In situ construction of biocompatible Z-scheme α-Bi2O3/CuBi2O4 heterojunction for NO removal under visible light

The design of efficient, stable and biocompatible photocatalysts for air purification is still a challenge. In this work, we report a Z-scheme alpha-Bi2O3/CuBi2O4 composite with high-quality interfaces using an in situ synthesis method. The alpha-Bi2O3/CuBi2O4 displays significantly enhanced photocatalytic activity for NO removal (30 %) in comparison with alpha-Bi2O3 (17 %) under visible light irradiation. Based on characterizations, theoretical calculations and ESR tests, the Z-scheme migration mechanism of photoinduced electrons and holes on alpha-Bi2O3/CuBi2O4 heterojunction was proposed. The formation of intermediates and products was monitored by in situ DRIFTS. The NO adsorption and activation on alpha-Bi2O3/CuBi2O4 surface are more favorable than that on alpha-Bi2O3 surface. The alpha-Bi2O3/CuBi2O4 also shows high selectivity for the conversion of NO to NO- 3. Moreover, the cytotoxicity of alpha-Bi2O3/CuBi2O4 exposed to human alveolar epithelial cell has been evaluated for its potential application in air purification. This work provides a new perspective regarding the design of Z-scheme heterojunctions by an in situ method and a promising photocatalyst suitable for air pollution control.