Computational study of CO2 methanation over two-dimensional molybdenum carbide catalysts

Abstract

Two-dimensional molybdenum carbide (2D-Mo2C) is thought to be promising for catalytic hydrogenation of CO2 to CH4, but little is known about its catalytic reaction mechanism. In this work, we investigate the hydrogenation of CO2 to CH4 on 2D-Mo2C using density functional theory. Our calculations show that Mo on the surface can efficiently decompose CO2 to CO and O, and also H2 to H. The hydrogenation of CO produces CHO that is readily deoxygenated to CH, and CH is selectively hydrogenated to produce CH4. Interestingly, the embedded Ir1 on 2D-Mo2C can act as a single-atom promoter to improve the performance of CO2 methanation, while on the other hand maintaining its high selectivity for CH4. This work provides insight into the mechanism of 2D-Mo2C-catalyzed CO2 methanation reactions and suggests a strategy to improve the performance of such catalysts through single-atom promoters.