Single-atom catalysts on supported silicomolybdic acid for CO2 electroreduction: a DFT prediction

Abstract

The electrocatalytic CO2 reduction reaction (CO2RR) is an effective way to convert CO2 into fuels which relies on efficient catalysts due to extreme reaction activation barriers. As a new frontier in the field of catalysis, single-atom catalysts (SACs) play an important role in the CO2RR owing to their maximum atomic availability and unique properties. Herein, a new type of electrocatalyst combining transition metal (TM = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag and Cd) with α-Keggin type Na4[SiMo12O40] (Na4SiMo12) was investigated by density functional theory (DFT) calculations. Through comprehensive screening, TM@Na4SiMo12 (TM = Sc, Ti, V, Cr, Mn, Zn, Y, Zr, Nb and Cd) have been found to exhibit robust stability. Among them, TM@Na4SiMo12 (TM = Sc, Cr, Mn, Ti, and V) have excellent catalytic activity for the CO2RR; in particular, the limiting potential (UL) for CO2RR by Cr@Na4SiMo12 is −0.23 V and the product is HCOOH. Meanwhile, Mn@Na4SiMo12 has high CO2RR selectivity and good catalytic performance (UL = −0.48 V). During the electrochemical CO2RR, polyoxometalates (POMs) act as “electron sponges”, accepting and donating electrons. It is expected that the present work will spur the development of new SACs for the CO2RR.