纳米碳材料负载体系的制备及其电催化性能研究

发布时间：2018-01-13 00:30

本文关键词：纳米碳材料负载体系的制备及其电催化性能研究　出处：《上海电力学院》2017年硕士论文　论文类型：学位论文

【摘要】：Pd基催化剂作为甲酸燃料电池阳极催化剂有更优越的性能,但是Pd基催化剂低的电催化稳定性却限制了其发展。可以通过采用加入其它原子来制备Pd基复合催化剂这种方法来提高其电催化稳定性。然而,实际应用Pd基复合催化剂作为甲酸燃料电池的催化剂仍面临巨大挑战。第一,据报道,已有的Pd基催化剂中Pd加上其它金属的总含量都是占催化剂质量的20-30%之间,采用如此大量的金属抑制了金属在载体表面的分散并且减小了催化过程中可利用的有效活性面积。第二,对甲酸电氧化过程中双金属(由价键控制的)的表面电子的性能和结构稳定性的研究还不明确。本论文中,将研究不同原子比例的Pd-Cu合金负载在碳纳米管上的催化剂催化甲酸电氧化的性能。在烧结和还原处理的过程中官能团化的碳纳米管嵌入到已形成的合金纳米颗粒的晶体中并且促进金属颗粒的分散。从甲酸氧化的结果可知富含Cu的Pd-Cu双金属催化剂比其他含Cu量少的Pd-Cu双金属催化剂催化甲酸氧化的活性和稳定性更好。不仅如此,表面和结构分析显示富含Cu的Pd-Cu合金的表面电子性能可能是控制催化途径的关键。本论文中尝试了制备多孔碳材料的新方法,在此基础上进行了掺氮改性和负载氢氧化钴。通过一系列表征手段分析了这个新材料的形貌结构,并且将这几种催化剂作为电极材料进行了超级电容器的电化学性能测试,结果表明该三维多孔碳结构有优异的物理结构和电催化性能,改性和负载金属后的催化剂在超级电容器应用中有较高的比电容,为超级电容器电极材料的制备提供了新思路。本文的研究工作主要在以下几个方面开展:1、浸渍法制备不同原子比例的Pd-Cu合金负载在碳纳米管上的催化剂,通过表征分析其形貌与结构,并测试其对甲酸的催化性能。2、介绍制备碳量子点(CQDs)的方法,制备其衍生物三维碳结构(3D PCFs)。对它们进行形貌结构表征,在此基础上又对3D PCFs进行修饰,制备氮掺杂碳三维结构(N-3D PCFs),并对其进行表征分析。初步测试了3D PCFs在超级电容器中的应用。3、采用化学液相合成(氮掺杂)碳三维结构负载氢氧化钴催化剂,对其进行表征,探究其结构及形貌并且测试其超级电容器催化性能。基于以上研究及分析,本论文从碳材料入手,通过掺杂非金属元素进行改性并且负载金属的手段实现碳材料负载体系在甲酸电氧化及超级电容器电极材料等电催化领域的广泛应用。
[Abstract]:PD-based catalyst has better performance as anodic catalyst for formic acid fuel cell. However, the development of PD based catalysts is limited by their low electrocatalytic stability. The electrocatalytic stability can be improved by adding other atoms to prepare PD based composite catalysts. The application of PD based composite catalyst as catalyst for formic acid fuel cell still faces great challenges. First, it is reported. The total content of PD and other metals in the existing PD based catalyst is 20-30% of the mass of the catalyst. The use of such a large number of metals inhibits the dispersion of metals on the surface of the carrier and reduces the effective active area available in the catalytic process. Second. The study of surface electron properties and structural stability of bimetallic metal (controlled by valence bond) in the process of formic acid electrooxidation is not clear. The electrooxidation of formic acid catalyzed by catalysts supported on carbon nanotubes with different atomic ratios of Pd-Cu alloys was studied. Functionalized carbon nanotubes were embedded into the formed alloys during sintering and reduction treatment. The results of formic acid oxidation show that Pd-Cu bimetallic catalysts rich in Cu are more efficient than other Pd-Cu bimetallic catalysts with less Cu content. Oxidation is more active and stable. Not only that. Surface and structure analysis showed that the surface electronic properties of Cu-rich Pd-Cu alloy may be the key to control the catalytic pathway. In this paper, a new method of preparing porous carbon materials was tried. On the basis of this, nitrogen-doped and supported cobalt hydroxide were carried out. The morphology and structure of the new material were analyzed by a series of characterization methods. The electrochemical properties of the supercapacitors were tested using these catalysts as electrode materials. The results show that the three-dimensional porous carbon structure has excellent physical structure and electrocatalytic performance. The modified and supported metal catalysts have higher specific capacitance in the application of supercapacitors, which provides a new idea for the preparation of electrode materials for supercapacitors. The research work in this paper is mainly carried out in the following aspects: 1. The catalysts supported on carbon nanotubes (CNTs) with different atomic ratios of Pd-Cu alloys were prepared by impregnation method. The morphology and structure of the catalysts were characterized and their catalytic performance for formic acid was tested. 2. The method of preparing carbon quantum dots (CQDs) was introduced. The three-dimensional carbon structure of its derivatives was prepared. The morphology and structure of the derivatives were characterized, and then the 3D PCFs was modified. N-doped carbon three-dimensional structure N-3D PCFs were prepared and characterized. The application of 3D PCFs in supercapacitors was preliminarily tested. Chemical liquid phase synthesis (nitrogen-doped) carbon supported cobalt hydroxide catalyst was characterized, its structure and morphology were investigated and its catalytic properties of supercapacitors were tested. In this paper, the carbon materials were modified by doping non-metallic elements and loaded with metals to realize the wide application of carbon materials in the field of electro-oxidation of formic acid and electrode materials of supercapacitors.
【学位授予单位】：上海电力学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TB383.1

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