Pt nanoparticles supported on multiwalled carbon nanotubes (MWNT) were synthesized and applied in the catalytic hydrogenation of furfural, the model reaction of mild stabilization of reactive bio-oil. The catalytic properties of the catalysts were modified by changing the surface concentration of oxygen-containing groups (OCGs) of MWNT. Various characterization techniques, including fluorescent labeling, nitrogen physisorption, powder X-ray diffraction, transmission electron microscopy, and in situ DRIFTS analysis, were employed to study both the supports and catalysts. Pt nanoparticles supported on MWNT with high OCGs show high activity and selectivity, attributed to the formation of small Pt particles as a result of the high concentration of OCGs.