In-situ FTIR study of dimethyl carbonate synthesis from CO2 and methanol: Crystal planes tailored lattice oxygen mechanism

The crystal planes tailored lattice oxygen mechanism for the competitive and promising process of directly synthesizing dimethyl carbonate (DMC) from carbon dioxide (CO 2 ) and methanol have been comprehensively investigated. Steady-state in-situ micro-reaction Fourier transform infrared spectroscopy (FTIR) combined with density functional theory (DFT) calculations were conducted on a series of CeO 2 model catalysts to elucidate the formation pathway of DMC. The previously theoretically predicted methoxycarbonyl (MC, CH 3 OCO*) intermediate was experimentally identified through FTIR spectroscopy. Only on the active (110) surface do lattice oxygen and Ov participate in the reaction cycle, facilitating critical reaction steps and shifting the reaction pathway from the electrophilic addition of methyl species to monomethyl carbonate (MMC, CH 3 OCOO*) on the (111) surface to the nucleophilic addition of methoxy species to MC. The established structure-activity relation holds a promise for providing effective guidance in CeO 2 -based catalyst design at a mechanistic level.