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

Abstract Multicomponent NiTiO 3 /A‐TiO 2 /R‐TiO 2 photocatalysts coated with nitrogen‐doped carbon (N‐C/NiTiO 3 /A‐TiO 2 /R‐TiO 2 ) for efficient H 2 production were fabricated by directly pyrolyzing NH 2 ‐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 2 production rate of N‐C/NiTiO 3 /A‐TiO 2 /R‐TiO 2 was even higher than that of its Pt‐containing counterpart (Pt/NiTiO 3 /A‐TiO 2 /R‐TiO 2 ). N‐C/NiTiO 3 /A‐TiO 2 and N‐C/NiTiO 3 /R‐TiO 2 as control photocatalysts were also prepared by simply adjusting the calcination temperature of NH 2 ‐MIL‐125(Ni/Ti) in air atmosphere. The H 2 production rate followed the order of N‐C/NiTiO 3 /A‐TiO 2 /R‐TiO 2 >N‐C/NiTiO 3 /A‐TiO 2 >N‐C/NiTiO 3 >R‐TiO 2 , which indicates that the multicomponent heterojunction plays a key role in photocatalytic H 2 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 3 /A‐TiO 2 /R‐TiO 2 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.