Piezoelectric polarization modulated novel Bi 2 WO 6 /g-C 3 N 4 /ZnO Z-scheme heterojunctions with g-C 3 N 4 intermediate layer for efficient piezo-photocatalytic decomposition of harmful organic pollutants.

It is of great significance to understand the role of carrier in piezocatalysis of composites by studying the separation mode of carriers under dynamic polarization field. Herein, the separation and migration pathways of carriers under piezoelectric field are investigated by synthesizing heterojunctions with Bi ₂ WO ₆ (BWO) nanosheets grown vertically on g-C ₃ N ₄ (CN) coated ZnO nanorods and directly on ZnO. Compared with the photocatalysis, the piezocatalytic efficiency of Rhodamine B (RhB) by BWO/ZnO is significantly increased to 0.121 min ^-1 , which indicated the polarization field promotes band tilt and Z-scheme formation. After introducing the CN interlayer, the piezocatalytic efficiency of BWO/CN/ZnO is further improved (0.217 min ^-1 ), which can be attributed to the unique core-shell structure with Z-scheme heterojunctions. This unique structure provides more active sites and excited carrier concentration, the intermediate layer CN also reduces the direct contact and recombination of electrons and holes controlled by polarization potential at the interface between BWO and ZnO. This work deeply analyzes the influence of carrier concentration, separation efficiency and transport process on piezocatalysis, which provides a reference for the design of efficient catalysts.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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