Water–gas shift activity of doped Pt/CeO2 catalysts

A series of platinum catalysts supported on cation (Me)-doped cerium oxide (Me = Ca, La, Mg, Zn, Zr, Yb, Y, Gd) have been prepared employing the urea-nitrate combustion method. The effects of Me-promotion on the physicochemical and chemisorptive properties of Pt/CeO2 catalysts and on their catalytic performance for the water–gas shift (WGS) reaction have been investigated. It has been found that the WGS activity of Pt/Ce-Me-O catalysts depends on the nature of the dopant employed, varying in the order of Yb > Gd > Zr > Mg > La > CeO2(undoped) > Ca > Y > Zn, with the Yb-promoted catalyst being about one order of magnitude more active than the Zn-promoted one, at 250 °C. Evidence is provided that promotion affects the reducibility and oxygen ion mobility of the CeO2 support, which in turn affects the WGS activity of dispersed platinum crystallites.