Constructing a Z-scheme ZnIn₂S₄-S/CNTs/RP nanocomposite with modulated energy band alignment for enhanced...

Energy band structures greatly determine the charge separation and transfer properties in heterojunction photocatalysts and consequently their photocatalytic activities. Herein, a well-designed Z-scheme ZnIn₂S₄-S/CNTs/RP (ZIS-S/CNTs/RP) nanocomposite was fabricated according to an energy band alignment steering strategy to realize superior photocatalytic H₂ evolution performance. The ZIS-S/CNTs/RP nanocomposite shows an efficient photocatalytic H₂ evolution rate of 1639.9 μmol g^-1h^-1, which is noticeably higher than that of pristine red phosphorus (RP) and CNTs/RP and ZIS-S/RP composites, as well as those of the compared heterojunctions using bulk RP or ZnIn₂S₄. Owing to the modification of nanosized RP and the introduction of sulfur vacancies in ZnIn₂S₄, a tailored energy band alignment of the heterojunction with a higher reduction potential and larger Fermi level potential difference was achieved, which resulted in significantly increased photogenerated electron-hole separation efficiency and a more efficient Z-scheme charge transfer mechanism, thus promoting the photocatalytic activity of ZIS-S/CNTs/RP. This work aims to provide a novel effective strategy for the construction of high-performance heterojunction photocatalysts by energy band engineering.