【摘要】：單分散性納米材料因其均一的尺寸分布、表面性質(zhì)的可控性、量子尺寸效應(yīng)而表現(xiàn)出特殊的物理化學(xué)性質(zhì)。構(gòu)建具有功能特性的納米材料在催化、高密度信息存儲、生物熒光標(biāo)記、核磁共振成像等領(lǐng)域已表現(xiàn)出潛在的應(yīng)用前景。目前,在制備單分散納米材料的方法中不可避免的要使用油酸(OA)或油胺(OAm)等長碳鏈有機分子作為表面活性劑來調(diào)控粒子的尺寸和形貌。而當(dāng)這些單分散納米粒子被應(yīng)用于催化、氣敏、電化學(xué)等領(lǐng)域時,包裹在粒子表面的長碳鏈有機分子往往會成為阻礙。為克服納米粒子應(yīng)用上的缺陷,本論文以Na2SO4作為導(dǎo)熱劑采用熔融鹽焙燒法,通過調(diào)整不同的實驗參數(shù)制備出Bi-Bi2O3/C納米材料,CoO/C納米材料和Ni/C納米材料。并對所合成的材料在光催化,電化學(xué)及氣敏方面的應(yīng)用進行了初步探究。主要研究內(nèi)容與結(jié)論如下:Bi-Bi2O3/C納米材料的制備和光催化性能研究:以Bi(OH)3@OA為前驅(qū)體,在Ar氣氛中以無機鹽Na2SO4作為犧牲模版,通過調(diào)節(jié)惰性氣體的流速并采用不同的焙燒溫度得到Bi-Bi2O3/C納米復(fù)合材料。采用X射線粉末衍射(XRD)技術(shù),透射電子顯微鏡(TEM)和掃描電子顯微鏡(SEM)對其進行物相、尺寸、形貌等微觀結(jié)構(gòu)的表征。結(jié)果表明:不同焙燒溫度條件下得到產(chǎn)物為碳膜上負(fù)載的尺寸在20-60 nm之間的Bi-Bi2O3納米球。并考察了四種Bi-Bi2O3/C納米材料對亞甲基藍(MB),甲基橙(MO)和羅丹明B(RhB)染料溶液的光催化降解能力。光催化結(jié)果表明:在100 W汞燈光照下,400℃焙燒得到的Bi-Bi2O3/C納米材料在3.5 h內(nèi)使10 mg/L的MB,MO,RhB染料溶液降解完全。CoO/C納米材料的制備和電化學(xué)性能研究:以Co(OH)2@OA為前驅(qū)體,在Ar氣氛中以無機鹽Na2SO4作為犧牲模版,考察不同的焙燒溫度對CoO/C和Co/C納米材料的物相和電化學(xué)性能影響。結(jié)果表明,350℃,400℃和500℃焙燒得到碳膜上負(fù)載的CoO納米顆粒,600℃焙燒則得到碳膜上負(fù)載的單質(zhì)Co納米顆粒,且CoO和單質(zhì)Co納米顆粒尺寸均在7-12 nm之間。材料電化學(xué)測試結(jié)果表明:400℃下合成的材料,在電流密度為70 mA·g-1時,首次放電容量達1139.1mAh·g-1,經(jīng)50圈循環(huán)后放電容量為642.1 mAh·g-1,容量保持率為95%。Ni/C納米材料的制備和氣敏性能研究:以Ni(OH)2@OA為前驅(qū)體,在Ar氣氛中以無機鹽Na2SO4作為犧牲模版,通過調(diào)控溫度發(fā)現(xiàn),當(dāng)焙燒溫度為400℃時,得到尺寸和形貌分布均勻的Ni/C納米材料。將此材料采用不同溫度和時間利用Kirkendall effect氧化時可得到尺寸在20-70 nm之間的中空結(jié)構(gòu)NiO球。通過對得到的NiO納米材料進行氣敏性能的初步研究。結(jié)果表明:在氧化條件為500℃,4 h時得到的NiO材料對正丁醇表現(xiàn)出優(yōu)異的選擇性和較高的響應(yīng)性(1000 ppm,Rg/Ra=9.0)。
[Abstract]:Monodisperse nanomaterials exhibit special physical and chemical properties due to their uniform size distribution, controllable surface properties and quantum size effect. The fabrication of functional nanomaterials has shown potential applications in the fields of catalysis, high density information storage, bioluminescence labeling, magnetic resonance imaging and so on. At present, it is inevitable to use long chain organic molecules such as oleic acid (OA) or oleamine (OAM) as surfactants to control the size and morphology of nanoparticles in the preparation of monodisperse nanomaterials. However, when these monodisperse nanoparticles are applied in the fields of catalysis, gas sensitivity, electrochemistry and so on, the organic molecules with long carbon chains on the surface of the particles often become obstacles. In order to overcome the defects in the application of nano-particles, Bi-Bi2O3 / C nanomaterials and Ni / C nanomaterials were prepared by using Na _ 2SO _ 4 as heat conduction agent by molten salt roasting method and by adjusting different experimental parameters. The applications of the synthesized materials in photocatalysis, electrochemistry and gas sensitivity were also discussed. The main contents and conclusions are as follows: the preparation and photocatalytic properties of Bi-Bi _ 2O _ 3 / C nanomaterials were studied: using Bi (OH) _ 3SO _ 3 as precursor and inorganic salt Na _ 2SO _ 4 as sacrificial template in ar atmosphere. Bi-Bi _ 2O _ 3 / C nanocomposites were prepared by adjusting the flow rate of inert gas and using different calcination temperatures. X-ray powder diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscope (SEM) were used to characterize the phase, size and morphology. The results showed that Bi-Bi2O3 nanospheres with the size of 20-60 nm were obtained under different calcination temperature. The photocatalytic degradation of methylene blue (MB), methyl orange (MO) and rhodamine B (RhB) dyes by four Bi-Bi _ 2O _ 3 / C nanomaterials was investigated. The photocatalytic results showed that Bi-Bi _ 2O _ 3 / C nanomaterials calcined at 400 鈩，

本文編號：2130021