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  本文關(guān)鍵詞： 硫摻雜 石墨烯量子點(diǎn) Pb~(2+) Ag~+ 鈦酸鹽納米片 可見光催化　出處：《浙江理工大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：石墨烯量子點(diǎn)(graphene quantum dots,GQDs)是一種新型的熒光碳納米材料。它是尺寸小于100 nm且厚度小于10層的石墨烯薄層,也稱為零維石墨烯。與傳統(tǒng)熒光材料相比,GQDs集量子限域效應(yīng)、尺寸效應(yīng)及邊緣效應(yīng)于一體,還兼具良好的生物相容性、優(yōu)異的發(fā)光性能和帶隙可調(diào)等優(yōu)勢。對石墨烯量子點(diǎn)進(jìn)行異原子摻雜或表面官能團(tuán)功能化,可調(diào)整GQDs的禁帶寬度和電荷密度,進(jìn)而提高熒光量子產(chǎn)率、增加活性位點(diǎn)和顯示化學(xué)選擇性。近年來,GQDs作為熒光探針和光催化劑或光敏化劑在金屬離子檢測和光催化中的應(yīng)用研究備受關(guān)注。本論文以1,3,6-三硝基芘為碳源,采用不同摻雜劑,合成了兩種硫摻雜石墨烯量子點(diǎn)(S-GQDs1、S-GQDs2)和新型氧摻雜石墨烯量子點(diǎn)(O-GQDs),并研究了上述的三種石墨烯量子點(diǎn)在金屬離子檢測和光催化中的應(yīng)用。具體研究內(nèi)容如下:(1)建立了硫摻雜石墨烯量子點(diǎn)(S-GQDs1)的制備方法并研究了其在Pb2+選擇性檢測中的應(yīng)用。采用一步水熱法,以具有石墨烯母核結(jié)構(gòu)的1,3,6-三硝基芘為碳源、Na2S為硫原子摻雜劑、Na OH溶液為反應(yīng)介質(zhì),在水熱過程中通過分子融合一步合成了S-GQDs1。采用紫外-可見吸收光譜(UV-vis)和熒光光譜對S-GQDs1的光學(xué)性質(zhì)進(jìn)行了分析;通過原子力顯微鏡(AFM)、透射電子顯微鏡(TEM)、X射線光電子能譜(XPS)對S-GQDs1的形貌、尺寸分布、化學(xué)組成等進(jìn)行了表征。結(jié)果表明,S-GQDs1在365 nm紫外光照射下發(fā)射黃綠色熒光,熒光光譜的最大激發(fā)波長為490 nm,最大發(fā)射波長為535 nm。熒光發(fā)射具有激發(fā)波長非依賴性,熒光量子產(chǎn)率為11.6%。S以-C-SOx-C-(x=2,3,4)硫橋形式摻雜入GQDs骨架中,S-GQDs1平均粒徑為3.2 nm,結(jié)晶性好�？疾炝薙-GQDs1對不同金屬離子的選擇性,發(fā)現(xiàn)Pb2+可選擇性猝滅S-GQDs1的熒光�；赑b2+對S-GQDs1的熒光猝滅,建立了Pb2+的熒光檢測方法。檢測Pb2+的最優(yōu)p H條件為7.0,反應(yīng)孵育5 min,檢測線性范圍為0.1μM~1.0μM、1.0μM~140.0μM,檢測限為0.03μM。(2)建立了硫摻雜石墨烯量子點(diǎn)(S-GQDs2)的制備方法并研究了其在Ag+選擇性檢測中的應(yīng)用。采用一步水熱法,以1,3,6-三硝基芘為碳源、3-巰基丙酸為反應(yīng)硫源,在水熱過程中通過水相分子融合一步合成了S-GQDs2。采用UV-vis和熒光光譜對S-GQDs2的光學(xué)性質(zhì)進(jìn)行了分析;通過AFM、TEM、XPS對S-GQDs2的形貌、尺寸分布、化學(xué)組成等進(jìn)行了表征。結(jié)果表明,S-GQDs2在365 nm紫外光照射下發(fā)射亮藍(lán)色熒光,熒光光譜的最大激發(fā)波長為360 nm,最大發(fā)射波長為450 nm。熒光發(fā)射具有激發(fā)波長非依賴性,熒光量子產(chǎn)率為9.2%。S以-C-SO_2~-C-硫橋和-C-S-C-噻吩形式摻雜入GQDs骨架中,S-GQDs2平均粒徑為2.5 nm,結(jié)晶性好�？疾炝薙-GQDs2對不同金屬離子的選擇性,發(fā)現(xiàn)Ag+可選擇性猝滅S-GQDs2的熒光�；贏g+對S-GQDs2的熒光猝滅,建立了Ag+的熒光檢測方法。在p H 7.0、反應(yīng)孵育10 min時進(jìn)行檢測,檢測線性范圍為0.1μM~130.0μM,檢測限為0.03μM。(3)以合成的S-GQDs1為可見光催化劑,實(shí)現(xiàn)了S-GQDs1對堿性品紅的光催化降解。考察了溶液p H、染料濃度、S-GQDs1添加量對催化降解率的影響。結(jié)果表明,在溶液p H為7.0、染料濃度為5 mg L-1、S-GQDs1添加量為20%(體積分?jǐn)?shù))時,催化降解率最高。相比于無硫摻雜GQDs(S-free GQDs),S-GQDs1在可見光區(qū)有較明顯的紫外吸收和更高的光生載流子分離率,S-GQDs1的禁帶寬度為2.43 e V。對比了S-GQDs1和S-free GQDs對堿性品紅的催化降解活性。結(jié)果表明,S-GQDs1的催化活性是S-free GQDs的9倍,是堿性品紅自降解的45倍。(4)合成了富含含氧基團(tuán)的氧摻雜石墨烯量子點(diǎn)(O-GQDs),并將其與以堿剝離的鈦酸鹽納米片(TNSs)復(fù)合,通過一步靜電絮凝法成功制備了O-GQDs修飾的TNSs復(fù)合材料(O-GQDs/TNSs),并實(shí)現(xiàn)了O-GQDs/TNSs對羅丹明B的可見光催化降解。采用粉末X射線衍射法(XRD)、TEM、X射線能量色散譜(EDS)、循環(huán)伏安法(CV)、電化學(xué)阻抗譜(EIS)等對O-GQDs/TNSs的形貌、化學(xué)組成及光電化學(xué)性質(zhì)進(jìn)行表征。結(jié)果表明,靜電絮凝過程中TNSs的二維層狀結(jié)構(gòu)并未被破壞,O-GQDs成功修飾于TNSs表面,O-GQDs/TNSs的禁帶寬度為3.09 e V。以羅丹明B為模擬污染物,以rs-TNSs、O-GQDs為對照材料,考察了O-GQDs/TNSs的光催化性能和重復(fù)利用性。結(jié)果表明,該復(fù)合材料在可見光照射下對羅丹明B具有良好的降解活性并能重復(fù)利用,催化降解性能是單純O-GQDs的22倍,rs-TNSs的5倍。通過可見光催化降解結(jié)晶紫、活性藍(lán)、茜素紅等染料和光催化制氫考察該復(fù)合材料的通用性和普適性。結(jié)果表明,O-GQDs/TNSs具有優(yōu)良的通用性和普適性,O-GQDs/TNSs的光催化制氫速率是純rs-TNSs的68倍。初步探討O-GQDs/TNSs可見光催化下降解羅丹明B的機(jī)理。認(rèn)為光催化過程中空穴(h+)和超氧自由基(?O_2~-)起主導(dǎo)作用。
[Abstract]:Graphene quantum dots (graphene quantum, dots, GQDs) is a new type of fluorescent carbon nano materials. It is a size less than 100 nm and a thickness of less than 10 thin graphene layer, also known as zero dimensional graphene. Compared with the traditional fluorescent material, GQDs quantum confinement effect, size effect and edge effect in one also, with good biocompatibility, excellent luminescence properties and tunable band gap and other advantages. Different atoms or functional groups on the surface functionalization of graphene quantum dots, can adjust the band gap of GQDs and the charge density, and improve the fluorescence quantum yield, increase the active sites and chemical selectivity. In recent years, GQDs as a fluorescent probe and application of photocatalyst or photosensitizer in metal ions detection and photocatalysis has attracted much attention. In this paper, 1,3,6- three nitropyrene as carbon source, using different dopants, two kinds of sulfur doped synthetic stone Graphene quantum dots (S-GQDs1, S-GQDs2) and a new type of oxygen doped graphene quantum dots (O-GQDs), and to study the application of three kinds of graphene quantum dots in the metal ion detection and photocatalysis. The specific contents are as follows: (1) the establishment of the sulfur doped graphene quantum dot (S-GQDs1) system the preparation method and its application in Pb2+ selective detection. By using a one-step hydrothermal method with nuclear structure of graphene parent 1,3,6- three nitropyrene as carbon source, Na2S sulfur atom doping agent, Na OH solution as reaction medium, in the hydrothermal process by molecular fusion was synthesized by one step S-GQDs1. the UV Vis absorption spectra and fluorescence spectra (UV-vis) optical properties of S-GQDs1 are analyzed; by atomic force microscopy (AFM), transmission electron microscopy (TEM), X ray photoelectron spectroscopy (XPS) on S-GQDs1 morphology, size distribution and chemical composition were characterized. The results show that the S-GQDs1 emission of yellow green fluorescence at 365 nm under UV light irradiation, the fluorescence spectra of the maximum excitation wavelength is 490 nm, the maximum emission wavelength with excitation wavelength dependent fluorescence emission of 535 nm., the fluorescence quantum yield of 11.6%.S to -C-SOx-C- (x=2,3,4) doped sulfur bridge form into the framework of the GQDs, S-GQDs1 average particle size 3.2 nm, good crystallinity was studied. The selectivity of S-GQDs1 to different metal ions, the fluorescence quenching of S-GQDs1 Pb2+ was found to be selective. The fluorescence quenching of Pb2+ S-GQDs1 based on the established fluorescence detection method of Pb2+. The detection of Pb2+ optimal P of H was 7, the reaction was incubated for 5 min, the linear range of detection was 0.1 M~1.0 M, 1 M~140.0 M, the detection limit was 0.03 M. (2) established a sulfur doped graphene quantum dot (S-GQDs2) preparation method and study its application in Ag+ selective detection. By using a one-step hydrothermal method with three nitro 1,3,6- Pyrene as the carbon source, 3- mercaptopropionic acid as reaction sulfur source, through water molecule fusion step by S-GQDs2. UV-vis and fluorescence spectra of the optical properties of S-GQDs2 were analyzed in the hydrothermal synthesis process; through AFM, TEM, S-GQDs2 XPS on the morphology, size distribution and chemical composition were characterized. The results showed that S-GQDs2, at 365 nm under the irradiation of ultraviolet light emission light blue fluorescence, the fluorescence spectra of the maximum excitation wavelength is 360 nm, the maximum emission wavelength with excitation wavelength dependent fluorescence emission of 450 nm., the fluorescence quantum yield of 9.2%.S to -C-SO_2~-C- and -C-S-C- thiophene sulfur bridge form doped into the framework of the GQDs S-GQDs2, the average particle size of 2.5 nm and good crystallinity was studied. The selectivity of S-GQDs2 to different metal ions, the fluorescence quenching of S-GQDs2 Ag+ was found to be selective. The fluorescence quenching of Ag+ S-GQDs2 based on the established fluorescence detection Ag+ method in P H 7, The reaction was detected at 10 min of incubation, the linear range of detection was 0.1 M~130.0 M, the detection limit was 0.03 M. (3) synthesized S-GQDs1 as photocatalyst, the photocatalytic degradation of basic fuchsin S-GQDs1. The effect of solution P H, dye concentration, the amount of S-GQDs1 on the catalytic effect the degradation rate. The results showed that in the solution of P H was 7, the dye concentration of 5 mg L-1, S-GQDs1 content is 20% (volume fraction), the photocatalytic degradation rate was the highest. Compared to the non sulfur doped GQDs (S-free GQDs), S-GQDs1 has the obvious purple in the visible region and higher light absorption the carrier rate of separation, the band gap of S-GQDs1 is 2.43 e V. compared the photocatalytic activities of S-GQDs1 and S-free GQDs to basic fuchsin. The results showed that the catalytic activity of S-GQDs1 is 9 times that of S-free GQDs, is 45 times since the degradation of basic fuchsin. (4) the amount of oxygen doped graphene rich oxygen containing groups. Synthesis Quantum dots (O-GQDs), and with titanate nanosheets alkali peeling (TNSs) composite, through a successful step electrostatic flocculation of the TNSs composites modified by O-GQDs (O-GQDs/TNSs), and the photocatalytic degradation of Luo Danming B O-GQDs/TNSs. Using powder X ray diffraction method (XRD, TEM, X) and energy dispersive X-ray spectroscopy (EDS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) on the morphology of O-GQDs/TNSs, and photoelectrochemical properties of chemical composition were characterized. The results show that the layered structure of two-dimensional TNSs electrostatic flocculation process has not been destroyed, O-GQDs successfully modified on the surface of TNSs and the band gap of O-GQDs/TNSs is 3.09 e V. with Luo Danming B as a model pollutant to rs-TNSs, O-GQDs as control material, investigated the photocatalytic properties of O-GQDs/TNSs and reusablity. The results show that the composite material in visible light irradiation of Luo Danming B has good The degradation activity and can be used repeatedly, the photocatalytic degradation is 22 times higher than that of pure O-GQDs, 5 times of rs-TNSs. The photocatalytic degradation of crystal violet, active blue, alizarin red dye and photocatalytic hydrogen production and the general investigation of PU composite materials used. Results show that O-GQDs/TNSs has the versatility and universality excellent, photocatalytic hydrogen production rate of O-GQDs/TNSs is 68 times higher than the pure rs-TNSs. Preliminary study on degradation of rhodamine B under visible light. The catalytic mechanism of O-GQDs/TNSs photocatalytic process that the holes (h+) and superoxide radical (? O_2~-) plays a leading role.

【學(xué)位授予單位】：浙江理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ127.11;TB383.1

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