Effect of Pt addition on the isomerization properties of MoO2 − x(OH)y deposited on TiO2

Isomerization of n-hexane and n-pentane were studied using equivalent 5 monolayers of MoO₃ deposited on TiO₂. Addition of 2.5% Pt by weight of MoO₃ on the Mo catalyst resulted in an increase in the catalytic activity of the system in favor of hydrocracking products. Surface characterization by XPS-UPS and ISS reveal that the sample surface contains Oxygen, Molybdenum, Platinum and Titanium. Apparently, the metallic properties of the deposited Pt favors the hydrocracking reactions and becomes dominant at reaction temperatures higher than 623 K. Balanced metal-acid functions in MoO_2 − x(OH)_y phase seems to be in optimized condition toward the hydroisomerization process. The contribution of Platinum addition to this catalytic reaction is not obvious. Combination of surface XPS-UPS, ISS and catalytic reactions carried out at similar experimental conditions enabled us to have better insight concerning the catalytic activities of the different chemical species present on the sample surface.