Yangfei Fang, Xiaohui Chen, Kaijie Liu, Yaqun He, Xiachuan Li, Yannan Li, Zhaoxu Yuan, Jun Ye, Hai Liu, Yibo Zhang, Xiangguang Yang
The thermal stability of Pt-based catalysts, which is pivotal for air pollutant abatement, is dictated by a delicate balance between nanoparticle sintering and redispersion into single atoms. Probing the intrinsic interaction between Pt and CeO 2 crystal facets at comparable Pt surface densities to precisely control these dynamic structural transformations remains a grand challenge. Herein, we synthesized uniform Pt nanoparticles and supported them on CeO 2 with different morphologies exposing distinct crystal facets, aiming to investigate the influencing factors and critical conditions for the redispersion behavior of Pt nanoparticles induced by CeO 2 morphology. Catalytic performance for CO and C 3 H 8 oxidation was used for evaluation. The results revealed a pronounced facet-dependent SMSI effect. The rCeO 2 (110) facet exhibited the strongest interaction, inducing Pt cluster redispersion to single atoms efficiently at a notably low 400 °C. In contrast, the oCeO 2 (111) facet showed the weakest interaction, failing to promote effective Pt redispersion into single atoms even at 600 °C, while cCeO 2 displayed intermediate behavior with redispersion at 500 °C. Crucially, we demonstrate that the initial theoretical Pt atomic density, influenced by the support’s specific surface area, acts as a critical threshold (1 atom nm –2 ), significantly affecting apparent redispersion. By carefully adjusting Pt loading to control this density, we confirmed that redispersion trends are intrinsic to the facet-metal interface. The Pt state profoundly influenced the activity in a reaction-dependent manner. For CO oxidation, over-redispersion on rCeO 2 could diminish low-temperature activity. Remarkably, for propane oxidation, the 0.275Pt/oCeO 2 catalyst, which resisted redispersion and maintained stable particulate Pt, exhibited superior thermal stability. After calcination at 400 and 600 °C, its T 50 for CO and C 3 H 8 decreased minimally by only 20 and 3 °C, respectively. These findings challenge the notion that maximal single-atom dispersion universally optimizes the performance, offering a rational framework for designing highly stable and active Pt/CeO 2 catalysts via precise facet engineering and Pt loading optimization.