Structural requirements and reaction pathways of hydrogenolytic C−C bond cleavage in naphthenes over supported platinum and iridium domains

The structural requirements and reaction pathways of C-C bond cleavage in cyclic hydrocarbons have been explored over Pt and Ir catalysts devoid of Brnsted acidity.The C-C bond cleavage rates monotonically increase with increasing Pt particle size, while the hydrogenolysis rates first decrease and then increase with Ir particle size.For Ircatalyzed hydrogenolysis of six-membered naphthenes, low-coordination atoms and high H*-coverage favor single endocyclic C-C bond cleavage over multiple and exocyclic C-C bond cleavage, whereas the low-index planes and high temperature do the opposite.The endocyclic C-C bond hydrogenolysis proceeds via a rate-limiting C-C bond rupture of partly dehydrogenated intermediates.H-deficiencies of the catalytic intermediates determine the product selectivities along different reaction pathways.The presented indepth analysis of hydrogenolysis on metal surfaces allows identifying parameters as guidelines for designing active and selective catalysts for fuel upgrading.Die strukturellen Anforderungen und Reaktionswege der C-C-Bindungsspaltung in zyklischen Kohlenwasserstoffen wurden ber Pt und Ir-Katalysatoren frei von Brnsted-Aciditt untersucht.Die Raten der C-C-Bindungsspaltung steigen mit zunehmender Pt-Partikelgre monoton an, whrend die Raten der Hydrogenolyse zuerst abnahmen und dann mit der Ir Partikelgre zunahmen.Fr die