Graphene wrapped MnO2-nanostructures as effective and stable electrode materials for capacitive deionization desalination technology

Due to its marvelous characteristics, huge surface area and excellent electric conductivity, graphene is-an optimum electrode in the capacitive deionization (CDI) units if the specific capacitance could be improved. In this study, novel strategy for rapid transformation of graphite into graphene-intercalated with nanostructure MnO2 with morphology control is introduced by one-pot reaction, low-time consuming and eco-environmentally method. Conversion of graphite into the graphene structure was suggested through vigorous oxidation using ammonium peroxysulphate and hydrogen peroxide in the presence of manganese sulfate followed by a reduction step using piperidine under a microwave irradiation. It was demonstrated that formation of MnO2 nanostructures during the exfoliation process has a great impact to separate the graphene sheets as the metallic nanostructures wedged among the sheets. Interestingly, morphology control could be performed; MnO2-nanorods and MnO2-nanparticles @graphene could be prepared. As an electrode in the CDI unit, the synthesized MnO2-nanorods@graphene revealed excellent results in specific capacitance (292 F/g), distinct electrosorptive capacity (5.01 mg/g), amazing salt removal efficiency (similar to 93%) and distinguished recydability. Overall, this work introduces an effective technique to improve the interfacial contact area between MnO2 and graphene nanosheets which enhances the electrochemical performance and recommends utilizing the introduced material as a promising electrode for CDI units. (C) 2014 Elsevier B.V. All rights reserved.