Highly sensitive H2O2 sensor based on annealed MnO2/Al2O3 nanofibers prepared by a novel spray pyrolysis deposition

In the present work, we report the annealing effect on the properties of MnO2 nanofibers prepared onto sapphire substrate for electrochemical detection of H2O2. The MnO2/sapphire nanocomposite films prepared by a novel spray deposition route were investigated for its optical and microstructural properties. The red shift in the absorption peak with increase in the annealing temperature was attributed to strain relaxation in MnO2 crystallites. The film annealed at 400 °C show significant change in morphology from nanofibre to nanonoodles like structure with large diameter, which provided large electro chemical active surface favorable for sensing. The electrochemical performance of nanocomposited MnO2/Al2O3 electrode annealed at 400 °C revealed larger specific capacitance of 320 F/g. The sensor exhibited detection limit as low as 0.05 μM towards H2O2, suggesting that the MnO2/Al2O3 electrode represents a challenging opportunity to develop next generation of electrochemical sensing material.