高度分散二氧化锰纳米纤维的水热合成和对双氧水电流检测

摘要

A high dispersed nanofiber cryptomelane-type manganese dioxide was synthesized by a facile hydrothermal reduction route.The morphological characterization was examined by scanning electron microscopy (SEM) and transmission electron microscopy (TEM).The structure and electrochemical properties of the synthesized manganese dioxide were characterized by X-ray diffraction (XRD),BrunauerEmmett-Teller (BET) surface area analyses,and an electrochemical workstation (EW).A glassy carbon electrode (GCE) modified with the nanostructured cryptomelane-type manganese dioxide was investigated for amperometric detection of hydrogen peroxide (H2O2) in phosphate buffer solution with a pH 7.4 at an open circuit potential of 0.2 V.The oxidation peak current was found to increase by 1.3 μA with the addition of 0.1 mmol· L-1 H2O2 based on a MnO2 nanofiber-gelatin/GCE electrode.The amperometric signals are linearly proportional to the H2O2 concentration in the range 0.1-1.5 mmol· L-1 with a correlation coefficient of 0.996 using the GCE modified with 0.1％ (w,mass fraction) cryptomelane-type manganese oxides.The sensor is sensitive and its significant electrocatalytic activity results from the nanostructure of the cryptomelane-type manganese oxides.In addition,the sensor has a good reproducibility,a low detection limit,simplicity,and a low cost of construction.These results demonstrate that this material with high electrocatalytic activity offers great promise as a new class of nanostructured electrodes for biosensors.%采用水热还原氧化法合成了高度分散的具有纳米纤维结构的钾矿型二氧化锰,并将其用来制作检测双氧水浓度的传感器.运用X射线衍射(XRD)仪、电子扫描显微镜(SEM)、透射电子显微镜(TEM)和比表面积(BET)及孔隙度分析仪观察和表征二氧化锰纳米纤维的结构和表面形貌;用电化学工作站(EW)检测其传感性能.结果表明:在pH为7.4的磷酸缓冲溶液中,开路电压为0.2V的条件下对0.1％(w,质量分数)的二氧化锰纳米纤维修饰的玻碳电极(GCE)进行测试,测试结果为随着双氧水的浓度每增加0.1 mmol·L-1,响应电流的峰值就增加约1.3μA,在双氧水的浓度在0.1-1.5 mmol·L-1范围内得到的线性相关系数为0.996,这种电极的高灵敏度和优异的电化学活性可能归因于钾矿型二氧化锰纳米纤维的特殊纳米结构.这种传感器有很高的灵敏度和很好的重现性.综上说明这种廉价并且有很好的电化学活性的材料为设计新型电极生物传感器提供了更大可能.