Study On Synthesis And Performance Of TiO₂ Nanobelts And TiO₂ Nanobelts-based Composites Materials

The rapid development of industry brought us social progress,but also caused a lot of environmental problems.Organic dyes and pigments are common water pollutants,which are frequently found in industrial effluents of textile.The colors of these dyes can be easily observed even at low concentration make water highly detrimental,which leads the harmful to the environment and human health.The traditional water pollution treatment method used in the production process is purely skilled,but there is a drawback that the handling process is cumbersome or the processing effect is poor.Semiconductor photocatalytic technology has attracted extensive research interest due to it can be the depth of organic wastewater treatment and has high efficiency.At the same time,air pollution problems have led to the rapid development of gas sensors.TiO₂ is not only a good photocatalyst,but also a potential sensitive material which has gas sensitivity to variety of gases,TiO₂ is a multifunctional nanomaterial.Industrial titanium dioxide powder?P25?has a higher photocatalytic efficiency,but its nanoparticle size is small,so it is difficult to recover.Directly used P25 for photocatalytic water treatment not only increases the cost,but also may cause secondary pollution to water.One-dimensional titanium dioxide nanomaterials are easily recovered by filtration because of their special morphology.For gas-sensing properties,one-dimensional titanium dioxide nanomaterials reduce the possibility of loss of electrons due to the presence of large amounts of grain boundaries,which facilitates the transport of surface carriers,so theoretically one-dimensional TiO₂ nanomaterial is more ideal for gas-sensitive materials than titanium dioxide nanoparticles.Therefore,this paper has prepared TiO₂ nanobelts by simple hydrothermal method.In order to improve its photocatalytic activities,gas sensing properties and recyclability,surface-coarsed TiO₂ nanobelts and several heterostructures based on TiO₂ nanobelts were fabricated by modification.The main researh contents as fellows:?1?Surface-coarsed TiO₂ nanobelts was synthesized through acid-assistant hydrothermal method.The results show that the main diffraction peaks of as-obtained TiO₂ nanobelts corresponding to the anatase TiO₂,and the belts are 50-200 nm in width,and up to a few millimetres in length withsubstantially coarsened surfaces.According to the photocatalytic test and gas sensing test,the surfaced-coarsed TiO₂ have good photocatalytic activity and gas sensing properties.The experimental parameters,including hydrothermal time,acid corrosion time and calcination temperature,are investigated in detail.The results show that with the increase of hydrothermal time,the nanobelts has a tendency to develop to the nanotubes.the decolorizing ability of the TiO₂/H2Ti3O7 nanobelts increases with increasing time of acid treatment,but the morphologies of the nanobelts with acid corrosion time longer than 24 h are completely destroyed.Heat treating at 500 oC,the sample transformed H2Ti3O7 to anantase TiO₂,continue to increase the calcination temperature,the anatase will be transformed into the rutile phase.?2?Surface-coarsed TiO₂ nanobelts was synthesized through acid-assistant hydrothermal method,and Fe₃O₄-TiO₂ nanobelts heterostructures were synthesized through co-precipitation method.Then,the composites was coated with Ag metal ions by deposition for get one-dimensional Ag@Fe₃O₄-TiO₂ magnetic nanomaterial.According to the SEM,TEM results,the Ag@Fe₃O₄-TiO₂ is belts which are 100-200 nm in width and some nanoparticles with a diameter of 5-30 nm on its surfaces.Ag@Fe₃O₄-TiO₂ shows enhanced photocatalytic properties and can be easily separatedfrom the solution with the help of external magnetic force.The enhancement of photo-catalytic activity is attributed to Ag act as electron acceptors.?3?TiO₂ nanobelts was synthesized through hydrothermal approach.The ZnO/TiO₂ nanocomposites were prepared by simple chemical-solution-deposition process combined with subsequent calcination.According to the SEM,TEM results,the as-obtained ZnO/TiO₂ nanocomposites have belts-sructure with diameters of 100²00 nm and ZnO nanoparticles with diameters of 40⁵0 nm randomly distribute on the surface.The ZnO/TiO₂ nanocomposites have better photocatalytic activity and shows higher sensitivity,rapid response and better selectivity to acetone.