Fabrication of RuO2-Ag3PO4 heterostructure nanocomposites: Investigations of band alignment on the enhanced visible light photocatalytic activity

The RuO2-Ag3PO4 heterostructured nanocomposite was successfully synthesized by facile in situ deposition of porous ruthenium oxide (RuO2) nanoparticles on the surface of the silver phosphate (Ag-3 PO4). Under visible light irradiation, the 0.5 wt.% RuO2-Ag3PO4 heterostructure photocatalyst exhibits enhanced photocatalytic efficiency compared to other composites of RuO2-Ag3PO4 and Ag3PO4. The optimized 0.5 wt.% RuO2-Ag3PO4 nanocomposites exhibited 1.5 times enhanced photocatalytic activity towards the degradation of methylene blue (MB) than Ag-3 PO4. Moreover, the degradation rate of 0.5 wt.% RuO2-Ag-3 PO4 nanocomposite towards the cationic dyes MB and rhodamine B (RhB) was nearly 6.6 times and 4.7 times higher than that towards the anionic dye methyl orange (MO). The formed heterojunction electric field of 310 mV at the interface between RuO2 and Ag3PO4 heterostructure induces downward band bending of Ag3PO4. Also, this electric field increases the separation efficiency of electrons-holes resulting higher degradation efficiency. The quenching effect of scavengers test confirms that holes are reactive species and the RuO2-Ag3PO4 nanocomposite is highly stable, exhibited 88% of MB degradation after 4 recycles. The RuO2-Ag3PO4 nanocomposites inhibit self oxidation of Ag3PO4 resulting improved efficiency and stability. (C) 2017 Published by Elsevier B.V.