Study on facet oriented supported Cu2O@LaOBr photocatalyst for ammonia synthesis based on double built-in electric field

A key challenge in developing efficient ammonia synthesis photocatalysts lies in preserving the reduction potential of photogenerated electrons, minimizing bulk recombination losses, and increasing the number of active electrons. In this study, a facet-oriented Cu 2 O@LaOBr photocatalyst was constructed by integrating heterojunction design with crystal plane control. Multiple characterizations confirmed the oriented loading of Cu 2 O onto the (1   1   0) facet of LaOBr. Photoelectrochemical tests revealed a high photocurrent response and low interfacial resistance for Cu 2 O@LaOBr(1   1   0), indicating enhanced charge separation and transfer. The catalyst achieved a nitrogen reduction rate of 378.24 μmol·g −1 ·h −1 —8.9, 5.2, and 2.4 times higher than LaOBr, Cu 2 O, and Cu 2 O@LaOBr-R, respectively—demonstrating the efficacy of facet-oriented loading in boosting photocatalytic performance. Through photo-deposition, ESR, and DFT studies, a synergistic mechanism was elucidated: the built-in electric field (BIEF) between crystal planes concentrates electrons on LaOBr(1   1   0), while the interphase BIEF and Z-scheme heterojunction further enhance electron separation and transfer. Together, these effects promote efficient nitrogen reduction on the active surface.