本文選題：CdSe量子點 + 雙金屬離子摻雜��； 參考：《江蘇大學》2017年博士論文

【摘要】：隨著工業(yè)化程度的日益提高,越來越多的有機物被投入到現(xiàn)代生產(chǎn)和生活中,造成水環(huán)境中出現(xiàn)大量有機物殘留,這些有機物殘留對環(huán)境造成的污染日益加劇。近年來,利用太陽能光降解有機污染物的綠色光催化技術(shù)引起了科研工作者的廣泛關注,如何獲得高性能低成本的半導體光催化材料已然是光催化技術(shù)發(fā)展的關鍵問題。量子點材料由于具有尺寸小、比表面積大、光響應能力強、獨特的電子態(tài)和光學吸收性能等優(yōu)勢,已成為光催化領域新興的研究熱點。同時,硒化鎘(CdSe)半導體光催化材料具有合適的禁帶寬度,獨特的晶體結(jié)構(gòu)特征以及在可見光下顯示出優(yōu)異的光降解有機污染物性能的優(yōu)勢,具有較高的研究價值。因此,結(jié)合量子點材料和CdSe半導體的多重優(yōu)勢,選擇CdSe量子點作為光催化材料來降解環(huán)境廢水中有機污染物具有很好的應用前景。但是由于單一 CdSe量子點材料存在著一些缺陷嚴重制約了其應用范圍,例如:易于團聚,抗光腐蝕性差,穩(wěn)定性較低等。為了克服CdSe量子點材料的這些缺點,本論文采取多種修飾技術(shù)對其進行改性,如離子摻雜技術(shù)對其進行修飾,克服CdSe量子點光生電子和空穴易復合的問題;結(jié)合貴金屬納米粒子等離子體共振效應,在提高光生電子與空穴的分離效率的同時還提高了光能利用率;選擇合適載體制備負載-復合型多組分光催化材料,解決CdSe量子點材料吸附能力差、穩(wěn)定性不高等問題。同時,通過多種分析測試方法,系統(tǒng)地研究了改性CdSe量子點光催化材料的物化特性以及光降解環(huán)境中有機污染物的反應機理。具體研究工作如下:(1)采用軟模板法合成方案,以十六烷基三甲基氯化銨為表面活性劑,經(jīng)過簡單水浴回流過程,合成了 CdSe量子點囊泡狀分級結(jié)構(gòu)光催化材料。根據(jù)TEM等測試手段分析了囊泡狀結(jié)構(gòu)的成型機制。經(jīng)過XRD、TEM、TGA等分析測試手段對量子點光催化材料的物化性質(zhì)進行表征。相對于粒子結(jié)構(gòu)CdSe量子點材料,該結(jié)構(gòu)具有較大的比表面積和豐富的孔道結(jié)構(gòu)。降解實驗結(jié)果表明,CdSe量子點囊泡狀分級結(jié)構(gòu)光催化材料對鹽酸四環(huán)素(Tetracycline hydrochloride,TC·HCl)展現(xiàn)出優(yōu)異的光催化降解活性。通過活性物種捕獲實驗,分析其光催化降解反應機理。通過循環(huán)降解實驗,考察催化劑的循環(huán)利用率。(2)采用簡單的一步水熱法,以3-巰基丙酸為修飾劑,合成了雙離子共摻雜CdSe量子點光催化材料。通過調(diào)節(jié)離子摻雜種類以及摻雜比例,制備不同的金屬離子摻雜CdSe量子點光催化材料。TEM研究發(fā)現(xiàn),制備的金屬離子摻雜CdSe量子點材料,納米粒子尺寸均一,呈球狀分布,納米粒子平均尺寸約為8 nm。UV-vis DRS表明制備的所有離子摻雜CdSe量子點樣品在可見光范圍內(nèi)均具有很強的光響應能力,相比于單一 CdSe量子點材料,金屬離子摻雜CdSe量子點材料帶隙值降低。同時,以TC·HCl溶液為目標物廢水、詳細探討了光催化降解機理并研究不同條件對光催化降解性能的影響。通過考察摻雜金屬離子的種類及比例,得出3%Co-4%K/CdSe量子點材料具有最佳的光催化性能。在30min內(nèi),其對TC·HCl的降解率達到78.4%。通過對降解不同時間的溶液質(zhì)譜進行測定,分析了 TC·HCl降解的中間過程。(3)采用簡單的水熱法,將Al2Ti05陶瓷材料與CdSe量子點復合,構(gòu)建異質(zhì)結(jié)復合材料。在此基礎上,制備了納米Ag粒子修飾CdSe量子點負載Al2Ti05復合光催化劑。利用XRD、TEM、電化學等多種分析測試手段對光催化劑進行物化性質(zhì)表征。以典型的亞甲基藍染料(Methylene blue,MB)溶液為降解目標物驗證制備的復合光催化劑的光催化活性�？疾炝� Al2Ti05的引入比例對復合材料光催化性能的影響。通過活性物種捕獲實驗,分析了光催化降解過程中起主要作用的活性因子并詳細探討了光催化降解有機染料的機理。(4)以箭竹葉為生物原材料,采用無氧炭化法制備蜂窩管狀竹葉生物炭。通過XRD、SEM、N2吸脫附等多種不同分析測試手段對竹葉生物炭的物化性能進行表征。以竹葉生物炭為載體,可溶性金屬鹽溶液為金屬源,硼氫化鈉為還原劑,原位生長法與水熱法相結(jié)合,成功制備了金屬離子摻雜CdSe量子點負載竹葉生物炭復合光催化劑。通過光催化降解TC·HCl溶液驗證其光催化活性�？疾焐锾考尤肓繉λ苽涞膹秃喜牧闲阅艿挠绊懸�(guī)律;探究了金屬離子摻雜比例對所制備的材料性能的影響規(guī)律。最終得出結(jié)論,生物炭加入量為35 wt%、Co離子摻雜比例為3%-7%時最佳。另外,通過多種實驗手段相結(jié)合探討了光催化降解抗生素廢水的反應機理,揭示了其提高光催化性能的本質(zhì)原因。
[Abstract]:With the increasing degree of industrialization, more and more organic compounds have been put into modern production and life, resulting in a large number of organic residues in the water environment, and the pollution of these organic residues to the environment is aggravated. In recent years, the green photocatalytic technology for the use of solar energy to degrade organic contaminants has caused scientific research workers. Widely concerned, how to obtain high performance and low cost semiconductor photocatalytic materials has been the key problem in the development of photocatalytic technology. Quantum dots have become a new research hotspot in the field of photocatalysis because of their advantages of small size, large specific surface area, strong light response ability, unique electronic state and optical absorption properties. Cadmium (CdSe) semiconductor photocatalyst has a suitable band gap, unique crystal structure characteristics and excellent advantages of showing excellent photocatalytic degradation of organic pollutants in visible light. Therefore, combining quantum dots and CdSe semiconductors, CdSe quantum dots are selected as photocatalytic materials. The degradation of organic pollutants in environmental wastewater has a good application prospect. However, there are some defects in the single CdSe quantum dot material which seriously restrict its application, such as easy reunion, poor anti light corrosion and low stability. In order to overcome these shortcomings of CdSe quantum dots, this paper adopts a variety of modification techniques to it Modification, such as the modification of ion doping technology, overcomes the problem that the photoelectrons and holes of the CdSe quantum dots are easily compound, and the efficiency of optical electron and hole separation is enhanced with the plasma resonance effect of noble metal nanoparticles. Catalytic materials can solve the problem of poor adsorption capacity and low stability of CdSe quantum dots. At the same time, the physicochemical properties of the modified CdSe quantum dots photocatalytic materials and the reaction mechanism of organic pollutants in the photodegradation environment are systematically studied by a variety of analytical testing methods. The specific research work is as follows: (1) a soft template synthesis scheme is used. With sixteen alkyl three methyl ammonium chloride as surface active agent, a CdSe quantum dot vesicular structured photocatalytic material was synthesized through a simple water bath reflux process. The forming mechanism of the vesicular structure was analyzed by TEM and other testing methods. The physicochemical properties of the quantum dots photocatalyst were characterized by XRD, TEM, TGA and other analytical methods. Compared with the particle structure CdSe quantum dots, the structure has a large specific surface area and rich pore structure. The results of degradation experiments show that the photocatalytic activity of CdSe quantum dots vesicular graded structure photocatalytic materials to Tetracycline hydrochloride (TC. HCl) is superior to the photocatalytic degradation activity. The reaction mechanism of photocatalytic degradation was analyzed. The cyclic utilization rate of the catalyst was investigated by cyclic degradation. (2) a simple one step hydrothermal method was used to synthesize a double ion Co doped CdSe quantum dot photocatalyst with 3- mercapto propionic acid as the modifier. The study of CdSe quantum dots photocatalytic material.TEM found that the prepared metal ions doped CdSe quantum dots were uniform in size and spherical distribution. The average size of the nanoparticles was about 8 nm.UV-vis DRS, indicating that all the ions doped CdSe quantum dots have strong light response ability in the range of visible light, compared with those in the visible light range. The band gap value of metal ions doped CdSe quantum dots is reduced by single CdSe quantum dots. At the same time, the photocatalytic degradation mechanism and the effect of different conditions on photocatalytic degradation are investigated in detail with TC / HCl solution as target wastewater. By investigating the species and proportion of doped metal ions, the 3%Co-4%K/CdSe quantum dots materials are obtained. With the best photocatalytic performance. In 30min, the degradation rate of TC HCl was reached to 78.4%. by the determination of the solution mass spectra at different time. The intermediate process of TC HCl degradation was analyzed. (3) a simple hydrothermal method was used to combine the Al2Ti05 ceramics with the CdSe quantum dots to construct the heterojunction composite. On this basis, the preparation was made. Nano Ag particles modified CdSe quantum dots loaded with Al2Ti05 composite photocatalyst. The physicochemical properties of photocatalyst were characterized by XRD, TEM, electrochemistry and other analytical testing methods. The photocatalytic activity of the composite photocatalyst prepared with the typical methylene blue (Methylene blue, MB) solution as the degradation target was investigated. The effect of the introduction ratio on the photocatalytic properties of composite materials. Through the experiment of active species capture, the active factors which play the main role in the process of photocatalytic degradation were analyzed and the mechanism of photocatalytic degradation of organic dyes was discussed in detail. (4) honeycomb shaped bamboo leaf biological charcoal was prepared by oxygen free carbonization by using arrows bamboo leaves as biological raw materials. The physicochemical properties of bamboo leaf biological carbon were characterized by XRD, SEM and N2 desorption. The bamboo leaf biological charcoal was used as the carrier, the soluble metal salt solution was used as the metal source, the sodium borohydride was the reductant, and the in situ growth method was combined with the hydrothermal method to prepare the gold ion doped CdSe quantum dots loaded bamboo leaf bio carbon composite successfully. Photocatalyst. The photocatalytic activity was verified by photocatalytic degradation of TC / HCl solution. The effects of carbon content on the properties of the composites were investigated, and the influence of the proportion of metal ions on the properties of the prepared materials was explored. Finally, it was concluded that the amount of bio carbon added to 35 wt% and the proportion of Co ion doping at 3%-7% was 3%-7%. In addition, the reaction mechanism of photocatalytic degradation of antibiotic wastewater was discussed through a variety of experimental methods, and the essential reasons for improving the photocatalytic performance were revealed.
【學位授予單位】：江蘇大學
【學位級別】：博士
【學位授予年份】：2017
【分類號】：X703;O643.36;O644.1

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