Structure-activity relationship of Pt catalyst on engineered ceria-alumina support for CO oxidation

In heterogeneous catalysis, the promotion of low temperature activity and enhancement of thermal stability simultaneously especially for precious metal catalysts is always highly demanded but very challenging. Herein we report a novel Pt catalyst on ceria-alumina (CeO2/Al2O3) support (Pt/CA-T) engineered by a two-step ceria deposition strategy, exhibiting superior thermal stability and lowtemperature carbon monoxide (CO) oxidation activity after activation. Pt single sites anchored to engineered CeO2 edge sites are much more stable than that to CeO2 (111) surface, and such stable single sites can be transformed into highly active Pt clusters for efficient low-temperature CO oxidation. Active site identification indicates that the CO oxidation activity of different Pt sites follows such sequence: Pt cluster step sites = Pt cluster terrace sites > Pt cluster corner sites >> Pt single sites on CeO2. The excellent low temperature activity of activated Pt/CA-T catalyst for CO oxidation is associated with its abundant Pt cluster step and terrace sites as well as rich Pt-CeO2 interfaces, which facilitate the adsorption of active CO species and superior oxygen activation/transfer ability. The present study provides new insights into the structure-activity relationship of Pt-CeO2-Al2O3 catalyst, which can also guide the preparation of other highly robust supported catalysts for important industrial applications. (c) 2021 Elsevier Inc. All rights reserved.

Automated summary

In this study, a novel Pt catalyst was prepared on a CeO2/Al2O3 support through a unique deposition strategy, demonstrating excellent thermal stability and low-temperature CO oxidation activity. The stable Pt single sites were transformed into highly active Pt clusters, resulting in efficient CO oxidation at low temperatures. The identification of active sites revealed that Pt cluster step and terrace sites, as well as Pt-CeO2 interfaces, played crucial roles in the catalyst's activity.