多孔Co基氧化物的制备及电化学性质研究

发布时间：2018-02-27 09:10

  本文关键词： ZIF-67模板 钴基氧化物 核壳结构 葡萄糖检测 电催化析氧 超级电容器　出处：《哈尔滨工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：金属有机骨架材料(MOFs)具有较大的比表面积、高孔隙率、可调谐的孔径和功能等特性,成为多孔材料中具有代表性的材料。以MOFs为模板制备的多孔半导体金属氧化物由于其在结构上继承了MOFs的特点,具有独特的机械性能、光学性能以及优异电化学性能,一直被大量研究,并被广泛应用在催化、能量存储、药物释放、生物传感器等方面。因此,本论文以ZIF-67为前驱体,通过共沉淀法及相应热处理成功引入锌和碳元素合成了双金属氧化物Zn0.35Co2.65O4及具有核壳结构的CoO@Co3O4/C复合物,用于电化学葡萄糖传感器、电催化产氧及超级电容器电极材料。研究内容如下:(1)以ZIF-67为模板,通过共沉淀法合成双金属氧化物Zn0.35Co2.65O4,利用扫描电子显微镜(Scanning Electron Microscope,SEM)及透射电子显微镜(Transmission Electron Microscope,TEM)、X射线衍射(X-Ray Diffraction,XRD)、X射线光电子能谱(X-Ray Photoelectron Spectroscopy,XPS)和Mapping等测试手段对双金属氧化物的形貌、晶型、化学组成进行表征,结合时间电流曲线测试考查双金属氧化物在pH为7.4缓冲溶液及碱性环境中无酶葡萄糖检测方面的性能。当电解液为pH=7.4的PBS溶液时,电极检测窗口为13.28μM-13 mM,检测限为1.3μM(S/N=3),灵敏度为47.71μA m M-1 cm-2,响应时间少于3 s,当电解液为0.1M的NaOH溶液时,电极检测窗口为5μM-13 mM,检测限为1.41μM(S/N=3),灵敏度为41.8μA mM-1 cm-2,响应时间少于2 s。与Co3O4进行对比,Zn离子的引入使得样品在检测葡萄糖时,具有更好的检测限及拟合效果,响应时间更短,但是灵敏度有所下降。(2)以ZIF-67为前驱体,通过浸泡葡萄糖溶液进行表面修饰及退火处理,得到具有核壳结构的CoO@Co3O4/C复合材料。利用SEM、高倍透射电子显微镜(High Transmission Electron Microscope,HTEM)、XRD和XPS等测试手段对复合材料的形貌、晶型及化学组成进行表征,结合循环伏安、恒电流充放电、交流阻抗谱、线性伏安扫描等测量方法考查复合材料在电容和电催化析氧等方面的性能。通过对比复合材料与Co3O4的比电容和过电位,分析样品表面碳元素的存在及核壳结构对样品在电化学方面的影响。测试结果显示,在电流密度为1 mA cm-1,样品比电容能达到184 F g-1,在电流密度为10 mA cm-1下,CoO@Co3O4/C的过电位值为386 m V,经过6 h的稳定性测试,催化剂仍保持原有电流密度的83.1%。证明CoO@Co3O4/C无论是在电容还是电催化析氧方面性能都得到了明显增强。同时结合表面光伏和瞬态光伏技术,研究核壳结构复合材料的光生电荷迁移行为,结果表明样品中的碳具有良好的电子输运及接受能力,钴基氧化物与碳的协同二元结构,加快光生载流子的有效传输和分离,核壳结构复合材料具有更长的光生寿命用于参与光电反应,具有较好光电性能。
[Abstract]:The metal-organic framework material (MOFs) has large specific surface area, high porosity, tunable pore size and function, etc. Porous semiconductor metal oxides prepared by using MOFs as template have unique mechanical properties, optical properties and excellent electrochemical properties due to their structural inheritance of MOFs. It has been widely studied and widely used in catalysis, energy storage, drug release, biosensor and so on. Bimetallic oxide Zn0.35Co2.65O4 and CoO@Co3O4/C complex with core-shell structure were successfully synthesized by introducing zinc and carbon elements through coprecipitation and heat treatment. Electrode materials for electrocatalytic oxygen generation and supercapacitors. The research contents are as follows: ZIF-67 as a template. Bimetallic oxide Zn0.35Co2.65O4 was synthesized by coprecipitation method. The morphology, crystal type and morphology of bimetallic oxides were measured by scanning electron microscopy (SEM) and transmission electron microscope (TEM), transmission Electron microscopesimetry (TEM) and X-ray diffraction (X-Ray DiffractionXRDX) X-ray photoelectron spectroscopy (X-Ray Photoelectron spectroscopyXPS4) and Mapping. The chemical composition was characterized, and the performance of bimetallic oxide in detecting enzyme free glucose in pH 7.4 buffer solution and alkaline environment was examined by time-current curve test. When the electrolyte was PBS solution with pH=7.4, The detection window of electrode is 13.28 渭 M-13 mm, the detection limit is 1.3 渭 M / s, the sensitivity is 47.71 渭 A m M -1 cm -2, the response time is less than 3 s, when the electrolyte is 0.1 M NaOH solution, The detection window of electrode is 5 渭 M-13 mm, the detection limit is 1.41 渭 M ~ (-1) S / N ~ (-1), the sensitivity is 41.8 渭 A mM-1 / cm ~ (-2), the response time is less than 2 s. Compared with Co3O4, the introduction of Zn ion makes the sample have better detection limit and fitting effect, and the response time is shorter. However, the sensitivity has decreased. 2) with ZIF-67 as the precursor, the surface was modified and annealed by soaking glucose solution. CoO@Co3O4/C composites with core-shell structure were obtained. The morphology, crystal form and chemical composition of the composites were characterized by means of SEM, high power transmission electron microscopy (HTEM), high power transmission electron microscopy (HTEM), high power transmission electron microscopy (HTEM), high power transmission electron microscopy (HTEM), high power transmission electron microscopy (HTEM), high power transmission electron microscopy (HTEM) and high power transmission electron microscopy (TEM). Ac impedance spectroscopy and linear voltammetry were used to examine the properties of the composite in capacitance and electrocatalytic oxygen evolution. The specific capacitance and overpotential of the composite and Co3O4 were compared. The presence of carbon elements on the surface of the sample and the effect of core-shell structure on the electrochemistry of the sample were analyzed. When the current density is 1 Ma cm-1, the specific capacitance of the sample can reach 184F g-1, and the overpotential value of CoOr Co3O4 / C is 386mV at the current density of 10mA cm-1. The stability of the sample has been tested after 6 hours. The catalyst still maintains the current density of 83.1. It is proved that the performance of CoO@Co3O4/C in both capacitance and electrocatalytic oxygen evolution has been significantly enhanced, and combined with surface photovoltaic and transient photovoltaic technology, The photoinduced charge transfer behavior of core-shell structure composites is studied. The results show that the carbon in the samples has good electron transport and receptivity, and the Co-base oxides and carbon have a synergistic binary structure, which speeds up the effective transport and separation of photogenerated carriers. The core-shell composite has longer photoinduced life to participate in photoelectric reaction and has better photoelectric properties.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.4;O646
，

本文编号：1542038