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 degrees 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. (c) 2007 Elsevier B.V. All rights reserved.