Kinetics of decomposition of hydrogen peroxide on the surface of magnetite at high temperature

• The kinetics of H2O2 decomposition on magnetite are measured up to 473 K.
• H2O2 concentration is measured electrochemically using a Pt probe.
• EIS is used to accurately measure the decomposition kinetics on the Pt probe.

A novel electrochemical method was employed to accurately measure the kinetics of H2O2 decomposition on the surface of magnetite at elevated temperatures and pressures. Electrochemical impedance spectroscopy was used to probe the decay of H2O2 concentration by tracking the charge transfer resistance on the surface of a platinum electrode. It was found that the decomposition kinetics follow a first-order rate law with respect to H2O2 concentration and vary from 8.1 × 10−4 to 7.9 × 10−2 min−1 when the temperature increases from 298 to 473 K (for a 0.2 g L−1 magnetite suspension). The mean calculated activation energy of 30 ± 1 kJ mol−1 showed that H2O2 decomposition on the surface of magnetite particles is a chemically controlled process.