Facile synthesis of ultralong MnO2 nanowires as high performance supercapacitor electrodes and photocatalysts with enhanced photocatalytic activities
Abstract
A simple hydrothermal route was developed for the synthesis of uniform α-MnO2 nanowires using a controllable redox reaction in a MnCl2–KMnO4 aqueous solution system. Electrochemical properties of the resulting products as an electrode were investigated by cyclic voltammetry, chronopotentiometry and electrochemical impedance tests. The electrode can provide a specific capacitance of 180 F g−1 at a current density of 1.0 A g−1. After 2000 cycles, the specific capacitance was maintained above 78%. Besides, the as-synthesized products were also used as the photocatalyst for the photocatalytic degradation of several dye molecules. The results show almost complete degradation (~99%) of Congo red dye molecules in 30 min. Such ultralong MnO2 nanowires are expected to have potential applications in wastewater treatment and energy storage.