Study on photogenerated charge transfer properties and enhanced visible-light photocatalytic activity of p-type Bi2O3/n-type ZnO heterojunctions

The composite Bi2O3/ZnO photocatalyst, a novel p-n type heterojunction with different molar ratios of Bi to Zn, has been fabricated using a hydrothermal method. The XRD, XPS, UV-vis DRS, SEM, HRTEM studies were used to characterize the as-obtained products. The photocatalytic activities of the p-Bi2O3/n-ZnO heterojunctions were investigated for their efficiency on the degradation of alizarin red (AR) dye under visible light irradiation (lambda > 420 nm), and the results showed that the composites possessed remarkable photocatalytic activities, which were conducive to their separation, recycling, and reuse. The photogenerated charge-transfer properties were tested by surface photocurrent (SPC) and surface photovoltage (SPV) experiments and results show that the interfacial electric field located between Bi2O3 and ZnO played an important role in promoting the separation of photogenerated electron and hole pairs. These results are helpful to design and construct high efficiency heterogeneous semiconductor photocatalysts.