Parameters Influencing the Photocatalytic Activity of Suspension Sprayed ZnO-TiO2 Coatings

Due to their promising photocatalytic properties under visible light irradiation, thermally sprayed ZnO-TiO2 coatings are of interest as substitute for TiO2 for various industrial applications, like hydrogen production via water splitting or the reduction of organic pollutants in water. Suspension spraying is an effective method to produce coatings in the binary ZnO-TiO2 system to form Zn2TiO4 in-situ during the spraying process. Aqueous suspensions containing fine dispersed ZnO and TiO2 particles are mixed at tailored composition and sprayed using the SHVOF and SPS spraying processes. Coatings with homogeneous distribution of elements and different surface structures and phase compositions are obtained. The phase composition is analyzed via XRD. UV-Vis spectroscopy measurements and photocatalytic tests of Rhodamin B degradation are performed. The potential to use appropriate binary suspension feedstock to produce ZnO-TiO2-Zn2TiO4 coatings with different microstructures and photocatalytic properties is presented.