A Superatom Pt<sub>21</sub><sup>-</sup> Cluster with Unique Stability and Aromaticity.

Lin, Shiquan; Zhang, Zhi-Chao; Sun, Wei-Ming; Luo, Zhixun · Nano Lett · 2025

basic_science · Level V

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Abstract

Platinum (Pt) clusters are vital in catalysis due to their stability and reactivity, yet their structure-property relationships remain inadequately comprehended. This study examines the stability of Pt<i><sub>n</sub></i><sup>-</sup> (<i>n</i> = 6-35) clusters as a function of size and their reactions with varying doses of common gases. We find two predominant clusters, Pt<sub>10</sub><sup>-</sup> and Pt<sub>21</sub><sup>-</sup>, surviving sufficient N<sub>2</sub> gas reactions. The Pt<sub>10</sub><sup>-</sup> cluster derives its stability from a tetrahedral geometry, whereas Pt<sub>21</sub><sup>-</sup> adopts a spheroidal and three-layer (7+7+7) structure with <i>D</i><sub>6</sub><i><sub>h</sub></i> symmetry, exhibiting superatomic orbital features and inorganic aromaticity. Adjacent clusters such as the cage-structured Pt<sub>22</sub><sup>-</sup> and Pt<sub>23</sub><sup>-</sup>, along with low-symmetry or distorted smaller Pt<i><sub>n</sub></i><sup>-</sup> clusters (<i>n</i> = 11-20), further contrast the unique stability of the trilaminar superatom Pt<sub>21</sub><sup>-</sup>. These findings elucidate critical structural and electronic factors that govern Pt cluster stability, enlightening atomic-level design of Pt catalysts with modest stability, devoid of N<sub>2</sub> contamination and poisoning effects.