Novel Synthesis of Gold Doped Silver Phosphate Nanoparticles by Hydrothermal Method for The Enhancement of Visible Light-Responsive Photocatalytic Degradation of Fast Green FCF Dye

Abstract

In this study, the gold (Au) noble metal doped Ag₃PO₄ nanoparticles (NPs) were synthesized by hydrothermal method. The obtained photocatalysts NPs were characterized via FE-SEM, EDX, XRD and UV-Vis spectrophotometer. The crystal structure and phase were identified by XRD characterization. From the XRD the structure of Ag₃PO₄ NPs was not altered after doping with Au as a noble metal; in addition the sharp and narrow peaks indicate that Ag₃PO₄ NPs are high purity and have a crystalline structure. And the XRD pattern of samples after doping indicates that Au distributed homogenously in Ag₃PO₄. The morphology of bare Ag₃PO₄ and Au doped Ag₃PO₄ were studied by FE-SEM. The average sizes of the synthesized Ag₃PO₄ and Au doped Ag₃PO₄ NPs were 747.81 nm and 96.77nm respectively. EDX is utilized for the elemental composition analysis of the synthesized NPs and the pattern consists of corresponding peaks for P, Ag, O, and Au ions and it confirms the doped of Au noble metal ion in the prepared samples . The optical properties and the band gap were estimated by UV-Vis spectrophotometer.  The band gap was found for undoped and doped Ag₃PO₄ NPs were 2.39 eV and 2.34 eV respectively. Furthermore, the photocatalytic performances for bare Ag₃PO₄ NPs and Au doped Ag₃PO₄ were studied with fast green FCF dye. As a result the Au@ Ag₃PO₄ could be considered the optimum photocatalyst because the target dye molecule is degraded in 15 min, in contrast the bare Ag₃PO₄ NPs needed 55min. The photo degradation rate of the Au@ Ag₃PO₄ NPs is ∼3 times higher than the rate of Ag₃PO₄ NPs. Finally, Au@ Ag₃PO₄ NPs confirmed the highest photodegradation catalyst compared with other bare Ag₃PO₄ NPs.