Evaluating the selectivity of CO2 reduction reaction on elementary metal particles with DFT calculations

Electrocatalytic CO2 reduction reaction (CO2RR) towards two-electron products is a competent technique to convert renewable electricity into chemical energy at ambient conditions. Poly-crystalline metals are well-known electrocatalysts for CO2RR. However, no theoretical research was reported to date that evaluates the selectivity of two-electron CO2RR on metal particles. In this work, we proposed a paradigm to evaluate the product selectivity of CO2RR on metal particles. The product selectivity on three low-index surfaces of six metals (In, Pb, Ag, Au, Ni, and Pt) was firstly determined based on the detailed reaction mechanisms established for CO2RR to products of HCOOH and CO. Then, the product selectivity of CO2RR on the first four metal particles was evaluated using the effective free energy barrier which accounts for the facet dependence of CO2RR on the metal particles. The computational results well rationalize the experimental observations, namely preference of HCOOH to CO on the In and Pb particles with higher HCOOH selectivity on the Pb particle, while CO preferred to HCOOH on the Ag and Au particles with higher CO selectivity on the Au particle.