Atomically Dispersed Cu on In2O3 for Relay Electrocatalytic Conversion of Nitrate and CO2 to Urea

Urea electrosynthesis from coelectrolysis of NO₃^- and CO₂ (UENC) holds a significant prospect to achieve efficient and sustainable urea production. Herein, atomically dispersed Cu on In₂O₃ (Cu₁/In₂O₃) is designed as an effective and robust catalyst for the UENC. Combined theoretical calculations and in situ spectroscopic analysis reveal the synergistic effect of the Cu₁-O₂-In site and the In site to boost the UENC energetics via a relay catalysis pathway, where the Cu₁-O₂-In site drives *NO₃ → *NH₂ and the In site catalyzes *CO₂ → *CO. The generated *CO is then migrated from the In site to the Cu₁-O₂-In site, followed by C-N coupling with *NH₂ on the Cu₁-O₂-In site to generate urea. Consequently, Cu₁/In₂O₃ assembled within a flow cell exhibits an impressive urea yield rate of 28.97 mmol h^-1 g^-1 with a urea-Faradaic efficiency (FE_urea) of 50.88%.