金铂和金钯双金属纳米材料的高压水热可控合成研究

发布时间：2018-05-17 06:41

本文选题：金铂合金 + 金钯核壳　；参考：《华南理工大学》2015年硕士论文

【摘要】：双金属纳米材料因其良好的催化性能而广泛地被用作各种化学反应的催化剂,尤其是金铂和金钯双金属纳米材料。然而,无论是金、铂还是钯,都属于贵重金属,在自然界中储量有限而且价格高昂。因此,设法提高其催化效率从而降低其使用成本成为科研工作者研究的重中之重。而双金属纳米材料的催化性能高度依赖于其尺寸与形貌。因此,制备出特定尺寸和形貌的金铂和金钯双金属纳米材料,提高其催化效率而降低催化剂成本尤为关键。同时,通过一种简单有效的方法来调控金铂和金钯双金属纳米粒子的表面结构、尺寸和形状具有非常大的意义。本论文用高压水热方法,首次合成了金铂花状合金纳米粒子和双六棱锥状金钯核壳结构纳米粒子,并用透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、X-射线能量散射谱(EDX)、X-射线衍射谱(XRD)对其组成和形貌等进行了表征,同时探究了反应温度、初始压力、前驱体的浓度比等因素对产物形貌和尺寸的影响。本论文取得的主要成果如下:(1)以氯铂酸(H2Pt Cl6)和氯金酸(HAu Cl4)作为前驱体,以十六烷基三甲基氯化铵(CTAC)作为包裹剂和稳定剂,以聚乙烯吡咯烷酮(PVP)为还原剂,首次用高压水热法制备了花状金铂合金纳米粒子。通过改变包裹剂CTAC浓度、前驱体浓度比、反应初始压力和反应物总浓度成功地实现了金铂纳米粒子尺寸和形貌的可控合成。有趣的是,仅通过改变CTAC的浓度可以将金铂纳米粒子的形貌由花状转变为卫星状。(2)以氯钯酸(H2Pd Cl4)和氯金酸(HAu Cl4)为前驱体、十六烷基三甲基溴化铵(CTAB)为络合剂和包裹剂、PVP为还原剂,首次用高压水热法制合成了双六棱锥形状的金钯核壳纳米粒子。通过改变反应温度、系统初始压力、前驱体浓度比和PVP浓度成功地实现了金钯纳米粒子尺寸和形貌的可控合成。
[Abstract]:Bimetallic nanomaterials are widely used as catalysts for various chemical reactions due to their good catalytic properties, especially gold platinum and gold palladium bimetallic nanomaterials. However, gold, platinum and palladium are precious metals, limited and expensive in nature. Therefore, how to improve its catalytic efficiency and reduce its use cost has become the most important research. The catalytic performance of bimetallic nanomaterials is highly dependent on their size and morphology. Therefore, it is very important to prepare gold platinum and gold palladium bimetallic nanomaterials with specific size and morphology to improve their catalytic efficiency and reduce the catalyst cost. At the same time, it is of great significance to regulate the surface structure, size and shape of gold platinum and gold palladium bimetallic nanoparticles by a simple and effective method. In this paper, gold platinum alloy nanoparticles and bihexagonal pyramidal gold and palladium core shell nanoparticles were synthesized by high pressure hydrothermal method for the first time. Its composition and morphology were characterized by transmission electron microscope (TEM) and high resolution transmission electron microscope (HRTEM). The composition and morphology of the Tem were investigated. The reaction temperature and initial pressure were also investigated. The influence of the concentration ratio of the precursor on the morphology and size of the product. The main results obtained in this paper are as follows: (1) using chloroplatinic acid (H2PtCl6) and chlorauric acid (HAU Cl4) as precursors, cetyltrimethylammonium chloride (CTAC) as encapsulant and stabilizer, and polyvinylpyrrolidone (PVP) as reducing agent. For the first time, flower-like gold platinum alloy nanoparticles were prepared by high pressure hydrothermal method. By changing the concentration of CTAC, the concentration of precursor, the initial pressure of reaction and the total concentration of reactant, the size and morphology of gold platinum nanoparticles were successfully synthesized. Interestingly, only by changing the concentration of CTAC, the morphology of gold platinum nanoparticles can be changed from flower-like to satellite-shaped.) the precursor is chloro-palladium acid (H2PdCl _ 4) and chlorauric acid (hau Cl _ 4). Cetyltrimethylammonium bromide (CTAB) was used as complexing agent and encapsulating agent PVP as reducing agent to synthesize bihexagonal gold and palladium core shell nanoparticles by high pressure hydrothermal method for the first time. By changing the reaction temperature, the initial pressure of the system, the concentration ratio of precursors and the concentration of PVP, the size and morphology of gold and palladium nanoparticles were successfully synthesized.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O611.4

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