Abstract: Catalyst compositions are provided that are useful in selectively removing carbon monoxide from a hydrogen-containing gas. These catalyst compositions preferably have the formula: nN/Ce1−(x+y+z)AxA′yA″zO2−&dgr;, where A, A′, A″ are independently selected from the group consisting of: Zr, Gd, La, Sc, Sr, Co, Cr, Fe, Mn, V, Ti, Cu and Ni; N is one or more members of the group consisting of: Pt, Pd, and Au; n is a weight percent between 0 and 25; x, y and z are independently 0 to 0.9; x+y+z is 0.1 to 0.9; and &dgr; is a number which renders the composition charge neutral; or nN/(MOx)y(CeO2−&dgr;)1−y, where M is one or more members of the group selected from: Zr, Co, Cr, Fe, Mn, V, Ti, Ni and Cu; N is one or more members of the group selected from: Pt, Pd, and Au; n is a weight percent between 0 and 25; y is 0.1 to 0.9; and x and &dgr; make the compositions charge neutral.