本文選題：熒光碳點 + 三氧化鎢　； 參考：《遼寧大學》2017年碩士論文

【摘要】：隨社會的快速發(fā)展,環(huán)境污染問題和能源危機越來越受到關注。作為一種可再生的清潔能源,如何利用太陽能光催化降解有機污染物已成為研究熱點之一。三氧化鎢可以用作光催化劑利用太陽能光催化降解水中的污染物,已成為一種解決污染問題的有效方法之一。但是,WO_3存在著可見光利用率較低問題。熒光碳點(CDs)除具有良好的光學性能外,還是良好的電子供體和受體,常用于改進一些光催化劑的光催化性能。本研究分別采用簡單的溶劑熱和微波法,先成功的制備出兩種CDs,隨后制備出CDs摻雜的WO_3復合材料(CDs-WO_3),并分別研究了復合光催化劑在可見光照射下的光催化性能。具體內容如下:1、以檸檬酸為碳源和甘氨酸為修飾劑,無水乙醇作為溶劑,采用溶劑熱法一步合成發(fā)射黃色熒光的CDs。利用XRD、TEM、熒光光譜、紫外-可見吸收光譜和FT-IR光譜等技術對所得到的CDs的形貌、結構、光學性質和表面官能團等進行表征。并對反應溫度、反應時間和甘氨酸的用量等實驗條件進行了優(yōu)化,研究了pH值和鹽濃度對熒光強度的影響。研究結果表明:該方法合成的碳點屬于無定形碳結構,顆粒大小約為10nm左右;碳點的熒光量產子率為26.0%,其表面含有大量的羥基和羧基等含氧官能團,增強了碳點的水溶性;用不同波長激發(fā)光照射,碳點表現(xiàn)出激發(fā)波長依賴性行為。此外還發(fā)現(xiàn),所制備碳點還具有良好的耐光漂白和抗高鹽能力。在溶劑熱一步合成CDs的過程中,再加入WO_3,制備出CDs-WO_3復合材料,并研究其在可見光照射下對亞甲基藍的光催化降解能力。使用XRD、SEM、EDS、Raman光譜、紫外-可見光漫反射光譜和紅外光譜等技術對復合材料的形貌、結構和光學特性等進行了表征。此外,考察了光照時間、催化劑用量、pH值和制備過程中WO_3加入量等因素對CDs-WO_3的光催化降解活性影響。實驗表明,在可見光照射下,片狀的CDs摻雜的WO_3復合材料對亞甲基藍具有良好的光催化降解性能。亞甲基藍的初始濃度為10mg/L,復合材料用量為0.75g時,兩小時內的光降解率達到60.0%。2、采用微波法,以酒石酸為碳源和甘氨酸為鈍化劑,超純水作為溶劑,一步合成發(fā)射綠色熒光的CDs。利用XRD、TEM、熒光分光光度計、紫外吸收光譜和FT-IR等技術對所得到的CDs的形貌、結構、光學性質和表面官能團進行了表征。研究中,對微波功率、加熱時間、甘氨酸用量等實驗條件進行了優(yōu)化,并進一步討論了pH值、無機鹽濃度對CDs熒光發(fā)光強度的影響。研究結果表明:此方法制備的CDs具有無定形態(tài)的特征峰;其顆粒大小約為10nm;其表面含有大量的羥基和羧基等官能團,使水溶性增強;該CDs在不同激發(fā)光條件下,其發(fā)射峰發(fā)生Stokes shift位移,表現(xiàn)出波長依賴性行為;其量子產率為11.5%,并表現(xiàn)出良好的耐光漂白性;在較高鹽濃度存在下,其熒光強度幾乎不變,即具有較強的耐鹽性。將制備好的CDs和WO_3放在水熱反應釜內,在90℃下加熱90min,制備出CDs-WO_3復合材料,并研究其在可見光照射下對亞甲基藍的光催化降解能力。使用XRD、SEM、EDS、Raman、紫外-可見光漫反射光譜和紅外光譜等技術對復合材料的形貌、結構、元素種類、光學特性和具有官能團進行表征。探究光照時間、催化劑用量、pH值和制備過程中WO_3加入量等因素對光催化降解活性的影響。實驗表明:在可見光照射下,CDs-WO_3復合材料對亞甲基藍具有良好的光催化降解性能。亞甲基藍的初始濃度為10mg/L,加入6mLCDs溶液制備出的CDs-WO_3復合材料用量為25mg,兩小時內的光降解率達到55.0%。3、本文用制備的兩種CDs摻雜WO_3得到復合材料,光催化性能顯著提高,表明摻雜CDs提高催化性能,成為可行的方法。
[Abstract]:With the rapid development of society, environmental pollution and energy crisis have attracted more and more attention. As a renewable clean energy, how to use solar energy to photocatalytic degradation of organic pollutants has become one of the hot spots. Tungsten trioxide can be used as a photocatalyst to degrade pollutants in water using solar energy, and it has become a solution. It is one of the effective methods to solve the problem of pollution. However, WO_3 has a low utilization rate of visible light. The fluorescent carbon point (CDs), in addition to good optical properties, is still a good electron donor and receptor. It is commonly used to improve the photocatalytic performance of some photocatalysts. This study was successfully prepared by a simple solvent heat and microwave method. Two kinds of CDs were produced and CDs doped WO_3 composites (CDs-WO_3) were prepared, and the photocatalytic properties of the composite photocatalyst under visible light were studied. The content of the photocatalyst was as follows: 1, using citric acid as carbon source and glycine as modifier and anhydrous ethanol as solvent, CDs. used XRD to synthesize CDs. using XRD for emitting yellow fluorescence. The morphology, structure, optical properties and surface functional groups of the obtained CDs were characterized by TEM, fluorescence spectra, UV visible absorption spectroscopy and FT-IR spectroscopy. The experimental conditions of the reaction temperature, reaction time and the dosage of glycine were optimized. The effects of pH and salt concentration on the fluorescence intensity were studied. The carbon dots synthesized by this method belong to the amorphous carbon structure, the size of the particles is about 10nm, the fluorescence yield of the carbon point is 26%, and the surface contains a large number of hydroxyl and carboxyl groups, which can enhance the water solubility of the carbon point. The carbon preparation points also have good photobleaching and high salt resistance. In the process of one step synthesis of CDs in solvent heat, the CDs-WO_3 composite is prepared by adding WO_3, and the photocatalytic degradation ability of methylene blue under visible light is studied. XRD, SEM, EDS, Raman spectroscopy, UV visible diffuse reflectance spectroscopy and infrared spectroscopy are used. The morphology, structure and optical properties of the composites were characterized. In addition, the effects of light time, amount of catalyst, pH value and WO_3 addition on the photocatalytic degradation activity of CDs-WO_3 were investigated. The experimental results showed that the WO_3 composites of WO_3 doped CDs were good for methylene blue under visible light irradiation. The initial concentration of methylene blue is 10mg/L, when the content of the composite is 0.75g, the photodegradation rate is 60.0%.2 within two hours. The microwave method is used to use the tartaric acid as the carbon source and the glycine as passivating agent and the ultra pure water as the solvent. The CDs. using XRD, TEM, fluorescence spectrophotometer and UV absorption is used in one step. The morphology, structure, optical properties and surface functional groups of the obtained CDs were characterized by spectral and FT-IR techniques. In the study, the microwave power, the heating time, the dosage of glycine and other experimental conditions were optimized, and the effect of the pH value and the concentration of inorganic salt on the fluorescence intensity of CDs was further discussed. The CDs has an amorphous characteristic peak, its particle size is about 10nm, and its surface contains a large number of hydroxyl and carboxyl groups and other functional groups, which can enhance the solubility of water. The emission peak of the CDs has a Stokes shift displacement and a wavelength dependent behavior under different stimulated luminescence conditions, and its quantum yield is 11.5%, and it shows good photobleaching resistance. In the presence of high salt concentration, the fluorescence intensity is almost constant, that is, it has strong salt tolerance. The prepared CDs and WO_3 are placed in a hydrothermal reactor, and the CDs-WO_3 composite is prepared by heating 90min at 90 C, and the photocatalytic degradation ability of methylene blue under visible light is studied. XRD, SEM, EDS, Raman, UV visible using XRD, SEM, Raman, and UV visible. The morphology, structure, element species, optical properties and functional groups of the composites were characterized by optical diffuse reflectance spectroscopy and infrared spectroscopy. The effects of light time, catalyst amount, pH value and WO_3 addition on the photocatalytic degradation activity were investigated. The experiment showed that the CDs-WO_3 composite was irradiated by visible light. The methylene blue has a good photocatalytic degradation performance. The initial concentration of methylene blue is 10mg/L, the amount of CDs-WO_3 composites prepared by adding 6mLCDs solution is 25mg and the photodegradation rate is 55.0%.3 within two hours. In this paper, two kinds of CDs doped WO_3 are used to get the composite, the photocatalytic performance is greatly improved, indicating that the doping CDs is improved. Catalytic performance is a feasible method.
【學位授予單位】：遼寧大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O643.36;O644.1

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本文編號：2106603