A Study On Morphology And Structure Controlled Synthesis Of Sno₂Nanomaterials

As an important low-cost, n-type wide band gap semiconductor, SnO₂is well-known forits potential applications in transparent conductive electrodes and lithium rechargeablebatteries, dye-sensitized solar cells, ultrasensitive gas sensors and catalyst supports, due totheir excellent physiochemical properties. Thus, the tin dioxide has attracted great attentionfor a long time. Couple with the development of technology and economy in recent years,there’s more requirements with physicochemical property of SnO₂, and it becomes animpotant research topic that how to utilize the potential superior performance of SnO₂better.Some studies have shown that many fundamental physical or chemical properties ofsemiconductor materials strongly depend on the size and morphology of the materials, whichdefine their further applications for example the gas sensitivity, catalytic properties. Thus, ishas a lots of meaning to have the research on the controllable synthesize SnO₂nanocrystalswith desired structure and morphology.In this paper, firstly, we studied the structure and morphology controlled preparation ofSnO₂nanocrystals via the hydrothermal method. The PEG400, Zn2+, CTAB were used as thestructure directing agent in the process of hydrothermal treatment, technological conditionswere explored, the corresponding growth mechanisms were discussed. Secondly, we studiedthe fabrication of ordered SnO₂nanowires via a anodic alumina membrane （AAM） template,the technological conditions of preparation of AAM were explored, the best technologicalcondition of AAM for depositon of SnO₂nanowires was found, and the SnO₂nanowires arraywere obtained by a Sn（OH）4sol-gel approach and heat treatment. The structure andmorphology of SnO₂was characterized.With the help of PEG400in the process of one step hydrothermal reaction, when themolar ratio of SnCl4/NaOH is1:6, the nanostructure of SnO₂turns out to be thesingle-layered hollow microsphere with the diameters of2⁵μm, when the molar ratio ofSnCl4/NaOH is1:7, the nanostructure of SnO₂turns out to be the sheets and pieces with thethickness of about200nm. And it will be the flowerlike nanosphere composed of SnO₂submicron rods with the diameters of200³00nm when molar ratio of SnCl4/NaOH is1:8.With the help of Zn2+in the process of one step hydrothermal reaction, when the molar ratioof SnCl4/NaOH is1:6, the nanostructure of SnO₂turns out to be the nanospheres with the diameter of150nm, when the molar ratio of SnCl4/NaOH is1:8, the nanostructure of SnO₂turns out to be the flowerlike structure with the diameters of800nm, when molar ratio ofSnCl4/NaOH is1:9.6, the flowerlike structure with the diameters of1.2μm, when molar ratioof SnCl4/NaOH is1:9.6, there’s ZnSn（OH）6exist. With the help of CTAB in the process ofone step hydrothermal reaction, the nanostructure of SnO₂turns out to be the nanospherescomposed of small squares with the diameter of800nm.In the process of preparation of AAM, the best quality AAM was obtained using0.4mol/L oxalic acid at a voltage of45V, and the highly orderd pores with a diameters about84nm was obtained, the thickness of pores was32nm and the structure of pores was perfecthexagon. The pores were arrayed like honeycomb. The SnO₂nanowires were successfullyobtained by the depositon of SnO₂through a Sn（OH）4sol-gel approach and heat treatment.The diameter of nanowires was85nm which corresponds to the best quality AAM’s diameterof pores.