Effect of Silica Content on Support-Iridium Active Phase Interactions on the Nanocatalyst Activity

Abstract

To discuss the potential role of the support for iridium catalyst, we have proceeded to prepare a series of supported catalysts with the same active phase content, but different silica content, to elucidate the changes in surface structure and the reaction process of hydrous hydrazine decomposition on catalyst. The obtained iridium catalysts contained 20 wt% of nanoparticles dispersed on spherical mesoporous alumina and aluminosilicate supports for hydrogen generation from hydrous hydrazine. Iridium nanoparticles with different morphologies and diameters could be produced over the catalyst supports depending on its nature. The iridium catalysts were characterized by some techniques such as XRD, FESEM, BET, TGA, H2-TPR, and mechanical properties. The type of catalyst support played an important role in the effectiveness of the catalyst particles, leading to different activities for hydrazine monohydrate decomposition. Under the given test conditions, the performance of the catalyst was better when using alumina granular as the catalyst support than when using aluminosilicate granular. Since the aluminosilicate support was less reactive than the alumina, hydrogen selectivity was relatively small; consequently, the reaction rate was lower when using the aluminosilicate support than when using the alumina support.