Photocatalytic degradation of Rhodamine B using Ag₃PO₄ microcrystals synthesized by the microwave-assisted hydrothermal method

Full text: The morphologies, optical properties, and electronic structures of silver phosphate (Ag₃PO₄) microcrystals were systematically characterized using a combination of theoretical calculations and experimental techniques. This material was synthesized by the microwave-assisted hydrothermal method at 140°C for 64 minutes. X-ray diffraction, Rietveld refinements and Fourier transform infrared spectroscopy were employed in the structural analysis. The morphology of these microcrystals was observed by scanning electron microscopy. First-principles computational studies were used to calculate the geometries of bulk Ag₃PO₄ and their (010), (100), (001), (110), (101), (011), and (111) surfaces. A continuous decrease in the values of surface energy for the (001) surface allowed to find a good agreement between experimental and theoretical morphology. These investigations are meaningful to gain further understanding of how to achieve shape-controlled microcrystal synthesis by tuning the surface chemistry. The optical properties were investigated by ultraviolet-visible spectroscopy and photoluminescence (PL) measurements at room temperature, with maximum PL emission in 444 nm. The as-synthesized sample presented high photocatalytic activity, when evaluated via photocatalytic degradation of Rhodamine B dye. Then, the photocatalytic activity and PL behaviour were correlated with the morphology. (author)