Silver metalized mixed phase manganese-doped titania: Variation of electric field and band bending within the space charge region with respect to the silver content

• Mn2+ acts as a shallow trap for the photogenerated charge carriers.
• Mn2+ attains stable electronic configuration in charge transfer dynamics.
• Heterojunctions formed at the interface of mixed phase act as good charge separator.
• Energy level of optimum Ag content is crucial in charge transfer dynamics.
• The interfacial charge transfer mechanism in Ag/rutile/anatase/Ag is explained.

Silver was deposited on manganese-doped titanates (Mn–TiO2) by photoinduced deposition method. The catalyst shows enhanced photocatalytic activity due to the synergistic effect of bicrystalline framework of anatase and rutile structures with high intimate contact due to the similarity in their crystallite sizes. The deposited metal nanostructures help in the formation of resonant surface plasmons in response to a photon flux, localizing the electromagnetic energy close to their surfaces. Better charge separation is achieved near the semiconductor surface due to the localized field. Silver deposition was varied from 0.1 to 1.5% on the surface of Mn–TiO2. The mechanism of interfacial electron transfer at heterojunctions in mixed phase induced by the plasmonic catalysis is explained. The extent of band bending, the variation of potential field in the space charge region with respect to the size of the deposited Ag metal particles is discussed. The photocatalytic activity of silver deposited Mn–TiO2 was evaluated by taking resorcinol (Rs) as the model compound along with oxidants such as hydrogen peroxide (H2O2) and ammonium per sulfate (APS) under UV/solar light illumination. The electronic level of the dopant, high intimate contact between the anatase and rutile phases along with efficient electron trapping by silver particles, plays a significant role in the photocatalytic process.

The interfacial charge transfer mechanism in Ag/rutile/anatase/Ag is explained.Figure optionsDownload high-quality image (136 K)Download as PowerPoint slide