Nanostructured ZnO/BiVO₄ I-scheme heterojunctions for piezocatalytic degradation of organic dyes via harvesting ultrasonic vibration energy

BiVO₄ porous spheres modified by ZnO were designed and synthesized using a facile two-step method. The resulting ZnO/BiVO₄ composite catalysts have shown remarkable efficiency as piezoelectric catalysts for degrading Rhodamine B (RhB) under mechanical vibrations, they exhibit superior activity compared to pure ZnO. The 40wt% ZnO/BiVO₄ heterojunction composite displayed the highest activity, along with good stability and recyclability. The enhanced piezoelectric catalytic activity can be attributed to the formation of an I-scheme heterojunction structure, which can effectively inhibit the electron-hole recombination. Furthermore, hole (h⁺) and superoxide radical (·O ₂ ⁻ ) are proved to be the primary active species. Therefore, ZnO/BiVO₄ stands as an efficient and stable piezoelectric catalyst with broad potential application in the field of environmental water pollution treatment.