Enhanced photodynamic antimicrobial performance of WO3/CuxO double Z-type heterojunction using carrier multichannel conversion

Bacterial infections pose a severe threat to human health and the living environment. Photodynamic antimicrobial strategies have attracted attention since they are not affected by the development of drug resistance by the organisms. Cuprous oxide (Cu 2 O) is a promising material for application in the photocatalytic antimicrobial field due to its excellent photo responsiveness. However, the fast recombination of photogenerated carriers and poor stability limit the application of Cu 2 O. This paper uses the advantages of the exceptional strength of copper oxide (CuO) and the photocatalytic potential of tungsten trioxide (WO 3 ) to design a photocatalytic antimicrobial WO 3 /Cu x O composite agent. The structure of the composite material reveals that CuO particles and WO 3 nanosheets are grown in-situ on octahedral Cu 2 O crystals, with the outermost layer primarily consisting of WO 3 . Simultaneously, the ternary composite structure utilizes interfacial interactions to regulate the electronic structure, which acts as the conduit for electron transfer. The killing effect of WO 3 /Cu x O on Escherichia coli ( E. coli ) after visible-light irradiation reaches 100.00%, which is 2.57 times higher than that of Cu 2 O and 34 times higher than that of WO 3 . The outstanding antimicrobial ability is attributed to the constructed stepped double Z-type heterojunction structure, which realizes multi-channel transfer of carriers and retains the carriers with superior redox capacity, increasing the quantum yield of reactive oxygen species (ROS). The ROS generated by photoexcitation of WO 3 /Cu x O is the main reason for the superior antibacterial performance. The detection results indicate that ROS oxidizes the bacterial physiological structure, resulting in noticeable depressions, wrinkles, and ruptures in Escherichia coli. Meanwhile, during the mixing and collision process between bacteria and the material, metal ions can denature protein structures, and the bacterial cell surface can be punctured or even torn. These factors collectively affect bacterial activity. This work provides effective ways and methods for designing efficient antimicrobial agents.