类石墨烯—卟啉二维纳米复合材料的制备及其光电催化性能研究

发布时间：2018-04-24 11:51

本文选题：二维纳米材料 + 石墨烯　；参考：《湖南科技大学》2017年硕士论文

【摘要】：类石墨烯二维纳米材料是以石墨烯为代表的具有原子级厚度的超薄二维层状结构的一类新型纳米碳材料,具有优异的电学和光学性质,拥有巨大的比表面积和出色的电子转移能力。卟啉具有独特的大π分子结构,是一种性能稳定的光敏材料,具有良好的给电子能力,因此将具有强吸光能力和给电子能力的卟啉与具有电子转移能力的类石墨烯材料结合起来,实现卟啉与类石墨烯材料之间的电子传递和增强光电性能是当下研究石墨烯和卟啉的热点之一,这类复合材料在光电转换器、分析传感器、光电催化剂等领域具有广泛的应用前景,本文研究内容主要包括以下几个方面:(1)由氧化石墨烯出发通过化学还原法制备还原程度递增的还原氧化石墨烯(rGO),表面带有梯度减少的负电荷量,阳离子卟啉(5,10,15,20-四[4-丙基吡啶基]卟啉,TPPyP)可自发组装到其表面获得rGO/TPPyP,进一步发现在常温下Zn2+可有效嵌入到卟啉环内形成rGO/TPPyP-Zn复合物,且嵌入速度与rGO表面电荷量直接相关。实验结果表明rGO上TPPyP的组装和Zn2+的嵌入过程会导致紫外可见吸收光谱中的卟啉特征吸收峰明显红移,原子力显微镜下的二维纳米片厚度发生变化,荧光光谱发生显著的猝灭效果。由此发展了一种在常温下可控制备水溶性金属锌卟啉-石墨烯纳米复合材料的新方法,而且所制备的rGO/TPPyP-Zn纳米复合材料对CO2还原具备较高的光电催化活性。(2)由石墨出发采用超声液相剥离法直接制备表面带负电荷的水分散的石墨烯(wG),随着超声时间延长表面负电荷梯度增加,将该石墨烯与金属阳离子卟啉(铜卟啉和锌卟啉)作用可形成系列石墨烯-金属卟啉复合材料。紫外可见吸收光谱、原子力显微镜、Zeta电位等实验结果表明,wG表面电荷量直接影响复合材料的光谱性质,该复合物可用于CO2光电催化还原。(3)以三聚氰胺为前驱体采用热缩聚法合成了石墨相氮化碳(g-C3N4),再经过酸化超声处理得到超薄g-C3N4纳米片,其表面正负电荷性质随溶液pH改变。实验发现该纳米片对于不同类型的染料罗丹明B(RhB)和变色酸2R(Ch2R)具有pH调控的光降解催化活性。此外,将g-C3N4纳米片与阳离子卟啉(5,10,15,20-四[4-羟丙基吡啶基]卟啉,THPPyP)和阴离子卟啉(5,10,15,20-四[4-磺酸基苯]卟啉,TPPS4)在合适条件下作用可获得g-C3N4/THPPyP和g-C3N4/TPPS4纳米复合材料,利用紫外、荧光、电化学等手段进行了一系列的表征,将g-C3N4/THPPyP在FTO上通过电荷作用层层组装获得复合薄膜修饰电极,光电流响应随着膜层数的逐渐增加,且复合薄膜对于CO2还原具有一定的光电催化能力。
[Abstract]:Graphene like two-dimensional nanomaterials, represented by graphene, are a new kind of nano-carbon materials with ultrathin two-dimensional layered structure with atomic thickness, and have excellent electrical and optical properties. It has huge specific surface area and excellent electron transfer ability. Porphyrin has a unique large 蟺 molecular structure, it is a kind of stable Guang Min material, and has good electron feeding ability. Therefore, porphyrins with strong absorptivity and electron giving ability are combined with graphene like materials with electron transfer ability. The realization of electron transfer between porphyrins and graphene like materials and the enhancement of their optoelectronic properties are one of the hot topics in the research of graphene and porphyrin. Photoelectric catalysts and other fields have a wide range of applications, The main contents of this paper include the following aspects: 1) from graphene oxide, the reductive graphene oxide rGOA with increasing reduction degree is prepared by chemical reduction method, and the surface has a negative charge with gradient reduction. The cationic porphyrin (Cationic porphyrin) can be spontaneously assembled onto its surface to obtain rGO- / TPPyP. It is further found that Zn2 can be effectively embedded into porphyrin ring to form rGO/TPPyP-Zn complex at room temperature, and the embedding rate is directly related to the surface charge amount of rGO. The experimental results show that the assembling of TPPyP on rGO and the embedding process of Zn2 will result in the red shift of the characteristic absorption peak of porphyrin in UV-Vis absorption spectrum, and the change of the thickness of two-dimensional nanochip under atomic force microscope. The fluorescence spectrum has a remarkable quenching effect. A new method for preparing water-soluble zinc porphyrin graphene nanocomposites at room temperature was developed. Moreover, the prepared rGO/TPPyP-Zn nanocomposites have high photocatalytic activity for CO2 reduction. The surface negative charge gradient increases, A series of graphene-metalloporphyrin composites can be formed by the interaction of the graphene with metal cationic porphyrin (copper porphyrin and zinc porphyrin). The UV-Vis absorption spectra, atomic force microscope (AFM) Zeta potential and other experimental results show that the surface charge content of WG has a direct effect on the spectral properties of the composites. The composite can be used in the photocatalytic reduction of CO2. (3) the graphite phase carbon nitride (C _ 3N _ 3N _ 4N _ 4) was synthesized by thermal condensation with melamine as the precursor. The ultrathin g-C3N4 nanoparticles were obtained by acidizing ultrasonic treatment. The positive and negative charge properties of the surface changed with the pH of the solution. It was found that the nanoparticles had the photocatalytic activity of pH regulation for different dyes Rhodamine (RhB) and chromotropic acid (2RX Ch2R). In addition, g-C3N4 nanocomposites and g-C3N4/TPPS4 nanocomposites were obtained by the reaction of g-C3N4 nanoparticles with cationic porphyrin 5101010T- [4-hydroxypropylpyridyl] porphyrin (THPPyP) and anion porphyrin 510151520- [4-sulfonic benzene] porphyrin (TPPS4) under suitable conditions. A series of characterizations were carried out by electrochemical methods. G-C3N4/THPPyP was assembled on FTO by charge interaction layer by layer to obtain composite film modified electrode. The photocurrent response increased with the increase of the number of layers. The composite film has certain photocatalytic activity for CO2 reduction.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB332;O643.36

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