Hydrogen production from dry reforming of methane, using CO 2 previously chemisorbed in the Li 6 Zn 1-x Ni x O 4 solid solution

Li 6 ZnO 4 was chemically modified by nickel addition, in order to develop different compositions of the solid solution Li 6 Zn 1-x Ni x O 4. These materials were evaluated bifunctionally; analyzing their CO 2 capture performances, as well as on their catalytic properties for H 2 production via dry reforming of methane (DRM). The crystal structures of Li 6 Zn 1-x Ni x O 4 solid solution samples were determined through X-ray diffraction, which confirmed the integration of nickel ions up to a concentration around 20 mol%, meanwhile beyond this value, a secondary phase was detected. These results were supported by XPS and TEM analyses. Then, dynamic and isothermal thermogravimetric analyses of CO 2 capture revealed that Li 6 Zn 1-x Ni x O 4 solid solution samples exhibited good CO 2 chemisorption efficiencies, similarly to the pristine Li 6 ZnO 4 chemisorption trends observed. Moreover, a kinetic analysis of CO 2 isothermal chemisorptions, using the Avrami-Erofeev model, evidenced an increment of the constant rates as a function of the Ni content. Since Ni 2+ ions incorporation did not reduce the CO 2 capture efficiency and kinetics, the catalytic properties of these materials were evaluated in the DRM process. Results demonstrated that nickel ions favored hydrogen (H 2 ) production over the pristine Li 6 ZnO 4 phase, despite a second H 2 production reaction was determined, methane decomposition. Thereby, Li 6 Zn 1-x Ni x O 4 ceramics can be employed as bifunctional materials.