Superior 3DOM Y2Zr2O7 supports for Ni to fabricate highly active and selective catalysts for CO2 methanation

Abstract

To fabricate CO2 methanation catalysts having application potentials, 3DOM structured Y2Zr2O7 pyrochlores with high surface area and hierarchically pores were prepared for the first time to support NiO/Ni. Compared with an Y2Zr2O7-CP support synthesized by a co-precipitation method, NiO has a much stronger interaction with the Y2Zr2O7-3DOM supports, thus achieving much higher active Ni surface after reducing. Furthermore, larger quantities of surface active O2−/alkaline sites are also formed. The surface Ni sites can activate H2 molecules into adsorbed H atoms, and react with the CO2 molecules adsorbed on the surface O2−/alkaline sites to form adsorbed CO, which will then be reduced by H atoms into CH4. Therefore, the concerted interaction between surface active Ni and O2−/alkaline sites determines the reaction performance. Ni/Y2Zr2O7-3DOM700 owns abundant surface O2−/alkaline sites and high active Ni surface, hence exhibiting superior reaction performance, which exceeds the literature reported catalysts up to date.