纳米WO_3/DWCNTs材料的制备及其光催化性能

Fabrication of WO_3/DWCNTs Composite Photocatalyst with Enhanced Photocatalytic Activity

通过液相法制备出钨酸/DWCNTs和纯钨酸2种前驱体,然后在氮气气氛下焙烧至700℃,保温2 h,分别生成了WO_3/DWCNTs和WO_3粉末。采用扫描电子显微镜和X射线衍射仪对产物的形貌和结构进行表征。在11 W可见光的照射下,分别利用WO_3/DWCNTs和WO_3粉末对有机染料亚甲基蓝进行光催化降解反应;利用紫外-可见分光光度计测定出样品的紫外可见吸收光谱,通过朗伯比尔定律计算出光催化降解率。当光照时间为30 min时,WO_3/DWCNTs降解率达到87.50%,纯WO_3降解率仅为25.39%。结果表明,DWCNTs的加入可以有效抑制颗粒的团聚,减小颗粒尺寸,增大WO3的比表面积,增强WO_3的吸附能力,显著提高WO_3对亚甲基蓝的光催化降解效率。

Two precursors,tungstic acid/DWCNTs and pure tungstic acid,prepared by a liquid phase method,were calcinated at 700 ℃for 2 h in nitrogen atmosphere.Therefore,WO_3/DWCNTs and WO_3 powder were obtained.The structure and morphology of as-synthesized products were characterized by powder X-ray diffraction（XRD） and Scanning electron microscope（SEM）.The photocatalytic activity of the samples was evaluated by photocatalytic degradation of the methylene blue under visible light（11 W） irradiation.The clear upper layer solution was analyzed by a Milton Roy Spectronic 3000 Array spectrophotometer（New York,USA）.The photocatalytic degradation rate of the samples was calculated according to the lambert beer＇s law.Results show that the degradation rate of WO_3/DWCNTs and pure WO_3 is 87.50% and 25.39%,respectively,under photocatalytic degradation for 30 min.As the size of particles decreases,the specific surface area increases,and the adsorption capability of WO_3/DWCNTs is improved;all these effects are ascribed to the addition of DWCNTs.Therefore,the WO_3/DWCNTs composite photocatalyst exhibits much higher photocatalytic activity than pure WO_3.