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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]

Taking alcohol from the nanobar The cover picture shows the use of nickel and cerium nano‐oxyhydride catalysts in hydrogen production from ethanol in the presence of water and oxygen. In their Full Paper on p. 2207 ff., L. Jalowiecki‐Duhamel et al. describe the characterization and catalytic properties of the nano‐compounds. Hydrogen production (45 mol %) and total conversion of ethanol remain almost constant over at least 75 h time‐on‐stream with only a small energy input (reaction in oven at 60 °C), thanks to the presence of hydride species stored in the solid. [ABSTRACT FROM AUTHOR]

• Chemical looping dry reforming of methane (CLDRM) is highly selective to syngas. • Ni/CeO 2 carriers are active and selective at high temperature (>650 °C). • Preparation method has limited effect on properties of Ni/CeO 2 carriers. • Co/CeO 2 shows the best selectivity at low temperature (600 °C). • Commercial CeO 2 , iron or zirconia doping show the lowest activity and/or selectivity. Chemical looping dry reforming of methane (CLDRM) consists in reacting CH 4 with an oxygen carrier (OC) to produce syngas and subsequently oxidizing the OC using CO 2. Based on previous work on Ni/CeO 2 , several ceria based OCs are explored. First, different preparation methods are compared. OCs obtained by Ni impregnation on homemade ceria or coprecipitation method show similar results while the use of a commercial ceria leads to an inactive carrier. Second, Zr doping of the carrier is shown to improve the thermal stability of the material but the increased oxygen mobility promotes the total oxidation of methane instead of syngas production. Simultaneously higher amounts of coke are produced. Then, the substitution of Ni by other active elements is explored. Iron doped OC leads to very low CLDRM activity in the temperature range explored (600–800 °C). Furthermore, selectivity is negatively affected as iron oxide can contribute as oxygen carrier together with ceria, contrary to Ni or Co. Finally, substitution of Ni with Co is studied resulting in a lower reactivity towards methane. This proves to be particularly interesting at low temperature (600–650 °C) by providing good balance between surface properties for methane activation and bulk mobility of oxygen species. [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]

Chemical looping dry reforming of methane (CLDRM) is performed by exposing a Ni/CeO 2 solid to CH 4 and CO 2 in a cyclic way. The solid acts as an oxygen vector producing syngas (CO + H 2 ) during exposure to CH 4 , and is re-oxidized during exposure to CO 2 . Absence of CO 2 during syngas production allows suppressing reverse water gas shift reaction and reaching high selectivity. Exposure to CO 2 restores the oxygen capacity of the support and removes residual carbon formed at the surface, thus fully regenerating the catalyst. Solids were characterized by TPR, XRD, Raman scattering, and XPS. Results show that part of the Ni is reduced and remain in metallic state during the looping process. On the other hand, Ni 2+ species in strong interaction with Ce cations are observed even after exposure to methane. Both Ni species play important roles on reactants activation and oxygen supply by the solid. Ni loading is a crucial parameter for controlling the reduction behavior of the support and therefore for CLDRM process optimization. [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]

• Mixed oxides based hydride reservoirs with Ni2+ cations are performant catalysts. • CO 2 conversion overcomes the predicted value at 500−600 °C. • H 2 /CO ratio of 1.3 is obtained at 600 °C. • No carbon formation at 600 °C in O 2 /CH 4 ratio of 0.3. The oxidative dry reforming of CH 4 (ODRM) was studied at 500−800 °C in harsh conditions (CH 4 /CO 2 /O 2 /N 2 = 1:0.7:α:N 2 with 20 % of CH 4 , 96,000 mLh−1g cat −1 and α varying from 0 up to 0.5) on CeNi X Al 0.5 H Z O Y (0.5 ≤ x ≤ 5) nano-oxyhydride catalysts. At low temperature (500−600 °C), the conversion of CH 4 reaches the thermodynamic limit while those of CO 2 overcomes the predicted value in particular at 500 °C. At 600 °C with an O 2 /CH 4 ratio of 0.3, the CeNi 2 Al 0.5 H Z O Y catalyst allows getting CH 4 and CO 2 conversions of about 63 % and 50 %, respectively, and a H 2 /CO ratio of about 1.3, without carbon formation. The physico-chemical characterizations performed before and after test show the existence of strong interactions existing between Ni2+ cations with other cations and the presence of nano-oxyhydride compound. The mixed oxide based nano-materials corresponding to hydride reservoirs with the presence of Ni2+ cations are shown to be highly active, selective and stable catalysts. [ABSTRACT FROM AUTHOR]