Evaluation of sunlight induced structural changes and their effect on the photocatalytic activity of V2O5 for the degradation of phenols

• Published in: Journal of hazardous materials 2015-04, Vol.286, p.127-135
• Main Authors: Aslam, M., Ismail, Iqbal M.I., Salah, Numan, Chandrasekaran, S., Qamar, M.Tariq, Hameed, A.
• Format: Article
• Language: English
• Subjects: 2-Aminophenol; 2-Chlorophenol; 2-Hydroxyphenol; 2-Nitrophenol; Aminophenols - analysis; Catalysis; Catechols - analysis; Chlorophenols - analysis; Chromatography, High Pressure Liquid; Electrochemistry - methods; Electrons; Hydrogen-Ion Concentration; Ions; Microscopy, Electron, Scanning; Nitrophenols - analysis; Particle Size; Phenol; Phenol - analysis; Phenol - chemistry; Photochemistry - methods; Photons; Reactive Oxygen Species; Semiconductors; Solubility; Spectrophotometry, Ultraviolet; Sunlight; V2O5; Vanadium Compounds - chemistry; X-Ray Diffraction
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2014.12.022

•The interaction of UV photons of sunlight induces defects in V2O5.•The photon induced defects promotes the trapping and transfer of excited electrons.•The nature of the substituent at 2-position affects the degradation process.•The formation of the intermediates is influenced by the nature of substituents.•The released ions are subjected further transformation. Despite knowing the fact that vanadium pentoxide is slightly soluble in aqueous medium, its photocatalytic activity was evaluated for the degradation of phenol and its derivatives (2-hydroxyphenol, 2-chlorophenol, 2-aminophenol and 2-nitrophenol) in natural sunlight exposure. The prime objective of the study was to differentiate between the homogeneous and heterogeneous photocatalysis incurred by dissolved and undissolved V2O5 in natural sunlight exposure. V2O5 was synthesized by chemical precipitation procedure using Triton X-100 as morphology mediator and characterized by DRS, PLS, Raman, FESEM and XRD. A lower solubility of ∼5% per 100ml of water at 23°C was observed after calcination at 600°C. The study revealed no contribution of the dissolved V2O5 in the photocatalytic process. In sunlight exposure, V2O5 powder exhibited substantial activity for the degradation, however, a low mineralization of phenolic substrates was observed. The initial low activity of V2O5 followed by a sharp increase both in degradation and mineralization in complete spectrum sunlight exposure, was further investigated that revealed the decrease in the bandgap and the reduction in the particle size with the interaction of UV photons (