Comprehensive Mechanism of CO2 Electroreduction on Non-noble Metal Single-atom Catalyst of Mo2CS2-MXene.

In the work, a series of non-noble metal single-atom catalyst of Mo 2 CS 2 -MXene for CO 2 reduction were systematically investigated by well-defined density-functional-theory (DFT) calculations. It is found that nine types of transitional metal (TM) supported Mo 2 CS 2 (TM-Mo 2 CS 2 ) are very stable, while eight of which can effectively inhibit the competitive hydrogen evolution reaction (HER). After comprehensively comparing the changes of free energy for each pathway in CO 2 reduction reaction (CO 2 RR), it is found that the products of these TM-Mo 2 CS 2 are not completely CH 4 . Furthermore, Cr-, Fe-, Co- and Ni-Mo 2 CS 2 are found to render excellent CO 2 RR catalytic activity, and their limiting potentials are in the range of 0.245-0.304 V. In particular, Fe-Mo 2 CS 2 with a nitrogenase-like structure has the lowest limiting potential and the highest electrocatalytic activity. Ab initio molecular dynamics (AIMD) simulations have also proven that these kinds of single-atom catalysts with robust performance could exist stably at room temperature. Therefore, these single TM atoms anchored on the surface of MXenes can be profiled as a promising catalyst for the electrochemical reduction of CO 2 .