The effect of bimetallic catalyst preparation and treatment on behavior for propane hydrogenolysis

摘要

This study examined the effect of bimetallic catalyst preparation techniques and subsequent pre-treatments on alumina-supported Pt/Sn,Ir/Sn and Pt/Ir catalyst behavior for propane hydrogenolysis.Comparisons were made of conventional co-impregnated catalysts and "composite" catalysts,i.e.pellets in which a porous binder connected separately impregnated/calcined powders.The pre-treatments studied included sintering,Cl_2-induced redispersion,and pre-sulfiding with H_2S.Relative to platinum,iridium was confirmed to be much more active for hydrogenolysis and more sensitive to pre-sulfiding.Propane hydrogenolysis over Ir/Al_2O_3 appeared to be structure-sensitive,probably due to an ensemble effect.Results indicated alloy cluster formation for co-impregnated Pt/Ir,but the effect of tin in Pt/Sn and Ir/Sn was too weak to allow a firm conclusion regarding alloy cluster formation.