Dynamics of VOCs degradation and bacterial inactivation at the interface of AgxO/Ag/TiO2 prepared by HiPIMS under indoor light

AgxO/Ag/TiO2 photoactive thin films were produced by different modes of magnetron sputtering (namely, DCMS and HiPIMS). The spectral and microstructural properties of the Ag-AgxO/TiO2 thin films were studied by Diffuse Reflection Spectroscopy (DRS) and X-ray Photoemission Spectroscopy (XPS). The atomic deposition of TiO2 and Ag in the thin sputtered film were studied by TEM. AgxO/Ag/TiO2 exhibited fast photocatalytic volatile organic compounds (VOCs) degradation and bacterial inactivation under low visible light intensity. The Langmuir Hinshelwood model was applied to highlight the photocatalytic performance of the AgxO/Ag/TiO2 catalyst. The oxidative states of Ag-AgxO/TiO2 were studied by XPS. Deconvolution of the Ag3d peak of the AgxO/Ag/TiO2 thin films showed the presence of AgO and metallic Ag. It is suggested that the mechanism involving the degradation of VOCs on AgO/Ag/TiO2 catalysts is due to the transfer of holes from AgO to TiO2 via the AgO/Ag/ TiO2 heterojunction. The electrostatic interaction between both semiconductors allows this charge transfer. In addition, the contribution of reactive oxygen species (ROS) in bacterial inactivation at the interface of AgO/Ag/ TiO2 thin film was also examined. Light-induced interfacial charge transfer (IFCT) between AgO and TiO2 leading to pollutants oxidation appears to require low photons' energy and can oxidize pollutants even at high concentrations. The sputtered coatings have also been studied for repetitive reuse, showing the sustainable activity of the prepared materials.

Automated summary

AgxO/Ag/TiO2 photoactive thin films were produced using different modes of magnetron sputtering and their spectral and microstructural properties were studied. The films exhibited fast photocatalytic degradation of VOCs and bacterial inactivation under low visible light intensity. The mechanism of VOCs degradation on AgO/Ag/TiO2 catalysts involves hole transfer and reactive oxygen species. The study also found that the prepared materials have repetitive reuse capability.