This work firstly reported catalytic activity of copper species supported on Shirasu-based materials for decomposition of nitrous oxide. From the results of EDS and XPS analyses, the bulk and surface compositions of the supported copper species depends on its impregnation conditions. The copper species were preferably supported on the surface silica sites of the Shirasu-based materials with addition of ammonia during the impregnation process, and the amount of the copper species increased with increasing the amount of ammonia. The catalysts with the active copper species preferably supported on the silica sites exhibited high activity for decomposition of nitrous oxide. The catalytic activity also depended on the kinds of Shirasu-based materials, and the copper-supported catalyst on a Shirasu balloon, A3NN, showed the highest activity. The catalytic activity improved with addition of ammonia into the feed reactant gas, and nitrous oxide in the mixed gas was completely decomposed above 673 K.

This work investigated influence of various treatments on activity of Shirasu-based materials for hydrogen evolution from aqueous ammonia borane solution. The compositions and activity of the Shirasu-based materials were significantly influenced on various solution and calcination treatments. The activity of Shirasu-based materials increased with increasing surface aluminum ratio and decreasing silicon oxide crystalline impurity. The sample treated with treated with ammonia following calcination at 723 K included the highest surface aluminum ratio and the lowest silicon oxide crystals impurity and exhibited the highest activity for the hydrogen evolution.

The present study investigated influence of various treatment on activity of Shirasu-based materials for hydrogen evolution from aqueous ammonia borane solution. Various solution treatments and calcination treatment significantly affected on the morphology, compositions, and activity. The sample with high surface aluminum ratio and low silicon oxide crystalline impurity showed high activity for the hydrogen evolution. The sample treated with treated with ammonia following calcination at 723 K included the highest surface aluminum ratio and the lowest silicon oxide crystals impurity and exhibited the highest activity for the hydrogen evolution.

This work investigated ability of Shirasu‐based material for adsorption of metal ions and their promotion effect for catalytic decomposition of nitrous oxide. Catalytically active cobalt and copper species were adsorbed on the Shirasu‐based material by immerse process of aqueous matal solutions. In all the Co/Cu ratios (Co/(Co+Cu)=1, 0.75, and 0.5), cobalt species were preferentially adsorbed on the Shirasu‐based material. The cobalt species tended to be adsorbed on the silica sites of the sample with Co/(Co+Cu)=0.75. and the catalyst exhibited the highest activity for decomposition of nitrous oxide. Introduced nitrous oxide was completely decomposed at the reaction temperatures above 673 K.