TiO2納米管論文：改性TiO_2納米管光電極制備及可見光下光電催化性能研究

1、 TiO2納米管論文：改性TiO_2納米管光電極制備及可見光下光電催化性能研究【中文摘要】TiO2催化劑由于其成本低、無毒、活性高、無二次污染等優(yōu)點在環(huán)境保護領(lǐng)域被廣泛應(yīng)用于去除難降解有機物。然而,其存在禁帶寬度過大（3.2 eV）等缺陷,限制了其在污染治理中的應(yīng)用。通過對TiO2進行過渡金屬離子摻雜能夠有效減小其禁帶寬度,拓寬光譜響應(yīng)范圍。作為內(nèi)分泌干擾物的一種,壬基酚廣泛存在于洗滌劑、紡織、造紙等工業(yè)生產(chǎn)中,它能夠長期存在于自然界中,很難被生物降解,其降解一直是國內(nèi)外研究的熱點和難點。本文采用陽極氧化法制備了TiO2納米管光電極,通過電沉積對其進行W摻雜改性,拓寬了其光譜響應(yīng)范圍,研究了W

2、/TNT光電極對壬基酚的光電催化降解效果。采用陽極氧化法制備了TiO2納米管（TNT）光電極。考察了制備電壓、時間、煅燒溫度等條件對TNT陣列的表面形貌和結(jié)構(gòu)的影響,利用掃描電子顯微鏡（SEM）、X射線衍射（XRD）、能量散射X射線能譜（EDX）等手段對光電極進行了表征。以羅丹明B為目標(biāo)污染物,考察了不同制備條件對TNT光電極在可見光下的光催化性能的影響。結(jié)果表明,通過調(diào)節(jié)陽極氧化過程中的參數(shù)可以實現(xiàn)對不同尺寸和結(jié)構(gòu)的TNT光電極的可控制備。采用電化學(xué)沉積的方法,以TNT陣列光電極為基體,制備了W摻雜的TiO2納米管陣列光電極。優(yōu)化了W/TNT光電極的最佳摻雜條件,考察了W/TNT光電極的光催

3、化性能。結(jié)果表明,光電極的最佳制備條件為:沉積電壓為3V、電極間距為1cm、沉積液（NH4）2WO4濃度為1.0g/L、沉積時間為10min、煅燒處理溫度為550。W/TNT光電極的表征結(jié)果顯示W(wǎng)的摻雜會抑制銳鈦礦相TiO2晶粒的生長以及晶相轉(zhuǎn)變過程;XPS圖譜分析表明W元素通過摻雜進入到了TiO2晶格內(nèi)部形成W-Ti-O鍵;WTNT光電極對可見光的光譜響應(yīng)范圍發(fā)生紅移;改性與未改性TiO2納米管光電極對羅丹明B的降解效果表明,相對于未摻雜的TNT光電極,W/TNT光電極對羅丹明B的降解效果更優(yōu),摻雜后的光電極具有更佳的光（電）催化活性。采用W/TNT光電極在可見光下對內(nèi)分泌干擾物壬基酚進行光

4、電催化降解,考察了壬基酚光電催化降解過程中的影響因素,研究了該過程中壬基酚的礦化過程。結(jié)果表明,pH值在中性條件下,光電極對壬基酚的光電催化降解效果最佳;隨著反應(yīng)中壬基酚初始濃度增加,W/TNT光電極對壬基酚的降解效率逐漸下降;隨著外加偏壓的增加,壬基酚的光電催化降解效率逐漸增大,而外加偏壓高于2.0V時,進一步增加電壓反而不利于壬基酚的降解;催化劑面積的增大,有利于光電極對壬基酚光電催化降解效果的提高。在壬基酚光電催化反應(yīng)過程中,壬基酚分子在·OH的作用下經(jīng)過一系列反應(yīng)轉(zhuǎn)化為中間產(chǎn)物,而不是被完全礦化成CO2和H2O?！居⑽恼縏itanium dioxide （TiO2） ha

5、s 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 applicat

6、ion 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 （

7、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

8、 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 endocrin

9、e 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 photoe

10、lectrodes 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 degradat

11、ion 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-

12、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 depo

13、sition 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+

14、 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 propert

15、y 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

16、the PEC degradation of NP were investigated. TOC analysis was carried out to evaluate the mineralization of NP on the W/TNT by the PEC treatment.It can be seen that at nearly neutral nature pH, NP shows the highest degradation efficiency. The result indicates that the degradation efficiency is decre

17、ased with increasing the initial concentration of NP. It is observed that the degradation efficiency of NP is increased with increasing the bias potential from 0 to 2.0 V. However, when the potential was further increased to higher than 2.0 V, the PEC degradation rate was reduced. The increase of ca

18、talyst area was beneficial to the degradation of NP.In the process of NP degradation, the lower TOC removal efficiency means that many NP molecules are actually degraded to intermediates instead of mineralized to CO2 and H2O.【關(guān)鍵詞】TiO2納米管 金屬離子摻雜 光電催化 壬基酚【英文關(guān)鍵詞】TiO2 nanotube Transition metal ion-dopin

19、g Photoelectrocatalysis Nonyl Phenol【目錄】改性TiO_2納米管光電極制備及可見光下光電催化性能研究摘要4-6ABSTRACT6-7第1章 緒論11-211.1 課題背景及研究的目的和意義11-121.1.1 課題研究背景111.1.2 課題研究的目的及意義11-121.2 TiO_2 納米管光催化研究進展12-161.2.1 TiO_2 納米管制備方法12-151.2.2 TiO_2 納米管在水處理中的應(yīng)用15-161.2.3 TiO_2 催化劑存在的主要缺陷161.3 TiO_2 催化劑的改性研究現(xiàn)狀16-171.3.1 TiO_2 催化劑的改性方法16

20、-171.3.2 改性TiO_2 催化劑在水處理中的應(yīng)用171.4 內(nèi)分泌干擾物壬基酚處理技術(shù)研究進展17-191.4.1 壬基酚處理技術(shù)研究進展17-191.4.2 壬基酚檢測手段研究進展191.5 本文的主要研究內(nèi)容19-21第2章 實驗材料與方法21-302.1 實驗儀器與試劑21-222.1.1 實驗儀器212.1.2 實驗試劑與材料21-222.2 光電極的制備22-242.2.1 電極的預(yù)處理22-232.2.2 二氧化鈦納米管光電極的制備23-242.2.3 改性二氧化鈦納米管光電極的制備242.3 實驗方法24-282.3.1 光電催化反應(yīng)及裝置24-262.3.2 羅丹明B

21、的結(jié)構(gòu)與性質(zhì)262.3.3 壬基酚的結(jié)構(gòu)與性質(zhì)26-282.4 樣品表征及分析方法28-302.4.1 電極表面形貌分析282.4.2 電極晶型結(jié)構(gòu)分析282.4.3 元素組成及價態(tài)分析28-292.4.4 紫外-可見漫反射吸收光譜分析292.4.5 其它分析手段29-30第3章 TiO_2納米管光電極制備及光催化性能研究30-463.1 制備參數(shù)對TiO_2 納米管表面形貌的影響30-373.1.1 陽極氧化電壓30-323.1.2 氧化時間32-343.1.3 制備溫度34-353.1.4 電解液組成35-363.1.5 煅燒處理溫度36-373.2 晶型結(jié)構(gòu)分析37-393.3 能量散射X 射線能譜分析393.4 TiO_2 納米管光電極光催化性能研究39-443.4.1 陽極氧化電壓對TiO_2 納米管光催化性能的影響39-403.4.2 氧化時間對TiO_2 納米管光催化性能的影響40-413.4.3 制備溫度對TiO_2 納米管光催化性能的影響41-423.4.4 電解液組成對TiO_2 納米管光催化性能的影響42-433.4.5 煅燒溫度對TiO_2 納米管光催化性能的影響43-443.5 本章小結(jié)44-46第4章 W/TiO_2納米管光