Pillared
clay-supported NiMo catalysts were synthesized in their
reduced and sulfided forms and applied to the hydrodeoxygenation of
guaiacol (2-methoxyphenol) as a bio-oil model compound. The sulfided
catalyst displayed better activity and selectivity as compared to
the reduced catalyst, yielding phenol as the major product. Quasielastic
neutron scattering demonstrated that jump diffusion of guaiacol was
seen after adsorption on both the sulfide catalyst and pillared clay.
Inelastic neutron scattering was carried out in conjunction with an
infrared study and reveal that there were two types of interaction
of guaiacol with the catalyst. The first is guaiacol adsorbed via
various types of H-bonding interaction, as observed in the sulfided
catalyst. The second type of interaction is guaiacol adsorbed on the
surface, presumably at a Mo vacant site, by chemisorption through
formation of a methoxyphenate species as seen in the reduced catalyst.
The interactions were greater in the sulfided catalyst by which guaiacol
was selectively adsorbed in coordination with the Ni–Mo–S
site.