Investigation of the structure and the redox behavior of gadolinium doped ceria to select a suitable composition for use as catalyst support in the steam reforming of natural gas

Gadolinium doped cerias with a gadolinium content in the range 0 <= x(Gd) <= 0.5 were synthesized using a glycine-nitrate combustion process. The resulting materials are weak agglomerates showing low specific surface area, no microporosity and are stable against sintering. While the addition of gadolinium enhances the surface reactivity and thus the dynamic oxygen exchange capacity (OEC), it depresses bulk reduction. As a result, the total oxygen storage capacity (OSC) is much lower compared to pure ceria. For small-scale hydrogen production using the steam-reforming process, these support properties are expected to be beneficial. The materials with an intermediate gadolinium content of x(Gd) approximate to 0.2-0.25 are determined to be especially suitable for use as catalytic support material in this application. (C) 2007 Elsevier B.V. All rights reserved.