Preparation Of Visible-light Response Ce@TiO₂Modified With SO₄^2- And Their Catalytic Property

With the social and economic development, environmental pollution problems havegradually become the focus of researchers. Titanium dioxide (TiO2) has received a greatdeal of attention as its chemical stability, non-toxicity, high photo-oxidation, and otheradvantageous properties. However, titania shows photocatalytic activity only under UVlight irradiation because of its band gap value of around3.2eV. It is known that the UVpart of the solar spectrum only accounts for about2%of the incoming solar energy. If thenatural sunlight is used for the photo excitation of titania, only a few of the incidentradiation has enough energy for this process. So their application in treatment of theeffluent was difficult to accomplish.In this study, SO42-modified Ce@TiO2composite photocatalysts were successfullyobtained via sol-gel method and impregnating method using raw materials, includingtetrabutyl titanate and cerium nitrate. The photocatalytic activities of the preparedcomposite photocatalysts were evaluated via a probe reaction to degrade Rhodamine Bunder visible light and the study focus on the influence of Ce doping amount, H2SO4concentration and calcination temperature on the photocatalytic property. Experimentalresults indicated that SO42-modified Ce@TiO2presented much higher visible lightphotocatalytic activity than pure TiO2,TiO2/SO42-and Ce@TiO2samples. The highestphotocatalytic activity reached on the Ce@TiO2/SO42-composite with0.3%ofCeaddition, prepared under1.5%sulfuric acid concentration and500C calcinedtemperature. In addition, Zn@TiO2/SO42-was also prepared and their performanceswere preliminarily discussed.The properties of the result composites were characterized by X-raydiffraction(XRD), UV-vis absorbance spectroscopy, X-ray photoelectronspectroscopy(XPS), temperature programmed desorption(TPD), high resolutiontransmission electron microscopy(HRTEM), energy dispersive spectrometer(EDS) andFourier transform infrared (FTIR) spectra techniques. The UV-vis results showed thatCe@TiO2/SO42-has a good absorption performance in visible range; The results of XRDshowed that no characteristic peak of Ce species ascribe to cerium species dispersed wellon the surface of titania nanoparticles，At the same time, the TiO2grain growth was restrained because of the Ce existence, and then, to some extent, introducing defects onthe TiO2crystal plane; FTIR analysis showed that Ce@TiO2/SO42-catalysts contained Band L acid sites; TEM analysis showed that Ce@TiO2/SO42-catalysts had regularmorphology; In addition, the XPS analysis showed that the binding energy between theatoms in the Ce@TiO2/SO42-catalyst has changed, which leads to the changing ofelectron clouds in the TiO2surface.