Enhanced H2 Production of TiO2/ZnO Nanowires Co-Using Solar and Mechanical Energy through Piezo-Photocatalytic Effect

TiO2/ZnO nanowire arrays on stainless steel mesh for piezo-photocatalytic H2 production are synthesized via a two-step hydrothermal route. The photocatalytic H2 production efficiency under solar illumination can be enhanced by introducing mechanical vibration energy. As coutilizing the solar and mechanical energy (ultrasonic irradiation), the nanowires show high H2 production. The nanowire arrays also show excellent recyclability and stability. Additionally, this mesh-based structure can be retrieved easily from aqueous solution, which can meet the practical application demand. The working mechanism can be attributed to the piezo-photocatalytic effect, in which the piezoelectric field of bent ZnO nanowires and the built-in electric field of TiO2/ZnO heterostructures can efficiently separate the photogenerated electrons and holes for effectively producing H2. Present results provide a new strategy for developing photocatalytic H2 production techniques.