三维石墨烯的构造及其光催化应用

发布时间：2018-01-05 10:19

本文关键词：三维石墨烯的构造及其光催化应用　出处：《扬州大学》2016年硕士论文　论文类型：学位论文

【摘要】：石墨烯(Graphene)是一种单原子层的二维晶体结构,由6个碳原子通过sp2杂化形成的六边形蜂窝状结构。其原材料丰富、绿色无毒、价格低廉,其制备工艺相对简单、成熟、容易产业化,其二维纳米结构与半导体光催化剂易形成异质结构,并表现出独特的光电特性。因石墨烯长程有序的π键电子结构使其展现出独特的化学性能、光学性质、电学性能、热学性能以及力学性能,并使得石墨烯在储氢材料、太阳能光伏电池、锂电池、超级电容器、光电探测器以及光催化剂等领域有着独特的应用前景。特别是,三维石墨烯宏观结构兼具二维石墨烯固有特性以及多孔形貌,在光、电等物理性能、吸附催化降解、生物兼容等方面表现出很多特性,比如三维结构高吸附性能、强机械性能、高导电率、低体传输电阻与快电子传输性能、大比表面积和可塑性等等。为此,围绕如何构造复合有半导体光催化剂(如二氧化钛)的三维石墨烯结构,同时对该异质结构的吸附、光催化应用及其光生载流子动力学过程进行了研究,具体内容如下：1.通过控制氧化剂量的配比来氧化鳞片状石墨从而制备氧化石墨烯,并利用高温水热还原氧化石墨烯制成单层或少层石墨烯。通过X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)与透射电子显微镜(TEM)分别来分析氧化石墨烯和石墨烯的结构和形貌。采用红外光谱(FT-IR)和拉曼光谱(Raman)来证实氧化石墨烯和石墨烯的元素成分以及还原程度。最后通过紫外可见吸收光谱(UV-Vis)和光致发光光谱(PL)来研究其光学性质,为进一步探究三维石墨烯与光催化剂的复合材料奠定基础。2.通过一步水热自组装法,将修饰有Ti02纳米颗粒(NPs)的还原氧化石墨烯(RGO)纳米片负载于活性炭纤维(ACF)上,制备成三维(3D)宏观复合结构,实现了纳米尺寸材料的宏观化。我们将获得的ACF-RGO-TiO2复合结构通过降解有机染料(即罗丹明B),来概念性验证其实际效果,研究发现RGO NSs与TiO2 NPs的引入分别增强了复合物的吸附性能和光催化能力。而且,通过半导体光催化剂将吸附于材料表面的RhB染料光催化降解,使得ACF-RGO-TiO2复合结构的吸附性能得以恢复,概念性地提出两个实际价值：(1)降解染料污染物优于简单地吸附污染物;(2)吸附剂的回收利用优于吸附剂的大量消耗。3DACF-RGO-TiO2实现了协同功能化效应,主要是通过水热复合,不仅赋予了宏观结构吸附性能,同时赋予其光催化性能,最终拓展了复合结构在环境净化方面的应用。3.在光伏电池和光电化学(PEC)电池领域,构建高效的光子俘获与电荷积聚的光电子纳米系统是极具潜力的,所以制备出三维(3D)多孔光电极是非常有意义的,具备以下优势：大的活性比表面积、高效的光子俘获效率、以及快速的电荷分离及迁移率。因此,我们设计将还原氧化石墨烯(RGO)与均匀分布的TiO2纳米颗粒(NPs)复合制备成异质3D多孔光阳极,同时此光阳极在0.6 V(相对Ag/AgCl)外加电压下能产生2.59 mA cm-2的光电流密度,且其无需任何牺牲剂就能获得0.5%的光裂解水产氢转换效率。与TiO2 NPs基材料相比较,RGO-TiO2复合光阳极拥有卓越的PEC性能,其主要是由于3D RGO骨架的光陷域效应、快的电子迁移、热电导效应、高催化剂负载以及大量的电解液渗透等激励作用。
[Abstract]:Shi Moxi (Graphene) is a two-dimensional crystal structure of a single atomic layer of the hexagonal honeycomb structure formed by 6 carbon atoms by SP2 hybridization. The abundant raw materials, green non-toxic, low price, the preparation process is relatively simple, mature, easy industrialization, the Wiener meters structure and easy to form heterogeneous Semiconductor Photocatalysts the structure, and exhibit unique optoelectronic properties. Graphene for long-range ordered pi bond electronic structure which exhibits unique chemical properties, optical properties, electrical properties, thermal properties and mechanical properties, and the graphene in hydrogen storage materials, solar photovoltaic battery, lithium battery, super capacitor, photoelectric detector as well as the photocatalyst has a unique application. Especially, the macro structure of three-dimensional graphene has the inherent characteristics of two-dimensional graphene and porous morphology, in the light, electricity and other physical properties, adsorption and catalytic degradation, Biological compatibility and so on show a lot of characteristics, such as three-dimensional structure with high adsorption performance, high mechanical performance, high conductivity, low body resistance and fast transmission electron transport properties, large surface area and plasticity and so on. Therefore, on how to construct composite semiconductor photocatalyst (such as TiO2) three-dimensional graphene structure, at the same time the heterostructure of adsorption, and photocarrier dynamics process of photocatalytic application were studied, the contents are as follows: 1. by controlling the oxidation dose ratio to oxidation of flake graphite and graphene oxide was prepared, and the use of high temperature hydrothermal reduction of graphene oxide made of single or few layer graphene. By means of X ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) to analyze the structure and morphology of graphene oxide and graphene respectively. By using infrared spectroscopy (FT-IR) and pull Raman spectroscopy (Raman) to confirm the graphene oxide and graphene elements and the degree of reduction. Finally, UV visible absorption spectroscopy (UV-Vis) and photoluminescence spectroscopy (PL) to study the optical properties, lay the foundation for.2. by one step hydrothermal self-assembly method for composite three-dimensional graphene and further explore photocatalyst material, decorated with Ti02 nanoparticles (NPs) reduced graphene oxide (RGO) nano films supported on activated carbon fiber (ACF), prepared into three-dimensional (3D) macro composite structure, the macro nano size materials. The ACF-RGO-TiO2 composite structure we will get through the degradation of organic dye (Luo Danming B), to verify the actual effect of the concept, the study found that adsorption performance and photocatalytic ability of the composite materials were introduced into RGO NSs and TiO2 NPs increased respectively. Moreover, the semiconductor photocatalytic agent will be adsorbed on the surface of the RhB The photocatalytic degradation of dyes, the adsorption properties of ACF-RGO-TiO2 composite structure can be restored, the concept put forward two practical value: (1) better than the degradation of dye pollutants simply adsorption of pollutants; (2) recycling sorbent using large consumption of.3DACF-RGO-TiO2 is better than that of adsorbent to achieve a synergistic functional effect, mainly through hydrothermal synthesis that not only gives the adsorption properties of macro structure, and gives its photocatalytic properties, and eventually expand the composite structure in the application of.3. purification environment in photovoltaic and photoelectrochemical (PEC) field battery, optoelectronic system and efficient photon trapping of charge accumulation is of great potential, so prepare3-d (3D) light porous electrode is very meaningful, has the following advantages: large active surface area, high efficiency of photon capture, and charge separation and migration rate. Due to fast This, we design the reduction of graphene oxide (RGO) and TiO2 nanoparticles were uniformly distributed (NPs) composite were prepared by heterogeneous 3D porous light anode, and the anode at 0.6 V (relative to Ag/AgCl) and photocurrent density can produce 2.59 mA voltage of cm-2, and without any sacrifice agent can get cracking light hydrogen conversion efficiency of 0.5%. Compared with the TiO2 NPs based material, RGO-TiO2 composite anode has excellent PEC performance, which is mainly due to the 3D RGO domain skeleton light trapping effect, fast electron transfer, thermal conductive effect, high catalyst loading and a large amount of electrolyte penetration incentive.

【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;O644.1

【相似文献】