A Novel Hydrogen Peroxide Sensor Based on the Direct Electron Transfer of Catalase Immobilized on Nano-Sized NiO/MWCNTs Composite Film

MWCNTs-nanoNiO composite was used as a glassy carbon electrode modifier for construction of a novel catalase nanobiosensor for hydrogen peroxide. The immobilized catalase exhibited excellent electrocatalytic activity towards the reduction of H2O2. The resulting amperometric biosensor exhibited a linear response over a concentration range of 200 mu M to 2.53 mM with a low detection limit of 19.0 mu M. Electrochemical impedance measurements revealed that the modified electrode can be used for the sensitive detection of H2O2. The charge transfer resistance found to decrease significantly after enzymatic reaction of nanobiosensor with H2O2. The resulting impedance was highly sensitive to H2O2 over a linear range of 19170 nM with a detection limit of 2.4 nM.