碳负载金属合金用于小分子电催化研究

发布时间：2019-02-15 17:00

【摘要】：随着能源危机和环境污染的持续恶化,人们渐渐意识到清洁能源的重要性。氢气以其来源广、燃烧值高、产物无污染、可再生等优势,被认为是21世纪最佳的能源载体。而燃料电池作为一种可以高效的进行能量转换、零排放的能源储存、转移设备,同样受到了国内外的广泛关注,在学术界掀起了一场学术研究热潮。其中,析氢反应(HER)、析氧反应(OER)、以及氧还原反应(ORR)都是较为重要的电催化反应。然而这些反应的过电位都比较高,动力学过程缓慢,因此,必须使用催化剂来降低反应能垒,从而促进催化反应的发生。目前,运用于这些反应的催化剂都是铂、钯、铱、钌等贵金属催化剂,但是由于这些催化剂都存在资源稀少、成本昂贵、容易腐蚀、循环稳定性差等问题,从而成为了限制电解水、燃料电池商业化发展的主要障碍。针对这些问题,本论文采用了一步水热法和高温煅烧的方式制备了Pt2Pd/NPG催化剂。通过TEM、SEM、XRD、XPS等手段对催化剂的形貌结构、组成含量进行表征和测定。结果表明,在高温煅烧的过程中石墨烯被金属颗粒刻蚀出一些孔洞,且金属颗粒大小基本一致,分散均匀。同时,采用电化学测试手段如循环伏安、线性伏安测试等探究其催化性能,发现不管是在酸性条件中的析氢反应测试还是碱性条件下的氧还原反应测试,Pt2Pd/NPG催化剂均表现出了优异的催化活性、抗甲醇毒化性能以及出色的稳定性。采用了两步水热法和高温煅烧的方式制备了NC@MoW_3O/CC纳米片催化剂。通过SEM观察到,催化剂形貌从MoW_3O/CC纳米线自动转化为NC@MoW_3O/CC纳米片,均匀的生长在碳纤维上。采用XRD、XPS等表征手段对催化剂的晶相结构、元素含量进行表征。并对催化剂进行析氢反应和析氧反应测试,发现NC@MoW_3O/CC纳米片催化剂具有良好的催化活性,这主要是因为碳纤维这种新兴的三维碳材料为催化剂提供了巨大的比表面积和良好的导电性。
[Abstract]:With the energy crisis and environmental pollution worsening, people gradually realize the importance of clean energy. Hydrogen is considered to be the best energy carrier in the 21st century because of its advantages of wide source, high combustion value, no pollution and renewable products. Fuel cell, as a kind of energy conversion, zero-emission energy storage, transfer equipment, has also been widely concerned at home and abroad, which has set off an academic research boom. Among them, hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) are more important electrocatalytic reactions. However, the overpotential of these reactions is relatively high and the kinetic process is slow. Therefore, the catalyst must be used to reduce the energy barrier of the reaction so as to promote the catalytic reaction. At present, the catalysts used in these reactions are platinum, palladium, iridium, ruthenium and other precious metal catalysts. Therefore, it has become a major obstacle to the commercialization of electrolytic water and fuel cells. In order to solve these problems, Pt2Pd/NPG catalyst was prepared by one step hydrothermal method and high temperature calcination. The morphology and composition of the catalyst were characterized and determined by TEM,SEM,XRD,XPS. The results show that graphene is etched by metal particles in the process of high temperature calcination, and the size of the metal particles is basically the same and the dispersion is uniform. At the same time, electrochemical methods such as cyclic voltammetry and linear voltammetry were used to investigate their catalytic properties. Pt2Pd/NPG catalysts showed excellent catalytic activity, methanol toxicity resistance and excellent stability. NC@MoW_3O/CC nanocrystalline catalyst was prepared by two-step hydrothermal method and high temperature calcination. The morphology of the catalyst was automatically transformed from MoW_3O/CC nanowires to NC@MoW_3O/CC nanoparticles by SEM, and the catalyst was grown on carbon fiber uniformly. The crystal structure and element content of the catalyst were characterized by XRD,XPS. The hydrogen evolution reaction and oxygen evolution reaction of the catalyst were tested. It was found that the NC@MoW_3O/CC nanoplate catalyst had good catalytic activity. This is mainly because carbon fiber, a new three-dimensional carbon material, provides a large specific surface area and good conductivity for the catalyst.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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