Reversible Transformation and Distribution Determination of Diverse Pt Single-Atom Species

Chuanmin Ding; Qingqing Gu; Li-Juan Yu; Shaocheng Zhang; Yafeng Zhang; Zili Ma; Yuanyuan Meng; Hengxuan Zhang; Tao Wang; Junwen Wang; Lichao Ma; Gangsen Li; Bing Yang; Tao Zhang

doi:10.1021/jacs.2c12106

Reversible Transformation and Distribution Determination of Diverse Pt Single-Atom Species

J Am Chem Soc. 2023 Feb 1;145(4):2523-2531. doi: 10.1021/jacs.2c12106. Epub 2023 Jan 19.

Authors

Affiliations

¹ College of Chemical Engineering and Technology, Taiyuan University of Technology, 030024 Taiyuan, China.
² CAS Key Laboratory of Science and Technology on Applied Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 116023 Dalian, China.
³ Research School of Chemistry, The Australian National University, Canberra, 2601 ACT, Australia.
⁴ Shanxi Supercomputing Center, 033000 Lvliang, China.

PMID: 36657107
DOI: 10.1021/jacs.2c12106

Abstract

In single-atom catalysts (SACs), the complexity of the support anchoring sites creates a vast diversity of single-atom species with varied coordination environments. To date, the quantitative distribution of these diverse single-atom species in a given SAC has remained elusive. Recently, CeO₂-supported metal SACs have been extensively studied by modulating their local environments via numerous synthetic strategies. However, owing to the absence of a quantitative description, unraveling the site-specific reactivity and regulating their transformation remain challenging. Here, we show that two distinct Pt/CeO₂ SACs can be reversibly generated by oxidative and nonoxidative dispersions, which contain varied Pt₁O_n-Ce^δ+ single-atom species despite similar Pt charge states and coordination numbers. By means of Raman spectroscopy and computational studies, we semiquantitatively reveal the distribution of diverse Pt₁O_n-Ce^δ+ species in each specific SACs. Remarkably, the minority species of Pt₁O₄-Ce³⁺-O_v accounting for only 14.2% affords the highest site-specific reactivity for low-temperature CO oxidation among the other abundant counterparts, i.e., Pt₁O₄-Ce⁴⁺ and Pt₁O₆-Ce⁴⁺. The second nearest oxygen vacancy (O_v) not only acts synergistically with the nearby active metal sites to lower the reaction barrier but also facilitates the dynamic transformation from six-coordinated to four-coordinated sites during cyclic nonoxidative and oxidative dispersions. This work elucidates the quantitative distribution and dynamic transformation of varied single-atom species in a given SAC, offering a more intrinsic descriptor and quantitative measure to depict the inhomogeneity of SACs.