Photoelectrocatalytic degradation of oxalic acid using WO3 and stratified WO3/TiO2 photocatalysts under sunlight illumination

Y M Hunge; M A Mahadik; A V Moholkar; C H Bhosale

doi:10.1016/j.ultsonch.2016.09.024

Photoelectrocatalytic degradation of oxalic acid using WO₃ and stratified WO₃/TiO₂ photocatalysts under sunlight illumination

Ultrason Sonochem. 2017 Mar;35(Pt A):233-242. doi: 10.1016/j.ultsonch.2016.09.024. Epub 2016 Sep 28.

Authors

Y M Hunge¹, M A Mahadik², A V Moholkar¹, C H Bhosale³

Affiliations

¹ Electrochemical Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, India.
² Division of Biotechnology, Chonbuk National University, Iksan 570-752, South Korea.
³ Electrochemical Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, India. Electronic address: chbhosale@gmail.com.

PMID: 27720594
DOI: 10.1016/j.ultsonch.2016.09.024

Abstract

The WO₃ and stratified WO₃/TiO₂ thin films are successfully prepared by the spray pyrolysis method. The structural, morphological, compositional and photoelectrocatalytic properties of WO₃ and stratified WO₃/TiO₂ thin films are studied. XRD analysis confirms that films are polycrystalline with monoclinic and tetragonal crystal structures for WO₃ and TiO₂ respectively. The SEM images clearly show 3D sheeted porous structure of the as-prepared TiO₂ forms on WO₃ in stratified WO₃/TiO₂ samples. The synthesized photoelectrodes was used as catalyst for photoelectrocatalytic degradation of oxalic acid in aqueous medium. The rate constant (k) was evaluated as a function of the initial concentration of species. A significant decrease in concentrations of organic species was observed from COD analysis. The photoelectrocatalytic degradation effect is relatively higher in the case of the stratified WO₃/TiO₂ than WO₃ thin film photoelectrode in the degradation of oxalic acid and 83% removal efficiency of oxalic acid is obtained after 180min. Based on the obtained experimental data, the possible photoelectrocatalytic reaction mechanism was proposed. The photoelectrocatalytic experimental results indicate that stratified WO₃/TiO₂ photoelectrode is the promising material for removing of water pollutants.

Keywords: Chemical oxygen demand (COD); Oxalic acid (OA); Stratified WO(3)/TiO(2) thin film.