Rational construction of S-scheme BN/MXene/ZnIn2S4 heterojunction with interface engineering for efficient photocatalytic hydrogen production and chlorophenols degradation

Achieving structural optimization and component modulation in ZnIn2S4-based photocatalysts while performing photocatalytic hydrogen evolution and degradation performance is a great challenge. In this work, a BN/MXene/ZnIn2S4 S-scheme photocatalytic heterojunction was obtained by growing the etched BN/MXene on the ZnIn2S4 nanosheets directly. Among them, introducing a special electron trapping effect of MXene successfully avoids the photocatalytic inferiority caused by the broader band gap of BN with weak conductivity and poor photocatalytic response activity. Therefore, a stable photocatalytic heterojunction can be constructed by adding MXene. The S-scheme heterojunction was identified by UPS, EPRS, VB-XPS and Mott-Schottky measurements. The bifunctional composite heterojunction photocatalyst exhibited excellent hydrogen production performance (similar to 1455 mu mol center dot g(-1)center dot h(-1)) and 4-chlorophenol (4-CP) degradation ability (90 %) with good stability compared to the that of pure BN/MXene and the ZnIn2S4 samples. In particular, the formation of a built-in electric field at the interface between BN/MXene and ZnIn2S4 n-type semiconductors provides directional acceleration of effective separation of the photogenerated charges and preserves excellent redox capability of the semiconductors. With the excellent hydrogen production performance and 4-CP degradation efficiency of the constructed bifunctional BN/MXene/ZnIn2S4 heterojunction, this work provides a feasible strategy for constructing an S-scheme heterojunction for energy and environmental remediation.

Automated summary

In this study, a BN/MXene/ZnIn2S4 S-scheme photocatalytic heterojunction was constructed by growing the etched BN/MXene on the ZnIn2S4 nanosheets directly. The introduced electron trapping effect of MXene successfully avoided the photocatalytic inferiority caused by BN's broader band gap and poor conductivity. With the excellent hydrogen production performance and degradation efficiency, this work provides a feasible strategy for constructing an S-scheme heterojunction for energy and environmental remediation.