Solar-Light-Responsive Titanium-Sheet-Based Carbon Nanoparticles/B-BiVO4/WO3 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 4 and WO 3 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 4 enhanced its optical absorption in both UV and visible regions. The LSV measurements carried out in 0.1 M Na 2 SO 4 showed that the BiVO 4 - and WO 3 -based photoelectrode demonstrated significant photoactivity. CNP/B-BiVO 4 and CNP/B-BiVO4/WO 3 photoanodes gave photocurrent densities of approximately 0.83 and 1.79 mA/cm 2 , 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 4 < B-BiVO 4 < WO 3 < CNP-BiVO 4 < CNP/B-BiVO 4 < CNP/B-BiVO 4 /WO 3 , 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 -1 for BiVO 4 , WO 3 , CNP/B-BiVO 4 , and CNP/B-BiVO 4 /WO 3 , respectively. The chemical oxygen demand abatement after 3 h of electrolysis at the best performing photoanode was 58%. The study showed that BiVO 4 and WO 3 are promising anodic materials for photoelectrocatalytic water treatment plant.