Morphology and chemical composition dependent synthesis and electrochemical properties of MnO2-based nanostructures for efficient hydrazine detection

•MnO2-based nanostructures with different morphology and composition were prepared.•The morphology evolves from nanoflowers, nanorods, nanotubes, to nanofibers.•The electrochemical performance is dependent on its morphology and composition.•The Mn7O13·5H2O/α-MnO2 nanocomposite shows better performance than neat MnO2.•This novel hydrazine sensor shows very high sensitivity and low detection limit. In this contribution, various MnO2-based nanostructures with different morphologies and chemical compositions were prepared using a facile hydrothermal method. The structural evolution as a function of aging time from 3 to 72h was monitored. All the synthesized samples were thoroughly characterized using XRD, SEM, and FTIR, etc. The results indicated that pure α-MnO2 and Mn7O13·5H2O/α-MnO2 nanocomposite with various morphologies including nanoflowers, nanoflowers & nanorods, nanorods, nanotubes, and nanofibers can be obtained. Then, the electrochemical performance of all the prepared MnO2 based electrodes for the detection of hydrazine was investigated. Comparing to pure α-MnO2, the Mn7O13·5H2O/α-MnO2 nanocomposite was much more efficient, which showed a very high sensitivity of 109.55μAmM−1cm−2, a low detection limit of 2.06μM (S/N=3), and a wide linear range from 30μM to 2.83mM. The results revealed that both the morphology and the chemical composition of the MnO2 based electrode nanomaterials are crucial for their electrochemical properties and the Mn7O13·5H2O/α-MnO2 nanocomposite represents a novel and promising electrode material for the efficient detection of N2H4.