TiO2纳米管论文：改性TiO 2纳米管光电极制备及可见光下光电催化性能研究

TiO2 纳米管论文：改性 TiO_2 纳米管光电极制备及可见光下光电催化性能研究【中文摘要】TiO2 催化剂由于其成本低、无毒、活性高、无二次污染等优点在环境保护领域被广泛应用于去除难降解有机物。然而,其存在禁带宽度过大（3.2 eV）等缺陷,限制了其在污染治理中的应用。通过对 TiO2 进行过渡金属离子掺杂能够有效减小其禁带宽度,拓宽光谱响应范围。作为内分泌干扰物的一种,壬基酚广泛存在于洗涤剂、纺织、造纸等工业生产中,它能够长期存在于自然界中,很难被生物降解,其降解一直是国内外研究的热点和难点。本文采用阳极氧化法制备了 TiO2 纳米管光电极,通过电沉积对其进行 W 掺杂改性,拓宽了其光谱响应范围,研究了 W/TNT 光电极对壬基酚的光电催化降解效果。采用阳极氧化法制备了 TiO2 纳米管（TNT）光电极。考察了制备电压、时间、煅烧温度等条件对 TNT 阵列的表面形貌和结构的影响,利用扫描电子显微镜（SEM） 、X 射线衍射（XRD） 、能量散射 X 射线能谱（EDX）等手段对光电极进行了表征。以罗丹明 B 为目标污染物,考察了不同制备条件对 TNT 光电极在可见光下的光催化性能的影响。结果表明,通过调节阳极氧化过程中的参数可以实现对不同尺寸和结构的 TNT 光电极的可控制备。采用电化学沉积的方法,以 TNT 阵列光电极为基体,制备了 W 掺杂的 TiO2 纳米管阵列光电极。优化了 W/TNT 光电极的最佳掺杂条件,考察了 W/TNT 光电极的光催化性能。结果表明,光电极的最佳制备条件为:沉积电压为 3V、电极间 距为 1cm、沉积液（NH4）2WO4 浓度为 1.0g/L、沉积时间为 10min、煅烧处理温度为 550。W/TNT 光电极的表征结果显示 W 的掺杂会抑制锐钛矿相 TiO2 晶粒的生长以及晶相转变过程;XPS 图谱分析表明W 元素通过掺杂进入到了 TiO2 晶格内部形成 W-Ti-O 键;WTNT 光电极对可见光的光谱响应范围发生红移;改性与未改性 TiO2 纳米管光电极对罗丹明 B 的降解效果表明,相对于未掺杂的 TNT 光电极,W/TNT光电极对罗丹明 B 的降解效果更优,掺杂后的光电极具有更佳的光（电）催化活性。采用 W/TNT 光电极在可见光下对内分泌干扰物壬基酚进行光电催化降解,考察了壬基酚光电催化降解过程中的影响因素,研究了该过程中壬基酚的矿化过程。结果表明,pH 值在中性条件下,光电极对壬基酚的光电催化降解效果最佳;随着反应中壬基酚初始浓度增加,W/TNT 光电极对壬基酚的降解效率逐渐下降;随着外加偏压的增加,壬基酚的光电催化降解效率逐渐增大,而外加偏压高于2.0V 时,进一步增加电压反而不利于壬基酚的降解;催化剂面积的增大,有利于光电极对壬基酚光电催化降解效果的提高。在壬基酚光电催化反应过程中,壬基酚分子在·OH 的作用下经过一系列反应转化为中间产物,而不是被完全矿化成 CO2 和 H2O。【英文摘要】Titanium dioxide （TiO2） has been widely utilized in the environmental protection as the photocatalyst for the degradation of organic pollutants due to its low cost, non-toxicity, excellent stability and without secondary pollution.However, the wide band gap energy of TiO2 catalyst （3.2 eV） limits this photocatalysts application in the process of environmental protection. Photoelectrode doping could effectly decrease the band gap energy of TiO2 by doping with transition metal elements, which could extend the response of TiO2 to visible light.As one of the typical Environmental Endocrine Disruptors （EEDs）, Nonyl Phenol （NP）, has attracted great attention owing to their widely used in the manufactures of detergent, textile and papermaking, which are long-standing and bio-refractory organic compounds. It is of significant importance to develop new treatment technologies for the degradation of NP in the environment.In this work, the TiO2 nanotube（TNT） photoelectrodes were prepared by means of anodic oxidation. W doped TNT photoelectrodes were fabricated via electrochemical deposition, which could extend the response of TiO2 photocatalyst to visible light. The present work also studied the degradation of endocrine disrupting chemicals NP using W/TNT photoelectrodes.TNT photoelectrodes were prepared by means of anodic oxidation process with post-calcination. The effect of anodization conditions including anodic voltage, anodic time and clacination temperature on the morphology and crystal structure of photoelectrodes were studied. Scanning electronic microscopy （SEM）, X-ray diffraction （XRD） and Energy dispersive X-ray detector （EDX） were used to characterize the morphology and crystal structure of photoelectrodes.Photocatalytic activity of the TNT photoelectrodes was evaluated in terms of the degradation of NP in aqueous solution. The effects of the preparation conditions on the photocatalytic activity were investigated in detail. The results indicated that the preparation of TNT electrodes with ideal size and structure were controllable in terms of adjustment of the anodization parameter.The W-doped TNT photoelectrode was prepared on TNT photoelectrode substrate by electro-deposition method. The doping conditions of W/TNT electrodes were optimized. The photocatalytic activity of W/TNT electrodes were evaluated in detail. The results showed that the optimal preparation conditions were deposition voltage 3V, electrode spacing 1cm, （NH4）2WO4 concentration 1.0g/L, deposition time 10min and calcination temperature 550.The results of characterization showed that W6+ concentrates on TiO2 crystal lattice, hindering both the crystal growth and anatase to rutile transition. Meanwhile, the W6+ may be incorporated into the titania lattice and replaced Ti4+ to formW-O-Ti bonds or located at interstitial sites.Significant red-shift in the spectrum of UV-vis absorption was observed. The degradation of Rhodamine B showed the W/TNT photoelectrodes exhibit excellent photoelectrochemical property and photocatalytic activity under visible light, compared with non-doped TNT photoelectrodes.W-doped TNT photoelectrodes were used for the photoelectrocatalytic（PEC） oxidation of endocrine disrupting chemicalsNP. The effects of anodic bias potential, initial pH, and initial concentration of NP on the PEC degradation of NP were investigated. TOC analysis was carried out to evaluate the mineraliz