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"Dumeignil, Franck"
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Liquid Phase Furfural Oxidation under Uncontrolled pH in Batch and Flow Conditions: The Role of In Situ Formed Base
Selective oxidation of furfural to furoic acid was performed with pure oxygen in aqueous phase under mild conditions and uncontrolled pH using hydrotalcite-supported gold nanoparticles as catalyst. Hydrotalcites with different Mg: Al ratios were tested as support. The effects of reaction time, temperature and furfural/catalyst ratio were evaluated. The catalyst Au/HT 4:1 showed the highest activity and selectivity to the desired product, achieving a complete conversion of furfural to furoic acid after 2 h at 110 °C. Further, stability tests were carried out in a continuous stirred-tank reactor and a progressive deactivation of the catalyst due to the leaching of Mg2+ cations from the support inducing changes in the pH of the reaction medium was observed.
Journal Article
Strengthening the Connection between Science, Society and Environment to Develop Future French and European Bioeconomies: Cutting-Edge Research of VAALBIO Team at UCCS
The development of the future French and European bioeconomies will involve developing new green chemical processes in which catalytic transformations are key. The VAALBIO team (valorization of alkanes and biomass) of the UCCS laboratory (Unité de Catalyse et Chimie du Solide) are working on various catalytic processes, either developing new catalysts and/or designing the whole catalytic processes. Our research is focused on both the fundamental and applied aspects of the processes. Through this review paper, we demonstrate the main topics developed by our team focusing mostly on oxygen- and hydrogen-related processes as well as on green hydrogen production and hybrid catalysis. The social impacts of the bioeconomy are also discussed applying the concept of the institutional compass.
Journal Article
Oxygen Vacancy Formation at Metal‒TiO₂ Interface Yielding Enhanced Photocatalytic Hydrogen Generation
Strong Metal‐Support Interaction (SMSI) is a key concept in heterogeneous catalysis, but it remains underexplored in the context of photon‐to‐hydrogen conversion, as coupling of metallic nanoparticles with photocatalysts is overlooked and only discussed in terms of Schottky barrier formation. In this study, we provide deep insights into the effect of Au encapsulation with TiO2 overlayer on enhancing photocatalytic hydrogen generation. Our findings reveal that the construction of a SMSI‐like nanostructure induces the formation of oxygen vacancies at the Au‒TiO2 interface which actively facilitate charge carrier separation through interfacial band reconstruction. The presence of defects is evidenced by Electron Paramagnetic Resonance and X‐ray Photoelectron Spectroscopy, unveiling their relationship with photocatalytic activities. Consistent with experimental results, Density Functional Theory (DFT) calculations demonstrate that Au promotes oxygen vacancy formation. These vacancies located at the TiO2 surface significantly enhances H2O and MeOH adsorption during H2 evolution reactions. The SMSI‐like concept was extended to Pt, Pd, and Ag, in which the oxygen vacancy formation energy at the metal‐semiconductor interface varied depending on the metal, as computed by DFT. The results suggest that photocatalytic activity is related to the ease of oxygen vacancy formation, which is influenced by the nature of the metals. In this work, the oxygen vacancy formation is reported at the Au‐TiO2 interface in strong metal‐support interaction (SMSI) photocatalyst. The oxygen vacancies faciliate electron transfer and favor the adsorption of water and methanol at photocatalyst surface, thus enhancing the kinetic of photocatalytic hydrogen generation. The SMSI concept is extended to Pt, Pd, and Ag, in which the formation energy of oxygen vacancies at the metal‐semiconductor interface varied depending on the metal. The results indicate that the ease and the localization of oxygen vacancy formation is a critical factor governing photocatalytic acitivity.
Journal Article
Open Bioeconomy—A Bibliometric Study on the Accessibility of Articles in the Field of Bioeconomy
Open access (OA) to scientific information is one of the major challenges and objectives of actual public research policy. The purpose of this paper is to assess the degree of openness of scientific articles on bioeconomy, as one of the emergent research fields at the crossroads of several disciplines and with high societal and industrial impact. Based on a Web of Science (WoS) corpus of 2489 articles published between 2015 and 2019, we calculated bibliometric indicators, explored the openness of each article and assessed the share of journals, countries and research areas of these articles. The results show a sharp increase and diversification of articles in the field of bioeconomy, with a beginning long tail distribution. 45.6% of the articles are freely available and the share of OA articles is steadily increasing, from 31% in 2015 to 52% in 2019. Gold is the most important variant of OA. Open access is low in the applied research areas of chemical, agricultural and environmental engineering but higher in the domains of energy and fuels, forestry and green and sustainable science and technology. The UK and the Netherlands have the highest rates of OA articles, followed by Spain and Germany. The funding rate of OA articles is higher than of non-OA articles. This is the first bibliometric study on open access to articles on bioeconomy. The results can be useful for the further development of OA editorial and funding criteria in the field of bioeconomy.
Journal Article
Microscope Analysis of Au–Pd/TiO2 Glycerol Oxidation Catalysts Prepared by Deposition–Precipitation Method
Gold–palladium bimetallic nanoparticle catalysts prepared by a deposition–precipitation method were effective for aerobic oxidation of glycerol to carboxylic acids. The role of palladium was to suppress C–C bond cleavage that is responsible for the formation of C2 by-product molecules. The nanoparticles were observed by microscope techniques, which further enabled characterizing the respective locations of Au and Pd within the particles.
Graphical Abstract
Journal Article
Biorefinery
This book provides an introduction to the basic science and technologies for the conversion of biomass (terrestrial and aquatic) into chemicals and fuels, as well as an overview of innovations in the field. The entire value chain for converting raw materials into platform molecules and their transformation into final products are presented in detail. Both cellulosic and oleaginous biomass are considered. The book contains contributions by both academic scientists and industrial technologists so that each topic combines state-of-the-art scientific knowledge with innovative technologies relevant to chemical industries.
eBook
REALCAT: A New Platform to Bring Catalysis to the Lightspeed
Catalysis, irrespective of its form can be considered as one of the most important pillars of today’s chemical industry. The development of new catalysts with improved performances is therefore a highly strategic issue. However, the a priori theoretical design of the best catalyst for a desired reaction is not yet possible and a time- and money-consuming experimental phase is still needed to develop a new catalyst for a given reaction. The REALCAT platform described in this paper consists in a complete, unique, integrated and top-level high-throughput technologies workflow that allows a significant acceleration of this kind of research. This is illustrated by some preliminary results of optimization of the operating conditions of glycerol dehydration to acrolein over an heteropolyacid-based supported catalyst. It is shown that using REALCAT high-throughput tools a more than 10-fold acceleration of the operating conditions optimization process is obtained. La catalyse, quelle que soit sa forme, peut être considérée comme un des plus importants piliers de l’industrie chimique. Le développement de nouveaux catalyseurs aux propriétés catalytiques améliorées est ainsi d’une importance stratégique capitale. À ce jour la catalyse n’est pas une science prédictive et la conception théorique d’un catalyseur pour une réaction donnée n’est pas encore possible et une approche expérimentale consommatrice en temps et en ressource est nécessaire. La plateforme REALCAT décrite dans cet article consiste en un ensemble complet, intégré et unique au monde d’équipements de criblage permettant une accélération significative de la recherche dans le domaine de la catalyse. Un premier exemple d’optimisation des conditions opératoires de la déshydratation du glycérol en acroléine sur catalyseur hétéropolyanionique est donné à titre d’illustration. Il montre que les outils de la plateforme REALCAT permettent de réduire par au moins un facteur 10 le temps d’optimisation des conditions opératoires de la réaction étudiée.
Journal Article
La bioéconomie en France. Une étude scientométrique
Dans le cadre d’une recherche sur l’application des principes de la science ouverte au domaine de la bioéconomie, nous avons mené une étude scientométrique de la production scientifique de la France dans ce domaine, pour la période de 2015 à 2019. L’étude a permis d’identifier 1913 publications dans la base de données Scopus. Nous avons analysé ce corpus sous différents aspects : types et sources des documents, avec volumétrie et impact ; auteurs, organismes et établissements ; sources de financement ; degré d’internationalité et taux d’ouverture (libre accès). La discussion porte sur la terminologie et les sources d’une telle étude scientométrique, sur l’accessibilité des publications et sur la position de la France dans ce domaine. La conclusion propose quelques recommandations pour la conduite d’une étude similaire, notamment à destination des professionnels de l’information.
Journal Article
Glycerol Oxidation in the Liquid Phase over a Gold-Supported Catalyst: Kinetic Analysis and Modelling
The present work deals with the kinetic analysis and modelling of glycerol (GLY) oxidation in the liquid phase over a supported gold catalyst. A Langmuir-Hinshelwood model was proposed, after considering the effect of the reaction temperature, the NaOH/GLY ratio and the initial concentrations of GLY and GLY-Product mixtures. The proposed model effectively predicted the experimental results, and both the global model and the individual parameters were statistically significant. The results revealed that the C–C cleavage to form glycolic and formic acids was the most important reaction without a catalyst. On the other hand, the supported Au catalyst promoted the GLY oxidation to glyceric acid and its further conversion to tartronic and oxalic acids. Regarding the adsorption terms, glyceric acid showed the highest constant value at 60 °C, whereas those of GLY and OH− were also significant. Indeed, this adsorption role of OH− seems to be the reason why the higher NaOH/GLY ratio did not lead to higher GLY conversion in the Au-catalysed reaction.
Journal Article