Inelastic Neutron Scattering Investigation of the Nature of Surface Sites Occupied by Hydrogen on Highly Dispersed Platinum on Commercial Carbon Black Supports

It is shown that inelastic neutron scattering is uniquely suitable to study the surface sites occupied by atomic hydrogen at the surfaces of 2–4-nm platinum particles on hydrogen-containing, high-surface-area carbonaceous support materials. Molecular and atomic hydrogen species can be discriminated under 800–1200 mbar of hydrogen pressure relevant for the operation conditions of fuel cells and other platinum-based catalysts. The distribution of sites suggests that the shape of the particles is intermediate between cubic and cuboctahedral.