Probe of the surface of a heterogeneous catalyst: Double NMR of carbon monoxide chemisorbed on highly dispersed platinum

Abstract

The detailed NMR line of Pt195 atoms in the surface layer of small particles of Pt metal on which CO has been chemisorbed has been observed. The surface Pt195 are resolved from the Pt195 resonances of atoms deeper in the particle by spin-echo double resonance between Pt195 and C13. The Pt195 resonance position and C13-Pt195 indirect spin coupling are found to be very similar to those in diamagnetic Pt-carbonyl molecules. The results show that CO bonds via the C atom and verify that concepts deduced from studies of large single crystals are valid for the small particles. © 1982 The American Physical Society.