Surface defect engineering of Fe-doped Bi7O9I3 microflowers for ameliorating charge-carrier separation and molecular oxygen activation

Abstract

Effective charge-carrier separation and molecular oxygen activation are crucial factors for photocatalytic environmental purification. Herein, an efficient Fe-doped Bi7O9I3 microflowers photocatalyst was synthesized. It was discovered that Fe doping could not only tune the concentration of oxygen vacancies of Bi7O9I3 to optimize the dissociation of excitons, but also promote the separation of charge-carriers and the activation of oxygen molecules. Meanwhile, the inducing of surface oxygen vacancies and Fe3+/Fe2+ by Fe optimal doping can act as the activation center for catalytic reactions, which also significantly enhances the photocatalytic activity. Benefiting from the optimized properties, the photocatalytic activity of Fe-doped Bi7O9I3 photocatalyst has been significantly improved by more than 4 times. Finally, we proposed that a highly efficient catalytic oxidation reaction mechanism can be achieved via modulating Fe doping to induce oxygen vacancies to promote charge separation and molecular oxygen activation. This work provides a novel approach for designing efficient photocatalysts.