Surface plasmon resonance and heterojunction formation in Ag/AgI/Ag3VO4 photocatalyst for efficient photodegradation of methyl orange

Abstract

A novel Ag/AgI/Ag3VO4 plasmonic photocatalyst was synthesized through ion exchange technique, followed by photoreduction. Various techniques including X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible diffuse reflection (UV-DRS) were undertaken to characterize the phase structure, morphology, chemical composition, and optical properties of Ag/AgI/Ag3VO4. The catalytic activity measurements were conducted using decomposing methyl orange (MO) irradiated with visible light. Compared with Ag/AgI and pure Ag3VO4, the Ag/AgI/Ag3VO4 composite significantly enhanced catalytic activity, resulting in 94.4% degradation of MO within 15 min of visible light. Ag/AgI/Ag3VO4 exhibited remarkable catalytic activity, which was because of the intimate heterojunction formation, and the surface plasmon resonance (SPR) effect of Ag nanoparticles (NPs), thereby boosting carrier separation. Furthermore, quenching tests confirmed that the majority of active species were •O2− and h+ during the catalytic reaction. This study discussed a plausible catalytic system mechanism that effectively separates photocreated carriers in the Ag/AgI/Ag3VO4 composite to enhance MO degradation activity.