Spatially Matched C–N Coupling within Carbon Defect Confined Interlayer Fe Clusters for Efficient Urea Electrosynthesis

Abstract

Abstract Tailoring spatially matched multi‐site structure to simultaneously coordinate CO 2 and NO 3 − activation and coupling remains a significant challenge for urea electrosynthesis. Herein, interlayer Fe atomic clusters is constructed (Fe acs ) in expanded 2H‐graphitic carbon via a carbon defect‐confinement strategy, where spatially matched Fe acs between graphite layers act as ideal nanoreactors for cooperative C─N coupling. These interlayer Fe acs are achieved by kinetically modulating cascade reactions (FeO x reduction, H 2 /CO 2 ‐mediated carbon etching, and vacancy trapping) during pyrolysis under H 2 /Ar atmosphere with low flow rates. As a result, the interlayer Fe acs catalyst exhibits a high urea Faradaic efficiency of 39.80% and a normalized production rate of 3643.65 m m h −1 gFe −1 , which is 7.98‐ and 9.88‐fold higher than control samples (Fe particles without interlayer structure). In‐situ fourier transform infrared spectroscopy (FTIR) and density functional theory (DFT) calculations further reveal that the spatial matched interlayer Fe acs structure promotes the adsorption of *CO intermediate and lowers energy barriers for the dehydration of NH 2 OH, while carbon defects favor water dissociation kinetics, accelerating subsequent hydrogenation steps and promoting C─N coupling within the interlayer Fe acs . This work provides a paradigm for designing catalysts with spatial matched active sites for sustainable urea synthesis.