钨基自支持纳米结构的制备及其电催化析氢研究

发布时间：2018-01-18 00:29

本文关键词：钨基自支持纳米结构的制备及其电催化析氢研究　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：氢气作为一种清洁可再生能源,一直被认为是未来最具发展优势的新能源。由于环境问题和能源危机变得越来越严重,关于电解水制氢的研究变得越来越受欢迎。电解水析氢反应是一个吸收能量的过程。因此,催化剂的催化活性在整个析氢反应过程中起到至关重要的作用,而一个性能优异的析氢催化剂应该具有导电性好、比表面积大、析氢过电势低、电化学性能稳定和耐腐蚀等特点。目前,Pt等贵金属催化剂具有优异的电解水析氢催化活性,但因其储存量小、价格昂贵而不能得到商业上的广泛应用。所以发展催化活性好的非贵金属析氢催化剂就显得尤为重要。本文通过水热的方法在碳纤维纸上负载钨/二氧化钨纳米线(W/WO_2NA@CP)和二硫化物纳米片(WS_2 NS@CP)催化剂并对其形貌结构、物相组成和电化学析氢性能进行研究,所得研究结果如下:(1)提出一种简单合成W/WO_2 NA@CP的方法。该实验是通过水热和热处理还原的方法将W/WO_2纳米线负载在碳纤维纸上。W/WO_2 NA@CP在析氢反应中作为电催化剂。在酸性电解液中,电流密度为20 mA cm-2时所需要的析氢过电位是-340 mV vs.RHE。其法拉第效率接近于100%。并且能够持续稳定工作54h。以碳纤维纸为基底负载催化剂,减小W/WO_2内部的电子转移电阻。并且催化剂由W和WO_2两种物质组成,W可以提高催化剂本身导电性,而WO_2则可表现出析氢活性。(2)提出一种水热和低温硫化共同作用的方法在碳纤维纸上负载硫化钨(WS_2)纳米片(WS_2 NS@CP)来作为析氢催化剂。WS_2 NS@CP催化剂在酸性电解液中展现出很好的催化活性,当电流密度为20和100 mA cm-2时,催化剂的析氢过电位分别为-159和-209 mV vs.RHE。通过比较理论产生氢气的量和实际产生氢气的量可得出析氢效率高达93%。通过恒电位测量实验来证明WS_2NS@CP可以在酸性电解液中稳定工作25 h。并且通过分析形貌、电化学阻抗和活性面积来寻找催化剂的最佳硫化条件。本实验通过硫化的方法将铵基氧化钨纳米线转变为硫化钨纳米片,这种片状结构使硫化钨暴露出更多的活性边缘从而增强催化剂的析氢活性。本文所引进的制备催化剂的方法为设计和探索高效析氢催化剂提供了一个方便有效的途径。
[Abstract]:As a kind of clean and renewable energy, hydrogen has always been regarded as the most promising new energy in the future. Due to environmental problems and energy crisis, it has become more and more serious. The research on hydrogen production from electrolytic water has become more and more popular. The hydrogen evolution of electrolytic water is a process of absorbing energy. Therefore, the catalytic activity of catalyst plays an important role in the whole process of hydrogen evolution. An excellent catalyst for hydrogen evolution should have good conductivity, large specific surface area, low hydrogen evolution potential, stable electrochemical performance and corrosion resistance. Pt and other noble metal catalysts have excellent catalytic activity for hydrogen evolution in electrolytic water, but their storage capacity is small. It is very important to develop non-noble metal hydrogen evolution catalysts with good catalytic activity. In this paper, tungsten / tungsten oxide nanocrystals are loaded on carbon fiber paper by hydrothermal method. Line (. W / WO _ 2NA@ CP) and disulfide nanochip WSS _ 2NSR _ P _ P _ 2 catalyst and their morphology and structure. Phase composition and electrochemical hydrogen evolution were studied. The results of the study are as follows:. A simple synthesis method of W/ WO _ 2 NA@CP is proposed, in which W/ WO _ 2 nanowires are loaded on carbon fiber paper by hydrothermal and heat-treatment reduction. NA@CP acts as an electrocatalyst in hydrogen evolution and in acidic electrolyte. The required hydrogen evolution overpotential at a current density of 20 Ma cm-2 is -340 MV. The Faraday efficiency of vs.RHE. is close to 100 and can work steadily for 54 hours. The catalyst is supported on carbon fiber paper. The electron-transfer resistance in W / WO _ 2 can be reduced, and the conductivity of the catalyst can be improved by the composition of W and WO_2. While WO_2 can exhibit hydrogen evolution activity. (2) A method of hydrothermal and low temperature vulcanization is proposed to support tungsten sulfide WS2 on carbon fiber paper. WS2 NS@CP catalyst showed good catalytic activity in acidic electrolyte. When the current density is 20 Ma and 100mA cm-2. The hydrogen evolution overpotential of the catalyst is -159 and -209 MV, respectively. By comparing the amount of hydrogen produced in theory with the amount of hydrogen produced in practice, the hydrogen evolution efficiency is as high as 933.Through the potentiostatic measurement experiment, it is proved that WS_2NS@CP can be used in acidic electrolyte. Medium-stabilization work 25. H. and by analyzing the morphology. Electrochemical impedance and active area were used to find the best curing conditions of the catalyst. In this experiment, the ammonium based tungsten oxide nanowires were transformed into tungsten sulfide nanowires by the method of vulcanization. This flake structure exposes more active edges of tungsten sulfide and enhances the catalytic activity of the catalyst. The method of preparing catalyst introduced in this paper provides a convenient and effective method for the design and exploration of high efficiency hydrogen evolution catalyst. Means.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;TQ116.2

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