HYDROGEN IN MOLYBDENUM AND COBALT SULFIDE CATALYSTS - A NEUTRON COMPTON-SCATTERING STUDY ON THE ISIS ELECTRONVOLT SPECTROMETER

The mean kinetic energy of chemisorbed hydrogen in molybdenum and coba lt sulfide catalysts has been measured by Compton neutron scattering o n the electronvolt spectrometer (eVS) at the Rutherford Appleton Labor atory ISIS facility. Assuming an isotropic harmonic oscillator, the fu ndamental wavenumbers of vibrations associated with chemisorbed hydrog en are 1430 +/- 34 cm(-1) for MoS2 and 1392 +/- 26 cm(-1) for CoMoS2; there was no hydrogen peak in the eVS spectrum of Co9S8. The frequenci es are closer to the mean values expected for H-S stretching and bendi ng vibrations (ca. 1300 cm(-1)) than for H-Mo (ca. 1100 cm(-1)); the c hemisorbed hydrogen observed by eVS is evidently bound to sulfur.