Ti表面修饰纳米TiO_2膜电极的电催化活性

Electrocatalytic Activity of Nanocrystalline TiO_2 Film Modified Ti Electrode

用电化学合成法在Ｔｉ表面修饰一层纳米ＴｉＯ２膜,ＴＥＭ和ＸＲＤ测试表明晶型为锐钛矿型,晶粒平均尺寸为２５ｎｍ．用循环伏安法、循环方波伏安法和电解合成法研究了纳米ＴｉＯ２膜电极在硫酸介质中的氧化还原行为以及对硝基苯还原的电催化活性．结果表明,纳米ＴｉＯ２膜电极具有异相氧化还原催化行为,膜中的Ｔｉ(Ⅳ)/Ｔｉ(Ⅲ)作为媒质间接电还原硝基苯为对氨基苯酚,收率和电流效率分别达９１．６%和９５．２%．

The precursor Ti(OEt)4 was prepared by anodic dissolution of metallic titanium in absolutionethanol and directly hydrolyzed to prepare nanocrystalline TiO2 film on titanium electrode (Ti/nano-TiO2)by a sol-gel process. TEM and XRD were used to characterize the structure of nanocrystalline TiO2 film(Anatase, 25 nm). Redox behavior and electrocatalytic activities of the Ti/nano-TiO2 electrode were in-vestigated by cyclic voltammetry and cyclic osteryoung square wave voltammetry and bulk electrolysis. Theresults indicated that there were two pairs of well-defined redox peaks for Ti/nano-TiO2 electrode in 1 mol/L H2SO, with Epc1= -0.56 V, Epc2= -0.95 V(vs. SCE) at 100 mV/s and the heterogeneous catalyticredox behavior of this electrode in nitrobenzene(NB) in H2SO4 medium. It was found that the indirect elec-troreduction of NB to p-aminophenol(PAP) by Ti(Ⅳ)/Ti(Ⅲ) redox system occurred on nanocrystallineTiO2 film surface. In preparative electrolysis under optimal conditions, the average yield and current effi-ciency for PAP were 91.6% and 95.2% respectively.