【作者】 NDAMANISHA Jean Chrysostome；

【导师】 Professor Liping GUO；

【作者基本信息】 东北师范大学 ， Analytical Chemistry， 2009， 博士

【摘要】 近来,介孔碳的发展引起人们极大兴趣。这类碳材料有很高的表面积,均匀可调的孔径,高的热稳定性,可变的结构组成以及高的化学稳定性。这些特点使得介孔碳成为用来检测某些物质电化学行为的新型材料。尽管已有一些工作用来研究介孔碳的电催化应用,但是了解它的电化学活性仍然是很重要的。此外改善这些介孔材料的物理化学以及电催化性质也是很重要的。在这个工作中,在改善这些性质以前,我们试着应用它的电化学活性去探测一些物质。在论文第一部分中,我们介绍了介孔碳在硫醇类物质的电催化活性中所起的重要作用,以及介孔碳结构的变化导致这些性质的下降。结果显示,在介孔碳修饰的电极上,谷胱甘肽的氧化过程与半光氨酸有很大的不同,在此电极上半光氨酸的峰电位在0.47 V处。这个差异对于检测谷胱甘肽时减少半光氨酸的干扰是有帮助的。高表面积,有序的介孔结构,高灵敏度以及低的检测限使得介孔碳成为一种新颖的无酶安培葡萄糖传感器。论文第二部分介绍了介孔碳改性。结果显示将二茂铁固定在介孔碳上,介孔碳的有序结构未被破坏。介孔碳-二茂铁的电化学表征显示二茂铁是电化学活性的。在pH 7.3的缓冲溶液中,介孔碳-二茂铁修饰电极对抗坏血酸有很高的电催化活性,与裸的玻碳电极相比过电位有很大的下降,并且阳极电流有显著的增强。抗坏血酸是测定尿酸的主要干扰物,在抗坏血酸存在的条件下我们用介孔碳-二茂铁修饰电极检测了尿酸。由于抗坏血酸和尿酸的伏安信号能被很好的区分,峰电位差为308 mV,所以修饰电极能够同时检测抗坏血酸和尿酸。我们用一个新颖的方法实现了将氧化铁粒子掺杂在介孔碳中,并且没有降低介孔碳的表面积。通过分解二茂铁衍生物在有序介孔碳结构中产生了铁粒子。我们还对比了介孔碳包含铁粒子材料与介孔碳的性质,发现该新材料的物理化学性质得到改善。由于介孔碳大的表面积以及在碳的结构中出现了氧化铁粒子,使得介孔碳-铁材料对过氧化氢的电催化得到增强。更多还原

【Abstract】 Recently, there has been interest in the development of ordered mesoporous carbons (OMC). Those carbon materials exhibit high surface area, well- defined pore size, high thermal stability, flexible framework composition and chemical inertness. Those properties make OMC potential novel materials for investigating electrochemical behavior of substances. Although some works have been done on the application of OMC in the electrocatalysis, understanding its electrochemical activity is of great importance. It is also important to improve the physico-chemical and electrocatalytic properties of these porous carbon materials. In this work, before the improvement of these properties, we tried to understand how the electrochemical activity is applied in the determination of some biomolecules.In the first part of this work, it has been demonstrated that the ordered mesostructure of OMC plays an important role in the electrocatalytic activity towards the thiols and the destruction of this structure results in the decrease of such properties. Results showed that the oxidation process of glutathione (GSH) at OMC electrode is different from that of cysteine (CySH) at the same electrode by a peak at 0.47 V associated to CySH and this difference helped to reduce the interference of GSH during the determination of CySH in the presence of GSH. The high active surface area of OMC and its ordered mesostructure allowed fabricating a novel nonenzymatic amperometric glucose sensor based on the OMC with high sensitivity and low detection limit.The second part corresponds to the improvement of the properties of OMC. The results showed that, after anchoring ferrocene on the mesoporous, the ordered mesostructure of the material (OMC-Fc) remains intact. The electrochemical characterization of OMC-Fc showed that Fc is electrochemically accessible. In aqueous buffer solution (pH 7.3), the OMC-Fc modified electrode exhibits a high electrocatalytic activity towards ascorbic acid (AA) oxidation with a decrease of overpotential and a drastic enhancement of the anodic currents compared to the bare glassy carbon (GC) electrode. The detection and determination of uric acid (UA) in the presence of ascorbic acid (AA), the main interferent, were achieved at this OMC-Fc modified electrode. The voltammetric signals due to UA and AA were well separated with a potential difference of 308 mV, a separation that can allow the simultaneous determination of UA and AA.A novel method for the incorporation of iron oxide species in the carbon framework of OMC without decreasing the surface area has also been possible. The decomposition of ferrocene derivative yields iron species that facilitate the formation of the carbon framework. The performance of ordered mesoporous carbon containing iron oxide (OMC-Fe) has been compared to OMC and the properties of the new material were found to be improved. Electrocatalytic properties towards hydrogen peroxide were enhanced because of the large surface area of the mesoporous carbon and the presence of iron oxide species incorporated in the carbon framework of OMC-Fe.更多还原