Single‐Product Faradaic Efficiency for Electrocatalytic of CO2 to CO at Current Density Larger than 1.2 A cm−2 in Neutral Aqueous Solution by a Single‐Atom Nanozyme

Abstract Electroreduction of CO 2 to CO is a promising approach for the cycling use of CO 2 , while it still suffers from impractical current density and durability. Here we report a single‐atom nanozyme ( Ni−N 5 −C ) that achieves industrial‐scale performance for CO 2 ‐to‐CO conversion with a Faradaic efficiency (FE) exceeded 97 % over −0.8–−2.4 V vs. RHE. The current density at −2.4 V vs. RHE reached a maximum of 1.23 A cm −2 (turnover frequency of 69.7 s −1 ) with an FE of 99.6 %. No obvious degradation was observed over 100 hours of continuous operation. Compared with the planar Ni−N 4 site, the square‐pyramidal Ni−N 5 site has an increase and a decrease in the and d xz / yz orbital energy levels, respectively, as revealed by density functional theory calculations. Thus, the Ni−N 5 catalytic site is more superior to activate CO 2 molecule and reduce the energy barriers as well as promote the CO desorption, thus boosting the kinetic activation process and catalytic activity.