Electrochemical Sensor Based On Porous Carbon Nanocomposites: Preparation And Their Application

Porous carbon materials are essential for many modern applications due to their favourable properties, including high electrical conductivity, distinctive porous structure, good thermal and mechanical stability. In particular, the combination of large specific surface area and large number of defect sites makes porous carbon very promising as a support platform for the deposition of nanoparticles. Porous carbon materials are of great interest in various applications, ranging from electro-catalyst supports, fuel cells, supercapacitors, Li-ion batteries and electrochemical sensor.In the introduction, the methods for synthesis and functionalization of porous carbon materials as well as their electrochemical applications were summarized. In this dissertation, porous carbon materials were used as catalysts support for modification of nanoparticles or heterogeneous element was emphasized especially. Environmental pollutants and biological molecules were selected as marked molecules to evaluate the electrochemical activity of porous carbon-based nanocomposites. This dissertation mainly consists of the following several aspects:(1) Novel Pt nanoparticles ensemble on macroporous carbon(MPC) hybrid nanocomposites(Pt/MPC) were prepared through a rapidly and simple one-step microwave-assisted heating procedure. In the procedure, poly-(diallydimethylammonium chloride, PDDA) is highly effective in dissolving MPC in water, and the positively charged PDDA attracted 26 Pt Cl- via electrostatic interaction. The obtained Pt nanoparticles can uniformly distribute on the surface of MPC. As a sensitive nitrobenzene sensor based on the Pt/MPC modified glassy carbon electrode, a wide linear range, low detection limit, high sensitivity and good stability were noticed.(2) The one-pot synthesis of a well-defined Au nanoparticles@polyoxometalates/ordered mesoporous carbon(Au@POMs/OMC) tri-component nanocomposite is reported, which is facile, green and rapid. The POMs were used as both reductant and bridging molecules. The novel nanohybrids of Au@POMs/OMC can provide new features of electrocatalytic activities, because of the synergetic effects of Au nanoparticles and OMC materials. In point of fact, the successful fabrication of Au@POMs/OMC holds great promise for the design of biosensors, and is a promising way to promote the development of new electrode materials.(3) Two-dimensional ordered mesoporous carbon nitride(OMCN) has been successfully prepared for the first time using SBA-15 mesoporous silica and melamine as template and precursor respectively, by a nano hard-templating approach. The OMCN-x samples have been synthesized by different pyrolysis temperatures. A sensitive electrochemical sensor for H2O2, nitrobenzene, and NADH was developed based on the modified glassy carbon electrode, which showed wide linear range, low detection limit, high sensitivity, and good stability. As a result, successful fabrication of OMCN not only holds great promise for the design of electrochemical sensors, but also promotes the development of new electrode materials.(4) MOF has received more and more attention in electrochemical applications. The large majority of electrochemical reactions are occurring in aqueous phase. Yet, one of the major short comings of several classes of MOF is their instability in the presence of moisture. The poor water stability gives rise to the framework collapse of the MOF, even leading to the electrochemical instability. The other current issue with implementing many types of MOF into practical electrochemical applications is their weak conductivity. Recently, our group has studied MOF-carbon combination composites. We reported the easy preparation of novel Cu-based MOF loaded on MPC hybrids. MPC skeleton exhibits a restriction effect on the growth of Cu-MOFs crystallites, and thus, the sizes of the crystallites match well with those of the macropores of the MPC matrix. This can largely decrease the size of crystalline structure. Another is that MPC seems to act as a strong support. The Cu-MOF can be firmly fixed with MPC, so that the crystalline structure of Cu-MOF is stable. Moreover, MPC can form good electron pathways between the electrode and electrolyte. As a result, the successful fabrication of Cu-MOF-MPC not only promotes the development of new porous composite materials, but also holds great promise for the design of electrochemical sensors.