Photodegradation of Methyl violet using Ag modified TiO2 nanotubes by UV and UV/ H2O2

Abstract

Titanium dioxide (TiO2) is a semiconductor material that is frequently utilized in photodegradation applications. Its application in photodegradation is constrained by its broad band gap of 3.2 eV and increased rate of photoelectron recombination. However, by doping TiO2 with metallic nanoparticles, the band gap can be modified and photodegradation can be improved. The present study explores the fabrication of Ag-modified TiO2 nanotube photocatalysts by electrochemical anodization followed by hydrothermal method. The structural, morphological, compositional, optical, and thermal properties of prepared photocatalysts were characterized by X-ray analysis, Field emission scanning electron microscopy, N2 adsorption desorption analysis, X-ray photoelectron spectroscopy, Energy dispersive X-ray spectroscopy, UV–Vis diffuse reflectance analysis and Thermogravimetric-differential thermal analysis. The prepared photocatalyst was utilized to investigate the degradation of methyl violet in the presence of UVA and UVC radiation. The effects of UVA and UVC illumination on the degradation process, the effect of Ag loading in the TiO2 nanotube arrays and the role of H2O2 in the degradation of pollutant were studied. The degradation efficiency of methyl violet in the presence of UVC light was three times that of UVA light. For pristine TiO2 photocatalyst, the maximum degradation of 70% was obtained under UVC illumination in 8 h. When H2O2 was added, complete degradation was observed within 3 h. Reusability studies have shown that photocatalysts are stable and can be used for the degradation of methyl violet.

Keywords

• TiO2 nanotube arrays
• Ag-modified TiO2 nanotubes
• Photocatalysis
• Methyl violet
• UV irradiation
• Hydrogen peroxide