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This study explores the performances of nickel‐based materials for the dry reforming of methane (DRM), an important process for hydrogen and syngas productions. Ni nanoparticles are issued from porous phyllosilicate phase exolution under reducing conditions (in situ or ex situ). Phyllosilicate precursors were obtained by deposition/precipitation with urea onto SBA‐15 porous silica, with metal loading up to 40 wt.%. Reaction was performed at 600–700 °C. The successful formation and stabilization of highly dispersed nanoparticles (2–6 nm) is revealed, even for highly loaded formulations (20 wt.% and 40 wt.%). In DRM‐700 (CH4/CO2=1, 20 % CH4, 480,000 mL gcat−1 h−1) the formulation at 20 wt.% metal loading (Ni_20 %) activated during reaction affords 50 % and 65 % of CH4 and CO2 conversions respectively at 700 °C. Ni_20 % is showing excellent resistance toward sintering after DRM stability test of 80 h. Characterizations made for spent catalyst show high resistance toward sintering and limited carbon formation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

CeNi XH ZO Y nano-oxyhydride catalysts were developed for the highly efficient sustainable hydrogen production from ethanol and water in the oxidative steam reforming reaction. After an in situ treatment in hydrogen in the temperature range of 200-300 °C, the cerium-nickel binary mixed oxides became hydrogen reservoirs, which were called oxyhydrides, in the presence of hydrogen species of the hydride nature in the anionic vacancies of mixed oxides. A novel technology was developed for the room temperature hydrogen production by using the chemical energy released from the reaction between CeNi XH ZO Y nano-oxyhydride catalysts and oxygen, which completely converted ethanol specifically at 60 °C (oven temperature) and simultaneously produced hydrogen, carbon dioxide, and carbon monoxide along with small amounts of methane and ethanal. CeNi XH ZO Y nano-oxyhydride catalysts demonstrated excellent catalytic stability, which was attributed to the graphitic filamentous carbon formed during the reaction. The unique activation phenomenon of the reaction (a huge variation in the temperature between the catalyst bed and the oven) was demonstrated in detail. Finally, the correlations among the catalyst properties, the catalytic performances, and the characterizations were thoroughly discussed. [ABSTRACT FROM AUTHOR]

Mg 2 AlNi X H Z O Y nano-oxyhydrides formation is evidenced during pre-treatment in H 2 at 450 °C of Mg 2 AlNi X O Y nano-compounds leading to highly performant catalysts in ethanol conversion and H 2 formation, particularly at low temperature, through catalytic steam reforming (SRE) and oxidative steam reforming (OSRE). Total conversion of ethanol is obtained in SRE and OSRE with high stability. A higher production of H 2 (60 L h −1 g cat −1 ) can be achieved at a reaction temperature of 300 °C in OSRE conditions compared to SRE (10 L h −1 g cat −1 ) mainly because of a beneficial use of a high concentration of ethanol (14 mol%) in presence of O 2 . Moreover, carbon formation is decreased and a much lower input of energy of 50 °C is used to get a temperature of 300 °C when O 2 is added. Different physico-chemical characterizations and in particular in H 2 (TPR, H 2 -XRD, INS) and after tests allow to conclude that the presence of Ni 2+ cations in strong interaction with other cations, anionic vacancies and hydride species on and inside the solid play an important role in the catalytic performance (conversion and selectivity) and stability. [ABSTRACT FROM AUTHOR]

For a sustainable society, it is highly desirable to produce H 2 from renewable sources and with low energy consumption. Functional, cheap and easy-prepared Mg 2 AlNi X H Z O Y nano-oxyhydrides materials were successfully developed from Mg 2 AlNi X O Y nano-composites ex-hydrotalcites. After an in situ treatment in H 2 at low temperature (450 °C), the Mg 2 AlNi X O Y nano-composites (x > 1) become hydrogen reservoirs, called oxyhydrides, with the presence of hydrogen species of hydride nature that can be stored in the anionic vacancies of the solid. Advanced techniques in presence of H 2 including TPR, in situ XRD and INS were used to study the nano-composites with different Ni contents. The Mg 2 AlNi X H Z O Y nano-oxyhydrides (x > 1) are shown to be able to simultaneously provide hydride species and to totally convert ethanol and produce H 2 from a water-ethanol mixture in presence of O 2 , with very low energy input. In complement to the exothermic partial oxidation reaction, the chemical energy delivered from the strong exothermic reaction between hydride species and O 2 is used. The reaction is sustainable because hydride species are replaced and provided by ethanol. [ABSTRACT FROM AUTHOR]

H 2 production from ethanol was studied on a cerium nickel based (CeNi 1 O Y ) catalyst in presence of water (SRE), in presence of oxygen with different concentrations (POE) and in presence of oxygen and water (OSRE). The influence of different parameters was analyzed, such as the reaction temperature, reactants concentration (oxygen/ethanol/water), and in situ pre-treatment in H 2 . At low temperature a high activity i.e., ethanol conversion and H 2 formation can be obtained when the solid is previously in situ treated in H 2 at 250 °C i.e., in the oxyhydride form. Adding O 2 allows increasing ethanol conversion at low temperature. Different physicochemical techniques, including Inelastic Neutron Scattering (INS), were used to characterize the catalyst. An active site based on the formation of anionic vacancies and a mechanism involving a heterolytic abstraction of a hydride species from ethanol are envisaged. [ABSTRACT FROM AUTHOR]

Inexpensive Ni X Mg 2 AlO Y nanocomposites with high Ni content (Ni wt% > 40%) are developed as efficient catalysts for the sustainable hydrogen production from a mixture of ethanol and water at low temperature. The Ni X Mg 2 AlO Y nanocomposites are composed of small and uniform nanoparticles (4–6 nm) of NiO, Ni–Mg–(Al)–O and/or MgO. The strong interactions existing between Ni 2+ cations and Mg 2+ and/or Al 3+ cations either in the Ni–Mg–(Al)–O solid solution and/or at the interface of nanoparticles of NiO and/or Ni–Mg–(Al)−O make the catalyst highly active and stable. The behavior of the solids is analyzed in the presence of low and high concentrations of ethanol while maintaining a H 2 O/EtOH molar ratio of 3. The Ni X Mg 2 AlO Y catalysts are shown to be efficient toward H 2 production between 250 and 650 °C. In the presence of low concentration of ethanol, on the highly loaded Ni compound (Ni 12 Mg 2 AlO Y ), total conversion of ethanol is obtained at 250 °C without formation of CO and carbon, and at 300 °C a H 2 yield of 3 mol mol EtOH −1 is obtained without the formation of CO, exhibiting a remarkable stability with the time on stream even if some carbon is formed. In high concentration of ethanol, total conversion of ethanol is obtained at 450 °C on the highly loaded Ni compound (Ni 12 Mg 2 AlO Y ). In such conditions, a stable co-generation of carbon nanofibrous materials which amount increases with Ni content is also obtained. The catalytic stability is related to the type and morphology of the carbon species formed. The correlations among the catalyst properties, the catalytic performances and the characterizations are thoroughly discussed. [ABSTRACT FROM AUTHOR]

Highlights: [•] Co-precipitation method allows obtaining well-tuned NiXMg2AlOY mixed oxides. [•] The effect of Ni content, activation treatment, and reaction conditions are studied. [•] Total conversion of ethanol at 450°C and CO-free H2 production of 3.0molmolEtOH−1. [•] Good catalytic stability even though solid carbon is formed. [•] Active site involves anionic vacancies, O2− species and cations in close interaction. [ABSTRACT FROM AUTHOR]