Low-temperature preferential oxidation of CO over Ag monolayer decorated Mo₂C (MXene) for purifying H₂

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 Mo₂C can be used as an effective low cost catalyst with high activity, selectivity and stability for preferential oxidation of CO. Ag monolayer decorated Mo₂C can also be used as a filter membrane for separating H₂ and CO. Meanwhile, the high selectivity is achieved because H₂ 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 O₂ supply because it can resist CO poisoning with promoted activity for CO oxidation at higher CO concentration. We anticipate that Ag monolayer decorated Mo₂C can be used as a promising H₂ 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 H₂ and inspire more researches on the application of MXene catalysts.