Efficient C–N coupling for urea electrosynthesis on defective Co3O4 with dual-functional sites

Abstract

Urea electrosynthesis under ambient conditions is emerging as a promising alternative to conventional synthetic protocols. However, the weak binding of reactants/intermediates on the catalyst surface induces multiple competing pathways, hindering efficient urea production. Herein, we report the synthesis of defective Co₃O₄ catalysts that integrate dual-functional sites for urea production from CO₂ and nitrite. Regulating the reactant adsorption capacity on defective Co₃O₄ catalysts can efficiently control the competing reaction pathways. The urea yield rate of 3361 mg h⁻¹ g_cat⁻¹ was achieved with a corresponding faradaic efficiency (FE) of 26.3% and 100% carbon selectivity at a potential of −0.7 V vs. the reversible hydrogen electrode. Both experimental and theoretical investigations reveal that the introduction of oxygen vacancies efficiently triggers the formation of well-matched adsorption/activation sites, optimizing the adsorption of reactants/intermediates while decreasing the C–N coupling reaction energy. This work offers new insights into the development of dual-functional catalysts based on non-noble transition metal oxides with oxygen vacancies, enabling the efficient electrosynthesis of essential C–N fine chemicals.