Chinese Journal of Catalysis ›› 2026, Vol. 91: 135-146.DOI: 10.1016/S1872-2067(26)65213-8

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Efficient urea synthesis via electrocatalytic CO2 reduction reaction coupled with nucleophilic addition reaction of NH3

Shuchang Fan, Peize Li, Tianyu Sun, Yan Wei, Zhaoshi Yu, Jiandong Zhang, Mingkui Wang, Yan Shen*()   

  1. Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
  • Received:2025-12-07 Accepted:2026-03-14 Online:2026-12-18 Published:2026-10-13
  • Supported by:
    National Key Research and Development Program of China(2022YFB3803600);National Natural Science Foundation of China(22372065);Hubei Provincial Key Research and Development Program(2023BAB113)

Abstract:

The electrocatalytic CO2 reduction reaction coupled with nucleophilic addition reaction of NH3 represents a promising route to synthesis urea. Relying on interfacial reactions between surface-adsorbed CO2•- from CO2 reduction and dissolved NH3. However, its efficiency is limited by competing CO formation and weak NH3 adsorption, which restrict the C-N coupling efficiency. Thus, achieving synergistic co-adsorption of CO2•- and NH3 while suppressing the CO pathway is essential. This study presents a dual-site catalyst with Pd clusters and Ni single atoms (Pd1.0/NiSAs-N-C). In 0.5 mol·L-1 NH4HCO3 solution at -1.3 V vs. RHE, Pd1.0/NiSAs-N-C achieves a record urea production rate of 3.10 mmol·L-1·g-1·h-1, substantially exceeding NiSAs-N-C (0.22 mmol·L-1·g-1·h-1). Experimental and theoretical analyses reveal that electronic interaction between Ni and Pd sites induces charge redistribution, which enhances NH3 adsorption on Pd via d-p orbital hybridization and optimizes CO2•- binding on Ni. This synergy suppresses CO formation and promotes CO2•- transfer to Pd sites, thereby increasing the “collision” probability between CO2•- and NH3 and reducing the C-N coupling energy barrier from 0.40 to 0.24 eV, which accelerates the overall kinetics. The “site division-intermediate migration” mechanism offers a new paradigm for electrocatalytic coupling systems.

Key words: Urea, Dual-site catalyst, Competitive reactions, Ammonia adsorption, Intermediate migration