Study of surface atom behaviour on Pt/SiO2 and Pt/Al2O3 catalysts by isotopic exchange of oxygen from CO2

Abstract

Isotopic exchange of oxygen from CO₂ was used to study and characterize the lability of oxygen species at the surface of a catalyst. The catalysts were Pt supported on silica or alumina with several Pt loadings. Pt dispersion could be determined and was found to be in excellent agreement with oxygen–hydrogen titration and electron microscopy. Some surface oxygen species from the support and neighbouring Pt particles were made more labile. This indicates that interaction has occurred between Pt particles and the support, leading to more mobile surface oxygen which may be related to the spill-over effect.