Surface engineering on bulk Cu₂O for efficient electrosynthesis of urea

Electrochemical urea synthesis has recently emerged as a fascinating energy-efficient alternative route, while it remains challenging to achieve simultaneously high production rate and Faradaic efficiency. Herein, we realize an energy-favorable electrochemical C-N coupling path through CO₂ and NO₃^- co-reduction at the heterointerfaces of Cu/Cu₂O microparticles, generated by in-situ electrochemical engineering on bulk Cu₂O. We achieve urea production rate of 632.1 μg h^-1mg_cat.^-1 with a corresponding Faradaic efficiency of 42.3% at -0.3 V (versus RHE) under ambient conditions. Operando synchrotron radiation-Fourier transform infrared spectroscopy, along with theoretical calculations, reveals the coupling of intermediates NOH* and CO* at the heterointerfaces, benefiting from the modified electronic structure. This work provides a practical route for catalyst design and insights into urea electrosynthesis systems.