Site-Selective Bimetallic Heterogeneous Nanostructures for Plasmon-Enhanced Photocatalysis of Nitrobenzene Hydrogenation

Nitrobenzene hydrogenation, a critical pathway for synthesizing aniline, typically requires a high temperature and pressurized hydrogen for effective and selective reduction. It is of great significance to find a catalyst with a favorable reaction rate toward the selective hydrogenation of nitroaromatics. Herein, anisotropic Au–Pd tipped NPs were specially synthesized and found to exhibit efficient plasmon-enhanced hydrogenation of nitrobenzene to aniline. Under light, Au–Pd tipped NPs exhibited a TOF of 166 h–1 with high selectivity (>92%). Simulation results demonstrated that site-selective bimetallic heterogeneous nanostructures maintain a strong electromagnetic field, which further promotes the generation and transfer of energetic hot electrons for photocatalysis. Meanwhile, in situ X-ray photoelectron spectroscopy and quasi-in situ electron paramagnetic resonance revealed that the movement of hot electrons facilitates the enhanced participation of hot holes in the oxidation of the hydrogen donor. Our findings underscore that the rational design of bimetallic structures not only exposes rich active sites for incoming reactants but also prolongs the lifetime of hot carriers for efficient transfer and injection.