电沉积法制备过渡金属氧化物薄膜与电催化性能研究

发布时间：2018-01-05 02:37

  本文关键词：电沉积法制备过渡金属氧化物薄膜与电催化性能研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

  更多相关文章： 析氧反应 过渡金属氧化物 薄膜 循环伏安法 催化性能

【摘要】：析氧反应(OER)作为光电分解水的半反应之一,其自身固有的缓慢的动力学是限制水分解的总效率的重要影响因素。现阶段,开发高效的OER催化剂已成为可再生能源技术的核心,并因此激起广泛的研究兴趣。第一行过渡金属(Mn、Fe、Co、Ni和Cu)氧化物,氢氧化物(羟基氧化物),包括单金属或多金属元素,都对OER反应具有一定的催化活性。电沉积法以其简单、快速、高效的优点而常被用于制备OER催化剂。其在含有单金属/多金属离子或者金属络合物的前驱体溶液中,通过阴极/阳极电沉积法将催化剂薄膜沉积至电极表面。它仅需一台电化学工作站,便能精确的调控催化剂的成核和生长过程,纯度,结构以及形貌,有利于实现电催化剂的大规模工业化生产。因此,详细探讨利用成本低廉的电沉积法制备高效的过渡金属氧化物催化剂变得极具意义。本次研究内容主要分为下述几点:1.以铟锡氧化物(ITO)作为基底,在含有Fe3+等混合金属离子的前驱体溶液中,利用阳极循环伏安法(CV)制备得到一系列的Fe基薄膜催化剂(包括二元、三元以及四(五)元金属氧化物薄膜)。并以沉积二元FeNiOx氧化物薄膜为例,通过探索沉积电位窗口、沉积时间以及前驱体中金属离子配比,以最终制备的催化剂性能优劣作为衡量标准,获得最优沉积条件。并以此作为制备Fe基催化剂的基准,结果发现,沉积的二元金属氧化物 CoFeOx、FeNiOx,三元金属氧化物 NiCoFeOx、CuNiFeOx、CuCoFeOx,以及四元金属氧化物CuCoNiFeOx在碱性介质中具有较高的OER催化活性。除此之外,辅以无铁的Ni-Co系列催化剂与之进行对比,得到NiCoOx的OER性能可与FeNiOx相媲美。通过XRD、SEM、EDS以及XPS分析不同金属氧化物薄膜的结构、表面形貌、组成以及价态,进而详细的研究金属掺杂对OER催化性能的影响。通过比较电荷转移电阻Rct以及活性面积ECSA的大小,从本质上比较催化活性的优劣。2.在阳极CV沉积法的基础上,衍生出一种逐步沉积法,分别以ITO和泡沫镍(NF)作为基底,先经阴极恒电位沉积Ni、Co以及NiCo,再更换至含Fe3+的NaOAc溶液中,通过阳极CV沉积法制得NiFeOx、CoFeOx以及NiCoFeOx薄膜。通过该法制备的样品形貌与一步阳极CV沉积的催化剂有所差异。Fe基薄膜催化剂在碱性条件下均展现出优异的OER催化活性以及优秀的稳定性。值得一提的是,以NF作基底时,Fe基金属氧化物构建出独特的层状多孔结构,使催化剂具有大的工作表面积以及优秀的气泡消散能力,从而在催化过程中暴露出更多的活性位点,OER性能得到进一步提升。
[Abstract]:As one of the half reactions of photoelectricity to decompose water, the inherent slow kinetics of oxygen evolution reaction is an important factor to limit the total efficiency of water decomposition. The development of efficient OER catalysts has become the core of renewable energy technology and has aroused extensive research interest. Hydroxide (hydroxyl oxide), including monometallic or polymetallic elements, has a certain catalytic activity for OER reaction. Electrodeposition method is simple and rapid. The advantages of high efficiency are often used in the preparation of OER catalysts in precursor solutions containing monometallic / polymetallic ions or metal complexes. The catalyst film is deposited on the electrode surface by cathodic / anodic electrodeposition. It requires only an electrochemical workstation to accurately control the nucleation and growth process, purity, structure and morphology of the catalyst. It is advantageous to realize the large-scale industrial production of electrocatalyst. It is of great significance to prepare high efficient transition metal oxide catalysts by low cost electrodeposition. The main contents of this study are as follows: 1. ITO is used as the substrate. A series of Fe-based thin film catalysts (including binary) were prepared by anodic cyclic voltammetry in the precursor solution containing Fe3 and other mixed metal ions. Taking binary FeNiOx oxide films as an example, the potential window, the deposition time and the ratio of metal ions in the precursor were explored. The optimum deposition conditions were obtained according to the performance of the final prepared catalysts, and the results showed that the deposited binary metal oxides (CoFeOx) were used as the basis for the preparation of Fe-based catalysts. FeNiOx, a ternary metal oxide NiCoFeOx-CuNiFeOx-CuCoFeOx. In addition, the quaternary metal oxide CuCoNiFeOx has higher catalytic activity for OER in alkaline medium. In addition, a series of iron-free Ni-Co catalysts are used to compare with it. The OER properties of NiCoOx are comparable to those of FeNiOx. The structure and surface morphology of different metal oxide films are analyzed by XRDX SEMDS and XPS. The effect of metal doping on the catalytic performance of OER was studied in detail. The size of the charge transfer resistance (Rct) and the active area (ECSA) were compared. On the basis of anodic CV deposition method, a kind of step by step deposition method was derived, which was based on ITO and foamed nickel (NFN), respectively. NiCo and NiCowere deposited by cathodic potentiostatic deposition, and then replaced into NaOAc solution containing Fe3. NiFeOx was prepared by anodic CV deposition. CoFeOx and NiCoFeOx thin films. The morphology of the samples prepared by this method is different from that of the catalysts deposited by one-step anode CV deposition. Fe-based thin film catalysts exhibit excellent O in alkaline conditions. ER catalytic activity and excellent stability. When NF was used as the substrate, a unique layered porous structure was constructed, which made the catalyst have a large working surface area and excellent bubble dissipating ability. As a result, more active sites were exposed in the catalytic process, and the performance of OER was further improved.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.2;O643.36
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本文编号：1381236