Carbon-based Materials Electrochemical Sensor Research

Carbon-based nanomaterials have special structure, which results in series ofinteresting physical and chemical properties. The application of nanomaterials hasinvolved in nanoelectronics, nanochemistry, catalysis, biosensing, environmentaldetection, medicine and so on. This thesis is goal to develop and design some highlyselective and sensitive electrochemical sensor by mean of the combination ofcarbon-based nanomaterials and electrochemical technique. Some new carbon-basednanomaterial modified electrode has been prepared for investigating theirelectrochemical response characteristics toward some environment pollutants. Someselective and sensitive methods have been established for their application inenvironmental monitoring. The electrochemical behaviors of the nanocompositematerials were studied. Additionally, the carbon nanomaterials based on electrodeswere applied as electrochemical sensors with satisfied results. The main points of thisthesis were summarized as follows:Chapter I: An efficient sensing platform based on functionalized reducedgraphene oxide (rGO) for the detection of nitro aromatic compounds was developedin this work. Firstly, rGO was functionalized with1,3,6,8-pyrene tetra sulfonic acidsodium salt (PyTS) through π–π interaction among molecules, which could not onlyimprove the solubility and dispersibility of the rGO in aqueous solution but alsoprovide more binding sites for nanoparticles. Secondly, palladium nanoparticles (PdNPs) were uniformly decorated on the functionalized rGO nanosheets with the help ofsulfonic acid group. Finally, the electrochemical sensor was built up by casting PdNPs-PyTS/rGO on the surface of glassy carbon electrode (GCE) and electrochemicalproperties of the nitro aromatic compounds have been studied by cyclic voltammetry(CV) and differential pulse voltammetry (DPV) techniques. The results showed thatPd NPs-PyTS/rGO modified electrode possessed higher electrocatalytic activity andsensitivity for nitrobenzene (NB). The detection limit was as low as0.62ppb. Thismay be attributed to the combination of the large surface area of rGO and effective electrocatalytic property of Pd NPs. Experimental results showed that PdNPs-PyTS/rGO modified the electrode was a fast, simple and controllable method forelectrochemical sensor. The modified electrode also exhibits good stability andreproducibility.Chapter II: In this study, an electrochemical sensor of nitro aromatic compoundbased on three-dimensional porous Pt-Pd nanaoparticles (Pt-Pd NPs) supported byreduced graphene oxide (rGO) nanosheets-multi walled carbon nanotube (CNTs)nanocomposite (marked as Pt-Pd NPs/CNTs-rGO) was investigated for the first time.This hybrid nanocomposite has been prepared via a facile and versatile hydrothermalsynthetic strategy while its structure and property are evaluated by the X-raydiffraction (XRD), transmission electron microscopy (TEM) and electrochemicalimpedance spectroscopy (EIS). The result shows that3D porous Pt-PdNPs/CNTs-rGO nanocomposite had a large specific surface area of326.6m2g-1andexhibited ultrahigh rate capability and good cycling properties at high rates.Electrochemical studies have been performed for the nitro aromatic compoundsdetection by using different pulse voltammetry (DPV) technique. The proposednanocomposite exhibited much enhanced elctrocatalytic activity and high sensitivitytoward the detection of nitro aromatic compounds which compared with Pt-Pd NPsdispersed on functionalized rGO, Pt-Pd NPs dispersed on functionalized CNTs,rGO-CNTs and bare glass carbon electrode (GCE). On the basis of the abovesynergetic electrochemical sensing and synthesis procedure, the hybrid material canbe recommended as a robust material for sensor-related applications. Moreover, theproposed sensor exhibits high reproducibility, long-time storage stability andsatisfactory anti-interference ability.