Synergetic effect of iridium cluster complex and palladium metal particle on dehydrogenation of 2-propanol

摘要

A diphosphine-chelated iridium tetranuclear cluster complex Ir_4 (CO)_8 (dppp)_2, prepared from Ir_4 (CO)_(12), was coordinated with SnCl_3~- additionally in a 1-butanol solution of NEt_4SnCl_3 at 120 deg C for 12 h, which was identified and characterized with IR and ~(31)P-NMR spectroscopies. The iridium tetranuclear cluster complex thus synthesized was mixed under N_2 atmosphere at 200 deg C with carbon-supported platinum or palladium catalysts. Synergetic effects on catalytic dehydrogenation of 2-propanol with these composite catalysts were well demonstrated under boiling and refluxing conditions. The composite catalyst between carbon-supported nano-size palladium particles and newly synthesized Ir_4(CO)_4 (dppp)_2 (SnCl_3)_4 complex exhibited an especially high ability of hydrogen spillover toward the carbon support, which would be useful for taking the role as the negative electrode catalyst of a newly proposed fuel cell, because spillovered hydrogen can be transferred to the positive electrode as proton through an electrolyte membrane and as electron via the outer circuit, constituting a fuel cell of hydrogen-concentration type as the consequence of acetone conversion into 2-propanol at the other side.