Unveiling Electrochemical Urea Synthesis by Co-Activation of CO and N with Mott-Schottky Heterostructure Catalysts.

Electrocatalytic C-N bond coupling to convert CO and N molecules into urea under ambient conditions is a promising alternative to harsh industrial processes. However, the adsorption and activation of inert gas molecules and then the driving of the C-N coupling reaction is energetically challenging. Herein, novel Mott-Schottky Bi-BiVO heterostructures are described that realize a remarkable urea yield rate of 5.91 mmol h  g and a Faradaic efficiency of 12.55 % at -0.4 V vs. RHE. Comprehensive analysis confirms the emerging space-charge region in the heterostructure interface not only facilitates the targeted adsorption and activation of CO and N molecules on the generated local nucleophilic and electrophilic regions, but also effectively suppresses CO poisoning and the formation of endothermic *NNH intermediates. This guarantees the desired exothermic coupling of N=N intermediates and generated CO to form the urea precursor, NCON.