Plasmon Bi/BiFeO3 heterojunctions for achieving optimized photothermal-photocatalytic performance

Abstract

Heterojunctions are of great importance for improving photocatalytic performance. Using simple solvothermal and solid reduction techniques, plasmon bismuth (Bi⁰) nanoflake-decorated BiFeO₃ (BBFO) heterojunction photocatalysts with numerous oxygen vacancies (OVs) were created. The OVs not only improved photo-generated carrier separation, but also the sorption and activation of antibiotic compounds (tetracycline hydrochloride, TC). Furthermore, the surface plasmon resonance (SPR) effect of the Bi⁰ nanoflakes can boost visible light absorption and inhibit charge carrier recombination, resulting in an excellent ability for TC elimination under visible light illumination. The removal ratio of TC for BBFO is up to 99%, which is several times higher than that for pure BiFeO₃. The obvious photothermal effect could further enhance the photocatalytic activity owing to an SPR effect and defect engineering. Trapping experiments indicate that the emergence of plentiful OVs, the participation of metal Bi⁰ nanoflakes, and the formation of heterojunctions can significantly promote photogenerated charge separation, thus improving photothermal-photocatalytic performance. This work combines thermal and chemical energies in solar energy conversion for efficient degradation of pollutants, which would bring new ideas to solve the problems of environmental pollution and energy shortage.