Ru(NO)(NO3)(3)/SiO2 catalyst precursors were characterized via XPS and
in-situ reflectance IR spectroscopy before, during and after reductio
n by hydrogen over the temperature range 300-800 K. IR results indicat
ed that the catalyst precursor lost NO3 groups first, with subsequent
loss of NO both in a reducing atmosphere and during thermal annealing.
XPS was used to derive information on the oxidation state of Ru in th
e various steps of the annealing and/or reduction processes. (C) 1997
Elsevier Science B.V.