Efficient Electrochemical Urea Synthesis From CO₂ and N₂ in Moderate Pressure

Although electrochemical nitrogen fixation emerges as a sustainable pathway to revolutionize the nitrogen cycle using renewable electricity, the overwhelming dominance of the hydrogen evolution reaction over N₂ activation in aqueous systems imposes fundamental limitations on simultaneously achieving high production rates and Faradaic efficiency. Inspired by Le Chatelier's principle, in this work, an appropriate pressure field was innovatively coupled with electrochemical reduction into the N₂-CO₂ co-fed urea synthesis system, achieving concurrently suppression of gaseous byproducts of CO/H₂ and enhancement of C-N coupling. Atomically dispersed amorphous Bi_xNi_{1- x}O_y clusters were engineered as tandem catalyst, the pressure-driven in situ electronic modulation of the liquid-immersed catalyst-originating from increased surface coverage-is for the first time confirmed: Bi sites exhibit a progressive increase in oxidation state, while Ni centers undergo gradual reduction. The rational atomic-scale integration of multimetallic active centers and system engineering principles for interfacial microenvironment modulation via moderate pressurization achieved breakthrough performance with a high urea production rate of 8.71 mmol h^-1 g^-1 _cat, coupled with remarkable 50% nitrogen fixation efficiency, pointing to one of the best catalysts in aqueous systems among those reported so far. By integrating pressure engineering with atomic-scale catalyst design, this work provides a guiding paradigm for gas-involved electrochemical reactions.