Manganese dioxide-vulcan carbon@silver nanocomposites for the application of highly sensitive and selective hydrazine sensors

Manganese dioxide (MnO₂)-vulcan carbon (VC)@silver (Ag) (core@shell) nanocomposites were synthesized through a simple wet chemical method without using hazardous organic reagents, polymeric micelles, templates or catalysts. The synthesized MnO₂-VC@Ag exhibited a MnO₂-VC core and Ag shell, and the thickness of shell was found to be 23 nm. The obtained diffraction patterns confirmed that the prepared nanocomposite consists of tetragonal and face-centred cubic structures of MnO₂ and Ag nanostructures, respectively. Cyclic voltammetry and amperometric techniques were adopted to electrochemically characterize the MnO₂-VC@Ag nanospheres for hydrazine oxidation in phosphate buffer solution. Under the optimized conditions, the fabricated sensor exhibited a good electrochemical performance toward hydrazine oxidation, offering a broad linearity of 0.1 to 350 μM, with a relatively low detection limit of 100 nM and a high sensitivity of 0.33 μA μM^-1 cm^-2. In addition, anti-interference properties, good reproducibility, long term performance, good repeatability and real sample analysis were achieved for the constructed sensor, owing to the synergetic effects of the Ag and MnO₂-VC nanostructures. The aforesaid attractive analytical performance and facile preparation of the MnO₂-VC@Ag core-shell nanospheres are new features for electrocatalytic materials and may hold promise for the design and development of effective hydrazine sensors.