Nm. Popova et al., RUTHENIUM-CONTAINING CATALYSTS FOR GAS PURIFICATION FROM CO, NO, AND C3H6 .1. SYNTHESIS AND CHARACTERIZATION OF PLATINUM-RUTHENIUM CATALYSTS, Kinetics and catalysis, 38(5), 1997, pp. 685-691
The results of physical and chemical studies of alumina-supported plat
inum-ruthenium-cerium catalysts are reported. The effect of support, b
inder, cerium additive, and preparative procedure on the formation of
ruthenium-containing catalysts was analyzed by RAD, XRD, EXAFS, XPS, T
PR, and X-ray fluorescence. The reasons for the catalyst stabilization
upon its exposure to oxygen and high temperatures were conjectured. T
he reduced platinum-ruthenium-cerium catalyst is the mixture of CeO2,
CeAlO3, and unconnected clusters of platinum and ruthenium, rather tha
n an alloy. Ruthenium readily transforms to RuO2 and reduces to RuO ev
en at 433-443 K. This property stipulates its role in the activation a
nd reduction of NO to Nz. Platinum and ruthenium are stabilized in the
oxidizing medium by the formation of connected PtOx and RuO2 clusters
and a perovskite-like surface moiety involving cerium and, probably,
ruthenium.