Photocatalytic Evaluation of Anatase TiO₂ Coating on Ceramic Tiles by Raman Spectroscopy

Abstract

The present work reports a convenient way to evaluate the photocatalytic activity of anatase TiO₂ films by monitoring the degradation of methylene blue (MB) directly on the TiO₂ coated tiles under simulated solar light (1 sun condition; AM 1.5G simulator) using Raman spectroscopy. For this purpose, nanocrystalline TiO₂ films of aesthetic quality (thickness ∼80±5 nm) were deposited by the sol-gel method on the glazed tiles. XRD and Raman studies of the calcined coatings (500°C/2 h in air) confirmed the formation of anatase phase of TiO₂. The water contact angle (θ) value of the coated tiles was found to be 20±1° (hydrophilic) and no significant change of θ was noticed after storing in ambient condition for 3 months. The MB decomposition on the TiO₂ coating under 1 sun condition was monitored by recording the Raman spectra with respect to time. Using this technique, the apparent rate constant (k_app) value of MB degradation was found to be 0.2554 min⁻¹. The total photo-decomposition of dye and its repeatability studies through direct Raman monitoring of the coating surface ensured the self-cleaning ability of the TiO₂ coatings.

GRAPHICAL ABSTRACT

Keywords:

• Nanocrystalline TiO₂ coatings
• Sol-gel
• Hydrophilic
• Self-cleaning
• Photocatalytic degradation
• Raman spectroscopy