddle-shaped nanographenes (Ru@1 and Ru@2). The resemblance to graphene-supported MNPs makes these non-planar nanographene-stabilized RuNPs very attractive systems to further investigate graphene–metal interactions. A combined theoretical/experimental study allowed us to explore the coordination modes and dynamics of these nanographenes at the Ru surface. The curvature of these saddle-shaped nanographenes makes them efficient MNP stabilizers. The resulting RuNPs were found to be highly active catalysts for the hydrogenation of aromatics, including platform molecules derived from biomass (i.e. HMF) or liquid organic hydrogen carriers (i.e. N-indole). A significant ligand effect was observed since a minor modification on the hept-HBC structure (C]CH2 instead of C]O) was reflected in a substantial increase in the MNP activity. Finally, the stability of these canopied RuNPs was investigated by multiple addition experiments, proving to be stable catalysts for at least 96 h.European Research Council (ERC) GA 677023FEDER(EDRF) Junta de Andalucia-Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades P18-FR2877Agencia Estatal de Investigacion (AEI)Center for Forestry Research & Experimentation (CIEF) GVA: ACIF/2019/076HPC CALcul en MIdi-Pyrenees (CALMIP) P0611Spanish Government RYC2020-030031-

Boosting the catalytic performance of graphene-supported Pt nanoparticles via decorating with -SnBun: an efficient approach for aqueous hydrogenation of biomass-derived compounds

The pursuit of new catalysts for the aqueous transformation of biomass-derived compounds under mild conditions is an active area of research. In the present work, the selective hydrogenation of 5-hydroxymethylfurfural (HMF) to 2,5-bishydroxymethylfuran (BHMF) was efficiently accomplished in water at 25 °C and 5 bar H pressure (after 1 h full conversion and 100% selectivity). For this, a novel nanocatalyst based on graphene-supported Pt NPs decorated with Sn-butyl fragments (-SnBu) has been used. More specifically, Pt NPs supported on reduced graphene oxide (rGO) were functionalized with different equivalents (0.2, 0.5, 0.8 and 1 equiv.) of tributyltin hydride (BuSnH) following a surface organometallic chemistry (SOMC) approach. The synthesized catalysts (Pt@rGO/Snx) were fully characterized by state-of-the-art techniques, confirming the presence of Sn-butyl fragments grafted on the platinum surface. The higher the amount of surface -SnBu, the higher the activity of the catalyst, reaching a maximum conversion with Pt@rGO/Sn0.8. Indeed, the latter has proven to be one of the most active catalysts reported to date for the aqueous hydrogenation of HMF to BHMF (estimated TOF = 666.7 h). Furthermore, Pt@rGO/Sn0.8 has been demonstrated to be an efficient catalyst for the reduction of other biomass-derived compounds in water, such as furfural, vanillin or levoglucosenone. Here, the catalytic activity is remarkably boosted by Sn-butyl fragments located on the platinum surface, giving a catalyst several times faster than non-functionalized [email protected] authors thank Instituto de Tecnología Química (ITQ), Instituto de Investigaciones Químicas (IIQ), Consejo Superior de Investigaciones Científicas (CSIC), Universitat Politècnica de València (UPV) and Universidad de Sevilla (US) for the facilities. We also thank the electron microscopy service of the UPV for TEM analysis. The authors also acknowledge Agencia Estatal de Investigación, Ministerio de Ciencia e Innovación (PID2021-126080OA-I00, TED2021-132087A-I00 and RYC2020-030031-I), Junta de Andalucía (ProyExcel_00706, P20_01027 and PYC 20 RE 060 UAL) and the University of Seville (VI PP A.TALENTO; 2022/00000400) for financial support. C. Cerezo-Navarrete is grateful for the Generalitat Valenciana predoctoral fellowship (GVA: ACIF/2019/076)

Controlling the selectivity of bimetallic platinum-ruthenium nanoparticles supported on N-doped graphene by adjusting their metal composition

Mono and bimetallic platinum-ruthenium nanoparticles have been generated on N-doped graphene (NH-rGO) following an organometallic approach. Surface and structural studies confirmed the formation of bimetallic MNPs with controlled metal compositions. To evaluate the activity/selectivity of the different materials prepared we used the hydrogenation of acetophenone as a model reaction. We found that both the activity and selectivity of the supported-bimetallic NPs are highly dependent on the support and the atomic composition. The higher the Pt/Ru ratio, the higher the selectivity towards 1-phenylethanol. Indeed, a remarkable activity and selectivity in the hydrogenation of acetophenone was observed for PtRu@NH-rGO. The reactivity of these catalysts was also investigated in the hydrogenation of other substrates such as functionalized arenes (i.e.nitrobenzene and benzaldehyde) or hydroxymethylfurfural (HMF), demonstrating that it is possible to control the activity and selectivity of bimetallic Pt-Ru MNPs supported on N-doped graphene by adjusting their metal composition.The authors thank Instituto de Tecnología Química (ITQ), Consejo Superior de Investigaciones Científicas (CSIC), and Universitat Politècnica de València (UPV) for the facilities, and Severo Ochoa excellence programme (SEV-2016-0683), “Juan de la Cierva” programme (IJCI-2016-27966) and Primero Proyectos de Investigación (PAID-06-18) for financial support. C. C.-N. gratefully thanks Generalitat Valenciana predoctoral fellowship (GVA: ACIF/2019/076). We also thank the Electron Microscopy Service of the UPV for TEM facilities and A. García Zaragoza for his assistance in catalytic reactions