Synergistic effect between orthorhombic α-Sulfur and TiO2 as co-photocatalysts for efficient degradation of methylene blue: A mechanistic approach

The synergistic effects between alpha-Sulfur (alpha-S) and TiO2 photocatalysts is studied under UV/solar light. An enhancement in photocatalytic activity was observed under UV light, due to formation of sulfate anions in the reaction mixture and these ions get adsorbed on TiO2 surface by electrostatic force of attraction or it may react with holes/hydroxyl radicals to generate sulfate radical anion. An increase in quantum efficiency is observed with sulfated TiO2 due to reduction in electron-hole recombination rate. The extended response of alpha-S under visible region is due to non-vertical absorption process, which paved a new way for elemental photocatalysis. (C) 2014 Elsevier B.V. All rights reserved.