Single-Atom-Anchored Two-Dimensional MoSi₂N₄ Monolayers for Efficient Electroreduction of CO₂ to Formic Acid and Methane

Efficient and selective CO 2 electroreduction into value-added chemicals and fuels emerged as a significant approach for CO 2 conversion; however, it relies on catalysts with controllable product selectivity and reaction paths. In this work, by means of first-principles calculations, we identify five catalysts (TM@MoSi 2 N 4, TM = Sc, Ti, Fe, Co, and Ni) comprising transition-metal atoms anchored on a MoSi 2 N 4 monolayer, whose catalytic performance can be controlled by adjusting the d-band center and occupation of supported metal atoms. During CO 2 reduction, the single metal atoms function as the active sites that activate the MoSi 2 N 4 inert base plane, and as-designed electrocatalysts exhibit excellent activity in CO 2 reduction. Interestingly, HCOOH is the preferred product of CO 2 reduction on the Co@MoSi 2 N 4 catalyst with a rate-determining barrier of 0.89 eV, while the other four catalysts prefer to reduce CO 2 to CH 4 with a rate-determining barrier of 0.81–1.24 eV. Moreover, MoSi 2 N 4 is an extremely air-stable material, which will facilitate its application in various environments. Our findings provide a promising candidate with high activity, catalysts for renewable energy technologies, and selectivity for experimental work.