In‐Situ Electrochemical Reconstruction of Copper Single‐Sites to Dual‐Sites for Ambient Urea Synthesis

Abstract Understanding and uncovering really catalytic active‐sites during electrocatalysis is vital for carbon–nitrogen coupling reaction to synthesize urea. Here, we report a Copper (Cu) single‐atom catalyst (Cu‐N 3 SAs) with a Cu–N 3 coordination structure for the electrochemical coreduction of CO 2 and NO 3 − into urea. The in situ X‐ray absorption spectroscopy (XAS) reveals that the Cu–N 3 configured single‐sites undergo electrochemically structural reconstruction to form N 2 –Cu–Cu–N 2 dual‐sites in Cu–N 3 SAs, exhibiting efficient urea synthesis performance. The in‐situ spectroscopy combined with mass spectrometry confirms that the initial C–N coupling reaction involves the formation of *CONH from *CO and *NH intermediates generated via the coreduction of CO 2 and NO 3 − on the N 2 –Cu–Cu–N 2 dual‐sites. The in‐situ electrochemical formed Cu dual‐sites not only enhance the adsorption of *CO, but also facilitates the multi‐electron transfer processes with lowered energy barrier for the formation of *CONH intermediates.