feature associated with oxygen bonded to partially
reduced Ni. The O 1s region of NiO milled with
Vertrel displays the same three states as NiO milled
with carbon. However, the ratios of the integrated areas
of these peaks differ. For NiO milled in carbon, the
ratio of the integrated areas of the 528.5 eV peak to
that of the 529.5 eV peak and 531 eV peak is 1:1.4:4.6.
For NiO milled in Vertrel, the corresponding ratio is
1:1.8:3.4. This difference is consistent with the BET
data that indicates that carbon acts as a milling aid,
cleaving NiO at a more rapid rate and creating a larger
number of surface defects. Finally, the O 1s region of
NiO milled in methanol shows three peaks centered at
529.5, 531.2, and 533.7 eV. The peak at 529.5 eV is
ascribed to the lattice oxygen of NiO, and the peak at
533.7 eV is ascribed to the intact alcohol [43,44].
While the peak at 531.2 eV is primarily associated with
surface defects as described above, it may also contain
contributions from the dissociation of methanol to
alkoxide and OH. Support for the presence of alkoxide
and OH is provided by the increased FWHM (3.1 eV)
and high integrated area of the 531.2 eV peak, almost