PbCrO ₄ /Pb Hybrid with Surface Unsaturated Metal Sites for Efficient CO ₂ ‐to‐Formate Reduction

Abstract The coordinatively unsaturated metal sites created by oxygen vacancies ( V o) at the surface are responsible for the high activity of CO 2 electroreduction reaction (CO 2 RR). In this work, the critical significance of surface exposed metal sites are highlighted and induced by Vo for CO 2 electrocatalysis in PbCrO 4 /Pb hybrid, wherein the electrons‐rich PbCrO 4 surface facilitates CO 2 activation, simultaneously bulk Pb nanorod boosts electron transfer. The Vo‐rich PbCrO 4 /Pb exhibits an excellent selectivity for formate with Faradaic efficiencies over 87% in a wide range of current densities of 100–800 mA cm −2 . Theoretical studies indicate that the introduction of Vo into PbCrO 4 increases the charge density near the Fermi level of unsaturated Pb sites, which are expected to promote CO 2 adsorption and stability of * OCHO intermediates. This finding provides a guideline for rationally designing electrocatalysts with abundant surface unsaturated metal sites for other reactions.