Ag-Loaded ZnO Nanocomposite Films as Photocatalysts for the Degradation of Pigments under Visible Light

Ag-loaded ZnO nanocomposite film photocatalysts were constructed by physical vapor deposition and thermal oxidation. The relationship between the surface morphology, optical properties, photoelectric properties, and photocatalytic activity of nanocomposite films were mainly investigated. The surface morphology of nanocomposite films exhibits a thickness dependence of the Zn layer, which can be acknowledged by the SEM image. Furthermore, under the surface plasmon resonance (SPR) effect of Ag particles, the nanocomposite films not only demonstrate a sensitivity to visible light but accelerate the photoelectron transfer efficiency at the interface between Ag particles and ZnO films. Photocatalytic experiments demonstrate that the photocatalytic activity of nanocomposite films is significantly enhanced in the photodegradation experiment of methyl orange (MO) or methylene blue (MB) pigments in comparison with pure ZnO films. It is relevant to note that hydroxyl radicals (•OH) contribute notably in photocatalytic degradation. The present work proposes a simple approach to preparing an efficient and recyclable nanoscale photocatalyst for the visible-light-induced purification to pigments in wastewater.