High-efficiency new visible light-driven Ag2MoO4–Ag3PO4 composite photocatalyst towards degradation of industrial dyes

Abstract

High-efficiency new visible light-driven Ag₂MoO₄–Ag₃PO₄ composite photocatalysts with different weight ratios were successfully synthesized by a facile solution-based in situ preparation method and characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV-visible diffuse reflectance spectroscopy (UV-vis DRS), photoluminescence spectroscopy (PL), and zeta potential measurement. Under visible light irradiation, the 10 wt% Ag₂MoO₄–Ag₃PO₄ composite photocatalyst exhibits enhanced photocatalytic degradation efficiency compared to other composites of Ag₂MoO₄–Ag₃PO₄, pure Ag₃PO₄ and pure Ag₂MoO₄ for the degradation of methylene blue (cationic dye). 10 wt% Ag₂MoO₄–Ag₃PO₄ composite photocatalyst is further used to investigate the photocatalytic degradation of rhodamine B (cationic dye) and methyl orange (anionic dye). The higher photocatalytic degradation efficiency of 10 wt% Ag₂MoO₄–Ag₃PO₄ towards cationic dye is closely related to its surface potential, and the observed degradation efficiency of MB is 2.7 and 16.87 times higher than that of RhB and MO, respectively. Based on the bandgap alignment, the photocatalytic degradation mechanism of Ag₂MoO₄–Ag₃PO₄ composite photocatalysts was examined. In addition, the quenching effect of different scavenger tests shows that holes and O₂⁻˙ are the most reactive species which play a major role in photocatalytic degradation of MB. The UV-vis DRS and photoluminescence study also support the higher photocatalytic degradation. TOC analysis was done to confirm the mineralization of dyes. The Ag₂MoO₄–Ag₃PO₄ composite photocatalyst is highly stable and 89% MB photocatalytic degradation was achieved after 4 recycle measurements under visible light irradiation. In addition, no phase changes of Ag₂MoO₄–Ag₃PO₄ composite photocatalyst and degraded product were confirmed.