Preparation of nitrogen-doped TiO₂ nanotube deposited with gold nanoparticles for photocatalytic phenol degradation under visible light

One of the many functions of TiO₂ photocatalysts is degrading organic compounds. TiO₂ photocatalysts have a band gap of 3.2 eV, which is equivalent to the energy of ultraviolet (UV) photons with a wavelength of 388 nm and allows them to be effectively activated only by UV light. However, they are less effective under visible (Vis) light. Researchers have developed many ways to use the photocatalytic properties of TiO₂ under visible light via nitrogen doping. Further, the photocatalytic activity of N-doped TiO2 can be improved via surface plasmon resonance. In this study, N-doped TiO₂ nanotubes (N-TiO₂ NTs) are prepared and deposited with Au nanoparticles (Au/N-TiO₂ NTs) via electrodeposition. The TiO2 NTs and Au/N-TiO₂ NTs are characterized using UV-VIS spectrometry, Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), field emission scanning electron microscopy, energy dispersive spectroscopy (EDS), and linear sweep voltammetry (LSV). The photocatalytic test under tungsten lamp illumination of a 20-ppm phenol solution in a batch reactor shows a phenol degradation of 60 %, whereas a 20-ppm bisphenol A (BPA) solution is degraded by 40 %.