The structure of platinum species in a model set of monodisperse Pt/?-Al 2 O 3 catalysts was studied using
radial
distribution function (RDF) of electron density. Catalyst preparation conditions were revealed to
considerably
affect the dispersion and structure of supported platinum. Cation vacancies on the ?-Al 2 O 3
surface were essential to anchor electron deficient platinum atoms and clusters. Platinum segregation
with
forming finely dispersed metal particles was evident in some catalysts. The methane total oxidation
over
the Pt/?-Al 2 O 3 catalysts was established to depend strongly on the platinum oxidation state. The
catalysts
containing oxidized platinum species and highly dispersed oxidizable Pt 0 particles were more
active.
The metal–support interaction improved the performance of the catalysts indirectly, by stabilizing
the
platinum dispersion.