In this work, the construction of heterostructures is considered to be an outstanding method to enhance the decomposition ratio in the piezocatalysis process. Piezoelectric BiFeO3/ZnO heterostructure nanomaterials synthesized via a mixing–calcining method exhibit an enhanced piezocatalysis performance through collecting vibration energy to decompose rhodamine B (RhB) dye. After undergoing 180 min vibration, with the different ZnO contents of 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt% and 5 wt%, the BiFeO3/ZnO heterostructures can respectively decompose 73.4%, 87.0%, 96.9%, 92.9%, 67.9% and 55.1% RhB dye. The kinetic rate constant of the RhB dye decomposition is 21.0 × 10−3 min−1 for the BiFeO3/2%ZnO heterostructures, while it is only 7.37 × 10−3 min−1 for the BiFeO3. The reason for the enhanced piezocatalytic dye decomposition ratio may be that the heterostructure effectively separates the positive and negative charges to reduce the recombination of the positive and negative charges. These main medium active species such as hydroxyl radicals (˙OH) in the process of piezocatalysis are confirmed on the basis of the results of both electron spin resonance and active species capture experiments. The BiFeO3/ZnO heterostructures, with a strongly enhanced piezocatalytic dye decomposition performance, offer a promising option to treat wastewater through collecting environmental vibration energy in the future.
In this work, a series of BiFeO 3 /ZnO composites with varying molar ratio of BiFeO 3 to ZnO (Bi:Zn = 2.5:1, 5:1, 10:1, 20:1) have been synthesized via a one-step hydrothermal method and evaluated for their efficiency in rhodamine B (RhB) degradation performance. The morphology results reveal that the microsphere-shaped ZnO is dispersed on the surface of the blocky-like BiFeO 3 , with intimate contact between the two phases. It has been found that the maximum piezocatalytic activity could be achieved at BiFeO 3 /ZnO molar ratio of 5:1, with a degradation rate up to 92% for RhB. Compared with pure BiFeO 3 and ZnO, the composites have superior piezocatalytic degradation performance. The reason for the enhanced piezocatalytic dye degradation rate may be that the BiFeO 3 /ZnO composites effectively separate the positive and negative charges to reduce the recombination of positive and negative charges. These active species, such as superoxide radicals ( O 2 • − ) in the process of piezocatalytic, are proved on the active species capture experiments. The BiFeO 3 /ZnO composites have good piezocatalytic degradation performance, which provides an option for collecting vibration energy to degradation dye wastewater in the future.
危险品化学品经营许可证（带存储）