ZIF-derived catalyst with inverse ZnO/Co structure for efficient CO2 methanation

Abstract

With the growing attention on both environmental and energy issues, the catalytic conversion of CO2 has gained tremendous interest of researchers. Herein, we report a bimetal CoZn-ZIF derived highly efficient catalyst CoZn-Z for CO2 methanation. After prereduction before the catalytic test, an inverse ZnO/Co structure with plentiful uniformly dispersed active sites could be formed, and the obtained CoZn-Z catalyst showed high Co dispersion with principally exposed Co (0002) lattice plane. Sufficient active sites, increased basicity and CO adsorption resulted in enhanced CO2 methanation catalytic activity, and CO2 conversion of 62.9 %, CH4 selectivity of 99.2 % with a STYCH4 of 0.21 molCH4·gcat.−1·h−1 were achieved at 300 °C, 2.6 times of monometallic Co-Z and exceeding most of the reported Co-based catalysts. Furthermore, based on in situ FTIR and DFT calculation, the formation of diverse reaction intermediates was studied and different dominant reaction pathways have been proposed for CoZn-Z and Co-Z. This investigation exhibited great potential of MOFs derived catalysts as superior CO2 methanation catalysts and elucidates the promoting effect of ZnO in Co-based CO2 methanation catalysts for the first time.