Enhancement in photocatalytic performance of Ag–AgCl decorated with h-WO3 and mechanism insight

Abstract

A h-WO3 decorated Ag–AgCl composite was prepared through facile precipitation and photoreduction methods and demonstrated to be a highly efficient and stable photocatalyst for the degradation of Rhodamine B (RhB) under visible light. Ag–AgCl/h-WO3 exhibited much improved photocatalytic performance was elucidated from the physical–chemical properties of AgCl and h-WO3 and the surface plasmon resonance effect of the Ag particles. The techniques of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectrometry (XPS) and photocurrent were used to characterize crystalline phases, morphology, composition and separation efficiency between electrons (e−) and holes (h+) of the synthesized composite photocatalyst. XPS results confirmed the existence of W5+ and W6+ on the surface of h-WO3 sample, which favored electrons transfer between AgCl and Ag, and generated superoxide radical for the degradation of RhB. The active species trapping experiments results further demonstrated that the formation of superoxide radical during the system. Finally, the underlying photocatalytic mechanism for the removal of RhB by Ag–AgCl/h-WO3 composite was examined.