光催化性能
(南京航空航天大学 材料科学与技术学院，南京 210016)
摘 要: 采用恒压直流阳极氧化法制备具有规则排列的TiO2纳米管阵列，并研究其在空气热处理过程中的晶型转变，同时用甲基橙的降解过程表征其光催化性能。结果表明：电解液采用0.5%(质量分数)HF水溶液时，电压在10~20 V之间，时间5 min以上才能形成TiO2纳米管阵列；随着氧化电压的提高，纳米管的平均管径和管长都增大；随着氧化时间的延长，纳米管管长明显增长，平均管径变化不大；纳米管阵列在空气中热处理时，280 ℃左右出现锐钛矿相，400 ℃左右出现金红石相，680 ℃左右锐钛矿相向金红石相的转变结束，600 ℃纳米管阵列结构仍然保持完整。光催化实验表明，在氧化电压为20 V、氧化时间为20 min时获得的纳米管阵列经过400 ℃热处理后，在40 min的光照时对甲基橙的光催化降解率高达99.6%。
关键字: TiO2纳米管阵列；阳极氧化；光催化
of self-organized TiO2 nanotubes
（College of Material Science and Technology, Nanjing University of Aeronautics
and Astronautics, Nanjing 210016,China）
Abstract:Self-organized TiO2 nanotube arrays were fabricated by anodic oxidation of a pure titanium sheet at constant potential. The results show that TiO2 nanotube arrays are regularly obtained when anodizing voltages ranges from 10 to 20 V, anodizing time keeps more than 5 min and HF concentration is 0.5%. The average diameter and length of the tube increase with increasing anodizing voltage. And the length of tube increases with longer anodization time obviously. After annealing for 3 h in ambient atmosphere, the anatase phase emerges at about 280 ℃, the rutile phase emerges at about 400 ℃, anatase transforms completely to rutile at about 680 ℃ and nanotube architecture can be preserved till 600 ℃. Furthermore, TiO2 nanotubes, fabricated at anodizing voltage of 20 V for 20 min and then annealed at 400 ℃, possess better photo-catalytic activity, i.e. the decolourisation of methyl orange irradiated for 40 min is 99.6%.
Key words: TiO2; nanotube arrays; anodic oxidation; photo-catalytic activity
