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 α-Bi₂O₃/CuBi₂O₄ composite with high-quality interfaces using an in situ synthesis method. The α-Bi₂O₃/CuBi₂O₄ displays significantly enhanced photocatalytic activity for NO removal (30 %) in comparison with α-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 α-Bi₂O₃/CuBi₂O₄ heterojunction was proposed. The formation of intermediates and products was monitored by in situ DRIFTS. The NO adsorption and activation on α-Bi₂O₃/CuBi₂O₄ surface are more favorable than that on α-Bi₂O₃ surface. The α-Bi₂O₃/CuBi₂O₄ also shows high selectivity for the conversion of NO to NO- 3. Moreover, the cytotoxicity of α-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.