【作者】 刘萍；

【导师】 李新勇；

【作者基本信息】 大连理工大学 ， 环境工程， 2006， 硕士

【摘要】 光电催化技术因具有能耗低、反应条件温和、操作简便、可减少二次污染等突出优点而日益受到重视,近年来在环境治理领域受到广泛研究。本文对传统的TiO₂/Ti电极进行了改性,采用复合TiO₂膜电极和TiO₂纳米管电极作为光阳极,对电极的光电化学性能进行了研究并且在自制反应器内考察了电极对偶氮染料酸性橙Ⅱ（AO7）的光电催化降解作用。 用钛酸四正丁酯为原料,采用溶胶-凝胶法,制备出TiO₂、TiO₂-SnO₂纳米膜电极。TiO₂、TiO₂-SnO₂晶体的晶相及表面形貌经XRD、AFM分析得知,样品均为锐钛矿型;TiO₂、TiO₂-SnO₂纳米粒子的平均粒径分别为20nm和15nm。考察了TiO₂、TiO₂-SnO₂膜电极的光电化学性能,TiO₂、TiO₂-SnO₂膜电极光电转换效率（IPCE）分别为10.4%、19.9%。在相同条件下,TiO₂-SnO₂膜电极对AO7光电催化的降解率要高于电化学、直接光解及光催化。最后讨论了复合膜电极降解AO7的主要影响因素:外加偏压V、AO7初始浓度、溶液的pH、电解质浓度。在最优条件,外加偏压0.8V、pH2.06、Na₂SO₄浓度0.1mol/L下,AO7的脱色率可达到99%。 以氢氟酸为支持电解质,用阳极氧化法在钛片上直接制备出TiO₂纳米管电极,纳米管顶部开口,分布均匀,管径为60-90nm。TiO₂纳米管的IPCE为36.8%。研究了不同降解方式下TiO₂纳米管电极对染料AO7的降解效果,得出光电协同催化的降解效果最好。在施加0.8V偏压下,AO7的脱色率为83%（λ=484nm）、萘环的降解率为66%（λ=310nm）。实验结果表明,TiO₂纳米管电极的光电化学性能要比TiO₂、TiO₂-SnO₂膜电极好。使用TiO₂纳米管电极的脱色率为78%,而使用TiO₂、TiO₂-SnO₂膜电极为61%、70%（λ=484nm）。TiO₂纳米管电极的反应动力学常数要比TiO₂膜电极高出48.7%。更多还原

【Abstract】 The photoelectrocatalytic oxidation technique has been paid more and more attention for the advantages of less energy cost, mild reaction condition, easy operation and less secondary pollution, so it is abroad researched in the field of environment pollution control now. The traditional TiO₂/Ti electrode is fabricated, composited TiO₂ film electrode and TiO₂ nanotubes electrode are photoanodes. The photo-electrochemical properties of different electrodes are studied and the photo-electrocatalytic degradation of azo dye-Acid Orange 7 （AO7） species with different electrodes in aqueous solution is investigated in the reactor designed by ourselves.The main results show, the man-sized TiO₂, TiO₂-SnO₂ semiconductor photocatalyst can be obtained by the sol-gel processing using tetrabutyl titanate as a precursor. Crystalline phase and surface appearance of TiO₂, TiO₂-SnO₂ crystal could be obtained by XRD and AFM analysis, the samples prepared in this experiment are anatase, and the average size of TiO₂, TiO₂-SnO₂ particles in the thin film are 20nm and 15nm, respectively. The photo-electrochemical properties of TiO₂, TiO₂-SnO₂ film electrodes are studied, and the IPCE of TiO₂ and TiO₂-SnO₂ film electrode are 10.4% and 19.9% respectively. The AO7 dye degradation efficiency of photo-electrocatalysis is found higher than that of electrocatalysis, photolysis and photocatalysis with TiO₂-SnO₂ film electrode at the same conditions. The photo-electrocatalytic degradation of AO7 species in aqueous solution over the mentioned composite electrode is investigated under the effect factors such as bias potential, the initial AO7 concentration, the initial pH value in solution, concentration of Na₂SO₄ etc. Under the maxmium conditions, bias potential is 0.8V, pH is 2.06, concentration of Na₂SO₄ is 0.1 mol/L, 99% of AO7 is bleached.Vertically aligned nanotubes arrays of titanium oxide are fabricated on the surface of titanium substrate by direct anode oxidation with HF being the supporting electrolyte. The top-opened TiO₂ nanotubes are well aligned and organized into high-density uniform arrays, with diameter from 60 to 90 nm. IPCE of TiO₂ nanotubes electrode is 36.8%. The degradation of AO7 dye in aqueous solution with TiO₂ nanotubes electrode is carried out using different processes. A significant photoelectrochemical synergetic effect is observed. By applying a biasing potential of 0.8 V to the photoanode, a bleaching of 83% at λ=484 nm and a degradation of 66% at λ=310 nm are obtained for AO7 dye. The result indicates photo-electrochemical property is significantly improved for TiO₂ nanotubes electrodecompared with the film electrodes of TiO2 and TiO2-SnO2. It is also found that nearly 78% of AO7 dye at X,=484 nm is bleached over T1O2 nanotubes electrode, whereas 61%, 70% of AO7 dye are bleached by employing T1O2 film electrode and TiO2-SnO2 film electrode, respectively. The kinetics constant of PEC degradation of AO7 using T1O2 nanotubes electrode is 48.7% higher than that using TiC>2 film electrode formed by sol-gel method.更多还原