Constructing and stabilizing Cu0/Cu+ sites through dual chlorine-induced strategy for CO2 electroreduction to C2H4

Bairong Chen; Wenjiong Li; Runlin Xia; Xiaoyu Wang; Hanchi Hu; Hangxiang Dai; Qingxin Guan; Cai Wang; Yuping Liu; Wei Li

doi:10.1016/j.jcis.2025.138237

Constructing and stabilizing Cu⁰/Cu⁺ sites through dual chlorine-induced strategy for CO₂ electroreduction to C₂H₄

J Colloid Interface Sci. 2025 Jun 18;699(Pt 2):138237. doi: 10.1016/j.jcis.2025.138237. Online ahead of print.

Authors

Bairong Chen¹, Wenjiong Li¹, Runlin Xia¹, Xiaoyu Wang¹, Hanchi Hu¹, Hangxiang Dai¹, Qingxin Guan¹, Cai Wang², Yuping Liu³, Wei Li⁴

Affiliations

¹ State Key Laboratory of Elemento-Organic Chemistry, Key Laboratory of Adv. Energy Mater. Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China.
² State Key Laboratory of Elemento-Organic Chemistry, Key Laboratory of Adv. Energy Mater. Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China. Electronic address: caiwang@nankai.edu.cn.
³ State Key Laboratory of Elemento-Organic Chemistry, Key Laboratory of Adv. Energy Mater. Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China. Electronic address: liuypnk@nankai.edu.cn.
⁴ State Key Laboratory of Elemento-Organic Chemistry, Key Laboratory of Adv. Energy Mater. Chemistry (Ministry of Education), College of Chemistry, Nankai University, Tianjin 300071, China. Electronic address: weili@nankai.edu.cn.

PMID: 40578090
DOI: 10.1016/j.jcis.2025.138237

Abstract

Cu-based catalysts with Cu⁰/Cu⁺ dual sites demonstrate unique synergistic advantages in promoting CO₂ electroreduction. To construct effective Cu⁰/Cu⁺ sites, inhibiting over-reduction of Cu⁺ species is essential while remains a critical challenge due to their inherent thermodynamic instability. Herein, we propose a dual chlorine regulation strategy involving chlorine doping within the Cu₂O matrix and chlorine supplementation in the electrolyte to enhance the stability and activity of Cu⁰/Cu⁺ sites during CO₂-to-C₂H₄ conversion. Notably, the chlorine-doped Cu₂O (Cl-Cu₂O) electrode in 0.1 M KHCO₃ + 0.2 M KCl exhibited a ∼2.5-fold improvement in ethylene Faradaic efficiency (FE_C2H4 increased from 13.0 % to 32.0 %) along with a 4-fold enhancement in operational lifetime compared to pristine Cu₂O evaluated in 0.3 M KHCO₃. The combined results of control experiments, theoretical calculations and in situ characterizations demonstrate that the strong electronic interaction between Cu⁺ and Cl^- effectively suppressed oxygen vacancy formation and retarded the reduction kinetics of Cu⁺ species in reconstructed Cu⁰/Cu⁺ active sites, which further lowered the energy barrier for adsorption of *CO intermediates and facilitated the C-C coupling. Furthermore, introducing Cl^- into the electrolyte significantly mitigated chlorine leaching from the catalyst surface, making Cu⁰/Cu⁺ active sites stably operate for C₂H₄ production. This study provided a novel insight into the stability enhancement mechanism of Cu⁰/Cu⁺ sites and offered a reference for design of Cu-based catalysts for more electrocatalytic reactions.

Keywords: CO(2) electroreduction; Cl-doped Cu(2)O; Cu(0)/Cu(+) sites; Ethylene; Stability.