Efficient photocatalytic and piezocatalytic performance in oxygen-vacant CdBiO2Br with localized internal electric field

The construction of efficient catalysts driven by both solar light and mechanical stress is meaningful for utilizing a more broad range of renewable energy. Defect engineering has recently attracted intense research interests owing to its unique advantages in catalytic performance enhancement. In this study, we hydrothermally synthesized CdBiO₂Br (CBOB) with various oxygen vacancy concentrations, which realizes efficient photocatalytic and piezocatalytic performance. The introduction of oxygen vacancies (OVs) reduces the work function to increase the electron density for creating a localized internal electric field (LIEF) within CBOB, which plays critical role in enhancing the separation and migradation of photogenerated charges. Therefore, the optimal CBOB catalyst (CBOB-OV2) exhibits a photocatalytic degradation efficiency of tetracycline (TC) of 86.07% within 45 min, which is 4.53 times higher than the bulk CBOB. The effects of catalyst dosage, pollutant concentration, and coexisting ions on photodegradation efficiency are also studied. Besides, the presence of OVs also enhances the piezoelectric properties of CBOB, resulting in a 1.71-fold increase in piezocatalytic TC degradation. The study not only illustrates the role of OVs in enhancing photocatalytic and piezocatalytic performance but also provides fresh insights for the development of high-efficiency catalysts triggered by multiple forms of renewable energies.