Local Steric Hindrance for CO2 Electroreduction at a Thermodynamic Potential and Wide Working Window

Abstract

AbstractTo improve the energy‐conversion efficiency and adaptability between a CO2 electroreduction system and intermittent renewable energy, small onset potentials, and wide working windows are highly important. Here, three indium metal–organic frameworks (In‐MOFs) have been projected using different ligands to adjust the local steric hindrance and electronic structure of In nodes, manipulating the whole workflow of CO2 during electroreduction including local CO2 transport, adsorption, activation, hydrogenation, and product desorption. Significantly, a CO2 electroreduction to formate process promoted by 2,5‐TDC In‐MOF shows an onset potential of −0.1 V versus RHE around the therymodynamic potential, over 90% FEforamte in a wide current‐density window from 0.1 to 0.9 A cm−2. Driven by solar cells, the system displays a high solar‐to‐chemical efficiency of 17.39%. In depth mechanism study indicates that the local CO2 transport and adsorption of all In‐MOFs are thermodynamically and kinetically favorable, while the energy barrier of potential‐determine step (*HCOOH desorption) is the lowest for 2,5‐TDC In‐MOF.