Synergistic Effects of Heteroatom decorated MXene catalyst for CO Reduction Reaction

Using density functional theory calculations, we present a strategy to improve the activity and selectivity of electrocatalytic CO reduction reaction (CORR) towards CH4 production occurring on single transition metal (TM) atom embedded in the defective MXene Mo2-xTiC2Oy with one oxygen vacancy. Owing to the unique geometric and electronic structures, the exposed TM-Mo-Mo triangle can serve as the active site, and the surrounding oxygen atoms can break the scaling relationships between the CORR intermediates via the steric hindrance. The synergistic effects result in the excellent catalytic performance of CORR. Based on the extensive investigation of a series of candidates, W decorated MXene was identified as the most promising CORR electrocatalyst, with highly-selective activity toward CH4 production and strong suppression of competing hydrogen evolution reaction (HER). The adsorption free energy of *COH [△Gads (*COH)] was proposed as a descriptor to establish the relationship with the catalytic activity. Our rational design principles and rapid screening methods may shed lights on the development of other highly efficient CORR electrocatalysts, as well as other electrochemical systems.