Preparation of iridium catalyst and its catalytic activity over hydrazine hydrate decomposition for hydrogen production and storage

Two nanometer sized Ir nanoparticle supported on γ-Al2O3 both in granule and honeycomb catalyst was prepared by the repeated soak-dry processes, drying, and subsequent reduction. Highly dispersed nanoparticles spread over the catalyst surface, referred from the results of TEM, AFM, XAFS and hydrogen chemisorption. The structure of nanoparticle changed with the increase of metal content. At 5.8 wt% loading, the nanoparticle was close contact with the catalyst surface and seemed to spread like raft. Upon increasing the iridium loading to 16.4 wt%, the particle grew to spherical shape having the reduced Ir core covered with oxygen. The hydrazine hydrate decomposition proceeded readily on the honeycomb catalyst containing 2 wt% Ir when the product water in the catalyst bed was removed properly.