Insight into phosphate doped BiVO4 heterostructure for multifunctional photocatalytic performances: A combined experimental and DFT study

Doping with non-metals like phosphorous has been extensively investigated to extend radiation absorption and improve the photocatalytic efficiency of TiO2. However, the effect of non-metal doping in BiVO4, whose smaller bandgap (2.4 eV) allows for efficient visible light absorption, has been scarcely investigated. Visible light accounts for 45% of solar energy (as compared to only 5% of UV light) reaching the Earth's surface. Due to its high efficiency in absorbing visible radiation, BiVO4 can, therefore, be a promising material to replace TiO2. Here we demonstrate the synthesis of phosphate doped visible-light-active BiVO4 by a microwave hydrothermal method as a promising alternative to TiO2. Subsequently, we investigated its photocatalytic activity for the removal of p-amino salicylic acid and ibuprofen, two cases of major pharmaceutical waste, as well as disinfection of multidrug resistance Staphylococcus aureus bacteria. In addition, the biofilm elimination efficiency of the undoped and phosphate doped BiVO4 was studied by crystal violet staining method. A 70% reduction in the biofilm biomass by phosphate doped BiVO4 was obtained. Also, a 4.1log reduction in the viable cells count was observed within 180 min when Staphylococcus aureus was irradiated with visible light mixed in phosphate doped BiVO4 powder. Under similar irradiation conditions, the degradation efficiency for p-amino salicylic acid and ibuprofen are 81% and 80% respectively, a 40% enhancement as compared to undoped BiVO4. First principle density functional theory calculations show that charge transfer from P to O in the doping site of the BiVO4 is responsible for the enhanced photocatalytic activity.