Sensing characteristics of hydrogen peroxide sensor using carbon-based electrode loaded with perovskite-type oxide

Carbon-based electrodes loaded with large surface area perovskite-type oxides showed good properties of potentiometric as well as amperometric sensing to H2O2. Electromotive force (EMF) of the electrode loaded with La0.6Ca0.4Ni0.7Fe0.3O3 was found to vary logarithmically with H2O2 concentration between 10(-5) and 10(-3) M. The 90% response time was ca. 5 min at 25 degrees 0. Interestingly, EMF of the sensor element was hardly affected by the concentration of dissolved oxygen in the solution. The electrodes loaded with large surface area perovskite-type oxide gave high activity to the electrochemical oxidation of H2O2, a limiting current was observed at the potential range between +0.6 and +1.0 V (versus SCE). The sensing current at +0.75 V of the carbon-based electrode loaded with La0.6Ca0.4MnO3 was found to be approximately proportional to H2O2 concentration up to 0.5 mM. The response time was as short as ca. 60 s at 25 degrees 0.