Photocatalytic activity of TiO2 and ZnO in the presence of manganese dioxides

Abstract The photocatalytic activity of TiO 2 and ZnO in the presence of MnO 2 , a particulate matter present in natural water and wastewater, has been studied. We found that a trace amount of MnO 2 particles deactivated TiO 2 photocatalysts, but its effect on the activity of ZnO was negligible. UV–visible diffuse reflectance spectra (DRS) and surface photovoltage spectroscopy (SPS) analysis implied that the interaction of MnO 2 with TiO 2 and ZnO could change the energetics of these two photocatalysts.