Papers by Author: Yun Lu

Abstract: Photocatalyst coatings had been successfully fabricated by molten salt treatment at 673 K for 3 h for titanium (Ti) coatings, which coated on alumina (Al₂O₃) balls by mechanical coating technique with Ti powder. The influence of molten salt treatment on the formed compounds, surface morphology and photocatalytic activity under visible light irradiation on degradation of MB solution and suppression of Microcystis aeruginosa of photocatalyst coatings was investigated. XRD results show that potassium titanate (K₂Ti₆O₁₃) forms on the surface of Ti coatings during molten salt treatment. The visible light photocatalytic activity of photocatalyst coatings has been effectively enhanced by molten salt treatment.

Abstract: Photocatalyst coatings on alumina (Al₂O₃) balls had been successfully fabricated by mechanical coating technique, with titanium carbide (TiC) powder and subsequent heat treatment in carbon powder. The effect of heat treatment conditions in carbon powder on the formed compounds, surface morphology and photocatalytic activity of photocatalyst coatings was investigated. XRD results show that the formed compounds change with increasing the heat treatment temperature in carbon powder, and rutile TiO₂ on the surface of TiC coatings at 1073 K and 1173 K. The generated oxygen vacancies confirmed by XPS measurement, are in favor of narrowing band gap to enhance the visible-light photocatalytic activity of photocatalyst coatings. The photocatalytic activity of photocatalyst coatings has been effectively enhanced, and the samples fabricated at 1073 K and 1173 K for 2 h show higher activity. The fabrication strategy provides us a facile preparation procedure of visible-light responsive photocatalyst coatings.

Abstract: A novel TiO₂/Cu composite photocatalyst thin film was successfully fabricated by 2-step Mechanical Coating Technique (2-step MCT). The composite photocatalyst thin film was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), among others. The formation process of Cu thin film and TiO₂/Cu composite photocatalyst thin film were also examined. The results revealed that the formation of Cu thin film can fall into the following stages: nucleation, growth of nuclei and connection, formation and thickening of continuous thin film, and the exfoliation of thin film. In addition, TiO₂/Cu composite thin film had a composite microstructure of TiO₂ islands coated on Cu thin film. Furthermore, the photocatalytic activity of TiO₂/Cu composite photocatalyst thin film was evaluated by measuring the degradation rate of methylene blue (MB). Enhancement on the photocatalytic activity of TiO₂ was confirmed. The improvement of the photocatalytic activity of TiO₂/Cu composite photocatalyst thin film should result from the increase of the charge separation efficiency and the mass increase of TiO₂ in the composite thin film.

Abstract: In the present study, the TiO₂-Ti compacts with Magneli phases Ti_nO_2n-1 were fabricated using the mixed powder of TiO₂ powder and addition Ti powder by spark plasma sintering (SPS). The composition and the crystal types of Magneli phases Ti_nO_2n-1 were examined. The results showed that various Magneli phases Ti_nO_2n-1 (single or multi Magneli phases) with the composition of Ti_1+yO_2-x were obtained. The Magneli phases Ti_nO_2n-1 were formed in the transformation from the mother phase rutile TiO₂ to TiO with increase in Ti addition fraction. In addition, the thermoelectric properties of the sintered compacts were also measured. The electrical resistivity of the sintered compacts decreased with increase in Ti addition fraction. The thermoelectric performance of the sintered compacts was improved by the formation of Magneli phases Ti_nO_2n-1 with the composition of Ti_1+yO_2-x.