Intermediate temperature exposure regenerates performance and active site dispersion in sintered Pd–CeO2 catalysts

Abstract

Methods that can impede or reverse the effects of high-temperature sintering and deactivation are necessary to improve the utilization of catalytic materials. This work demonstrates that exposure to intermediate temperatures (800 °C) can effectively regenerate catalytic performance in sintered Pd-CeO2 catalysts, through the disintegration and partial redispersion of agglomerated Pd, which increases the abundance of sites that interface strongly with the CeO2 support. Pretreating the catalyst at 800 °C before sintering forms highly dispersed Pd species that slow the sintering of small, polycrystalline CeO2 domains. This preserves the density of Ce3+ sites that trap mobile Pd, which improves the efficacy of regeneration. The regenerated catalyst is effective in the co-oxidation of CO and C3H8, two species which are known to competitively adsorb. The simplicity of this treatment makes it attractive for on-stream regeneration of catalyst performance.