Improved Properties Of Ordered Mesoporous Carbons: Synthesis And Applications

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.