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 pl atinum particles on hydrogen-containing, high-surface-area carbonaceous sup port materials. Molecular and atomic hydrogen species can be discriminated under 800-1200 mbar of hydrogen pressure relevant for the operation conditi ons of fuel cells and other platinum-based catalysts. The distribution of s ites suggests that the shape of the particles is intermediate between cubic and cuboctahedral. (C) 2000 Academic Press.