A Highly Active Molybdenum Carbide Catalyst with Dynamic Carbon Flux for Reverse Water-Gas Shift Reaction.

Molybdenum carbide has been reported as an efficient and stable catalyst for reverse water-gas shift (RWGS) reaction. The conventional understanding of the mechanism suggests domination of the surface phenomena, with only surface or subsurface layers partaking in the catalytic cycle. In this study, we presented a highly active MoC catalyst from carburization process, which showed a mass-specific reaction rate over 260 μm with dynamic carbon flux in the bulk phase of the catalyst. Through Isotopic Temperature-Programmed Reaction (ITPR) analysis and Environmental Transmission Electron Microscopy (ETEM), we discerned dynamic carbon flow circulating between the α-MoC bulk phase and the gas phase reactants under the RWGS reaction atmosphere. This circulation, essential to maintaining the structural stability of the metastable α-MoC and its ultra-high reactivity, is accompanied by thorough carbon component exchange among the bulk, the surface and the gas-phase reactants during the reaction process.