Kinetic and Mechanism of H2O2 Decomposition on Keplerate {Mo72Fe30} Nanoball

Hydrogen peroxide (H2O2) is an important regulator of cellular events leading to glucose transport activation in mammalian skeletal muscle. However, the hydroxyl radical produced by hydrogen peroxide causes DNA and membrane damage, lipid peroxidation, and cell death [1]. It is widely used as bleaching and oxidizing agent in medicine and chemistry. It has been previously reported that the catalytic decomposition of hydrogen peroxide follows the first-order kinetics with respect to H2O2 [2]. In this study, the kinetics and mechanism of hydrogen peroxide decomposition on the surface of Keplerate nanoclusters containing Fe(III) and Mo(VI) is investigated. The first-order kinetics with a rate constant of 3×10-4 s-1 at T=298 K was obtained for the decomposition of H2O2. To determine the activation energy, the rate constants as a function of temperature in the temperature interval T = [298–328] K was obtained. The activation energy of the reaction was found to be 58.74 kJ mol-1. The second-order rate constant for the reaction at 298 K was 3×10-8 ms-1. The negative results of scavenging experiments using terephthalic acid and methanol as OH radical trapping agents led us to propose a non-radical mechanism for hydrogen peroxide decomposition on the surface of cluster molecules