Engineering Migration Pathway for Effective Separation of Photogenerated Carriers on Multicomponent Heterojunctions Coated with Nitrogen-Doped Carbon.

Multicomponent NiTiO /A-TiO /R-TiO photocatalysts coated with nitrogen-doped carbon (N-C/NiTiO /A-TiO /R-TiO ) for efficient H production were fabricated by directly pyrolyzing NH -MIL-125(Ni/Ti) metal-organic framework microrods. Owing to the synergistic effect of the N-doped carbon coating layer and multicomponent heterojunctions, the H production rate of N-C/NiTiO /A-TiO /R-TiO was even higher than that of its Pt-containing counterpart (Pt/NiTiO /A-TiO /R-TiO ). N-C/NiTiO /A-TiO and N-C/NiTiO /R-TiO as control photocatalysts were also prepared by simply adjusting the calcination temperature of NH -MIL-125(Ni/Ti) in air atmosphere. The H production rate followed the order of N-C/NiTiO /A-TiO /R-TiO >N-C/NiTiO /A-TiO >N-C/NiTiO >R-TiO , which indicates that the multicomponent heterojunction plays a key role in photocatalytic H generation. The mechanism for the influence of the multicomponent heterojunction on photocatalytic activity was investigated in combination with molecular simulations, which showed that N-C/NiTiO /A-TiO /R-TiO has a so-called double type II heterojunction providing a perfect step-by-step migration pathway for effective separation of photogenerated electrons and holes. This work presents a simple and effective method for synthesizing efficient multicomponent photocatalysts.