Construction of a Visible Light Z‐scheme Photocatalyst: Curcumin Functionalized Cu 2 O/Ag Nanocomposites

Abstract A stage‐wise green synthesis protocol was used to prepare curcumin functionalized Cu 2 O/Ag nanocomposites. In this procedure, curcumin was used to reduce and functionalize Ag nanostructures on needle‐shaped Cu 2 O nanoparticles. The prepared nanoparticles were found to be efficient visible‐light photocatalysts for aqueous medium aerobic methyl orange (MO) degradation. Photocatalytic experiments in the presence of appropriate scavenger molecules showed that superoxide radicals were primarily responsible for MO degradation. Furthermore, the increase in the amount of Ag connecting the Cu 2 O and curcumin parts enhanced the recyclability of the photocatalyst. A Z‐scheme mechanism concentrates the electrons in the LUMO of curcumin, and holes in the valence band (VB) of the Cu 2 O. While the electrons in the curcumin reduced oxygen to produce superoxide radicals, the Cu 2 O VB holes oxidized water to sustain the process.