Band structure engineering enables to UV–Visible-NIR photocatalytic disinfection: mechanism, pathways and DFT calculation

Abstract Photocatalytic disinfection has been regarded as a promising strategy in terms of significantly reducing microbial contamination, in which the activity of photocatalyst mainly depends on UV or visible light, however the effect of full spectrum solar light for photocatalytic disinfection has been rarely considered. Herein, we report a UV–Visible-NIR responsive photocatalyst based on vanadate quantum dots (AgVO3 QDs) interspersed on vacancy-rich BiO2-X (AgVO3/BiO2-X) and achieve highly efficient photocatalytic disinfection for Methicillin-resistant Staphylococcus aureus (MRSA). With our approach, we achieved a 7-log inactivation of bacterial concentration within 30 min, with only a small amount of material (200 μg mL−1) under UV, visible and near-infrared light. The maximum absorption edge of AgVO3/BiO2-X red-shifts from 880 nm to 930 nm, which can be attributed to the inner defective structure and formation of heterostructures, resulting in abundant production of reactive oxygen species (ROS) for bacterial inactivation. DFT calculations confirm the intimate interface contact between BiO2-X and AgVO3, which benefit to the up-conversion photoluminescence properties of AgVO3 QDs and fast interfacial electron transport through the electron tunneling mechanism. In vitro results illustrated that ROS can severely damage the cell wall of bacteria and inhibit its virulence factors, which eventually leading to the death of MRSA. Notably, assessment of wound infection showed that the material was very effective for promoting cell proliferation and differentiation, by phosphorylation of protein kinase B (Akt) signalling pathway in bacterial infection, which shows great potential as a safe, low-cost and efficient multimodal heterostructured photocatalyst in eliminating the microbial contaminated water.