The Effect of Fuel Ratio on Activity of Suspension Flame Sprayed Titania Coatings

Abstract

The photocatalytic properties of titania are widely known with applications including solar water disinfection, solar hydrogen production and as anti-bacterial surfaces. Herein, we report the use of suspension flame spraying for the deposition of conformal TiO2 coatings. This process is carried out using aqueous titania suspension (ca. 5 wt%) injected into an acetylene flame (ca. 3100 °C), via an atomiser. Coatings deposited were adherent, majority anatase phase and retained their nanostructure after coating. In this study the acetylene/oxygen ratio was altered to determine the effect on the photoactivity of titania coatings produced, with photoactivity determined by photocurrent generation under illumination. All coatings produced were shown to be photoactive with a marked difference in photocurrent observed between coatings produced in the varying flame conditions. Photocurrent generation increased by up to 3.7 times with decreasing fuel ratio. This difference was attributed to the build-up of reduced titania species in the coating.