Mo基化合物纳米材料的制备及其电催化性能研究

发布时间：2018-02-14 22:10

本文关键词： 电解水产氢二硫化钼二氧化钼三维大孔结构电化学　出处：《天津大学》2016年硕士论文　论文类型：学位论文

【摘要】：氢气是一种很有潜力的未来能源载体,为可持续能源发展提供了广阔的应用前景,通过电化学水分解产氢是一种有效且环保的途径之一。这一反应通常需要电催化剂来降低过电位并提高反应速率。目前,最有效的催化剂为Pt族金属,但是高成本和低储量限制了其大规模的应用。二硫化钼具有独特的电学和光学性能,被认为是一种可替代Pt族金属的高效非金属催化剂。但是块体MoS_2的性能相对较差,对此我们提出了三种有效的方式来提高二硫化钼的电催化活性。1)用化学沉积法将Pd颗粒负载到水热合成的花状MoS_2纳米薄片表面,Pd修饰的未热处理的MoS_2展现出最高的析氢性能。而Pd修饰的热处理的MoS_2在电解水过程中对光照的响应最显著。2)通过将MoS_2纳米薄片填充到有序介孔碳分子筛中形成复合催化剂,碳材料能够保证MoS_2催化剂与电解液之间有效的电子传输。并且由于碳材料的存在,复合材料的催化活性随着扫描次数的增加而增加,该催化剂的析出氢气的起始电位最低可达-40 mV,在已知的二硫化钼催化剂中几乎是最低的。3)通过控制水热反应过程,把钨盐加入到Mo的前驱体体系中,得到部分钨原子取代钼原子位置的MoS_2,获得了更为无序的结构,增加了活性位点,该催化剂也表现出较好的析氢性能。另外,二氧化钼作为一种过渡金属Mo的氧化物,对其析氧性能的研究尚未有文献报道,我们通过模板法合成了三维有序的二氧化钼与碳的复合大孔结构,通过物理吸附的方法在其表面进行氧化亚钴颗粒的负载,并对其优异的析氧性能机制进行了研究。
[Abstract]:Hydrogen is a potential energy carrier in the future, which provides a broad application prospect for sustainable energy development. Hydrogen production by electrochemical water decomposition is one of the effective and environmentally friendly methods. This reaction usually requires an electrocatalyst to reduce overpotential and increase the reaction rate. At present, the most effective catalyst is Pt group metal. However, high cost and low reserves limit its large-scale application. Molybdenum disulfide, with its unique electrical and optical properties, is considered to be a highly effective non-metallic catalyst that can replace Pt group metals, but the performance of bulk MoS_2 is relatively poor. Three effective ways to improve the electrocatalytic activity of molybdenum disulfide were proposed. 1) the PD particles were loaded on the surface of hydrothermal MoS_2 nanocrystals to exhibit the highest PD modified unheat treated MoS_2 by chemical deposition. The PD modified heat treated MoS_2 has the most obvious response to illumination in the electrolysis process. The composite catalyst is formed by filling the MoS_2 nanocrystalline into ordered mesoporous carbon molecular sieve. Carbon materials can guarantee the efficient electron transport between MoS_2 catalyst and electrolyte, and the catalytic activity of composites increases with the increase of scanning times due to the existence of carbon materials. The starting potential of the hydrogen precipitated from the catalyst is as low as -40 MV, and almost the lowest of the known molybdenum disulfide catalysts. 3) by controlling the hydrothermal reaction process, the tungsten salt is added to the precursor system of Mo. MoS2, which is partially substituted for molybdenum atom by tungsten atom, is obtained with more disordered structure and more active sites. The catalyst also shows good hydrogen evolution performance. In addition, molybdenum dioxide is an oxide of transition metal Mo. The study of its oxygen evolution properties has not been reported in the literature. We synthesized the three-dimensional ordered composite macroporous structure of molybdenum oxide and carbon by template method, and carried out the loading of cobalt oxide particles on the surface by physical adsorption method. The excellent mechanism of oxygen evolution was studied.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TB383.1;O643.36

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