Acta Phys. -Chim. Sin.

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Mechanistic study of CO electroreduction to ethylene on oxide-derived copper controlled by surface reconstruction

Tingting Yin1, Yifan Sun1, Deyin Wu2, Liubin Zhao1   

  1. 1 Department of Chemistry, School of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715, China;
    2 State Key Laboratory of Physical Chemistry of Solid Surfaces and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, Fujian Province, China
  • Received:2026-07-11 Revised:2026-08-03 Accepted:2026-08-06
  • Contact: Deyin Wu, Liubin Zhao E-mail:dywu@xmu.edu.cn;lbzhao@swu.edu.cn

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Abstract: Understanding the correlation between surface structure evolution and reaction kinetics is pivotal for designing high-performance CO2/CO electroreduction catalysts. In this work, four oxide-derived copper (OD-Cu) surfaces were constructed by progressively removing lattice oxygen from Cu2O. Combined with microkinetic modeling, a comprehensive reaction network from CO conversion to C2 products was established. Computational results indicate that each OD-Cu surface can autonomously select the most favorable coupling mechanism under applied potentials. Specifically, the ECE and EEC mechanisms dominate on the Cu2O-0L and Cu2O-1L surfaces. On the Cu2O-2L and Cu2O-3L surfaces, the barrier for *CO dimerization decreases significantly to 0.24 and 0.08 eV, shifting the coupling toward the CEE mechanism. Among the considered C2 pathways, O-H hydrogenation of oxygenated intermediates is kinetically favored over C-H hydrogenation. This facilitates C-O bond cleavage and drives the reaction flux toward the deoxygenation pathway, ultimately leading to ethylene dominance. Within the potential range of -0.2 to -1.2 V, CO reduction undergoes a kinetic transition from electrochemical control to desorption control. Notably, the Cu2O-2L surface undergoes reconstruction upon adsorbing the C2 intermediate formed via C-C coupling. This process creates a disordered, heterogeneous structure that significantly lowers the ethylene desorption energy barrier and delays the onset of desorption control kinetics to more negative potentials. Consequently, the ethylene production rate increases exponentially with potential, achieving an enhancement of approximately six orders of magnitude compared to the pristine Cu2O surface. This study systematically reveals the atomic-scale mechanisms of C2 product formation on OD-Cu from the perspectives of coupling selectivity, reaction mechanism, and surface reconstruction. These findings provide theoretical guidance for designing highly selective C2 electrocatalysts.

Key words: Density functional theory, CO reduction reaction, Microkinetic model, C-C coupling mechanisms, Oxide-derived copper, Surface reconstruction