W掺杂二氧化钒的水热晶化机理及其相变性能  

Crystallization Mechanism and Phase Transition Properties of W-doped VO_2 Synthesized by Hydrothermal Method

作　　者：李尧[1] 卢怡[2] 曹文斌[1,3] 

机构地区：[1]北京科技大学材料科学与工程学院,北京100083 [2]解放军306医院口腔科,北京100101 [3]北京科技大学天津学院,天津301830

出　　处：《材料工程》2017年第11期58-65,共8页Journal of Materials Engineering

基　　金：国家重点研究发展计划资助项目(2016YFC0700901;2016YFC0700607)

摘　　要：以硫酸氧钒为钒源,采用沉淀-胶溶法制备VO_2溶胶。然后向溶胶中加入偏钒酸铵,利用溶胶水热晶化制备出W掺杂二氧化钒(W-VO_2,M相)粉体。通过XRD,FESEM和DSC对合成产物的物相组成、形貌和相变性能进行研究。结果表明:在280℃条件下水热处理4~48h,VO_2溶胶经过水热晶化生成长约1~2μm、直径约100~200nm棒状W-VO_2(B)晶体,伴随着B相向M相晶型转变,W-VO_2(B)逐渐消溶,而W-VO_2(M)逐渐长大,形貌由棒状转变为片状或雪花状;W-VO_2(M)相变温度随着W掺杂量增加而降低,当名义掺杂量为6.0%(原子分数)时,相变温度降低到28℃。根据水热晶化和形貌演变过程,提出了W-VO_2(M)可能的"形核-生长-转化-熟化"形成机理。VO2 sol was firstly prepared using vanadyl sulfate as a vanadium source by precipitation- peptization method. Then tungsten （W） doping vanadium dioxide （W-VO2） was prepared by hydro-thermal crystallization of prepared sol with the presence of ammonium metatungstate. The morpholo-gies ,crystal structure of the as-prepared samples and phase transition properties were studied by X-ray diffraction（XRD）,field emission scanning electron microscope （FESEM） and differential scan-ning calorimetry（DSC） analysis. The results indicate that rod-like W-VO2 （B） crystal with length of and radius of 100-200nm is firstly formed during hydrothermal treatment for 4-48h at 280℃, then the rod-like crystal dissolves gradually and sheet-like or snowflake-like crystal is formed with the phase transition from W-VO2（B） to W-VO2（M） and eventually, the W-VO2（M） crystals can further grow up while the W-VO2（B） gradually dissolves; the phase transition temperature of VO2 decreases with the increase in W doping content, and the phase transition temperature of W-VO2（M） reduces to about 28℃ when the nominal dopant concentration is 6.0% （atom fraction）. The “ nucleation-growth- transformation-ripening mechanism is proposed as the formation mechanism based on the hydrother-mal crystallization and morphological evolution process of W-VO2（M）.

关 键 词：二氧化钒 水热合成 相变温度 钨掺杂 

分 类 号：O614.51[理学—无机化学]