Comparison of ferrite nanoparticles obtained electrochemically for catalytical reduction of hydrogen peroxide

Ferrites of iron, cobalt, and nickel were used as a non-enzymatic sensor for detection of hydrogen peroxide. X-ray diffraction (XRD) and transmission electron microscopy revealed that the nanoparticles obtained by electrochemical route and varying the parameters synthesis show similar size of around 20 nm and a relation metal/iron equal to 1/2. The effect of pH, temperature, amount of nanoparticles, and potential has been studied to obtain the best sensor properties in terms of sensitivity and linear response. The mechanism has been attributed to the oxidation of Fe 2+ , Co 2+ , and Ni 2+ in the octahedral position of the spinel that enhances the catalytic reduction of hydrogen peroxide. The best sensor has been obtained with magnetite (iron ferrite) with a detection limit of 7.3 × 10 −6 M and a sensitivity of 4.0 × 10 −4 μA/M. The magnetite was also applied to determine hydrogen peroxide in commercial contact lens cleaner Novoxy® with satisfactory results.