基于钼酸钴复合材料的制备、表征及其电催化性能的研究

发布时间：2018-06-02 21:55

本文选题：燃料电池 + 氧还原　；参考：《东北师范大学》2017年硕士论文

【摘要】：电解水和燃料电池技术是清洁能源领域重要的研究方向,它们的发展受到了广泛关注。其中析氧反应(Oxygen Evolution Reaction,OER)对于电解水阳极是至关重要的,而氧还原反应(Oxygen Reduction Reaction,ORR)在燃料电池中发挥着重要的作用,因而研究和开发对OER和ORR反应有高催化活性的催化剂是发展两项技术的关键,最常用的催化剂是基于贵金属的材料,他们能够表现出优异的电催化活性,但贵金属的稀缺性、高成本和不稳定的缺点限制了高效电解水和燃料电池的广泛商业化应用。因此,开发出能够替代贵金属的优良催化剂材料是目前的研究重点。本文主要研究了如下两方面:1.利用一步水热法制备合成了钼酸钴/钼酸镍分层纳米片直接生长在三维导电碳布上的电极材料(XMoO4-CC,X=Co,Ni),并将该材料直接作为电极用于OER反应。研究发现CoMoO4-CC因为具有较大的电化学活性面积而展示了优于NiMoO4-CC电极的催化活性。同时钼酸钴纳米片与碳布的协同作用使该电极材料表现出增强的质核传输与三维传输通道以及大的电流密度和相对低的过电位,即在10 mA cm-2的电流密度时的过电位值为290 m V。此外,CoMoO4-CC纳米材料表现出优于IrO2-CC的稳定性,是一种很有前景的用于大规模水氧化的非贵金属材料。2.通过一步水热法制备了三维石墨烯负载钼酸钴的复合材料CoMoO4/rGO并用于催化ORR反应,其中在水热过程之前加入氨水对石墨烯进行氮掺杂。CoMoO4和rGO的复合极大的减少了CoMoO4纳米材料的聚集和片层石墨烯的堆叠,并且CoMoO4/rGO复合材料表现出优于单一的CoMoO4和rGO电极的ORR催化活性。石墨烯作为一种理想的钼酸钴纳米片的支撑框架,能够使材料暴露更多的活性位点,使该复合材料表现出更正的起始电位(0.89 Vvs.RHE)和大的电流密度,同时具有优于Pt/C催化剂的稳定性和抗甲醇性,是一种很有潜能的燃料电池阴极催化剂。
[Abstract]:Electrolytic water and fuel cell technology are important research directions in clean energy field. Oxygen evolution reaction (Oxygen Evolution reaction) is very important for electrolytic water anode, and oxygen Reduction reaction (ORR) plays an important role in fuel cell. Therefore, the research and development of catalysts with high catalytic activity for OER and ORR reactions is the key to the development of two technologies. The most commonly used catalysts are materials based on precious metals, which can exhibit excellent electrocatalytic activity, but rare metals. The shortcomings of high cost and instability limit the wide commercial application of efficient electrolytic water and fuel cells. Therefore, the development of good catalyst materials that can replace precious metals is the focus of current research. This paper mainly studies the following two aspects: 1. Cobalt molybdate / nickel molybdate layered nanochip was synthesized by one step hydrothermal method. The electrode material XMoO _ 4-CCO _ (4) -X _ (CoCoC) _ (Ni) was directly grown on a three-dimensional conductive carbon cloth, and the material was used directly as an electrode for OER reaction. It was found that CoMoO4-CC showed better catalytic activity than NiMoO4-CC electrode because of its large electrochemical activity area. At the same time, the synergistic action of cobalt molybdate nanoparticles and carbon cloth makes the electrode material exhibit enhanced nucleus transport and three-dimensional transmission channel, large current density and relatively low overpotential, that is, 290mV overpotential at current density of 10 Ma cm-2. In addition, CoMoO _ 4-CC nanomaterials exhibit better stability than IrO2-CC and are promising non-precious metal materials for large-scale water oxidation. Three-dimensional graphene supported cobalt molybdate composite CoMoO4/rGO was prepared by one-step hydrothermal method and used to catalyze ORR reaction. The addition of ammonia to graphene before hydrothermal process greatly reduces the aggregation of CoMoO4 nanomaterials and the stacking of graphene lamellae by nitrogen-doped. CoMoO4 and rGO. Moreover, the CoMoO4/rGO composite exhibited better ORR catalytic activity than the single CoMoO4 and rGO electrodes. Graphene, as an ideal supporting framework for cobalt molybdate nanoparticles, can expose the material to more active sites, resulting in a corrected starting potential of 0.89 Vvs.RHE) and a high current density. At the same time, it has better stability and methanol resistance than Pt/C catalyst, so it is a potential cathode catalyst for fuel cell.
【学位授予单位】：东北师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TB33

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