Morphology Effect of CeO₂ Support in the Preparation, Metal–Support Interaction, and Catalytic Performance of Pt/CeO₂ Catalysts

Abstract Pt/CeO 2 catalysts with various Pt loadings were prepared by a conventional incipient wetness impregnation method that employed CeO 2 cubes (c‐CeO 2 ), rods (r‐CeO 2 ), and octahedra (o‐CeO 2 ) as the support and Pt(NH 3 ) 4 (NO 3 ) 2 as the metal precursor. Their structures and catalytic activities in CO oxidation in excess O 2 and the preferential oxidation of CO in a H 2 ‐rich gas (CO‐PROX) were studied, and strong morphology effects were observed. The impregnated Pt precursor interacts more strongly with CeO 2 rods and cubes than with CeO 2 octahedra, and the reduction/decomposition of the Pt precursor impregnated on CeO 2 octahedra is easier than that on CeO 2 rods and cubes. With the same Pt loading, the Pt/o‐CeO 2 catalyst contains the largest fraction of metallic Pt, whereas the Pt/c‐CeO 2 catalyst contains the largest fraction of Pt 2+ species. The reducibility of pure CeO 2 and CeO 2 in the Pt/CeO 2 catalysts follows the order r‐CeO 2 >c‐CeO 2 >o‐CeO 2 , and the reducibility of CeO 2 depends on the Pt loading for the Pt/c‐CeO 2 catalysts but not much for the Pt/r‐CeO 2 and Pt/o‐CeO 2 catalysts. The catalytic performance of Pt/CeO 2 catalysts in both CO oxidation and the CO‐PROX reaction follows the order Pt/r‐CeO 2 >Pt/c‐CeO 2 > Pt/o‐CeO 2 . The Pt 0 ‐CeO 2 ensemble is more active than the Pt 2+ ‐CeO 2 ensemble in the catalysis of CO oxidation in excess O 2 . H 2 ‐assisted CO oxidation catalyzed by the Pt/CeO 2 catalysts was observed in the CO‐PROX reaction, and the Pt 2+ species and CeO 2 with a large concentration of oxygen vacancies constitute the active structure of the Pt/CeO 2 catalyst for the CO‐PROX reaction. The effect of the morphology of the CeO 2 support in the preparation, metal–support interaction, and catalytic performance of Pt/CeO 2 catalysts can be correlated the exposed crystal planes and surface composition/structure of the CeO 2 support with different morphologies. These results not only demonstrate that the structure and catalytic performance of oxide‐supported catalysts can be tuned by controlling the morphology of the oxide support but also deepens the fundamental understanding of CO oxidation reactions catalyzed by Pt/CeO 2 catalysts.