以电沉积二氧化硅为模板制备高性能纳米多孔析氧薄膜材料

发布时间：2018-05-25 06:47

本文选题：电沉积 + SiO_2模板　；参考：《浙江工业大学》2017年硕士论文

【摘要】：随着生活水平的提高和环境保护意识的日益增强,人们渴望寻找新能源以解决化石能源短缺及改善由于滥用化石能源所引起的环境污染等问题。氢能被认为是最清洁的能源之一,而电催化分解水是制氢的一种重要途径。然而,电解水制取氢气与氧气过程中,析氧电位过高导致能耗增加是制约电解水制备氢气的瓶颈。贵金属氧化物IrO_2及RuO_2是公认的最佳析氧电极材料。但两种材料由于其自身具有较大的毒性且储量稀少、价格昂贵,限制了其大规模的商业化应用。近年来,人们一直致力开发成本低且催化性能优异的新型催化剂材料以代替贵金属氧化物,其中过渡族金属氧化物,如:锰、钴、镍等氧化物或氢氧化物由于分布广泛,价格低廉,且在碱性环境中具有良好的稳定性而备受关注。除此之外,高比表面积也是提升催化剂析氧性能的关键,而模板法可有效提高纳米多孔电极材料的比表面积,因而受到人们的重视。本文提出以电沉积Si O_2为模板制备纳米多孔镍钴基析氧薄膜电极。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)等技术对薄膜电极的结构和形貌进行了表征,并考察了薄膜电极的电催化析氧活性和稳定性。第三章以Ni(NO3)2、Co(NO3)2和四甲氧基硅烷(TMOS)为前驱体溶液,采用恒电流沉积技术在不锈钢基体上沉积镍钴氢氧化物,经热处理后获得Ni Co2O4-SiO_2复合薄膜,并在1.0 mol/L KOH溶液中通过连续循环伏安技术去除SiO_2组分以得到多孔NiCo2O4薄膜。研究了沉积电流密度、沉积时间及TMOS体积浓度等参数对薄膜电催化析氧活性的影响。结果表明:在含1.0%TMOS溶液中,-1.0 mA cm-2电流密度下电沉积500s制备的薄膜具有较高的析氧活性和稳定性。该薄膜电极析氧反应的起始电位为~1.52 V(vs.RHE),电流密度在10mA cm-2和100 mA cm-2时的析氧过电位分别为0.293 V和0.358 V,Tafel斜率分别为43和142 mV dec-1。第四章以NiSO4、CoSO4和TMOS为前驱体溶液,采用恒电位沉积技术在不锈钢基体上沉积了Ni-Co-Si O_2复合薄膜。研究结果表明,溶液中各组分浓度及电沉积电位和时间对合金薄膜电极的微观形貌及析氧活性具有重要影响。在-0.8 V下电沉积500s制备的多孔镍钴合金薄膜电极具有较优的电催化性能和稳定性能。该薄膜电极析氧反应的起始电位为~1.48 V(vs.RHE),电流密度在10 mA cm-2和100 mA cm-2时的析氧过电位分别为0.287 V和0.326 V,Tafel斜率分别为65和149 mV dec-1。第五章为解决醇溶性TMOS与诸多无机盐相容性差导致无法制备复合薄膜的问题,提出以水溶性氟硅酸铵为硅源,制备多孔镍钴基薄膜电极,考察了电沉积时间和溶液中原料组成浓度对镍钴基电极电催化性能的影响。结果表明:氟硅酸铵与诸多镍盐、钴盐溶液体系均具有良好的相容性,可有效制备复合薄膜电极,且该电极的电催化活性均得到提高。该薄膜电极析氧反应的起始电位为~1.48 V(vs.RHE),电流密度在10 mA cm-2和100 mA cm-2时的析氧过电位分别为0.294 V和0.336 V,Tafel斜率分别为39和137 mV dec-1。
[Abstract]:With the improvement of living standards and the increasing awareness of environmental protection, people are eager to find new energy to solve the problem of shortage of fossil energy and improve the environmental pollution caused by the abuse of fossil energy. Hydrogen energy is considered as one of the most clean energy sources, and the electrocatalytic decomposition of water is an important way of hydrogen production. During the process of hydrogen and oxygen, the high oxygen evolution potential and the increase of energy consumption are the bottlenecks that restrict the preparation of hydrogen by electrolysis. Precious metal oxides IrO_2 and RuO_2 are recognized as the best oxygen evolution electrode materials. However, the two materials have their own large toxicity, scarce reserves and expensive prices, limiting their large-scale commercial applications in recent years. In addition, people have been developing new catalyst materials with low cost and excellent catalytic performance in place of noble metal oxides. In addition, transition metal oxides, such as manganese, cobalt, nickel and other oxides or hydroxides, are widely distributed, and have good stability in alkaline environment. The area is also the key to improve the oxygen evolution performance of the catalyst, and the template method can effectively improve the specific surface area of the nano porous electrode material, so people pay attention to it. In this paper, the nano porous nickel cobalt based oxygen evolution film electrode was prepared by electrodeposition of Si O_2 as a template. The scanning electron microscopy (SEM), transmission electron microscope (TEM) and X ray diffraction were used. The structure and morphology of the thin film electrode were characterized by XRD, X ray photoelectron spectroscopy (XPS) and other techniques. The electrocatalytic activity and stability of the electrocatalysis of the film electrodes were investigated. The third chapter used Ni (NO3) 2, Co (NO3) 2 and tetra methoxy silane (TMOS) as precursors solution to deposit nickel cobalt hydrogen oxidation on stainless steel substrate by constant current deposition. The Ni Co2O4-SiO_2 composite film was obtained after heat treatment, and the SiO_2 components were removed by continuous cyclic voltammetry in 1 mol/L KOH solution to obtain the porous NiCo2O4 film. The effects of the deposition current density, deposition time and TMOS volume concentration on the electrocatalytic activity of the film were investigated. The results showed that the 1.0%TMOS solution contained 1.0%TMOS solution. At -1.0 mA cm-2 current density, the films prepared by electrodeposition of 500s have higher oxygen evolution activity and stability. The initial potential of the oxygen evolution reaction of this film electrode is ~1.52 V (vs.RHE). The current density at 10mA cm-2 and 100 mA cm-2 is 0.293 V and 0.358 respectively, respectively, and the slope is 43 and 142 respectively. O4, CoSO4 and TMOS are precursor solutions, and Ni-Co-Si O_2 composite films are deposited on stainless steel substrate by constant potential deposition. The results show that the concentration of each component in the solution and the electrodeposition potential and time have an important influence on the micromorphology and oxygen evolution activity of the alloy film electrode. Electrodeposition of porous nickel prepared by 500s under -0.8 V The cobalt alloy film electrode has excellent electrocatalytic properties and stability properties. The starting potential of the oxygen evolution reaction of this film electrode is ~1.48 V (vs.RHE). The oxygen evolution overpotential of the current density at 10 mA cm-2 and 100 mA cm-2 is 0.287 V and 0.326 V respectively. The slope of Tafel is 65 and 149 mV dec-1. fifth to solve alcohol soluble and many inorganic compounds. The poor compatibility of salt leads to the problem that the composite film can not be prepared. A polyporous nickel cobalt based film electrode is prepared by using water-soluble ammonium fluorosilicate as the silicon source. The effect of electrodeposition time and the concentration of raw material in solution on the electrocatalytic performance of nickel cobalt base electrode is investigated. The results show that ammonium fluorosilicate is good for many nickel salts and cobalt salt solutions. Good compatibility can effectively prepare a composite film electrode, and the electrocatalytic activity of the electrode is improved. The starting potential of the electrode is ~1.48 V (vs.RHE). The current density at 10 mA cm-2 and 100 mA cm-2 is 0.294 V and 0.336 V respectively, and Tafel slope is 39 and 137 mV dec-1., respectively.
【学位授予单位】：浙江工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2;TQ116.2

【参考文献】