Electroanalytical Applications Of Dirac Nanomaterials And Analysis Of Electrochemical Reflected Microscopic Spectral Imaging

Nanostructured Dirac materials, such as graphene and topological insulators, arenamed for the Dirac cones they contain. The electrons at Dirac cones have noeffective mass and should be described by Dirac equation. Because of their distinctiveband structure, Dirac materials show some special physical properties and havereceived extensive attention only in the past few years. The purpose of this work is todiscover the electrochemical analytical applications of Dirac materials, especially inelectrochemical sensors. The main aspects were as follows：1. Reduced graphene sheets (rGSs) were synthesized chemically by animproved method for good dispersibility in aqueous solutions and a novelsandwich-like biosensor was fabricated for the amperometric detection of glucosebased on electrodeposited Prussian blue nanoparticles (PBNPs) firmly stuck betweentwo layers of reduced graphene sheets. The electrochemical behavior andelectrocatalytical ability of this sensor to hydrogen peroxide were, first of all,investigated in details. Taking many advantages of rGSs and thus-designed sandwichstructure, it exhibited excellent sensitivity and stability for H2O2determination at alow application potential. After introducing the GOD as the “meat stuffing”, thesandwich-like biosensor was constructed which was highly effective for detectingglucose and the blood sugar in real samples could be analyzed accurately.2. A novel and fast-fabricated Prussian blue/topological insulator Bi2Se3hybridfilm has been prepared by coelectrodeposition technique. Taking advantages oftopological insulator in possessing exotic metallic surface states with bulk insulatinggap, Prussian blue nanoparticles in the hybrid film have smaller size as well as morecompact structure, showing excellent pH stability even in the alkalescent solution ofpH8.0. An amperometric glucose biosensor was then fabricated by immobilizingglucose oxidase (GOD) on the hybrid film modified electrode. Under the optimalconditions, a wide linear range extending over3orders of magnitude of glucoseconcentrations (1.0×10-5to1.1×10-2M) was obtained with a high sensitivity of24.55μA/(mM·cm2). The detection limit was estimated for3.8μM defined from asignal/noise of3. Furthermore, the resulting biosensor was applied to detect the bloodsugar in human serum samples without any pretreatment, and the results werecomparatively in agreement with the clinical assay. In order to break through the limitations of traditional spectroelectrochemistry,an in situ electrochemical microscopic spectral imaging system was fabricated andthen investigated based on the electrodepositing procedure of Purssian blue to goldelectrode. A specially designed spectroelectrochemical interface (cell) was fabricated,coupling with a solid reference electrode. Three microscopic electrochemical spectralimaging analytical methods, the real-time time-resolved, spatially-resolved andpotential-resolved techniques, were established respectively based on the reflectionspectrum of the working electrode surface. The results show that the wavelengthrange this system could provide was from400nm to1000nm (from near-ultraviolet,visible radiation to near ultrared). The system has good performance in the part ofspectrum. However, the imaging part needs to be improved.