纳米线状α-MnO_(2)电极材料的制备及电催化性能的研究

Preparation of nanowireα-MnO_(2) electrode materials andthe study of electrocatalytic performance

以KMnO_(4)和MnCl_(2)·4H_(2)O为原料通过水热法制备出二氧化锰电极材料,利用SEM、XRD观察材料的微观形貌并确定其晶型,通过放电测试和电化学测试研究二氧化锰作为电极材料的ORR电催化性能。研究结果表明,水热反应温度为180℃、KMnO_(4)∶MnCl_(2)·4H_(2)O摩尔比为2.5∶1时,能够制得均匀纳米线状的α-MnO_(2),其作为催化剂制备的空气阴极在极化电压为1.0 V时极化电流密度最大,达到76.15 mA/cm^(2),并且具有最小的阻抗,说明氧还原反应阻力最小,在10,20,30,40 mA/cm^(2)电流密度下放电电压分别为1.64,1.49,1.36和1.23 V,放电性能相较于5%铂碳催化剂提升10%左右。

The manganese dioxide electrode material was prepared by hydrothermal method using KMnO_(4) and MnCl_(2)·4H_(2)O as raw materials.The microstructure of the material was observed by SEM and XRD,and the crystal shape was determined.The ORR electrocatalytic performance of manganese dioxide as electrode material was studied by discharge test and electrochemical test.The results show that homogeneous nanowireα-MnO_(2) can be prepared when the hydrothermal reaction temperature is 180℃and the molar ratio of KMnO_(4)∶MnCl_(2)·4H_(2)O is 2.5∶1.The polarization current density of the air cathode prepared by α-MnO_(2) as catalyst reaches 76.15 mA/cm^(2) at the polarization voltage of 1.0 V.It also has the smallest impedance,indicating that the resistance of oxygen reduction reaction is the least.At the current density of 10,20,30 and 40 mA/cm^(2),the discharging voltage is 1.64,1.49,1.36 and 1.23 V,respectively,and the discharge performance is improved by about 10%compared with that of 5%platinum carbon catalyst.