The poor electrical conductivity of MnO_2 limits its use as an electrode material.To overcome this limitation,we report an easy and rapid approach to deposit nanosized MnO_2 onto multi-wall carbon nanotubes functionalized with hydroxyl groups(MWCNTs-OH) by chemical reduction of KMnO_4 with MnSO_4 in aqueous solution under ambient conditions.Characterization with XRD and TEM reveals that the obtained MnO_2/MWCNTs-OH composite is nanocrystalline and partially covered by MnO_2 nanosheets with a thickness of 1-3 nm at a MnO_2 loading of 20 wt%.Cyclic voltammetry(CV) and galvanostatic charge-discharge measurements reveal that the MnO_2/MWCNTs-OH composite with a MnO_2 loading of 20 wt% has a relatively high specific capacitance of 234 F/g at a scan rate of 2mV/s and exhibits good cycling stability.Furthermore,the oxygen reduction reaction(ORR) shows that MnO_2/MWCNTs-OH composite may have potential applications as a non-noble metal electrocatalyst in fuel cells and metal-air batteries.
Yang LvHuanqiao LiYan XieShushuang LiJia LiYongheng XingYujiang Song
