Preparation Of Graphene Nanomaterial Chemically Modified Electrode By Using Electrochemical Method And Its Application

Chemically modified electrodes (CMEs) and the corresponding electrochemicalsensing techniques are one of the most active research areas in modern electrochemistryand electroanalytical chemistry. Graphene, a kind of new two dimensions carbon nanomaterial, has been fully investigated in many fields including physics, chemistry,information science, energy science and devices design since2004due to its excellentphysical and chemical properties. In electrochemistry and electroanalytical chemistry,especially, in electrochemical senseing field, graphene has attracted much attention dueto its favorable conductivity, large surface area and high electrocatalytic activity. Forpreparation of chemically modified electrodes based on graphene and correlativematerials, drop coating method.are usally used. However, there are many shortcomings inthis method such as complicated preparation procedure, bad stability and reproducibility.In recent years, electrochemical techniques get more and more attention in preparation ofnano structure electrochemical sensing interface due to the advantages of simpleequipments, simplicity and convenience of preparation, low enrgy consumption, smallenvironmental polluton, cheapness of raw materials, morphology-controlled, sizeadjustable and the tunable composition. Particularly, this technique is that thenanoparticle can directly be attached to the base electrode.In this thesis, several kinds of grapheme chemically modified electrodes have beenpreparaed by using direct electrochemical techniques. The electrochemical behavior ofsome environmental substances, such as nitrite, hydrazine, hydrogen peroxide, phenol,bisphenol A, hydroxylamine, catechol, resorcinol and hydroquinone have been fully investigated on the above modified electrodes. Based on the above investigation results,methods of amperometric determination the above substances are also established in myresearch work. The main contributions of this dissertation are the systematicinvestigation of various factors for preparing of graphene electrochemical sensinginterface by electrochemical method. Compared to other methods, electrochemicaltechiniques proposed in this thesis have the advantages of simplicity and convenience ofpreparation, good stability and reproducibility.The main contents of this paper are as follows:1. The graphene modified electrodes have been fabricated by using cyclicvoltammetry from the graphene oxide solution under alkaline, neutral and acidicconditions. The electrochemical behavior of nitrite, hydrazine and phenol at thesemodified electrodes are also investigated. The results show that graphene can be easilyelectrodeposited on the base electrode surface with high electrocatalytic activity. Inaddition, ampermetric methods are also established for the determination of nitrite,hydrazine and phenol in real samples by using the above grapheme modified electrodes.2. A CuO/ERGO and a nano-gold/ERGO modified electrode has been prepared bythe layer-layer electrochemical deposition method, respectively. The electrochemicalbehavior of hydrogen peroxide and hydroxylamine are studied on these two modifiedelectrodes, respectively. The results show that, the CuO/ERGO modified electrodeexhibite strongly electrocatalytic activity towards the oxidation of H2O2in0.10mol·L1NaOH solution. On the other hand, the nano-gold/ERGO modified electrode exhibitestrongly electrocatalytic activity towards the oxidation of hydroxylamine in0.10mol·L1PBS buffer solution. Based on this, ampermetric methods are established for thedetermination of hydrogen peroxide and hydroxylamine in real samples by using theabove modified electrodes.3. The electrochemical behavior of three dihydmxybenzenes isomers areinvestigated on the ERGO/PPyox/GCE modified electrode. The results show that, in0.10mol·L1PBS (pH=6.00) solution, the ERGO/PPyox/GCE modified electrode showed excellent electrocatalytic activity and selectivity for dihydmxybenzenes. Under theoptimum conditions, The oxidation peak currents show the linear relationship with theconcentration of catechol, hydroquinone and resorcinol. Furthermore, anano-gold/ERGO/PPyox hybrid film modified electrode has been also prpepared and theelectroctalytic activity for the oxidation of bisphenol A of this modified electrode is alsoinvestigated. The results show that nano-gold/ERGO/PPyox hybrid film modifiedelectrode has higher electrocatalytic activity for the oxidation of bisphenol A. Based onthis, amperomtric method is also applied for the determination of bisphenol A in realsample.