A preferential precursor for photocatalytically active titanium dioxide thin films: Titanium bis-ammonium lactato dihydroxide as an alternative to titanium tetra iso-propoxide

Abstract

Titanium bis-ammonium lactato dihydroxide (TiBALD) precursor is used in place of the traditional sol–gel precursor, titanium tetra-isopropoxide (TTIP), to determine which precursor produces the most photocatalytically active titanium dioxide thin films. Films were deposited on glass substrates using modified sol–gel routes and the effects of non-ionic surfactant addition with Brij 58 and Brij 98 investigated. The morphology and nanostructure of the films have been assessed using SEM, XRD and Raman spectroscopy. The photocatalytic performance of the films was assessed using resazurin dye, whereby TiBALD precursor was found to produce thin films with enhanced photocatalytic efficiency, with an average rate of degradation for resazurin dye of 9.52×1012of dye molecules reduced per cm−2s−1 compared to 1.76×1012 dye molecules reduced per cm−2s−1 as for TTIP prepared films. A smaller average particle size (10–25nm) was also observed for thin films produced with TiBALD precursor, opening up potential for this precursor to be used for applications where a small TiO2 particle size is required. An overview of the differences between the two precursors for sol–gel deposition of TiO2 thin films is given within this study, including a discussion into the proposed differing decomposition mechanisms that may occur during sol–gel preparation.