Hydrogen Production by γ-Ray Irradiation from Different Types of Zeolites in Aqueous Solution

Abstract

Dihydrogen (H2) production via irradiation of zeolite–water mixtures was studied to investigate the effect of zeolites on the reaction process for H2 production. Four types of zeolites were comparatively examined under anoxic and aerated conditions. High yields of H2 were observed for the zeolites with high aluminum contents, A-type and X-type zeolites, compared to the Y-type and mordenite-type zeolites. The difference in the H2 yields was considerable at weight fractions of water below 50 wt % under anoxic conditions. The experimental results demonstrated a reaction pathway for H2 production that has different yields between the four zeolites. The H2 yields were compared with chemical analyses of the zeolites, and the comparison suggested that the extraframework aluminum species in the zeolites are involved in the reaction pathway for H2 production. On the other hand, under aerated conditions, the H2 yields from the zeolites were lower than under anoxic conditions probably due to the H2O2 that was produc...