Electrodeposition of BiVO4 Nanoparticles on TiO2 Nanotubes: Characterization and Synergetic Photocatalytic Degradation Activity of Amido Black Dye

To enhance the photocatalytic performance of TiO₂ nanotubes (NTs) for the degradation of Amido Black as an organic pollutant, electrodeposition of bismuth vanadate (BiVO₄) nanostructures was successfully applied. The effect of electrodeposited BiVO₄ (25 s, 50 s, 150 s, 250 s), followed by a thermal treatment on TiO₂-NTs, was studied. The structures of the as-prepared samples were characterized by X-ray diffraction (XRD). Morphological behavior was investigated using Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM), both coupled with EDX. Optical characterizations were performed using photoluminescence and diffuse reflectance spectroscopy. The BiVO₄/TiO₂ NTs sample with 50 s deposition time gave the highest photocatalytic performance for Amido Black degradation, 99.4% after 150 min under UV light. This result has been achieved due to the structure and the optical properties of the sample. The heterojunction of both catalysts showed the synergetic effect on the photocatalytic performance where they remained stable after five cycling runs. Furthermore, quenching tests were conducted and proved that superoxide radicals (O₂^•) are the main active species during photodegradation process.