Low-temperature preferential oxidation of CO over Ag monolayer decorated MoC (MXene) for purifying H.

Selective removal of CO from reformate streams at low temperature is an important issue to be solved for anode catalysts of proton exchange membrane fuel cells (PEMFCs). Using density functional theory, we demonstrate that the Ag monolayer decorated MoC can be used as an effective low cost catalyst with high activity, selectivity and stability for preferential oxidation of CO. Ag monolayer decorated MoC can also be used as a filter membrane for separating H and CO. Meanwhile, the high selectivity is achieved because H hardly takes part in the reaction, and the good activity is obtained since the CO with moderate binding strength could be smoothly removed at various CO concentration. We propose a facile route for removing CO by injecting low O supply because it can resist CO poisoning with promoted activity for CO oxidation at higher CO concentration. We anticipate that Ag monolayer decorated MoC can be used as a promising H purifying pretreater by preferential oxidation of CO connecting to the anode of PEMFCs. We hope the present results could advance the development of catalysts for purifying H and inspire more researches on the application of MXene catalysts.