Curcumin-Functionalized Ag/Ag2O Nanocomposites: Efficient Visible-Light Z-scheme Photocatalysts

Abstract

Curcumin-functionalized Ag/Ag2O (c-Ag/Ag2O) nanocomposites with varying proportions of curcumin and Ag/Ag2O were prepared by a simple one pot green synthesis protocol in aqueous medium. The plasmonic band undergoes slight redshift, broadening and decrease in intensity with increase in the proportion of Ag2O formed. These composite nanoparticles were found to be efficient visible-light photocatalysts for aerobic oxidation of methyl orange and rhodamine B (RhB). Functionalization by curcumin significantly enhanced the photocatalytic activity with good reusability. The photocatalytic oxidation rate showed super linear increase with light intensity because of localized surface plasmon resonance (LSPR)-induced strong near field. The trapping experiments confirmed that superoxide radicals were the main active species responsible for the degradation reaction. A plasmonic Z-scheme photocatalytic mechanism is proposed to explain the possible charge transfer and separation behavior of electron–hole pairs among Ag, Ag2O and curcumin under visible-light irradiation. © 2018 The American Society of Photobiology