Constructing ZnIn2S4@WO3·H2O Z-type heterojunction to boost photocatalytic efficiency under visible-light irradiation

In this paper, hexagonal ZnIn 2 S 4 nanoflowers were grown in situ on tetragonal WO 3 ·H 2 O nanosheets, yielding a compact ZnIn 2 S 4 @WO 3 ·H 2 O (ZIS@WO) core-shell heterojunction. The formation of the ZIS@WO heterojunction was optimized by meticulously adjusting the quantity of WO 3 ·H 2 O nanosheets incorporated. The crystal structure and microstructure of ZIS@WO were comprehensively examined using XRD, TEM and EDS analyses. The photocatalytic properties of ZIS@WO heterojunctions were evaluated through the degradation of organic pollutants under visible light irradiation. The results demonstrated a marked enhancement in photocatalytic efficiency for the ZIS@WO heterojunction. Further investigation into the separation and transport of photogenerated carriers were performed using PL spectroscopy and photoelectrochemical measurement. Compared to the individual components of ZnIn 2 S 4 nanoflowers and WO 3 ·H 2 O nanosheets, the ZIS@WO heterojunction creates an internal electric field at the interface, along with a compact core-shell configuration. This internal electric field, in conjunction with the band structure of the heterojunction, effectively accelerates the separation of photogenerated electrons and holes. Additionally, a comprehensive analysis of the photocatalytic degradation mechanisms were presented, elucidating the intricate processes.