Unveiling the Curvature Effect on the Activity of MoSe₂ for Piezo-Photocatalytic C–N Coupling of Benzylamine

During the piezoelectric photocatalytic process, the surface curvature of the piezoelectric photocatalyst undergoes dynamic changes under the influence of external mechanical forces. However, the correlation between the surface curvature and catalytic performance remains largely unexplored. Here, we demonstrate that decreasing the radius of curvature of MoSe₂ significantly enhances its piezoelectric-photocatalytic activity for C-N coupling reactions, enabling imine synthesis from benzylamine. Comprehensive characterization and DFT calculations together show that the piezoelectric effect in the curved MoSe₂ structure inhibits photogenerated charge carriers from recombination, improving carrier utilization efficiency. Additionally, the surface curvature effect induced by ultrasonic driving reduces the band gap. It promotes the effective transfer of electrons from Mo atoms in MoSe₂ to -NH₂ in benzylamine, thereby facilitating the activation of the benzylamine molecule. As a result, the synergistic effects of the piezoelectric and curvature characteristics significantly enhance the photocatalytic performance of MoSe₂ toward the C-N coupling of benzylamine. This study not only provides new insights into interfacial reaction mechanisms in piezoelectric photocatalysis but also offers a novel perspective for designing high-performance catalytic systems.