Preparation of nanowire α-MnO2 electrode materials and the study of electrocatalytic performance
The manganese dioxide electrode material was prepared by hydrothermal method using KMnO4 and MnCl2·4H2O 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 nanowire α-MnO2 can be prepared when the hydrothermal reaction temperature is 180 ℃ and the molar ratio of KMnO4∶MnCl2·4H2O is 2.5∶1.The polarization current density of the air cathode prepared by α-MnO2 as catalyst reaches 76.15 mA/cm2 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/cm2,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.
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