High-performance visible-light responsive BiPO4@ZnWO4 photocatalyst for enhancing photodegradation characteristics

The rational construction of heterostructures plays a pivotal role in enhancing both the separation of photogenerated carriers in semiconductors and the photocatalytic activity. This paper successfully constructs a novel BiPO4@ZnWO4 p-n type heterojunction photocatalyst by hydrothermal and ultrasonic stirring methods. The BiPO4@ZnWO4 heterojunction exhibits outstanding photocatalytic performance, achieving a degradation efficiency of 99% for rhodamine B (RhB) under visible light illumination in just 40 min. Furthermore, its photocatalytic reaction rate constant is 3.9 and 96.51 times higher than that of pure ZnWO4 and BiPO4, respectively. Electrochemical characterization demonstrates a more robust photocurrent response and lower resistance in the composite sample, facilitating efficient transport of photogenerated carriers. In addition, the 20% BiPO4@ZnWO4 heterojunction also exhibits desirable photodegradation stability, maintaining a RhB removal rate above 80% even after 5 cycles. Within the context of the photocatalytic reaction system, the superoxide radical (<middle dot>O-2(-)) plays a key role, succeeded by the hydroxyl radical (<middle dot>OH) and the photoinduced hole (h(+)). This paper provides a feasible p-n type heterojunction photocatalyst for the treatment of dyeing wastewater.