TiO_2纳米管阵列的制备、热处理及光催化性能

Fabrication,anneal and photocatalysis applications of self-organized TiO_2 nanotubes

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10～20V之间,时间5min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20V、氧化时间为20min时获得的纳米管阵列经过400℃热处理后,在40min的光照时对甲基橙的光催化降解率高达99.6%。

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 ruffle 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%.