Ni-Zn-Al-Based Oxide/Spinel Nanostructures for High Performance, Methane-Selective CO.sub.2 Hydrogenation Reactions

In the present study, NiO modified ZnAl.sub.2O.sub.4 and ZnO modified NiAl.sub.2O.sub.4 spinel along with pure Al.sub.2O.sub.3, ZnAl.sub.2O.sub.4 and NiAl.sub.2O.sub.4 for comparison in the CO.sub.2 hydrogenation reaction have been investigated. It was found that NiAl.sub.2O.sub.4, NiO/ZnAl.sub.2O.sub.4 and ZnO/NiAl.sub.2O.sub.4 catalysts exhibited outstanding activity and selectivity towards methane even at high temperature compared to similar spinel structures reported in the literature. NiO/ZnAl.sub.2O.sub.4 catalyst showed CO.sub.2 consumption rate of ~ 19 [mu]mol/gÎs at 600 °C and ~ 85% as well as ~ 50% of methane selectivity at 450 °C and 600 °C, respectively. The high activity and selectivity of methane can be attributed to the presence of metallic Ni and Ni/NiO/ZnAl.sub.2O.sub.4 interface under the reaction conditions as evidenced by the XRD results.