The effect of ceria addition on the sulfation and desulfation characteristics of a model Ba-based lean NO (x) trap (LNT) catalyst was studied. According to DRIFTS and NO (x) storage capacity measurements, ceria is able to store sulfur during catalyst exposure to SO2, thereby helping to limit sulfation of the main (Ba) NO (x) storage phase and maintain NO (x) storage capacity. Temperature programmed desulfation experiments revealed that desulfation of a model ceria-containing catalyst occurred in two stages, corresponding to sulfur elimination from the ceria phase at 450 A degrees C, followed by sulfur loss from the Ba phase at 650 A degrees C. Significantly, the ceria-containing catalyst displayed relatively lower sulfur evolution from the Ba phase than its non-ceria analog, confirming that the presence of ceria lessened the degree of sulfur accumulation on the Ba phase.