Preparation, Characterization And Performance Research Of Indium-based Composite Materials

On the one hand,in this paper,template free method and a novel composite soft template method were used for controlling the synthesis of indium hydroxide and indium oxide micro-nanomaterials with various kinds of morphology such as 3D flowers-like and hollow spheres,respectively.In the synthesis of precursor In(OH)3,the effect of different parameters such as the additive concentration,the type of additive on structures,morphologies and sizes of the materials were investigated.Meanwhile,after the different thermal treatment temperature,the degradation efficiency of In(OH)3/InOOH heterojunction was focused on exploration under ultraviolet light.On the other hand,composite soft template method also was used for controlling the synthesis of the rambutan-like Al2O3/In2O3 micro-nanomaterials.The gas sensing response properties of a certain amount of In3+ doped Al2O3/In2O3 sensitive materials to NH3 were studied.The morphologies and sizes of micro-nanomaterials were characterized and analyzed by FE-SEM,TEM,HR-TEM,XRD,XPS,TG and BET,respectively.The main contents were as follows:1.The uniform morphologies In(OH)3 particles were prepared by template free method when urea was used as an alkali source.Each 3D flower-like In(OH)3 particle was self-assembled from a series of In(OH)3 1D nanorods with axial length of 400nm and external diameter of 90nm.Meanwhile,the effects of urea concentration and alkali source on the morphology and structure of In(OH)3 were investigated.The controlled synthesis of flower-like In(OH)3 can be realized by using urea as the base source and under the appropriate urea concentration.The precursor In(OH)3 calcined at 450? for 3h still has good inheritance.Under the different thermal treatment temperatures,using In(OH)3 as precursor,heterojunction In(OH)3/InOOH,In(OH)3/In2O3 and pure In2O3 were obtained.Results of ultraviolet photocatalytic degradation for Rh B shown that the photocatalytic activity of the heterojunction In(OH)3/InOOH is higher than that of single In(OH)3 or In2O3,and the photocatalytic activity decreased with the increased of content of In2O3.2.Taking CTAB-glutaric acid as the composite soft template and urea as an alkali source,In(OH)3 miro-nanomaterials with homogeneous hollow-sphere morphology were successfully synthesized by a simple hydrothermal method.The average diameters of the In(OH)3 hollow spherical nanostructures were about 300 nm and the shell thickness were about 70 nm.At the appropriate concentration,CTAB tended to form sphere-like micelles,and the two-carboxylate of glutaric acid played a role of bridging between CTAB and In3+,the glutaric acid not only enabled the formation of the complex soft template but also played the role of fixing In3+,thus In3+ was absorbed on the surface of composite template.At the same time,during the process of CTAB-glutaric acid soft template controlled synthesis of the hollow sphere In(OH)3,releasing OH-slowly was one of the key factors to form hollow structure.The precursor In(OH)3 calcined at 450? for 3h still were the same as before.Under the different thermal treatment temperatures,using In(OH)3 as precursor,heterojunction In(OH)3/InOOH,In(OH)3/In2O3 and pure In2O3 were obtained.Results of ultraviolet photocatalytic degradation for Rh B shown that the photocatalytic activity of the heterojunction In(OH)3/InOOH is higher than that of single In(OH)3 or In2O3,and the photocatalytic activity decreased with the increased of content of In2O3.3.Utilizing PEG4000-DL-aspartic acid as a composite soft template,a series of rambutan-like Al2O3/In2O3 composite materials were successfully synthesized by a simple atmospheric reflux method.These samples were used as sensitive materials for gas sensor.The 100ppm NH3 was used as the gas to be measured.It was found that Al2O3/In2O3 sensing film of the doped with 1%In3+ showed a good repetitive response to NH3.Moreover,there is a good linear relationship between the response of the sensor and the concentration of NH3,the sensitivity is about 9.88 Hz/ppm,and the response time is about 10s.After a month of testing,the response of the gas sensor still has basically stable.The fluctuation amplitude is 4.5%of the initial response frequency and has good stability.