Silver-Nafion coated cylindrical carbon fiber microelectrode for amperometric monitoring of hydrogen peroxide heterogeneous catalytic decomposition

Cylindrical carbon fiber microelectrode coated with a silver layer electrodeposited from silver nitrate solution containing Pluronic F127, a surface active agent, and also a Nafion layer prepared using a dip-dry method forms a sensitive, selective and stable amperometric hydrogen peroxide sensor, operating in the cathodic region of potential. The layer formed at the electrode is composed of porous, partially crystalline silver deposits with a significant fraction of attached silver nanoparticles. Using amperometry in stirred solution at 0 mV (vs. Ag/AgCl), the electrode is capable to monitor hydrogen peroxide over its wide concentration range (1 × 10−5 up to 0.1 M). The response of the electrode is sufficiently time-stable to enable the monitoring of hydrogen peroxide heterogeneous decomposition over manganese dioxide catalyst including the conditions where higher decomposition rates are observed, impossible to be monitored using batch titration.