EFFECT OF PEG LOADING ON THE MICROSTRUCTURE AND PHOTOCATALYTIC ACTIVITY OF TiO2 FILM ON CERAMIC TILE

Abstract

TiO₂ films have been used and deposited on various substrates due to its potential application in photocatalysis. However, when deposited on ceramic substrates, TiO₂ films commonly resulted in a cracked morphology of the film which lead to delamination and peel off of film from substrate. Therefore, a binder needs to be added into the composition of TiO₂ solution in an effort to improve TiO₂ film structure. In this work, polyethylene glycol 2000 (PEG2000) was added into TiO₂ sol as an additive to act as a binder, in order to improve the microstructure of TiO₂ films on unglazed ceramic tiles and glass substrate by sol-gel dip-coating. The crystalline phases were characterized by XRD, while film morphologies were analyzed by SEM. The photocatalytic activity was evaluated by degradation of methylene blue (MB) under UV-radiation. The use of PEG successfully eliminated cracks and delamination of TiO₂ films even at the smallest amount of PEG added (1 mol%). Also, the addition of PEG creates pores on the surface of the films. This contributes to a higher degradation of MB and enhanced photocatalytic activity. The best degradation of MB observed was at 3 mol% PEG due to bigger pores on the surface of the film.