Efficient C−N Coupling via Oxidation State Inversion in Asymmetric Copper–Zinc Amorphous‐Like Atomic Clusters Driving Photoelectrocatalytic Urea Synthesis

Abstract

Abstract Photoelectrochemical (PEC) coupling of CO 2 and nitrate presents a sustainable strategy for urea synthesis under ambient conditions. However, the complexity of the proton‐coupled electron transfer process restricts the selective formation of the key intermediates, impeding efficient C–N coupling. Here, copper–zinc amorphous‐like ultra‐small atomic clusters are developed for efficient urea synthesis. The atomically disordered arrangement in the amorphous‐like structure breaks the periodicity constraints of crystalline counterpart, enabling asymmetric Cu δ+ –Zn δ+ coordination featuring oxidation state inversion, where the Cu oxidation state elevates within a narrow valence range (0 < δ < 1) and the Zn oxidation state reduces compared to the crystalline counterpart. More importantly, the oxidation state inversion generates electron‐deficient Cu centers that stabilize the formation of new *NO intermediates, which are identified as a key intermediate that facilitates coupling with *CO species adsorbed on the electron‐rich Zn sites, effectively reducing the activation barrier for C–N coupling involved in the formation of *OCNO. Under simulated AM 1.5G irradiation, the PEC system demonstrated well‐balanced performance, achieving a high production rate of 64.03 mmol g −1  h −1 at a low external potential of −0.1 V versus the reversible hydrogen electrode, with a corresponding Faradaic efficiency of 46.60% and an incident photon‐to‐current conversion efficiency of 17.6% at monochromatic illumination.