Preparation Of Titanium Dioxide Nanomaterials And Graphene Composites And Their Photocatalytic Properties

With the development of the world,the problems of environment and energy have become the two key problems that are urgently needed to be solved in the world.As a renewable clean energy,solar energy has been considered as the most promising renewable energy in the world.Semiconductor photoelectricity and photocatalysis technology is an important way to solve the problem of energy crisis and environmental pollution.However the band gap of TiO₂ is relatively wide（3.0-3.2e V）,and it can only be excited by a small part of ultraviolet light in sunlight,and its utilization of sunlight is low.In addition,the TiO₂ photoelectron-hole pair has a higher probability of recombination.These factors greatly restrict the practical application of TiO₂ in the field of photoelectricity and photocatalysis.It is a hot topic to modify TiO₂ to improve its photoelectric and photocatalytic properties.In order to improve the photocatalytic performance of TiO₂,We have done a lot of work.And the main research contents are as follows:（1）Ca-doped TiO₂ nanofibers have been synthesized by electrospinning techniques with calcium acetate as the calcium source and titanium isopropoxide as titanium source.Their structure and morphology of the samples were analyzed and characterized by XRD and SEM,and the photocatalytic activity of TiO₂ nanofiber catalyst was investigated.The results show that the photocatalytic activity of TiO₂nanofibers for water-soluble Rhodamine B can be effectively improved by doping Ca2+.（2）Titanium dioxide nanotubes doped with different calcium were prepared by electrospinning with tetrabutyl titanate,calcium acetate polyvinylpyrrolidone and liquid paraffin as raw materialsas.It uses the insoluble characteristics of polyvinylpyrrolidone and liquid paraffin.Their structure and morphology of the samples were analyzed and characterized by XRD and SEM,and the photocatalytic activity of TiO₂ nanotubes catalyst was investigated.The photocatalytic experiments results showed that TiO₂ nanotubes doped with 5at.%calcium prepared by electrospinning had the highest catalytic activity,and the degradation rate of Rhodamine B was 92%in 30 min.（3）The Ca-doped TiO₂ nanowires were prepared by hydrothermal method using TiO₂ nanoparticles and calcium acetate as raw materials,and graphene was prepared by a acidification Hummer method using graphite as the raw material.Based on the above experiments,TiO₂/graphene nanocomposites with different Ca+concentration were successfully prepared by hydrothermal method,and their photocatalytic properties were investigated.The results show that Ca²⁺doping can effectively improve the photocatalytic activity of TiO₂/graphene nanocomposites for water-soluble methyl orange.