Ta_2O_5纳米管的阳极氧化法可控性制备研究

Research of controllably preparing Ta_2O_5 nanotubeby anodic oxidation method

以高纯钽板为基底,采用电化学阳极氧化法在H2SO4/HF溶液中制备出排列整齐,开孔率高,管壁光滑的Ta_2O_5纳米管。本实验通过优化样品前期处理工艺(在样品表面形成一层自组织的多孔Ta_2O_5氧化膜模板),同时调控阳极氧化电压和时间,实现了纳米管管径和管长的可控性生长,提高了Ta_2O_5纳米管的形貌质量。结果表明经过电解抛光后再进行阳极氧化得到的纳米管表面没有氧化物残留,开孔率高并且管壁光滑。阳极氧化电压恒定时,管径随氧化时间的增加基本保持不变,管长呈直线增长趋势。阳极氧化电压对于Ta_2O_5纳米管的形成及其形貌具有重要影响。当氧化时间为30 s时,在低电压5 V下并不会形成纳米管,在15 V和25 V条件下在钽基板上生成Ta_2O_5纳米管,其平均管径分别为45 nm和55 nm,纳米管的平均长度分别为1.46μm和4.03μm。XRD结果表明钽金属表面生成的一层纳米管薄膜为无定形态Ta_2O_5,并以罗丹明B为目标降解物,考察了Ta_2O_5纳米管薄膜的光催化活性,结果显示模拟太阳光下光照2 h后Ta_2O_5纳米管催化剂对罗丹明B染料的降解率为93%。

A highly ordered tantalum pentoxide(Ta2O5)nanotube film with high aperture ratio and smooth wall on tantalum substrate was fabricated using an electrochemical anodic oxidation method.The controllable growth of nanotube diameter and length was achieved and the quality of surface morphology of anodic Ta2O5 nanotube was improved by optimizing the pretreatment of tantalum template and changing oxidation voltage and time.The results show that high aperture ratio and smooth wall anodic Ta2O5 nanotube without oxide residue was obtained by introducing an electropolishing procedure before anodic oxidation.On the condition of constant anodic oxidation voltage,nanotube diameter nearly unchanged while the length of nanotube presented a linear growth trend with the extension of oxidation time.It was found that the formation and morphology of the Ta2O5 nanotube was greatly affected by the anodization voltage.Ta2O5 nanotube would not been formed at low voltage 5 V,however,when the anodic oxidation voltage were 15 V and 25 V,Ta2O5 nanotubes with average diameters of 45 nm and 55 nm were obtained,and the average lengths of Ta2O5 nanotube were 1.46μm and 4.03μm,respectively.XRD results showed that the nanotube films generated on the tantalum metal surface was amorphous Ta2O5,and the degradation of the dye rhodamine B was chosen to evaluate the photocatalytic activity of the film of Ta2O5 nanotube,showing that the degradation rate of the dye rhodamine B was 93%under the simulated sunlightafter 2 h.