光催化性能
(南京航空航天大學 材料科學與技術(shù)學院，南京 210016)
摘 要: 采用恒壓直流陽極氧化法制備具有規(guī)則排列的TiO2納米管陣列，并研究其在空氣熱處理過程中的晶型轉(zhuǎn)變，同時用甲基橙的降解過程表征其光催化性能。結(jié)果表明：電解液采用0.5%(質(zhì)量分數(shù))HF水溶液時，電壓在10~20 V之間，時間5 min以上才能形成TiO2納米管陣列；隨著氧化電壓的提高，納米管的平均管徑和管長都增大；隨著氧化時間的延長，納米管管長明顯增長，平均管徑變化不大；納米管陣列在空氣中熱處理時，280 ℃左右出現(xiàn)銳鈦礦相，400 ℃左右出現(xiàn)金紅石相，680 ℃左右銳鈦礦相向金紅石相的轉(zhuǎn)變結(jié)束，600 ℃納米管陣列結(jié)構(gòu)仍然保持完整。光催化實驗表明，在氧化電壓為20 V、氧化時間為20 min時獲得的納米管陣列經(jīng)過400 ℃熱處理后，在40 min的光照時對甲基橙的光催化降解率高達99.6%。
關(guān)鍵字: TiO2納米管陣列；陽極氧化；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
