Radiolytic Events in Nanostructured Aluminum Hydroxides

The radiolysis of nanosized Al(OH)3 and AlOOH has been examined. Irradiations were performed using electron beams. H2 radiolytic yields were determined with respect to structure and particle size. The measured yields have an order of magnitude of 10–9 mol J–1, which decreases when particle size is lowered. Surface and structure analysis techniques were used to detect any change before and after irradiation, and no differences were seen. Annealing experiments showed that a significant amount of molecular hydrogen was trapped inside AlOOH and Al(OH)3. H radicals, F centers, O– and O3– centers were identified by electron paramagnetic resonance (EPR) spectroscopy. A significant part of the absorbed energy remains stored into the nanomaterials and induces a secondary H2 production upon heating.