Mw. Kumthekar et Us. Ozkan, NITRIC-OXIDE REDUCTION WITH METHANE OVER PD TIO2 CATALYSTS .1. EFFECTOF OXYGEN CONCENTRATION/, Journal of catalysis, 171(1), 1997, pp. 45-53
Steady-state reaction studies were performed over a Pd/titania catalys
t for NO reduction using CH4 as a reducing agent. The catalyst was pre
pared using a wet impregnation technique and Pd-acetate as a precursor
for palladium. Characterization of the catalyst samples was performed
using the BET surface area technique, X-ray diffraction (XRD), laser
Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning e
lectron microscopy (SEM), and thermal analysis techniques. A fixed-bed
, flow reactor system was used for activity and selectivity measuremen
ts. Identification and quantification of reaction effluents were done
on-line using gas chromatography-mass spectrometry, chemiluminescence,
and wet chemistry techniques. Temperature-programmed reduction studie
s indicated that the catalyst was reducible by H-2 even at sub-ambient
temperatures. The catalyst was seen to reduce NO with conversions abo
ve 95% in the oxygen concentration range from 0 to 1.3%. Oscillatory b
ehavior was exhibited by the catalyst under certain reaction condition
s. The results obtained from the reaction experiments, together with t
he findings from the characterization studies, are used to explain the
mechanistic aspects of this reaction. (C) 1997 Academic Press.