| According to the principle of colloid and interface chemistry,a novel composite soft template method,which was constructed by the self-assembly of organized surfactant molecular assemblies with small organic compounds,was proposed for controlling the synthesis of indium hydroxide and indium oxide micro-nano materials.Besides,indium oxide of different shape possessed uniform sizes and structures.In the process of In(OH)3 nano material synthesis,the experimental conditions such as the additive concentration,additive type,and the reaction temperature were investigated to explore their effects on structures,shapes and sizes of nano materials.At the same time,the photocatalytic degradation feasibility and effectiveness of In(OH)3/In2O3 heterostructure to the aqueous solution of methylviolet were explored.In this paper,the physical and chemical properties and gas sensing properties of In2O3 were studied,and the gas sensing properties of In2O3 with different morphologies and sizes were also investigated.The morphologies and sizes of nano materials were characterized and analyzed by TEM,FE-SEM,TG-DSC,BET,XRD,XPS,FT-IR,Raman andUV-DRS,respectively.The main contents were as follows:1.The In(OH)3 nano rod about 1 μm in length with uniform morphologies were synthesized through the low-temperature hydrothermal method,using CTAB-2-(4’-Carboxyphenoxy)benzoic acid as the complex soft template and urea as a base source.The effects of synthesis conditions on morphology and structure of the sample were systematically investigated.At a suitable concentration,CTAB tended to form rod-like micelles,and the two-carboxylate of 2-(4’-Carboxyphenoxy)benzoic acid played a role of bridging between CTAB and In3+-which not only enabled the formation of the complex soft template but also played the role of fixing In3+,when In3+ adsorbed on the surface of composite template.Simultaneously,during the process of CTAB-oxalate soft template controlled synthesis of In(OH)3 microtubes,releasing OH-slowly was one of the important factors to form rod-like structures by self-assembly.At 450|℃,In(OH)3 nano rod were changed into In2O3 nano rod after calcining 3 hours,and morphologies of the obtained particles were the same as before.2.Precursor of In(OH)3 nano materials were calcined into In(OH)3/IIn2O3 heterostructure with virous contents of In2O3 at different temperature after 2 hours.And the photocatalytic activities of In(OH)3,In2O3,In(OH)3/InOOH and In(OH)3/In2O3 heterostructure were evaluated using methyl violet as a model reaction.Contrast experiment of sample with different morphologies was carried out to compare the importance of morphology nano materials.Results of ultraviolet photocatalytic degradation for methyl violet dyes showed that heterostructure has the best photocatalytic activity compare to single phase In2O3 and In(OH)3,and the photocatalytic activity decreased with the increased of content of In2O3 in heterostructure.3.The surface area of samples prepared at the first three chapters was measured by the low-temperature N2 adsorption method.The surface area of long nano rod,short nano rod,micro tube and hollow ball-shaped In2O3 micro-nano structures were 27.17 m2/g,59.58 m2/g,74.17 m2/g,73.66 cm2/g,respectively.Based on the QCM technology,In2O3 with different morphologies and structures were used as the sensing film materials and H2 sensors were fabricated for the room temperature detection.The important parameters of the sensors have been obtained,such as repeated response performance and sensive.Results showed that all kinds of morphology had a good response and repeatability performance to H2.Besides,the response of the sensor was in good linear proportion with the hydrogen concentration. |
