染料敏化太阳能电池中石墨烯基对电极材料的理论研究
发布时间：2018-08-07 19:19
【摘要】：染料敏化太阳能电池(DSSC)由于成本低,环境友好,易于生产,近年来作为有前途的新一代太阳能电池受到重视。DSSC的电化学性能直接取决于对电极的性能。作为传统的电极材料,铂(Pt)纳米材料被广泛使用。然而,铂金的高成本和有限的使用性限制了DSSC的大规模商业应用。因此,为了代替传统的铂材料,需要寻找具有较低成本,高导电性和优良催化活性的新对电极材料。石墨烯作为最热的明星材料之一,由于其独特的平面二维结构,特殊的单原子层以及丰富的特性,引起了广泛的关注。石墨烯材料由于其耐磨性、强度、耐热性、电学性、光学性等特点,可用于航空航天工程、物理、化学、材料、电信、计算机科学等多个领域。最近许多实验组报道了具有高电催化效率的石墨烯对电极材料的合成和应用。本论文中,应用密度泛函理论(DFT),对本征石墨烯和N、S掺杂的石墨烯材料的掺杂效应和吸附行为进行量子化学计算。计算结果对实验结果进行了很好的解释,并为有前景的电极材料的筛选和开发提供了理论支持。主要研究结果如下:使用B3LYP方法和高斯软件包,对本征石墨烯片段模型和N、S的掺杂石墨烯模型计算NBO(Natural Bond Orbital)原子电荷密度分布。结果表明N或S原子掺杂后产生了更多具有正电荷的活性位点。N/S共掺杂通过产生带有更大的正电荷的活性位点而引起协同效应,从而增强对电极材料的电催化活性。使用PBE泛函和VASP程序,建立了对石墨烯系列材料的周期模型,详细研究了本征石墨烯和N、S掺杂石墨烯对于I2的吸附行为。对于吸附能,吸附位点,电荷转移和带结构的计算表明,N/S共掺杂石墨烯比N或S单掺杂石墨烯具有更强的吸附能力。BADER电荷分析还揭示了N和S原子共掺杂的协同效应。基于片段或周期性石墨烯系列模型,理论计算得出非常一致的结论:石墨烯中N和S原子的掺杂导致形成更多的活性位点,这有助于I2的吸附。此外,N/S共掺杂产生协同效应,改善了石墨烯基电极材料的电化学性能。
[Abstract]:Dye-sensitized solar cell (DSSC) has attracted much attention in recent years because of its low cost, friendly environment and easy production. The electrochemical performance of DSSC is directly dependent on the performance of the opposite electrode. As a traditional electrode material, platinum (Pt) nanomaterials are widely used. However, the high cost and limited availability of platinum limit the large-scale commercial use of DSSC. Therefore, in order to replace the traditional platinum materials, it is necessary to find new opposite electrode materials with low cost, high conductivity and excellent catalytic activity. As one of the hottest star materials, graphene has attracted wide attention due to its unique planar two-dimensional structure, special monatomic layer and rich properties. Graphene materials can be used in aerospace engineering, physics, chemistry, materials, telecommunications, computer science and other fields due to its wear resistance, strength, heat resistance, electrical properties, optical properties and other characteristics. Recently, many experimental groups reported the synthesis and application of graphene electrode materials with high electrocatalytic efficiency. In this paper, the density functional theory (DFT),) is used to calculate the doping effect and adsorption behavior of graphene and Na-S doped graphene materials by quantum chemistry. The calculated results provide a good explanation for the experimental results and provide theoretical support for the screening and development of promising electrode materials. The main results are as follows: B3LYP method and Gao Si software package are used to calculate the charge density distribution of NBO (Natural Bond Orbital) atom for the intrinsic graphene fragment model and the doped graphene model. The results show that N or S atoms have more active sites with positive charge after doping. The co-doping of N / S leads to synergistic effect by producing active sites with larger positive charges, thus enhancing the electrocatalytic activity of electrode materials. Using PBE functional and VASP program, the periodic model of graphene series was established, and the adsorption behavior of I _ 2 for I _ 2 by intrinsic graphene and Na-S doped graphene was studied in detail. The calculation of adsorption energy, adsorption site, charge transfer and band structure shows that N / S co-doped graphene has a stronger adsorption ability than N or S doped graphene. The charge analysis of BADER also reveals the synergistic effect of N and S codoping. Based on the partial or periodic graphene series models, the theoretical calculations show that the doping of N and S atoms in graphene leads to the formation of more active sites, which is helpful to the adsorption of I2. In addition, the synergistic effect of N / S co-doping improves the electrochemical performance of graphene based electrode materials.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4
本文编号：2171093
[Abstract]:Dye-sensitized solar cell (DSSC) has attracted much attention in recent years because of its low cost, friendly environment and easy production. The electrochemical performance of DSSC is directly dependent on the performance of the opposite electrode. As a traditional electrode material, platinum (Pt) nanomaterials are widely used. However, the high cost and limited availability of platinum limit the large-scale commercial use of DSSC. Therefore, in order to replace the traditional platinum materials, it is necessary to find new opposite electrode materials with low cost, high conductivity and excellent catalytic activity. As one of the hottest star materials, graphene has attracted wide attention due to its unique planar two-dimensional structure, special monatomic layer and rich properties. Graphene materials can be used in aerospace engineering, physics, chemistry, materials, telecommunications, computer science and other fields due to its wear resistance, strength, heat resistance, electrical properties, optical properties and other characteristics. Recently, many experimental groups reported the synthesis and application of graphene electrode materials with high electrocatalytic efficiency. In this paper, the density functional theory (DFT),) is used to calculate the doping effect and adsorption behavior of graphene and Na-S doped graphene materials by quantum chemistry. The calculated results provide a good explanation for the experimental results and provide theoretical support for the screening and development of promising electrode materials. The main results are as follows: B3LYP method and Gao Si software package are used to calculate the charge density distribution of NBO (Natural Bond Orbital) atom for the intrinsic graphene fragment model and the doped graphene model. The results show that N or S atoms have more active sites with positive charge after doping. The co-doping of N / S leads to synergistic effect by producing active sites with larger positive charges, thus enhancing the electrocatalytic activity of electrode materials. Using PBE functional and VASP program, the periodic model of graphene series was established, and the adsorption behavior of I _ 2 for I _ 2 by intrinsic graphene and Na-S doped graphene was studied in detail. The calculation of adsorption energy, adsorption site, charge transfer and band structure shows that N / S co-doped graphene has a stronger adsorption ability than N or S doped graphene. The charge analysis of BADER also reveals the synergistic effect of N and S codoping. Based on the partial or periodic graphene series models, the theoretical calculations show that the doping of N and S atoms in graphene leads to the formation of more active sites, which is helpful to the adsorption of I2. In addition, the synergistic effect of N / S co-doping improves the electrochemical performance of graphene based electrode materials.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM914.4
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