環(huán)縮醛類化合物光還原法制備銀納米粒子的研究
發(fā)布時間：2018-11-23 07:35
【摘要】：金屬納米粒子,尤其是銀納米粒子,在制備、表征和應用方面有很長的歷史。銀納米粒子性能優(yōu)異,具有與眾不同的物理化學性質,包括：較高的導電性、熱導率、表面增強拉曼散射,化學穩(wěn)定性好,催化活性高,具有非線性光學行為等。納米粒子新穎的性質已經(jīng)被廣泛的應用到藥物、化妝品、可再生能源、環(huán)境修復和電子設備中。但是傳統(tǒng)的制備方法存在許多缺點,如反應條件苛刻、尺寸不均一、可控性差等。近年來,一種新的綠色環(huán)保的光化學還原法引起了人們廣泛的關注。此方法可在室溫條件下反應,適用范圍廣,制備過程方便,具有時間可控,空間選擇性制備等優(yōu)點,已被用于合成各種結構的單金屬、雙金屬納米粒子,還有復合材料。本文使用綠色植物提取物環(huán)縮醛化合物,用光化學還原的方法制備了銀納米粒子,替代目前光化學合成方法中使用的人工合成光引發(fā)劑,使得此方法更加綠色環(huán)保。并且對反應體系的影響因素和反應機理進行了研究。主要工作如下：1、設計了環(huán)縮醛化合物光化學還原制備銀納米粒子的路線。經(jīng)過對反應條件的探索,選擇硝酸銀作為銀前驅體,乙醇為溶劑,汞燈作為光源。X射線衍射結果表明產(chǎn)物為銀粒子,透射電子顯微鏡結果表明其為納米尺寸。2、研究了反應體系的影響因素：環(huán)縮醛化合物、溶液濃度、反應溫度對體系的影響。溶液濃度對納米粒子的尺寸有重要影響,溶液濃度增大,納米尺寸越大,分布變寬。溶液濃度為10-4 mol/L時,生成的銀納米粒子的粒徑分布窄。當濃度增大至0.01 mol/L時,形成的銀納米粒子變得不穩(wěn)定,部分懸浮在溶液中的納米粒子開始形成沉淀,粒徑分布變寬：體系溫度對形成的納米粒子有兩方面的影響,方面對納米粒子的尺寸有影響,另一方面對形成的納米粒子的數(shù)量有影響。隨著反應溫度的增加,形成的銀納米粒子的粒徑增大,納米粒子附著在玻璃表面的量增多。3、用紫外可見光譜和氣相色譜質譜聯(lián)用儀表征反應的機理。結果表明：BDO在光照下,在較活潑的亞甲基位置產(chǎn)生自由基。BDO自由基、溶液中的Ag+和溶劑醇類分子發(fā)生反應,自由基將銀離子還原,溶劑中的氫原子參與反應,生成2-甲(乙)氧基-1,3-苯并二氧戊烷,零價態(tài)的Ag原子和離子氫。零價態(tài)的Ag通過成核生長為銀納米粒子。
[Abstract]:Metal nanoparticles, especially silver nanoparticles, have a long history in preparation, characterization and application. Silver nanoparticles have excellent physical and chemical properties, including high conductivity, thermal conductivity, surface enhanced Raman scattering, good chemical stability, high catalytic activity and nonlinear optical behavior. The novel properties of nanoparticles have been widely used in medicine, cosmetics, renewable energy, environmental repair and electronic equipment. However, the traditional preparation method has many disadvantages, such as harsh reaction conditions, uneven size, poor controllability and so on. In recent years, a new green photochemical reduction method has attracted wide attention. This method can react at room temperature with wide range of application, convenient preparation process, controllable time, selective preparation of space and so on. It has been used to synthesize monometallic, bimetallic nanoparticles and composite materials with various structures. In this paper, silver nanoparticles were prepared by photochemical reduction with cyclic acetal compounds of green plant extracts, which replaced the synthetic photoinitiators used in the present photochemical synthesis methods, which made the method more green and environmentally friendly. The influencing factors and reaction mechanism of the reaction system were also studied. The main work is as follows: 1. The route of photochemical reduction of cyclic acetals to silver nanoparticles was designed. After exploring the reaction conditions, silver nitrate was selected as silver precursor, ethanol as solvent and mercury lamp as light source. The X-ray diffraction results showed that the product was silver particle, and the transmission electron microscope showed that the product was nano-sized. The effects of cyclic acetal compounds, solution concentration and reaction temperature on the reaction system were studied. The solution concentration has an important effect on the size of nanoparticles. The larger the solution concentration, the wider the distribution. The particle size distribution of silver nanoparticles was narrow when the concentration of solution was 10 ~ (- 4) mol/L. When the concentration increased to 0. 01 mol/L, the formed silver nanoparticles became unstable, and some of the nanoparticles suspended in the solution began to form precipitates, and the particle size distribution became wider: the temperature of the system had two effects on the formed nanoparticles. Aspects affect the size of nanoparticles, on the other hand, the number of formed nanoparticles. With the increase of reaction temperature, the particle size of the silver nanoparticles increased and the amount of the nanoparticles adhered to the glass surface increased. 3. The mechanism of the reaction was characterized by UV-Vis spectra and gas chromatography-mass spectrometry (GC-MS). The results show that BDO produces free radicals at active methylene sites under light. BDO radical reacts with solvent alcohols, free radicals deoxidize silver ions, and hydrogen atoms in solvents take part in the reaction. 2-Methyl (ethyloxy) -1-oxy-3-benzodioxopentane, zero-valence Ag atom and ionic hydrogen are formed. Ag with zero valence state grows into silver nanoparticles by nucleation.
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：O614.122;TB383.1
[Abstract]:Metal nanoparticles, especially silver nanoparticles, have a long history in preparation, characterization and application. Silver nanoparticles have excellent physical and chemical properties, including high conductivity, thermal conductivity, surface enhanced Raman scattering, good chemical stability, high catalytic activity and nonlinear optical behavior. The novel properties of nanoparticles have been widely used in medicine, cosmetics, renewable energy, environmental repair and electronic equipment. However, the traditional preparation method has many disadvantages, such as harsh reaction conditions, uneven size, poor controllability and so on. In recent years, a new green photochemical reduction method has attracted wide attention. This method can react at room temperature with wide range of application, convenient preparation process, controllable time, selective preparation of space and so on. It has been used to synthesize monometallic, bimetallic nanoparticles and composite materials with various structures. In this paper, silver nanoparticles were prepared by photochemical reduction with cyclic acetal compounds of green plant extracts, which replaced the synthetic photoinitiators used in the present photochemical synthesis methods, which made the method more green and environmentally friendly. The influencing factors and reaction mechanism of the reaction system were also studied. The main work is as follows: 1. The route of photochemical reduction of cyclic acetals to silver nanoparticles was designed. After exploring the reaction conditions, silver nitrate was selected as silver precursor, ethanol as solvent and mercury lamp as light source. The X-ray diffraction results showed that the product was silver particle, and the transmission electron microscope showed that the product was nano-sized. The effects of cyclic acetal compounds, solution concentration and reaction temperature on the reaction system were studied. The solution concentration has an important effect on the size of nanoparticles. The larger the solution concentration, the wider the distribution. The particle size distribution of silver nanoparticles was narrow when the concentration of solution was 10 ~ (- 4) mol/L. When the concentration increased to 0. 01 mol/L, the formed silver nanoparticles became unstable, and some of the nanoparticles suspended in the solution began to form precipitates, and the particle size distribution became wider: the temperature of the system had two effects on the formed nanoparticles. Aspects affect the size of nanoparticles, on the other hand, the number of formed nanoparticles. With the increase of reaction temperature, the particle size of the silver nanoparticles increased and the amount of the nanoparticles adhered to the glass surface increased. 3. The mechanism of the reaction was characterized by UV-Vis spectra and gas chromatography-mass spectrometry (GC-MS). The results show that BDO produces free radicals at active methylene sites under light. BDO radical reacts with solvent alcohols, free radicals deoxidize silver ions, and hydrogen atoms in solvents take part in the reaction. 2-Methyl (ethyloxy) -1-oxy-3-benzodioxopentane, zero-valence Ag atom and ionic hydrogen are formed. Ag with zero valence state grows into silver nanoparticles by nucleation.
【學位授予單位】：北京化工大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：O614.122;TB383.1
【共引文獻】
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1 李曉杰;羅寧;歐陽欣;閆鴻浩;王小紅;;合成碳包覆納米金屬材料的研究現(xiàn)狀[J];材料導報;2009年13期
2 羅寧;李曉杰;;碳包覆納米金屬材料的合成及應用進展[J];材料開發(fā)與應用;2009年03期
3 羅寧;李曉杰;閆鴻浩;王小紅;王立鶴;;爆轟合成碳包覆鈷、鎳磁性納米顆粒的探索[J];高壓物理學報;2009年06期
4 羅寧;李曉杰;費鴻祿;莫非;張程嬌;;爆轟法合成碳包覆鎳納米顆粒的研究(英文)[J];高壓物理學報;2011年02期
5 趙文秀;周奕華;錢俊;;基于印刷電子的透明導電薄膜研究進展[J];影像科學與光化學;2015年03期
6 劉世麗;辛智青;李修;方一;李亞玲;莫黎昕;李路海;;導電材料在透明電極中的應用研究[J];功能材料與器件學報;2015年04期
7 齊亮飛;朱超挺;楊曄;黃金華;李佳;趙世金;宋偉杰;;金屬網(wǎng)格透明導電薄膜研究現(xiàn)狀與應用分析[J];材料導報;2015年17期
8 Haifeng Qian;Xiaofeng Peng;Xiao Han;Jie Ren;Liwei Sun;Zhengwei Fu;;Comparison of the toxicity of silver nanoparticles and silver ions on the growth of terrestrial plant model Arabidopsis thaliana[J];Journal of Environmental Sciences;2013年09期
9 唐詩t，
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