Mechanism study on dissociation of hydrogen and carbon dioxide towards carbon dioxide methanation

Abstract

The study of carbon dioxide (CO2) methanation mechanisms widely argues on the nature and formation of intermediates. How reactants dissociate is still poorly understood. To gain deeper knowledge on its mechanism, we focused on studying reactants dissociation. After H2 dissociation and diffusion, the spillover H atom was observed, as well as the confirmation of H cluster formation on metal through aggregation by simulation and experiment. This H cluster facilitated C-O bond scission to easily form H ligand cobonded to metal, and thus resulted in high CO2 methanation performance. Four driving forces could dissociate CO2, three of them came from supports and metals, and another one was atomic H on metal as the strongest force. This simple and convenient method has wide adaptability and can be developed as an effective standard method for studying CO2 dissociation. The facile dissociation study of reactants would be very helpful in understanding the CO2 hydrogenation mechanism.