Solar-Light-Responsive Titanium-Sheet-Based Carbon Nanoparticles/B-BiVO/WO Photoanode for the Photoelectrocatalytic Degradation of Orange II Dye Water Pollutant.

We report the preparation and application of a heterostructured photoelectrocatalyst comprising carbon nanoparticles (CNPs) and boron codoped BiVO and WO for the removal of an organic dye pollutant in water. The materials, synthesized by hydrothermal method, were characterized by X-ray diffraction, diffuse reflectance UV-visible spectroscopy, energy-dispersive X-ray spectroscopy, and electron microscopy. The catalysts were immobilized on treated titanium sheets by drop-casting. The fabricated electrodes were characterized by linear sweep voltammetry (LSV) and chronoamperometry. Diffuse reflectance spectroscopy of the catalysts reveals that the incorporation of CNPs and B into the structure of monoclinic BiVO enhanced its optical absorption in both UV and visible regions. The LSV measurements carried out in 0.1 M NaSO showed that the BiVO- and WO-based photoelectrode demonstrated significant photoactivity. CNP/B-BiVO and CNP/B-BiVO4/WO photoanodes gave photocurrent densities of approximately 0.83 and 1.79 mA/cm, respectively, at 1.2 V (vs 3 M Ag/AgCl). The performance of the electrodes toward degradation of orange II dye was in the order BiVO < B-BiVO < WO < CNP-BiVO < CNP/B-BiVO < CNP/B-BiVO/WO, and the apparent rate constants obtained by fitting the experimental data into the Langmuir Hinshelwood kinetic model are 0.0924, 0.1812, 0.254, and 0.845 h for BiVO, WO, CNP/B-BiVO, and CNP/B-BiVO/WO, respectively. The chemical oxygen demand abatement after 3 h of electrolysis at the best performing photoanode was 58%. The study showed that BiVO and WO are promising anodic materials for photoelectrocatalytic water treatment plant.