Enhancement of Efficient Ag-S/TiO2 Nanophotocatalyst for Photocatalytic Degradation under Visible Light

A new photocatalyst (Ag-S/PEG/TiO2) was synthesized by adding polyethylene glycol (PEG) to an efficient Ag-S/TiO2 photocatalyst, to obtain a photocatalyst that is highly active under visible light. In addition to Ag-S/PEG/TiO2, Ag-S/TiO2 and pure TiO2 were prepared to compare their properties and activities. Specifically, the morphologies and microstructures of the nanophotocatalysts were characterized by means of powder X-ray diffraction (XRD), N-2 adsorption-desorption measurements, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) microanalysis, transmission electron microscopy (TEM), UV-visible diffuse reflectance spectroscopy (DRS), photoluminescence (PL) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). Moreover, to evaluate their activities, the synthesized powders were used for the degradation of acid orange 7 (AO7) and methylene blue (MB) azo dyes in aqueous solution under low-voltage light-emitting diodes (LEDs) as the visible-light source. It was found that addition of PEG to Ag-S/TiO2 increases the photodegradation of AO7 and MB by about 28.82% and 24.24%, respectively, in comparison with Ag-S/TiO2 without PEG addition.