Fabrication of molybdenum-substituted tungstophosphoric acid immobilized onto functionalized graphene oxide: Visible light-induced photocatalyst for selective oxidation of sulfides to sulfoxides

Abstract

Three set of molybdenum-substituted tungstophosphoric acid (H3PW12-yMoyO40 and y = 0, 6 and 12) was supported onto ethylene diamin functionalized magnetic graphene oxide (EDMG) and used to catalyze the selective oxidation of sulfides to sulfoxides under visible light illumination. It was found that Mo cations in the heteropoly acids (HPAs) structure has an important role in this photocatalysis system where the catalytic performance of samples was enhanced with increasing the molybdenum substitution content from y = 0 to 12. Noteworthy, this improved efficiency originated from noticeable synergetic effects between HPAs and graphene oxide layers, expanded responsivity to visible light, faster migration of photoinduced electrons on graphene oxide layers and also high power oxidation of this photocatalyst. Aided by magnetic nature of nanocomposite, separation process at the end of the reaction was easily done by external magnet. Furthermore, the optimum photocatalyst displays acceptable reusability after subsequent 10 runs. High yield, low reaction time and non-toxicity of the catalyst were indicated that H3PMo6W6O40@ethylene diamin functionalized magnetic graphene oxide is a promising catalyst for direct photocatalyst applications.