Effects of strong metal–support interactions on hydrocarbon reactions over titania-supported platinum. Mode of action of a near-selective hydrogenolysis catalyst

A highly dispersed 2% Pt/TiO2 catalyst (average d= 8 A) displayed a strong metal–support interaction (SMSl) after reduction at temperatures in the range 473–573 K as shown by substantially reduced hydrogen chemisorption. Reactions of saturated hydrocarbons in a flow of hydrogen (Phydrocarbon= 8–53 Torr, balance to 760 Torr hydrogen) showed an extremely high selectivity for hydrogenolysis and catalysts were essentially inactive for bond-shift isomerisation. In addition, the contribution of the NSCM route in the ring opening of methyl-cyclopentane at a hydrogen pressure of 1 atm was very small considering the high dispersion of the platinum. The reduction in hydrogen chemisorption and the absence of bond-shift isomerisation are explained in terms of a combination of a particle-size effect per se and the electronic effect of the support on the metal.