Study On Electrochemical Sensors Based On Transitional Metal Oxides/Carbon Nanocomposites

Transitional metal oxides as a group of valuable catalysts hold several advantages, such as anti-poisoning, good thermal stability, tedious and time-consuming and high selectivity for oxidation reactions. Ordered mesoporous carbon (OMC) owning well defined pore size, large pore volume as well as porous hollow materials captured much attention and is expected to be as support for well-dispersed catalyst due to their high surface area, high conductivity, good thermal and mechanical stability and good biocompatibility. In this paper, we prepared two kinds of nanocomposites of transitional metal oxides/carbon for fabricating electrochemical sensors and discussed the electrocatalytic performance. The main contents are as follows:(1) MnO2/C porous hierarchical hollow spheres (PHHSs) nanocomposites were prepared through a facile hydrothermal reaction route and subsequent oxidation-reduction treatment process at room temperature. It was found that the as-obtained MnO2/C PHHSs exhibit notable catalytic performance toward direct redox of glucose. When they were fabricated into the nonenzymatic electrochemical sensor for glucose, the possible electrocatalytic mechanism of MnO/C PHHSs toward glucose was proposed. The sensor showed high sensitivity, which is obviously superior to some other MnO2nanocomposites-based nonenzymatic glucose biosensors reported in literatures. Moerver, the sensor displayed good selectivity, robust reproducibility, long-term stability and also have great potential for detection glucose in human blood serum.(2) The MnO2/C PHHSs exhibit notable catalytic performance toward diret redox of H2O2. And a novel nonenzymatic electrochemical sensor for H2O2based on MnO2/C PHHSs was constructed. The possible electrocatalytic mechanisms of MnO2/C PHHSs toward H2O2was proposed. The results indicate that MnO2/CPHHS shows fast amperometric response to H2O2with a high sensitivity of4.68μAmM-1, low detection limit of7.54×10-7mol·L-1. Moerver, the sensor exhibited low applied potential, wide linear range, high selectivity and good stability.(3)CuO nanorods/ordered mesoporous carbon (CuO/OMC) nanocomposites were synthesized by a facial hydrothermal method. Compared with CuO nanorods, CuO/OMC nanocomposites exhibit more excellent catalytic performance to direct glucose oxidation. So a new nonenzymatic electrochemical sensor for glucose based on CuO/OMC was developed and the electrocatalytic mechanisms of MnO2/C PHHSs toward the oxidation of glucose was proposed. The results indicate that the sensor shows excellent sensing performance, including high sensitivity, wide linear range, good stability, robust reproducibility and excellent selectivity.