【摘要】：二氧化鈦,作為一種重要的過(guò)渡金屬氧化物,在環(huán)境凈化方面具有巨大的潛力。本文對(duì)二氧化欽光催化劑形貌結(jié)構(gòu)與性能之間的構(gòu)效關(guān)系,進(jìn)行了深入的研究。選擇特定形貌,在紫外光照射條件下,對(duì)花狀二氧化鈦降解直接藍(lán)溶液的光催化反應(yīng)動(dòng)力學(xué)進(jìn)行了初步的研究。通過(guò)氫化還原法制備氧缺陷型二氧化鈦光催化劑。并首次利用H2-TpR定量研究氧缺陷濃度與光催化性能之間的關(guān)系。主要研究?jī)?nèi)容如下:第一部分:二氧化鈦光催化降解直接藍(lán)的形貌效應(yīng)通過(guò)水熱合成法制備四種不同形貌(片狀、雙錐狀、花狀、球狀)的二氧化鈦。借助一系列表征測(cè)試手段,對(duì)所得二氧化鈦的相結(jié)構(gòu)和形貌等進(jìn)行分析。在自制的光催化裝置中對(duì)二氧化鈦光催化降解直接藍(lán)的性能進(jìn)行評(píng)價(jià)測(cè)試,以揭示形貌結(jié)構(gòu)與光催化活性之間的構(gòu)效關(guān)系。實(shí)驗(yàn)結(jié)果表明:不同形貌的二氧化鈦對(duì)直接藍(lán)的降解,展現(xiàn)出不同的光催化活性。其中,花狀二氧化鈦表現(xiàn)出較為優(yōu)異的光催化性能。紫外漫反射的研究為揭示形貌效應(yīng)提供了直接的證據(jù)。實(shí)驗(yàn)表明不同形貌的二氧化鈦,其禁帶寬度的差異是影響光催化活性的主要因素。第二部分:二氧化鈦光催化降解直接藍(lán)的動(dòng)力學(xué)研究在紫外光照射下,對(duì)花狀二氧化鈦光催化降解直接藍(lán)溶液的動(dòng)力學(xué)進(jìn)行了初步研究。一系列可能的操作影響因素被系統(tǒng)地研究,包括pH值、催化劑及H202添加量、有無(wú)Ag改性。在紫外光條件下,發(fā)現(xiàn)光催化降解直接藍(lán)的反應(yīng)過(guò)程滿足二級(jí)反應(yīng)動(dòng)力學(xué)反應(yīng)模型,并具有高回歸系數(shù)。實(shí)驗(yàn)結(jié)果表明,直接藍(lán)溶液的初始濃度及其相關(guān)的因素影響了光催化降解效率和對(duì)應(yīng)的動(dòng)力學(xué)參數(shù)。并且,動(dòng)力學(xué)參數(shù)k隨著降解效率增加而增加。第三部分:二氧化鈦氧缺陷構(gòu)筑及其光催化降解直接藍(lán)性能的研究光催化反應(yīng)過(guò)程中,光生電荷-空穴對(duì)分離效率低和光吸收波長(zhǎng)范圍窄是導(dǎo)致光催化劑活性不高的本質(zhì)原因。通過(guò)氫化還原的方法制得具有氧缺陷的二氧化鈦,以窄化其禁帶寬度,促進(jìn)光生電荷分離和遷移速率,提高光催化效率。實(shí)驗(yàn)結(jié)果表明,不同還原溫度條件下,所形成的氧缺陷濃度不同。在紫外光照射條件下,氫化還原后的二氧化鈦均顯示出較高的光催化活性。通過(guò)在可見光照射條件下對(duì)光催化降解直接藍(lán)的研究,發(fā)現(xiàn)氧缺陷型二氧化鈦的光響應(yīng)范圍由紫外光擴(kuò)展到可見光范圍,并展現(xiàn)出較好的可見光光催化活性。并首次使用H2-TpR技術(shù)定量研究氧缺陷濃度,建立氧缺陷濃度與可見光光催化活性之間的構(gòu)效關(guān)系。在測(cè)試條件范圍內(nèi),隨總氧缺陷濃度的增加,可見光光催化活性能先增大后趨于平穩(wěn);而隨表面氧缺陷濃度的增加,可見光光催化活性隨之增大。表面缺陷的引入是光催化劑活性提高的有效途徑。
[Abstract]:Titanium dioxide, as an important transition metal oxide, has great potential in environmental purification. In this paper, the structure-activity relationship between the morphology, structure and properties of the photocatalyst was studied. The kinetics of photocatalytic degradation of direct blue solution by flower-like TIO _ 2 was studied under UV irradiation. Oxygen defect titanium dioxide photocatalyst was prepared by hydrogenation reduction method. The relationship between oxygen defect concentration and photocatalytic activity was quantitatively studied by H2-TpR for the first time. The main research contents are as follows: the first part: the morphology effect of photocatalytic degradation of direct blue was prepared by hydrothermal synthesis of titanium dioxide with four different morphologies (flake, double cone, flower, spherical). The phase structure and morphology of TIO _ 2 were analyzed by a series of characterization methods. The photocatalytic degradation of direct blue by titanium dioxide was evaluated in a self-made photocatalytic device to reveal the structure-activity relationship between morphology and photocatalytic activity. The results showed that the degradation of direct blue by titanium dioxide with different morphology showed different photocatalytic activity. Among them, flower-like titanium dioxide showed excellent photocatalytic performance. The study of UV diffuse reflection provides direct evidence for revealing morphologic effects. The experimental results show that the difference of bandgap is the main factor affecting the photocatalytic activity of titanium dioxide with different morphology. Part two: kinetic study on photocatalytic degradation of Direct Blue by Titanium dioxide under UV irradiation, the kinetics of photocatalytic degradation of Direct Blue solution was studied. A series of possible operational factors were systematically studied, including pH value, catalyst and H202 addition, and Ag modification. It was found that the photocatalytic degradation of direct blue could satisfy the second-order kinetic reaction model and had a high regression coefficient. The experimental results show that the initial concentration of direct blue solution and its related factors affect the photocatalytic degradation efficiency and the corresponding kinetic parameters. Moreover, the kinetic parameter k increases with the increase of degradation efficiency. Part III: construction of oxygen defects in TIO _ 2 and its photocatalytic degradation of Direct Blue; in the process of photocatalytic reaction, the low separation efficiency of photogenerated charge-hole and the narrow wavelength range of photoabsorption are the essential reasons leading to the low photocatalytic activity. Titanium dioxide with oxygen defects was prepared by hydrogenation reduction to narrow the band gap, promote the separation and migration rate of photogenerated charges, and improve the photocatalytic efficiency. The experimental results show that the oxygen defect concentration is different at different reduction temperature. Under UV irradiation, the hydrogenated TIO _ 2 showed high photocatalytic activity. The photocatalytic degradation of direct blue was studied under visible light irradiation. It was found that the photoresponse range of oxygen deficient titanium dioxide was extended from ultraviolet to visible light, and showed good visible photocatalytic activity. The H2-TpR technique was used to quantitatively study the oxygen defect concentration for the first time, and the structure-activity relationship between the oxygen defect concentration and the visible light catalytic activity was established. In the range of test conditions, with the increase of the total oxygen defect concentration, the photocatalytic activity of visible light increases first and then tends to steady, and with the increase of surface oxygen defect concentration, the photocatalytic activity of visible light increases. The introduction of surface defects is an effective way to improve the activity of photocatalyst.
【學(xué)位授予單位】：西南石油大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：O643.36

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本文編號(hào)：2194908