Planar chlorination engineering induced symmetry-broken single-atom site catalyst for enhanced CO2 electroreduction
Shengjie Wei, Jiexin Zhu, Xingbao Chen, Rongyan Yang, Kevin Gu, Lei Li, Ching‐Yu Chiang, Liqiang Mai, Shenghua Chen
Abstract
Abstract Breaking the geometric symmetry of traditional metal-N 4 sites and further boosting catalytic activity are significant but challenging. Herein, planar chlorination engineering is proposed for successfully converting the traditional Zn-N 4 site with low activity and selectivity for CO 2 reduction reaction (CO 2 RR) into highly active Zn-N 3 site with broken symmetry. The optimal catalyst Zn-SA/CNCl-1000 displays a highest faradaic efficiency for CO (FE CO ) around 97 ± 3% and good stability during 50 h test at high current density of 200 mA/cm 2 in zero-gap membrane electrode assembly (MEA) electrolyzer, with promising application in industrial catalysis. At -0.93 V vs. RHE, the partial current density of CO ( J CO ) and the turnover frequency (TOF) value catalyzed by Zn-SA/CNCl-1000 are 271.7 ± 1.4 mA/cm 2 and 29325 ± 151 h -1 , as high as 29 times and 83 times those of Zn-SA/CN-1000 without planar chlorination engineering. The in-situ extended X-ray absorption fine structure (EXAFS) measurements and density functional theory (DFT) calculation reveal the adjacent C-Cl bond induces the self-reconstruction of Zn-N 4 site into the highly active Zn-N 3 sites with broken symmetry, strengthening the adsorption of * COOH intermediate, and thus remarkably improving CO 2 RR activity.