An Exfoliated Graphite-Bismuth Vanadate Composite Photoanode for the Photoelectrochemical Degradation of Acid Orange 7 Dye

This work investigates the removal of acid orange 7 dye from aqueous solution through photo electrochemical technique using a composite of exfoliated graphite and bismuth vanadate (EG-BiVO₄) as photoanode. Monoclinic sheelite BiVO₄ nanoparticles were synthesised through the hydrothermal route and subsequently added to prepared EG to form a composite. The EG-BiVO₄ composite was fully characterised through XRD, SEM and FTIR. The cyclic voltammograms of the EG-BiVO₄ electrodes were obtained in potassium ferricyanide and ferrocyanide redox probe. The XRD result revealed that the BiVO₄ has a monoclinic sheelite crystal lattice with particle size of 74.17 nm. The EG-BiVO₄ photoanode was applied for the photoelectrochemical degradation of acid orange 7 dye. Concentration decay of the dye was monitored using the UV-Vis spectrophotometer. The photo-assisted process gave improved degradation efficiency of 88% within 90 min. Kinetics study revealed that the process followed the pseudo first-order kinetics and fast with apparent rate constant of 1.60 × 10⁻² min⁻¹. The results of this investigation reveal the potential application of BiVO₄ photoanode in the photoelectrochemical treatment of dye contaminated water. [Figure not available: see fulltext.].