电解水产氢三维电极的构建与性能调控研究

发布时间：2017-12-27 19:34

本文关键词：电解水产氢三维电极的构建与性能调控研究　出处：《华南理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：高效稳定的电解水产氢催化剂是可再生能源氢能研究的关键,目前广泛研究的电解水产氢催化剂多为粉末状,需要添加粘结剂配成溶液负载在导电基底上才能参与电解水性能研究。但该过程不可避免地增大了催化剂与电解质溶液的接触电阻或造成粉末催化剂团聚,使得催化剂的电催化活性大打折扣。构建电解水三维电极不仅可以有效地解决上述问题,还可增大催化剂与电解质溶液的接触面积、增强催化稳定性。然而三维电极用作电解水产氢的文献报道并不多。近来研究表明,通过在三维基底如碳布、碳纤维纸上负载电解水产氢纳米材料或通过“范德华结构”将二维纳米材料进行可控组装可得到高效稳定的电解水催化剂。针对上述现状,本论文采用不同的方法合成三种不同的电解水产氢三维电极,并对其产氢催化性能进行研究。主要研究内容和结论如下:(1)通过水热-电沉积两步法,在碳纤维上合成了铂纳米颗粒/二硫化钼纳米片/碳纤维三维电极(Pt/MoS2/CFs)。详细的电化学性能表征表明,含铂量仅为2.03 wt%的Pt/MoS2/CFs催化剂在0.5 mol/L的硫酸电解质溶液中显示了极高的催化活性,其产氢过电势只有5 mV,塔菲尔斜率为53.6 mV/dec。长时间的循环伏安测试和电流-时间曲线测试,显示催化剂在酸溶液中具有较好的稳定性。(2)采用两步水热法合成了二硫化钼纳米片/硫化钴纳米线阵列/碳布三维电极(MoS2/CoS2/CC)。本实验选用碳布为基底,在其表面生长氢氧化钴纳米线阵列,然后与四硫钼酸铵水热反应硫化生成硫化钴纳米线阵列,并在硫化钴上沉积生长二硫化钼纳米片,同时实现对二硫化钼的钴氧掺杂。制备所得的MoS2/CoS2/CC显示了较低的过电势,在-87 mV的电压下可获得10 mA/cm2的电流密度,塔菲尔斜率为73.4 mV/dec,催化稳定性良好。(3)通过简单的真空抽滤和高温烧结,研制出一种钴纳米颗粒镶嵌在层状氮掺杂石墨烯间的柔性多孔三维电极(Co@NGF)。制备所得的石墨烯薄膜为柔性多孔结构,可直接用作电解水产氢电极,在0.5 mol/L的硫酸电解质溶液中有较高的电催化产氢活性,过电势仅为14 mV,在-124.6 mV的电压下可获得10 mA/cm2的电流密度,塔菲尔斜率为93.9 mV/dec。值得注意的是,本论文首次将Co@NGF电极作为阴极和阳极,即组成两电极体系进行电解水产氢测试,这为全方位的水解催化剂研究开僻了一种新的可能。这种制备技术,亦为水裂解技术的规模化提供了一种有效的途径。本论文采用多种工艺设计合成了三种高催化活性的电解水产氢三维电极,为柔性材料在可穿戴电子产品、柔性显示屏等应用上打下坚实基础。同时,通过深入研究催化剂组分和结构对产氢催化活性的影响,为高效稳定的电解水产氢催化剂提供重要指导。
[Abstract]:Highly efficient and stable electrolysis hydrogen production catalyst is the key of renewable energy hydrogen research. Currently, the widely researched electrolysis hydrogen catalysts are mostly powdery. It is necessary to add binder and solution to load on the conductive substrate to participate in the research of electrolytic water performance. But this process inevitably increases the contact resistance between catalyst and electrolyte solution, or causes agglomeration of powder catalyst, which makes the electrocatalytic activity of catalyst greatly reduced. The construction of electrolytic water three-dimensional electrode can not only effectively solve the above problems, but also increase the contact area of the catalyst and electrolyte solution, and enhance the catalytic stability. However, there are few reports on the use of three dimensional electrodes for the use of hydrogen in the electrolysis of aquatic products. Recent studies have shown that by electrolysis of hydrogen nanomaterials on three dimensional substrates, such as carbon cloth and carbon fiber paper, or by assembling and assembling two-dimensional nanomaterials by "Fan Dehua structure", efficient and stable electrolysis water catalysts can be obtained. In view of the above situation, three different kinds of electrolysis hydrogen electrode were synthesized by different methods, and the catalytic performance of hydrogen production was studied. The main research contents and conclusions are as follows: (1) through the two step process of Hydrothermal Electrodeposition, platinum nanoparticles / molybdenum disulfide nanosheets / carbon fiber three-dimensional electrode (Pt/MoS2/CFs) were synthesized on carbon fiber. The detailed electrochemical characterization showed that the Pt/MoS2/CFs catalyst containing only 2.03 wt% of platinum exhibited very high catalytic activity in sulfuric acid electrolyte of 0.5 mol/L, and its hydrogen generation potential was only 5 mV, and the Tafel slope was 53.6 mV/dec. The long time cyclic voltammetry and current time curve test showed that the catalyst had good stability in the acid solution. (2) a two step hydrothermal method was used to synthesize molybdenum disulfide nanoscale / cobalt sulfide nanowire arrays / carbon cloth three-dimensional electrodes (MoS2/CoS2/CC). In this experiment, carbon dioxide cloth was used as the substrate to grow cobalt hydroxide nanowire arrays on the surface. Then, the cobalt sulfide nanowire arrays were formed by hydrothermal reaction with ammonium molybdate four, and molybdenum sulfide nanosheets were deposited on cobalt sulfide. Meanwhile, cobalt oxide doped molybdenum disulfide was added. The prepared MoS2/CoS2/CC shows a low overpotential. Under the voltage of -87 mV, the current density of 10 mA/cm2 can be obtained. The slope of Tafel is 73.4 mV/dec, and the catalytic stability is good. (3) by simple vacuum filtration and high temperature sintering, developed a flexible porous three-dimensional electrode in layered nitrogen doped graphene between a cobalt nanoparticles embedded (Co@NGF). Graphene films prepared for flexible porous structure, can be directly used as electrolytic hydrogen electrode in sulfuric acid electrolyte solution of 0.5 mol/L in the electro catalytic activity of hydrogen production is high, the potential is 14 mV, the current density obtained at 10 mA/cm2 voltage -124.6 mV, Tafel slope is 93.9 mV/dec. It is worth noting that this is the first time to the Co@NGF electrode as the cathode and the anode, which consists of two electrode system for electrolytic hydrogen test, this research is a full range of hydrolysis catalyst provides a new possibility. This preparation technology also provides an effective way for the scale of water cracking technology. In this paper, three kinds of highly active three-dimensional electrolysis hydrogen hydrogen electrodes were designed and synthesized by various processes, which lay a solid foundation for flexible materials in wearable electronic products, flexible displays and other applications. At the same time, the influence of the catalyst composition and structure on the catalytic activity of hydrogen production is studied, which provides important guidance for the efficient and stable electrolysis hydrogen catalyst.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O643.36;TQ116.2

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