Selective hydrogenolysis of methylcyclopentane in the presence of excess methylcyclohexane by Ir cluster catalyst inside the micropores of MWW-type zeolite

During the methylcyclohexane (MCH)-toluene interconversion over a Pt/Al2O3 catalyst, a part of MCH is isomerized to undesirable five-membered ring compounds, which accumulate as impurities and lower the energy efficiency of the liquid organic hydrogen carrier system. In this study, we focused on the shape selectivity of zeolite materials to improve the selectivity for the hydrogenolysis of methylcyclopentane (MCP) and chose Si-ITQ-1 zeolite (MWW topology) with 10-ring micropores. The hydrothermal synthesis of an ITQ-1 zeolitic precursor (ITQ-1P) with a relatively high Ir content inside the micropores was possible when using N,N,N-trimethyl-1-adamantammonium and hexamethyleneimine as organic structure-directing agents (OSDAs). A direct H2 treatment at 400 °C promoted the reduction of cationic Ir to highly dispersed Ir0 clusters (ca. 0.9 nm), followed by the removal of OSDAs inside the micropores via catalytic hydrogenolysis by Ir0 species. The Ir/ITQ-1 catalyst showed high activity and selectivity for the hydrogenolysis of MCP in the presence of excess MCH at 200 °C.