本文選題：光化學(xué)還原反應(yīng)　切入點(diǎn)：納米材料　出處：《蘇州大學(xué)》2015年碩士論文

【摘要】：銅族(Au、Ag、Cu)納米材料由于其獨(dú)特的表面等離子共振(surface plasmon resonances,SPRs)而表現(xiàn)出優(yōu)異的物理化學(xué)性質(zhì),尤其是光學(xué)性質(zhì)。表面等離子體共振是一系列增強(qiáng)光譜技術(shù),如是表面增強(qiáng)拉曼、熒光增強(qiáng)等的重要增強(qiáng)機(jī)理。利用表面等離子體共振增強(qiáng)光譜技術(shù),科學(xué)家們已經(jīng)實(shí)現(xiàn)了痕量檢測(cè),甚至是單分子檢測(cè)的目的。此外,表面等離子體共振在光催化降解、紅外熱療、生物標(biāo)記等領(lǐng)域也具有極大的應(yīng)用價(jià)值。通過調(diào)控納米材料的組成、形貌、尺寸和納米材料的空間維度等,可實(shí)現(xiàn)對(duì)納米材料性質(zhì)的調(diào)控。已報(bào)道的研究工作主要集中在金、銀納米材料上,對(duì)Ag2O納米材料、銅基納米材料的研究相對(duì)較少。目前,用來制備納米材料的方法有很多,包括水熱法、脈沖-激光沉積法、溶膠-凝膠法、電化學(xué)沉積法、化學(xué)氣相沉積法等,其中光化學(xué)反應(yīng)法是很重要的一種。本論文旨在探索光化學(xué)還原合成法可控制備多山丘狀A(yù)g納米顆粒超結(jié)構(gòu)、Ag/Ag2O納米片、CuxOy納米片等納米晶體,并探討了各種納米結(jié)構(gòu)的生長機(jī)制。通過進(jìn)一步的固相熱分解法,制備了多孔Ag/Ag2O納米片和多孔Cu O納米片。主要開展的工作如下:1.光化學(xué)還原方法首次制備多山丘狀A(yù)g納米顆粒的超結(jié)構(gòu):在光化學(xué)還原反應(yīng)中,吸附在Zn O半導(dǎo)體表面的Ag+離子首先被光生電子還原為Ag0,后者進(jìn)一步生長為Ag納米顆粒。隨后,在螺旋位錯(cuò)的誘導(dǎo)下,現(xiàn)場(chǎng)生成的Ag納米顆粒通過BCF機(jī)制(Burton,Cabrera,and Frank)結(jié)晶生長為多山丘狀超結(jié)構(gòu)。研究結(jié)果顯示,這是一個(gè)以納米顆粒為結(jié)構(gòu)單元、在螺旋位錯(cuò)誘導(dǎo)下發(fā)生的晶體生長過程(BCF model)。研究還發(fā)現(xiàn),這些在Zn O表面生長的多山丘狀A(yù)g納米顆粒超結(jié)構(gòu)能夠精細(xì)地調(diào)控Zn O的光致發(fā)光性能(Photoluminesence,PL)。2.光化學(xué)還原法制備Ag/Ag2O納米片:通過調(diào)控UV輻射時(shí)間,成功地制備形貌、尺寸可控,直立生長于Zn O薄膜上的Ag/Ag2O納米片。討論Ag NO3濃度、UV輻射時(shí)間等因素從而探討Ag/Ag2O納米片的生長機(jī)理。研究發(fā)現(xiàn),Ag/Ag2O納米片的生長受兩種機(jī)制控制:首先,光化學(xué)還原法現(xiàn)場(chǎng)制備的Ag納米顆粒通過層層生長(layer-by-layer)機(jī)制進(jìn)一步結(jié)晶生長為表面粗糙、邊緣不規(guī)則且尺寸較小的納米片;然后,后者在紫外光的照射下進(jìn)一步轉(zhuǎn)化為表面光滑、邊緣整齊規(guī)則且尺寸較大的納米片。通過固相熱分解的方法,我們進(jìn)一步得到了多孔Ag/Ag2O納米片。與退火之前的Ag/Ag2O納米片相比,多孔Ag/Ag2O納米片具更好的SERS活性。3.光化學(xué)合成法制備CuxOy納米片:研究發(fā)現(xiàn),CuxOy納米片的生長機(jī)制與Ag/Ag2O納米片的生長機(jī)制相似,但是在相似的實(shí)驗(yàn)條件下,CuxOy納米片的生長速度要顯著快于Ag/Ag2O納米片,更為深入的生長機(jī)制仍然在研究當(dāng)中。最后,在350℃條件下,通過固相熱分解法處理CuxOy納米片,得到了多孔Cu O納米片。這些多孔Cu O納米片在催化、傳感領(lǐng)域有著廣泛的應(yīng)用前景。
[Abstract]:Due to its unique surface plasmon resonance (plasmon) resonance surface plasmon resonance (SPRs), copper nanomaterials exhibit excellent physical and chemical properties, especially optical properties.Surface plasmon resonance (SPR) is a series of enhanced spectroscopic techniques, such as surface enhanced Raman and fluorescence enhancement.Using surface plasmon resonance enhanced spectroscopy, scientists have achieved trace detection, even monomolecular detection.In addition, surface plasmon resonance (SPR) has great application value in photocatalytic degradation, infrared hyperthermia and biomarker.The properties of nanomaterials can be controlled by adjusting the composition, morphology, size and space dimension of nanomaterials.The reported researches are mainly focused on gold and silver nanomaterials, but relatively few on Ag2O nanomaterials and copper based nanomaterials.At present, there are many methods used to prepare nanomaterials, including hydrothermal method, pulse-laser deposition method, sol-gel method, electrochemical deposition method, chemical vapor deposition method and so on. Photochemical reaction is one of the most important methods.The aim of this thesis is to explore the controllable preparation of multi-mound Ag / Ag _ 2O nanocrystals by photochemical reduction synthesis, and investigate the growth mechanism of various nanocrystals, such as CuxOy nanocrystals.Porous Ag/Ag2O nanoparticles and porous CuO nanoparticles were prepared by further solid phase thermal decomposition.The main work to be carried out is as follows: 1: 1.In the photochemical reduction reaction, Ag ions adsorbed on the surface of Zn O semiconductors were first reduced to Ag _ 0 by photoelectron, and the latter was further grown into Ag nanoparticles.Subsequently, induced by spiral dislocations, Ag nanoparticles formed in situ grew into multi-hill superstructures through the BCF mechanism of Burton Cabreraragne and Frank.The results show that this is a crystal growth process induced by helical dislocations with nanocrystalline particles as the structure unit.It is also found that these massif Ag nanoparticles can fine regulate the photoluminescence properties of ZnO.Ag/Ag2O nanocrystals were prepared by photochemical reduction method. By controlling UV radiation time, Ag/Ag2O nanowires were successfully prepared with controllable size and upright growth on Zno thin films.The factors such as Ag NO3 concentration and UV radiation time are discussed to study the growth mechanism of Ag/Ag2O nanoparticles.It was found that the growth of Ag- / Ag2O nanoparticles was controlled by two mechanisms: firstly, the Ag nanoparticles prepared by photochemical reduction method were further crystallized and grown into coarse surface, irregular edges and smaller size by layer by layer growth mechanism.Then, the latter is further transformed into a large size nanocrystalline film with smooth surface, regular edges and large size under the irradiation of ultraviolet light.The porous Ag/Ag2O nanocrystals were further obtained by solid phase thermal decomposition.Compared with the Ag/Ag2O nanoparticles before annealing, the porous Ag/Ag2O nanoparticles have better SERS activity. 3.Preparation of CuxOy nanoparticles by photochemical synthesis: it was found that the growth mechanism of CuxOy nanoparticles was similar to that of Ag/Ag2O nanoparticles, but the growth rate of CuxOy nanoparticles was significantly faster than that of Ag/Ag2O nanoparticles under similar experimental conditions.More in-depth growth mechanisms are still being studied.Finally, porous CuO nanoparticles were prepared by solid phase thermal decomposition at 350 鈩，

本文編號(hào)：1729143