The thermodynamics and kinetics of oxygen radical formation process in a nanoporous crystal, 12CaO-7Al2O3, were examined by isothermal annealing experiments in dry atmospheres. It is clarified that the formation of oxygen radicals, O-2 and O-, in the crystal occurs in the following three steps; outward diffusion of extra-framework oxide ions, its oxidation by absorbed oxygen molecules to form O- and O-2 at the surface, and subsequent inward diffusion of the oxygen radicals. The instability of the extra-framework oxide ions is essentially the driving force for the process. Further, the analyses allow to predict the total oxygen radical content for a given annealing condition.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics