Enhancement in Photocatalytic Hydrogen Precipitation of BaTiO₃@TiO₂ through Piezoelectric Effect

Photocatalytic hydrogen production is constrained by technical bottlenecks, such as narrow light absorption range of the catalyst and low catalyst activity. Photocatalytic piezoelectric composite BaTiO₃@TiO₂ nanoflowers were synthesized by using a simple hydrothermal method. The structure and morphology were characterized by using XRD, SEM and TEM, while the effect of stirring speed on photocatalytic hydrogen precipitation performance of the composites was deeply studied by using stirring as the external pressure. It is observed that TiO₂ was tightly anchored on surface of the BaTiO₃ nanospheres, whereas a close-contact type Ⅱ energy band structure was established. The BaTiO₃@TiO₂-1.2 sample exhibited a hydrogen precipitation rate of as high as 45.48 µmol·g^-1·h^-1, at a stirring rotational speed of 900 r·min^-1, which was higher than that at a low rotational speed (300 r·min^-1) by 7.19 times. The excellent photocatalytic hydrogen precipitation performance can be attributed to the repeated changes of piezoelectric field that has promoted the photogenerated carrier transfer and charge separation.