In-situ formed stable Pt nanoclusters on ceria-zirconia solid solutions induced by hydrothermal aging for efficient low-temperature CO oxidation

Pt nanoclusters (Pt-C) on the surface of ceria-zirconia solid solutions exhibit superior low-temperature CO oxidation activity compared to Pt single atoms (Pt-1). However, the redispersion behavior of the Pt-C to Pt-1 lowers the efficiency of CO Oxidation. In this work, the stable surface hydroxyl groups were constructed by high-temperature hydrothermal aging treatment. Specifically, the Pt-1 catalyst (Pt/CZOe-SA) prepared by atom trapping was subjected to high-temperature hydrothermal treatment to obtain the stable Pt-C catalyst (Pt/CZOe-HT) with in-situ formed Pt-C. The experimental results showed that Pt-C with 2-3 nm size could achieve excellent low-temperature activity and thermal stability. In addition, the ab initio molecular dynamics and density functional theory calculations revealed the specific evolution process of dynamic dispersion for Pt-C with or without hydroxyl groups from the femtosecond scale, suggesting that the hydroxyl groups limited the dispersion of Pt-C in the form of "energy fence". The hydrothermal treatment not only introduced high-temperature stable hydroxyl groups to improve the stability of the in-situ formed Pt-C, but also optimized the ratio of Pt-1 and Pt-C, and then enhanced the low-temperature activity by the synergistic effect between Pt-1 and Pt-C. The present work can provide theoretical guidance for developing high-performance and high-stability Pt-based catalysts.