Lowering energy band gap and enhancing photocatalytic properties of Cu/ZnO composite decorated by transition metals

Abstract M/Cu/ZnO (M = Ag, Ni, Fe) photocomposites comprised of 1%M and 5%Cu-decorated ZnO surrounded by CuO on the surface were successfully synthesized via a simple sol-gel method. The structure, morphology and photocatalytic activity of the prepared materials was investigated. The findings demonstrated a hexagonal wurtzite structure with a small extra phase of CuO. Incorporation of M ions in the Cu/ZnO nanocomposite clearly narrowed the band gap energy. The Ag/Cu/ZnO nanocomposite shifted the band gap energy of Cu/ZnO from 2.95 to 2.79 eV. The photocatalytic activity of the photo-composites was examined via the photodegradation of malachite green (MG) under visible light illumination. The Ag/Cu/ZnO photocomposite system showed considerably enhanced photodegradation of MG up to 83% of its initial concentration after 75 min of illumination. This makes it a promising candidate photocomposite for the degradation of dyes under visible light.