INELASTIC NEUTRON-SCATTERING AS A TOOL FOR INSITU STUDIES OF CATALYSTS SURFACE HO-GROUPS OF ALUMINUM AND IRON-OXIDE HYDROXIDES

Inelastic neutron scattering (INS) is a spectroscopic technique which enables one to observe vibrational and rotational spectra of catalysts and sorbed species in situ. The spectrum is due to energy transfer from the incident neutrons to the scatterer. Since hydrogen is the strongest scatterer the INS technique is especially useful for investigating motions involving hydrogen atoms. Here we review applications of neutron scattering for situ catalytic studies and describe our INS study of hydroxylated molybdate on goethite and hydrated molybdate on alumina catalysts. Neutron scattering intensities were proportional to the surface concentrations of hydrogenic species. INS therefore provides a means of direct spectroscopic estimation of surface concentrations. Because of the penetrating power of neutrons INS has important potential as an in situ spectroscopic technique.