Curcumin functionalized CuO/Ag nanocomposite: Efficient visible light Z-scheme photocatalyst for methyl orange degradation

Abstract

An aqueous green synthesis protocol was used to prepare two different curcumin functionalized CuO/Ag photocatalysts. The procedure involved the precipitation of fine spherical nanostructures of Ag on ˜250 nm long (needle-shaped) CuO with curcumin as the reducing and functionalizing agent. Synthesized photocatalysts were characterized by XRD and TEM. In contrast to CuO nanocatalysts, these nanocomposites are efficient visible light photocatalysts for aerobic methyl orange (MO) degradation. There is almost five times increase in photocatalytic activity on the incorporation of a suitable amount of Ag in this nanocomposite. Moreover, these photocatalysts also demonstrate good recyclability for this reaction. Appropriate reactive species trapping experiments confirmed that superoxide radicals were the main active species responsible for the degradation reaction. On the other hand, the water oxidation transfers electrons to photo-generated valence band holes. The results suggest that the photocatalyst works by a Z-scheme charge transfer from the CuO to curcumin through the plasmonic Ag component. © 2019 Elsevier B.V.