阳极氧化法制备TiO_2纳米管及其光催化性能

纳米TiO_2对诸多环境污染物有显著的光催化降解作用,光催化已发展成为新型环境污染治理技术.本文采用阳极氧化法制备出TiO_2纳米管,对比了四种电解液组成(A氟化铵+硫酸铵+水;B氟化铵+硫酸铵+乙酸+水;C氟化铵+硫酸铵+甘油+水;D氢氟酸+二甲基亚砜(DMOS)+乙醇)对催化剂表面形貌及光催化性能的影响.结果表明,电解液A和C都制备出了形貌清晰的TiO_2纳米管,管径约为60～74 nm.样品经400℃煅烧,TiO_2晶型主要为锐钛矿相;经500℃煅烧,出现少量金红石相;经700℃煅烧,晶型全部为金红石相.具有良好形貌的TiO_2纳米管同时具有良好的紫外光吸收能力.当亚甲基蓝初始浓度为10mg·L~(-1),经500℃煅烧的TiO_2纳米管光催化活性最佳,光照30 min亚甲基蓝的降解率达89.98%.亚甲基蓝光催化降解反应符合一级反应动力学,反应速率常数为0.079 30.

Preparation of TiO_2 Nanotubes by Anodization and Its Photoeatalytic Properties

Nanosized TiO_2 was extensively studied due to its excellent photocatalytic activity. In this work, TiO_2 nanotubes were prepared by anodizing Ti in four electrolyte, ammonium fluoride+ammonium sulfate+water (electrolyte A); ammonium fluoride+ammonium sulfate+acetic acid+water (electrolyte B); ammonium fluoride+ ammonium sulfate+glycerin+water (electrolyte C); Hydrofluoric acid+Dmethyl sulfoxide+ethanol (electrolyte D). The influence of electrolyte composition on the morphology and phocatalytic performance of TiO_2 samples was investigated. The results indicated that TiO_2 nanotubes could be successfully fabricated using electrolyte A and C, and the tube diameter was in the range of 60～74 nm. When annealed under 400 ℃, anatase phase was dominant; while annealed under 500 ℃, a mixture of rutile and anatase phase appeared; and after annealed at 700 ℃, rutile phase was predominant. TiO_2 nanotubes with excellent morphology possess a high UV absorbance. TiO_2 nanotubes annealed at 500 ℃. Pseudo-first-order kinetics was also confirmed in the photocatalytic process of MB, and the apparent rate constant was 0.079 30.