新型纳米复合催化材料析氢性能的研究

发布时间：2018-02-10 19:14

本文关键词： 析氢性能 PtVFe/WC催化剂 PtVFe/WC/C催化剂　出处：《西南大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前我国经济迅速发展,工业水平不断提高,然而在这一过程中也出现了一系列的社会与环境问题,其中能源危机与环境污染显得尤为严重,尤其是近年来发生的大规模雾霾事件引起人们的广泛重视。为了解决这个问题人们越来越关注清洁能源的发展,例如风能,太阳能等,其中氢能因为其燃烧效率高,储量丰富,无污染物排放,是目前最有前景的能源之一。近年来储氢技术与新材料得到了极大地发展,氢能也在多种工业中发挥着更重要的作用。氢能的迅速获取主要得益于氢气能被大量快速的制备,电解水是氢气制备的最常用方法之一,其过程简单,无污染,电解效率高达80%且产物纯度高,使其得到了应用与发展。然而,在商业上氢能的广泛应用还是受到很大的限制,这主要是由于析氢反应中超电势造成的高能耗,导致了制氢成本偏高,因此制备高效、低廉的电催化剂成为析氢技术研究最重要的工作。Pt、V、Fe属于过渡金属,其d轨道的电子具有特殊的性质,使其更容易与氢发生吸附和脱附,即相对容易发生析氢反应,这使其引起人们的关注。自从人们发现WC有一些催化性能并证实WC的电催化性能与Pt非常相似以来,WC受到研究者们的广泛关注。本论文采用热分解和还原反应成功合成了PtVFe纳米颗粒,再将WC加入到制备的PtVFe纳米颗粒中,经过热处理以及煅烧成功制备了PtVFe/WC新型纳米复合催化剂。使用扫描电子显微镜(SEM)、能谱仪(EDS)、X射线衍射(XRD)以及透射电子显微镜(TEM)、选区电子衍射(SAED)、高分辨透射电子显微镜(HRTEM)等方法对新型纳米复合催化剂的表面形貌、尺寸、晶体组成与结构进行了测定及表征。实验结果表明,制得的新型纳米复合催化剂颗粒尺寸小,分布比较均匀,属于多晶结构。通过线性扫描(LSV)和Tafel分析了不同合成温度制备的PtVFe/WC具有不同的析氢性能,结果表明673K合成温度下制备的PtVFe/WC纳米复合催化剂比573K和1073K合成温度下制备的PtVFe/WC纳米复合催化剂具有更好的析氢性能,且其在H2SO4溶液中析氢反应的稳定性较好。本文主要研究了环境温度和电解液浓度对673K合成温度下制备的PtVFe/WC纳米复合催化剂析氢性能的影响。近年来,关于催化剂载体的研究引起了研究者们的广泛兴趣。人们尝试了不同的材料,将碳化钨与其它材料复合,可以在不同程度上提高所制备的复合催化剂的催化活性。研究发现WC有一定的催化活性,但是只用WC作载体析氢性能并不是很理想,将WC与C共同作为载体,这样能起到协同作用从而提升催化剂的析氢性能。本论文采用同样的方法制备了PtVFe/WC/C纳米复合催化剂,对其用相同的方法进行了物理表征,结果发现有海绵层铁存在。用线性扫描比较了PtVFe/C、PtVFe/WC和PtVFe/WC/C纳米复合催化剂在H2SO4溶液中的析氢性能,结果显示PtVFe/WC/C纳米复合催化剂在H2SO4溶液中析氢活性最好。本论文还进一步研究了环境温度和电解液浓度对673K合成温度下制备的PtVFe/WC/C纳米复合催化剂析氢性能的影响。
[Abstract]:The rapid development of China's economy, and constantly improve the level of industrial society, however, with a series of environmental problems also appeared in this process, the energy crisis and environmental pollution is particularly serious, especially large-scale haze events happened in recent years attracted widespread attention. In order to solve this problem, people pay more and more attention to development. Clean energy such as wind energy, solar energy, hydrogen energy which because of its high combustion efficiency, abundant reserves, no emissions, is currently one of the most promising energy. In recent years, hydrogen storage technology and new materials have been greatly developed, hydrogen also in many industries play a more important role. Hydrogen rapidly access is mainly due to the hydrogen can be rapidly prepared by water electrolysis is one of the most commonly used method for the preparation of hydrogen, which has the advantages of simple process, no pollution, high electrolytic efficiency reached 80% and the purity of the product High, have led to its application and development. However, widespread application of hydrogen energy in the business is largely limited, which is mainly due to the high energy consumption of the hydrogen evolution reaction in potential caused by the resulting hydrogen production cost is high, so the preparation of high efficient, low power has become a research work on hydrogen catalyst technology of.Pt, the most important V Fe, belonging to the electronic transition metal, the d orbital have special properties that make it more prone to adsorption and desorption and hydrogen, which is relatively prone to hydrogen evolution reaction, which caused the attention of people. Since it is found that WC has some catalytic properties and catalytic properties of Pt and WC confirmed very similar, WC has attracted extensive attention of researchers. This paper using thermal decomposition and synthesis of PtVFe nano particle reduction reaction, then WC was added to the PtVFe nanoparticles in the preparation of PtVFe/WC after heat treatment and calcination preparation work A novel nano composite catalyst. Using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X ray diffraction (XRD) and transmission electron microscopy (TEM), electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and other methods of novel nano composite catalyst surface morphology, agent size. The crystal composition and structure were characterized and measured. The experimental results show that the novel nano composite catalyst prepared with small particle size, uniform distribution, which belongs to the polycrystalline structure. By linear scanning (LSV) and Tafel analysis of the different synthesis temperature of PtVFe/WC prepared with different hydrogen evolution performance, results show that the hydrogen evolution property 673K temperature PtVFe/WC nano composite catalyst preparation is better than 573K and 1073K synthesis temperatures of PtVFe/WC nano composite catalyst preparation, and its stability in H2SO4 solution of the hydrogen evolution reaction is studied in this paper is better. Effect of temperature and concentration of electrolyte preparation of PtVFe/WC nano composite catalyst for hydrogen evolution performance of 673K synthesis temperature. In recent years, the research on the catalyst carrier has attracted many attentions. People try different materials, tungsten carbide and other composite materials, can improve the catalytic activity of composite catalyst prepared in different degrees. The study found that WC has a certain catalytic activity, but only WC as the carrier of hydrogen evolution performance is not very ideal, WC and C as the common carrier, it can play a synergistic effect so as to enhance the hydrogen evolution performance of the catalyst. The PtVFe/WC/C nano composite catalyst has been prepared by the same method the system, using the same method of physical characterization, the results showed the presence of a sponge layer of iron. PtVFe/C compared with linear scanning, PtVFe/WC and PtVFe/WC/C nano composite catalyst in H2SO4 solution The performance of hydrogen evolution in the liquid shows that PtVFe/WC/C nano composite catalyst has the best activity for hydrogen evolution in H2SO4 solution. In this paper, we further studied the effect of ambient temperature and electrolyte concentration on the hydrogen evolution performance of PtVFe/WC/C nanocomposite catalyst prepared at 673K synthesis temperature.

【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：O643.36;TQ116.2

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