Preparation Of Molybdenum Carbide Microspheres-Reduced Graphene Oxide And Electrochemical Detection Of Dopamine

Dopamine（Dopamine,DA）,as a chemical messenger,determines the physiological and psychological functions of human beings.The abnormal concentration of DA in extracellular fluid is related to many neurological syndromes such as Parkinson’s disease and Alzheimer’s disease.Early diagnosis of these diseases requires identification and verification of DA.However,due to its dynamic release and low concentration,the quantitative analysis of DA is challenging.Therefore,it is very important to develop a highly sensitive electrode material for effective DA detection.In this paper,firstly,the precursor Mo-dopamine chelate（Mo-polymine）is prepared by liquid phase reaction at room temperature,and it is transformed into Mo₂C at high temperature.Subsequently,it is self-assembled with graphene oxide（GO）prepared by improved Hummers method,and the molybdenum carbide-reduced graphene oxide modified（Mo₂C-r GO/ITO）electrode is obtained by annealing and calcination.The morphology and structure of Mo₂C,r GO and Mo₂C-r GO were characterized,and the formation mechanism is analyzed.The effects of concentration,heat treatment temperature and r GO doping amount on morphology and properties were investigated.The selectivity,reproducibility,repeatability and stability of Mo₂C-r GO/ITO electrode and its detection performance in practical samples were tested.The results show that Mo₂C-r GO shows a spherical morphology in which hollow Mo₂C microspheres with a diameter of about 400 nm are uniformly wrapped by wrinkled thin r GO nanosheets.The addition of dopamine hydrochloride has no effect on the size of the ball,but the heat treatment temperature and r GO doping content have great influence on the morphology and electrochemical properties of the material.When the precursor prepared by adding 300 mg dopamine hydrochloride is heat-treated at 800℃,Mo₂C is obtained,and when the ratio of Mo₂C to r GO content is7.5:1,the electrochemical performance of Mo₂C-r GO/ITO electrode is the best.DA detection shows a high sensitivity of 8.20μA·μM^-1and the low detection limit of0.058μM,which is superior to other DA detection electrode materials.The sensitivity is 8.01μA·μM^-1and decreased by merely 2.3%under the uric acid（Uric acid,UA）interference,with high selectivity.In addition,the electrode has good repeatability,reproducibility and stability.The Mo₂C-r GO/ITO electrode prepared in this experiment can be successfully used for quantitative analysis of DA in human urine.