Planar chlorination engineering induced symmetry-broken single-atom site catalyst for enhanced CO<sub>2</sub> electroreduction.

Wei, Shengjie; Zhu, Jiexin; Chen, Xingbao; Yang, Rongyan; Gu, Kailong; Li, Lei; Chiang, Ching-Yu; Mai, Liqiang et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Breaking the geometric symmetry of traditional metal-N<sub>4</sub> sites and further boosting catalytic activity are significant but challenging. Herein, planar chlorination engineering is proposed for successfully converting the traditional Zn-N<sub>4</sub> site with low activity and selectivity for CO<sub>2</sub> reduction reaction (CO<sub>2</sub>RR) into highly active Zn-N<sub>3</sub> site with broken symmetry. The optimal catalyst Zn-SA/CNCl-1000 displays a highest faradaic efficiency for CO (FE<sub>CO</sub>) around 97 ± 3% and good stability during 50 h test at high current density of 200 mA/cm<sup>2</sup> 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<sub>CO</sub>) and the turnover frequency (TOF) value catalyzed by Zn-SA/CNCl-1000 are 271.7 ± 1.4 mA/cm<sup>2</sup> and 29325 ± 151 h<sup>-1</sup>, 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<sub>4</sub> site into the highly active Zn-N<sub>3</sub> sites with broken symmetry, strengthening the adsorption of <sup>*</sup>COOH intermediate, and thus remarkably improving CO<sub>2</sub>RR activity.