Photoactive Ce-doped TiO2 and CeO2-TiO2 composite coatings deposited by suspension/solution plasma spray

In this work, Ce-doped TiO2 coatings were produced using a hybrid suspension (SPS) and solution precursor plasma spraying (SPPS) approach. CeO2-TiO2 composite coatings were also deposited by the SPS process. The photocatalytic activity of the coatings was evaluated by measuring the methylene blue degradation rate under visible light. Cerium doping and CeO2 composite coatings were characterized by X-ray diffractometer measurements and verified by energy dispersive spectroscopy mapping, Raman spectra, and X-ray photoelectron spectroscopy analysis. The hybrid SPS/SPPS technique presented a promising method to deposit doped ceramic coatings among thermal spray processes. According to the results, modifying TiO2 coatings decreased the bandgap of TiO2 from 3.25 to 2.3 eV using cerium dopant. However, a lower photocatalytic efficiency of TiO2 -CeO2 composite and Ce-doped TiO2 coatings compared to TiO2 could be related to the lower active surface area of TiO2 covered by submicron CeO2 particles and non-optimal dosage of cerium dopant, respectively.