Controlled synthesis of Co3O4 and Co3O4@MnO2 nanoarchitectures and their electrochemical capacitor application

• Sheet-like and needle-like Co(OH)2 precursors were synthesized by easily using different autoclave with different capacity.
• The obtained Co3O4 nanowire acts as the scaffold to deposit MnO2 nanocrystals to form Co3O4@MnO2 core/shell arrays.
• Results showed that Co3O4@MnO2 core/shell arrays have good electrochemical property.

Co3O4 nanoarchitectures with controlled morphologies and Co3O4@MnO2 core/shell arrays have been fabricated via a facile hydrothermal method. Co3O4 nanowires and nanosheets have been obtained by the thermal annealing Co(OH)2 precursors. Furthermore, the Co3O4 nanowires are used as the scaffold to deposit MnO2 nanosheets to form Co3O4@MnO2 core/shell arrays. MnO2 shells coated on the surface of Co3O4 nanowires show a porous-rich structure, which promotes the electrochemical performance of the electrochemical capacitor. The Co3O4@MnO2 core/shell arrays exhibit high specific capacitance of 1280 F/g, good rate performance, and excellent cycling stability. The growth roadmap in this work is a facile strategy to design and synthesize transition metal oxides and hydroxide hierarchical hetero-structures for the next generation electrochemical energy storage, catalysis, and gas sensing applications.

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