Efficient Electrochemical Reduction of CO 2 on g-C 3 N 4 Monolayer-supported Metal Trimer Catalysts: A DFT Study.

The electrochemical reduction of CO 2 into valuable chemicals and fuels is a promising but challenging method to realize the carbon cycle. In this work, a series of transition metal trimer clusters supported on g-C 3 N 4 catalysts (M 3 @g-C 3 N 4 , M=Cr, Mn, Fe, Co, Ni, Cu, and Ru) for electrochemical CO 2 reduction (CO 2 RR) toward C 1 and C 2 products were systemically studied using density functional theory (DFT) calculations. Our results show that CO 2 could be adsorbed and activated effectively on M 3 @g-C 3 N 4 from adsorption configurations and electronic structures analyses. Cu 3 @g-C 3 N 4 is a promising electrocatalyst for CH 4 production with a limiting potential of -0.42 V. Cr 3 @g-C 3 N 4 , Fe 3 @g-C 3 N 4 , and Co 3 @g-C 3 N 4 produce a low limiting potential of -0.64 V, -0.45 V, and -0.64 V for C 2 H 4 production, respectively. Hydrogen evolution reaction is refrained on Cu 3 @g-C 3 N 4 , Cr 3 @g-C 3 N 4 , and Co 3 @ g-C 3 N 4 . This work provides useful insights into transition metal trimer cluster catalysts with enhanced activity and selectivity in CO 2 RR.