Research On The Preparation And Photocatalytic Of MWCNTs-TiO2:Ce/Fe

Titanium dioxide, as an significant photocatalytic, is favored by scientists. It has advantages for its Green Initiative, deep oxidation-reduction ability and low price, etc. In particular, as research area of the carbon nanobutbes composites was continuously expand and deepen, the research of doped TiO2on MWCNTs is rapidly developed. The nature of the optical response of nano-solid materials depend on the electronic structure of TiO2nano-scale electronic structure and chemical composition, atomic arrangement, as well as the physical structure. Regulation of the electronic structure of TiO2nanoparticles by doping change of chemical composition can be achieved.In this study, the purification of carbon nanotubes mixed acid oxidation, with the advantage of the sol-gel and characteristics of the preparation of carbon nanotubes and titanium dioxide composite catalyst load cerium. Characterization by XRD, SEM, FIIR, UV-Vis means the product obtained in the purification of carbon nanotubes and preparation of composite catalyst, tested, explored the influence of experimental conditions on the final product, as follows:(1) The use of mixed acid oxidation, and purification of carbon nanotubes investigated by single-factor experiments the experimental conditions (reaction temperature, reaction time, mixed acid volume ratio) on the final product;and orthogonal experiment to optimize the results of single factor. Single factor experiments show excellent experimental conditions were as follows:reaction temperature130℃, reaction time120min, mixed acid ratio of3:1. Purification of carbon nanotubes mass loss as the reaction temperature, reaction time and the mixed acid volume ratio increases. Mixed acid oxidation purification of carbon nanotubes orthogonal experimental results show that various factors affect the size of the order of purified carbon nanotube mass loss as follows:reaction temperature> mixed acid volume ratio> reaction time. Orthogonal experiment, the best reaction conditions:reaction temperature130reaction time105, the mixed acid ratio of3:1. Characterization to determine the use of the orthogonal experiment, the optimum reaction conditions obtained purified carbon nanotubes, to display all of the original carbon nanotubes residual metal catalyst particles and carbon impurities removed, and introduced a new functional group of carbon nanotubes.(2)Preparation the load cerium iron multi-walled carbon nanotubes and titanium dioxide composite catalyst of the best experimental conditions, namely titanium dioxide and multi-walled carbon nanotubes mass ratio of1:0.067, and the gel time of72h, the calcination temperature was450℃, the quality of the relationship between load cerium iron1.5%,1%. Characterization, we see the load cerium composite catalyst, the surface of dense titanium dioxide particles, reunion, while multi-walled carbon nanotubes complete bending of the graphite structure did not entwined, was a hollow space network structure. UV-visible absorption spectra see load-cerium composite catalysts absorb light at500nm for visible light range, far beyond the scope of UV380nm This indicates that titanium dioxide was prepared by the modified complex catalyst has excellent catalytic activity and light utilization.(3)By UV and visible light irradiation, study of MWCNTs-TiO2load cerium:x%Ce,y,%of Fe catalytic activity and catalyst stability. The results showed that the catalytic activity and stability of the catalyst oxidation of methyl orange, are performing well. Activity evaluation, under ultraviolet light in of MWCNTs-of TiO2:1.5%of Ce,1%Fe catalytic oxidation of methyl orange90min, the decolorization rate reaches95%in150min after the decolorization rate of99%; in stability evaluation of MWCNTs-TiO2:1.5%Ce,1%Fe after repeated four times a total of10h reaction, the catalytic oxidation of methyl orange decolorization rate changes are less than5%.This indicates that under UV irradiation, the carbon nanotubes modified titanium dioxide composite catalyst load cerium iron strong catalytic activity and excellent stability. Cerium under visible light load of MWCNTs-TiO2:x%Ce, y%Fe activity evaluation of MWCNTs-TiO2:1.5%Ce,1%Fe catalytic oxidation of methyl orange150mm, the decolorization rate is reached96%decolorization rate reached99%in240min;stability evaluation of MWCNTS-TiO2:1.5%of Ce,1%Fe after repeated four times a total of16h of reaction, although in the fourth experiment was repeated, the catalytic oxidation of methyl orange with slight inactivation, but the composite catalyst catalytic oxidation of methyl orange decolorization rate of change of control in10%. This indicates that under UV irradiation, the carbon nanotubes modified titanium dioxide composite catalyst load cerium iron strong catalytic activity and excellent stability.