The Research On Hydrogen Peroxide Sensor Based On Nanomaterials Modified Electrodes

The nanomaterials have aroused intense attentions by people because of their high catalytic activity and larger surface area. And they have been emerging wide application prospects in many fields, especially in catalysis and sensors. For the sensors, the modified material determines their activity, selectivity and sensitivity directly. It is well known that enzymes may be quite susceptible to their working environment and and thus behave a poor stability. In this paper, the nonenzymatic sensors and their catalytic activity towards H2O2 were studied. The main content are as the follows:(1) NH2-functionalized silica (SiO2-NH2) was sythsized by using ethanol as solvent. After SiO2-NH2 adsorbing H2PtCl6, PPy/Pt hybird materials were formed on the surface of SiO2 in the pyrrole vapor. The PPy/Pt hollow microspheres were prepared by treating PPy/Pt/SiO2 with hydrofluoric acid. The hybird materials were charaterized by transmission electron microscopy (TEM).The results showed that the diameter of microspheres were about 140 nm and the thickness of shell range from 8 to 20 nm. The catalytic activities of modified electrodes towards H2O2 were tested by electrochemical methods. The results indicated that the sensors displayed a good electrocatalytic property, fast response of less 3s and a relatively low detection limit of 1.0μM.(2) NH2-functionalized silica was sythsized by taking methanol as the solvent. The PPy/Pt hybrid hollow microspheres were then prepared by treating the SiO2 template in a processs of absoption of H2PtCl6 via the NH2-group with pyrrole vapor and thus developed hydrogen peroxide sensor. The PPy/Pt hybrid hollow sphere materials were confirmed by TEM. The results showed that the diameter of hollow microspheres was found to be about 25 nm and the thickness of the shells ranged from 2 to 6 nm. The electrocatalytic properties of modified electrode were test by electrochemical methods. The results showed that the nonenzymatic sensor displayed a good electro-catalytic response to the oxidation of H2O2, and the resulting sensor had good anti-intereferences ability to uric acid and ascorbic acid. Clear responses could be still observed in i-t curve when the concentration of H2O2 was as low as 1.0μM.(3) A novel H2O2 sensor was fabricated by electrodeposition (CV method) of MnO2/Pt onto the surface of GO/GC Eelectrodes.The materials were characterized by TEM and SEM.The catalytic properties of sensors were tested by electrochemical methods. The results showed that MnO2/Pt/GO modified electrode had a good electrocatalytic property, a wide linear in the range of 1.33～16.8 mM (R2=0.9989, n=29) with sensitivities of 64.43 mA-M-1·cm-2 and detection limit of 2.0μM for the detection of H2O2.