Improved photocatalytic activity of Ag₂S quantum dots decorated TiO₂ nanotubes under visible light

In this paper, Ag₂S quantum dots (QDs) are successfully synthesized through a wet chemical method. Additionally, a hydrothermal method is employed to prepare Ag₂S QDs decorated TiO₂ nanotubes (Ag₂S@TNT) from Ag₂S decorated TiO₂ (Ag₂S@TiO₂). Furthermore, fluorescence spectroscopy (FL) is conducted to observe a substantial quantum confinement effect induced by Ag₂S QDs. The average particle size of Ag₂S@TNT is measured as 0.53 nm, as depicted in the high-resolution transmission electron microscopy (HR-TEM) images. The Brunauer–Emmett–Teller (BET) surface area analysis technique is utilized to assess the pore volume and surface area of the synthesized material. The electrochemical impedance spectra (EIS) analysis revealed that Ag₂S@TNT exhibited the smallest arc radius, signifying superior transfer and separation efficiency for photo-excited carriers compared to other samples. The photocatalytic degradation study demonstrates that Ag₂S@TNT exhibits impressive photocatalytic activity and stability in the presence of methylene blue (MB) as the target organic pollutant under simulated visible light.