THE INTERACTION BETWEEN HYDROGEN-PEROXIDE AND METAL-OXIDES - EPR INVESTIGATIONS

The interaction of hydrogen peroxide with various metal oxides has bee n followed by EPR in the aim of investigating the paramagnetic species formed along the complex processes of H2O2 decomposition and interact ion with the oxide. Data are reported about three systems (MgO, ZrO2 a nd Me(2+)/Y zeolite) which are representative of three classes of oxid es (insulators, semiconductors and aluminosilicate molecular sieves). Several radical species have been put into evidence in the various cas es. The superoxide O-2(-) ion has been observed in all cases while in the case of MgO also the OH radical and the O- radical ion have been i dentified. In the case of Zn2+/Y zeolite, beside the superoxide radica l anion, a new signal is observed which shows up upon treating the sam ple at 640 K and which is preliminarily assigned to a species in the t riplet state in the zeolitic cavity.