Internal Polarization Modulation in Bi₂MoO₆ for Photocatalytic Performance Enhancement under Visible-Light Illumination

A built-in electric field from polarization inside polar photocatalysts could provide the driving force for photogenerated electrons and holes to move in opposite directions for better separation to improve their photocatalytic performance. The photocatalytic performance of a polar photocatalyst of Bi₂MoO₆ has been enhanced through the precise control of its structure to increase internal polarization. DFT calculations predicted that a shortened crystal lattice parameter b in Bi₂MoO₆ could induce larger internal polarization, which was achieved by the modulation of the pH of the reaction solution during a solvothermal synthetic process. A series of Bi₂MoO₆ samples were created with reaction solutions of pH≈1, 4, and 8; the crystal lattice parameter b was found to decrease gradually with increasing solution pH. Accordingly, these Bi₂MoO₆ samples demonstrated a gradually enhanced photocatalytic performance with decreasing crystal lattice parameter b, as demonstrated by the photocatalytic degradation of sulfamethoxazole/phenol and disinfection of Staphylococcus aureus bacteria under visible-light illumination due to improved photogenerated charge-carrier separation. This study demonstrates an innovative design strategy for materials to further enhance the photocatalytic performance of polar photocatalysts for a broad range of technical applications.