【作者】 刘静；

【导师】 卢小泉；

【作者基本信息】 西北师范大学 ， 分析化学， 2015， 硕士

【摘要】 过渡金属氧化物纳米材料具有许多特殊的物理和化学性质,在电化学传感等领域有着非常重要的应用。作为一种多功能p型半导体,氧化钴在电化学传感领域发挥着重要的作用。为了提高基于氧化钴纳米材料的电化学传感器的灵敏度和电极材料的电催化活性,本论文通过向氧化钴中掺杂金属氧化物或复合碳材料,制备了功能化的纳米材料,并构筑了三种检测酚类化合物的电化学传感器,建立了检测酚类化合物的新方法。主要研究内容如下:1.制备了Sn⁴⁺掺杂的Co₃S₄纳米棒材料。通过扫描电镜（SEM）、透射电镜（TEM）、X-射线粉末衍射（XRD）和X-射线光电子能谱（XPS）等手段对所制备材料的形貌和结构进行了表征。构建了基于Sn⁴⁺掺杂Co₃S₄修饰电极检测对硝基苯酚（4-NP）的电化学传感器。结果显示,修饰电极对对硝基苯酚表现出了较高的灵敏度,宽的线性范围（0.89×10-6 mol/L⁰.92×10-4 mol/L）和低的检测限（1.12×10-7 mol/L）。此传感器也被成功地用于实际样品中对硝基苯酚的检测。2.利用简单的水热法成功地制备了具有不同质量比的还原氧化石墨烯/氧化钴纳米棒复合材料。使用扫描电镜（SEM）、透射电镜（TEM）、X-射线粉末衍射（XRD）、X-射线光电子能谱（XPS）等手段对复合材料的形貌和结构进行了表征。建立了基于还原氧化石墨烯/氧化钴纳米棒复合材料修饰的玻碳电极（r GO-Co₃O₄/GCE）同时检测对苯二酚（HQ）和邻苯二酚（CC）的新方法。r GO-Co₃O₄复合材料修饰电极对HQ和CC表现出了良好的电催化活性,这归因于复合材料良好的导电性和大的表面积。当还原氧化石墨烯与氯化钴的质量比为1:5时,合成的r GO-Co₃O₄（1:5）复合材料可将这两种异构体完全分离,表现出了较好的电化学响应。HQ和CC的氧化峰电流在3×10-6 mol/L¹×10-4 mol/L的范围内与它们的浓度成线性,HQ和CC的检测限分别是8.6×10-7 mol/L和5×10-7 mol/L。这些结果证明了复合材料修饰电极在电化学传感和电催化应用中是一种有前途的材料。此种传感器对大多数无机物和一些有机物、生物分子等有较好的抗干扰能力,并且被成功地用于实际样品中HQ和CC的同时检测,取得了令人满意的结果。3.采用水热法制备了Ag/Co₃O₄复合材料的前驱物,进而在400℃煅烧前驱物得到最终样品。通过扫描电镜（SEM）、X-射线粉末衍射（XRD）和X-射线光电子能谱（XPS）对所制备的样品进行表征。将Ag/Co₃O₄复合材料修饰在玻碳电极表面,研究了修饰电极对邻硝基苯酚的电催化还原性能。实验结果表明,相比于裸的玻碳电极,Ag/Co₃O₄[n（Co）:n（Ag）=3:2]复合材料修饰电极对邻硝基苯酚表现出了较好的电催化活性。更多还原

【Abstract】 Due to its many special physical and chemical properties, transition metal oxide nanomaterials possess very important application value in the field of electrochemical sensors. As a p-type semiconductor, Co₃O₄ has demonstrated great potentials in the applications of electrochemical sensors. In order to improve the sensitivity of sensors and electrocatalytic activity of electrode materials, we synthesized novel Co₃O₄-based nanomaterials by doping and combining with carbon materials. In this thesis, three kinds of electrochemical sensors based functional Co₃O₄ nanomaterials were constructed and used for detection of phenolic compounds. The main contents were summarized and presented as follows:1. Well-defined Sn⁴⁺ doped Co₃S₄ nanorods were fabricated. The morphology and structure of Sn⁴⁺ doped Co₃S₄ nanorods were characterized by scanning electron microscopy（SEM）, transmission electron microscop y（TEM）, X-ray diffraction（XRD）, and X-ray photoelectron spectroscopy（XPS）. An electrochemical sensor based on the Sn⁴⁺ doped Co₃S₄ was fabricated to study the electrocatalytic reduction performance for 4-NP. The Sn⁴⁺ doped Co₃S₄ modified glass carbon electrode displayed a high sensitivity to 4-NP ranging from 0.89×10-6 mol/L mol/L to 0.92×10-4 mol/L, and also a low detection limit of 1.12×10-7 mol/L（S/N = 3）. The sensor can also be used for the detection of 4-NP in real samples.2. We synthesized the graphene/cobalt oxide nanorods composites with different mass ratios by a facile hydrothermal method. The nanocomposites were characterized by scanning electron microscopy（SEM）, transmission electron microscopy（TEM）, X-ray diffraction（XRD） and X-ray photoelectron spectrom（XPS）. Also the application of r GO-Co₃O₄ nanocomposite in simultaneous determination of hydroquinone（HQ） and catechol（CC） was investigated. The r GO-Co₃O₄（1:5） nanocomposites modified electrode displays excellent electrochemical catalytic activities toward HQ and CC, which could be attributed to high electrical conductivity and larger surface area of r GO-Co₃O₄ nanocomposites. The oxidation peak currents of HQ and CC were linear over the range of 3×10-6 mol/L 1×10-4 mol/L with the detection limits of 8.6×10-7 mol/L for HQ and 5×10-7 mol/L for CC, respectively. In addition, the sensor showed excellent stability, reproducibility and anti- interference ability. The proposed sensor was successfully applied in the simultaneous determination of HQ and CC in tap and river water samples with satisfied results.3. Precursors of Ag/Co₃O₄ composites were synthesized via a hydrothermal process. The final samples were fabricated by calcing precursor at 400 ℃. Ag/Co₃O₄ composites were characterized by scanning electron microscopy（SEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）, respectively. Ag/Co₃O₄ composite samples were used as electrocatalysts modified on a glassy carbon electrode for o-nitrophenol reduction. The electrocatalytic results indicated that Ag/Co₃O₄ composites with n（Co）:n（Ag） =3:2 displayed better electrocatalytic activity for o-nitrophenol by comparing with bare glass carbon electrode.更多还原