Catalytic properties of one-dimensional electrides: A first-principles study

Electrides are ionic compounds in which “free” electrons (anionic electrons) are confined in a low-dimensional cavity space. The characteristic features of electrides—the existence of large void spaces and non–nucleus-bound anionic electrons—make them attractive for various applications, such as gas storage, electron/ion transport, and electrocatalytic processes. Recently, we identified Cs₃O as a new type of one-dimensional (1D) electride with nontrivial band topology. The compound Y₅Si₃ also was recently discovered, another 1D electride that exhibits excellent durability and catalytic efficiency. We demonstrate that hexagonal Y₅X₃ (X = Ge, Sn, and Pb) also can be classified as a 1D electride with different lattice parameters. A global structure search confirms that these compounds are thermodynamically stable. To understand the catalytic properties of Y₅X₃ as a reducing agent, the interaction between a Y₃X₃(001) surface and a Cu adsorbate is investigated, and the ability of the Y₅X₃ to donate electrons to Cu is quantitatively analyzed in terms of charge transfer. We further shed light on the role of anionic electrons in the electrochemical corrosion of Cu atoms. Our results are expected to provide a better understanding of catalytic properties of 1D electrides.