Enhancement and inhibition of photocatalytic hydrogen production by fine piezoelectric potential tuning over piezo-photocatalyst

The combination of piezoelectric and catalytic functionalities is a burgeoning area aimed at enhancing energy and catalytic efficiency. However, the lack of comprehension regarding the mechanism through which piezoelectric potential (piezopotential) influences the enhancement or inhibition of photocatalytic hydrogen production has impeded the effective design of piezo-photocatalysts. Herein, a configured monofunctional-piezoelectric component/monofunctional-photocatalytic component type quartz/TiO2 composite catalyst as well as the hydrogen evolution experiment, COMSOL simulation, PFM, and electrochemical measurement was employed to discuss how the piezopotential changed with microstructures and its effect on electron-hole recombination, energy band, and the photocatalytic hydrogen production. Our findings reveal that the ultrasonic-driven piezoelectric effect in the quartz/TiO2 catalyst is significantly affected by the grain size of the piezoelectric component (quartz) and by the different sacrificial agents used in the multi-phase photocatalytic hydrogen production reaction. Overall, a stronger piezopotential inhibits the photocatalytic hydrogen production efficiency, while a suitable weaker piezopotential enhances hydrogen production. We propose a "piezopotential switch" mechanism to reveal these observations, validated by our experiments, providing new insights into the piezoelectric-photocatalytic coupling mechanism and guiding the precise semi-quantitative design of future advanced piezoelectric photocatalytic materials.