Transforming Photocatalytic g‐C<sub>3</sub>N<sub>4</sub>/MoSe<sub>2</sub> into a Direct Z‐Scheme System via Boron‐Doping: A Hybrid DFT Study
Changzhi Ai, Jin Li, Liang Yang, Zhipeng Wang, Zhao Wang, Yamei Zeng, Rong Deng, Shiwei Lin, Cai‐Zhuang Wang
Abstract
Abstract Z‐scheme photocatalytic systems are an ideal band alignment structure for photocatalysis because of the high separation efficiency of photo‐induced carriers while simultaneously preserving the strong reduction activity of electrons and oxidation activity of holes. However, the design and construction of Z‐scheme photocatalysts is challenging because of the need for appropriate energy band alignment and built‐in electric field. Here, we propose a novel approach to a Z‐scheme photocatalytic system using density functional theory calculations with the HSE06 hybrid functional. The undesirable type‐I g‐C 3 N 4 /MoSe 2 heterojunction is transformed into a direct Z‐scheme system through boron doping of g‐C 3 N 4 (B‐doped C 3 N 4 /MoSe 2 ). Detailed analysis of the total and partial density of states, work functions and differential charge density distribution of the B‐doped C 3 N 4 /MoSe 2 heterojunction shows the proper band alignment and existence of a built‐in electric field at the interface, with the direction from g‐C 3 N 4 to MoSe 2 , demonstrating a direct Z‐scheme heterojunction. Further investigation on the absorption spectra reveals a large enhancement of the light absorption efficiency after boron doping. The results consistently confirm that electronic structures and photocatalytic performance can be effectively manipulated by a facile boron doping. Modulating the band alignment of heterojunctions in this way provides valuable insights for the rational design of highly efficient heterojunction‐based photocatalytic systems.