Tuning the band gap of TiO2 by tungsten doping for efficient UV and visible photodegradation of Congo red dye

Irfan Ullah; Ali Haider; Nasir Khalid; Saqib Ali; Sajjad Ahmed; Yaqoob Khan; Nisar Ahmed; Muhammad Zubair

doi:10.1016/j.saa.2018.06.046

Tuning the band gap of TiO₂ by tungsten doping for efficient UV and visible photodegradation of Congo red dye

Spectrochim Acta A Mol Biomol Spectrosc. 2018 Nov 5:204:150-157. doi: 10.1016/j.saa.2018.06.046. Epub 2018 Jun 13.

Authors

Irfan Ullah¹, Ali Haider², Nasir Khalid³, Saqib Ali⁴, Sajjad Ahmed¹, Yaqoob Khan⁵, Nisar Ahmed⁵, Muhammad Zubair¹

Affiliations

¹ Department of Chemistry, Quaid-i-Azam University, 45320-Islamabad, Pakistan.
² Department of Chemistry, Quaid-i-Azam University, 45320-Islamabad, Pakistan. Electronic address: ahaider@qau.edu.pk.
³ Chemistry Division, Pakistan Institute of Nuclear Science and Technology, Nilore, Pakistan.
⁴ Department of Chemistry, Quaid-i-Azam University, 45320-Islamabad, Pakistan. Electronic address: drsa54@hotmail.com.
⁵ Nanoscience and Technology Department, National Centre for Physics, QAU Campus Islamabad, Pakistan.

PMID: 29929179
DOI: 10.1016/j.saa.2018.06.046

Abstract

Tungsten-doped TiO₂ (W@TiO₂) nanoparticles, with different percentages of atomic tungsten dopant levels (range of 0 to 6 mol%) have been synthesized by the sol-gel method and characterized by UV-Visible spectroscopy, XRD, SEM, EDX, ICP-OES and XPS analysis. By means of UV-Vis spectroscopy, it has been observed that with 6 mol% tungsten doping the wavelength range of excitation of TiO₂ has extended to the visible portion of spectrum. Therefore, we evaluated the photocatalytic activity of W@TiO₂ catalysts for the degradation of Congo red dye under varying experimental parameters such as dopant concentration, catalyst dosage, dye concentrations and pH. Moreover, 6 mol% W@TiO₂ catalyst was deposited on a glass substrate to form thin film using spin coating technique in order to make the photocatalyst effortlessly reusable with approximately same efficiency. The results compared with standard titania, Degussa P25 both in UV- and visible light, suggest that 6 mol% W@TiO₂ can be a cost-effective choice for visible light induced photocatalytic degradation of Congo red dye.

Keywords: Congo red dye; Nanoparticles; Photocatalysis; Sol-gel method; W-doped materials.