Highly efficient visible-light-induced photocatalytic hydrogenation of nitrobenzene to aniline in water

Highly efficient visible-light-induced photocatalytic hydrogenation of nitrobenzene to aniline in water was observed over a Bi2MoO6 photocatalyst under N2 atmosphere in the presence of (NH4)2C2O4 as a hole scavenger. 100% of the nitrobenzene was converted and the selectivity of aniline was ∼97% after 20 min of visible light irradiation (λ ≥ 400 nm). The Bi2MoO6 photocatalyst showed good catalytic stability for the hydrogenation of nitrobenzene. Further experimental results revealed that both (NH4)2C2O4 and the N2 atmosphere were indispensable for the photocatalytic hydrogenation of nitrobenzene to aniline over the Bi2MoO6 photocatalyst. On the basis of the electron spin resonance analysis results, photoinduced electrons of the Bi2MoO6 photocatalyst were found to be the main active species for the hydrogenation of nitrobenzene. Moreover, a mechanism was proposed to explain the visible-light-induced photocatalytic hydrogenation of nitrobenzene to aniline over the Bi2MoO6 photocatalyst.