Photoelectrocatalytic activity and reaction mechanism of Ag2S/Ag3PO4/Ni nanothin films for rhodamine B

Ag2S/Ag3PO4/Ni thin films were prepared using an electrochemical method. The surface morphology, phase structure, optical characteristics and band structure of the thin films were analyzed using scanning electron microscopy (SEM), X-ray diffraction (XRD) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), respectively. Additionally, the films photoelectrocatalytic (PEC) activity and stability were evaluated using rhodamine B (RhB) as a model compound. Ag2S/Ag3PO4/Ni thin films that were prepared under optimum conditions contained nanoparticles that were approximately 25 nm in size and exhibited high PEC activity. At an optimum cathodic bias of -0.60V, the PEC degradation rate of RhB was 1.93 times greater than that of Ag3PO4/Ni thin film. Especially, the film displayed excellent PEC stability, even after being reused eight times. The possible PEC reactions between the film and RhB under visible-light irradiation are discussed in this paper.