Defect engineering in the inherently inert basal planes of transition metal dichalcogenides (TMDs), involving the introduction of chalcogen vacancies, represents a pivotal approach to enhance catalytic activity by exposing high-density catalytic metal single-atom sites. However, achieving a single-atom limit spacing between chalcogen vacancies to form ordered superstructures remains challenging for creating uniformly distributed high-density metal single-atom sites on TMDs comparable to carbon-supported single-atom catalysts (SACs). Here we unveil an efficient TMD-based topological catalyst for hydrogen evolution reaction (HER), featuring high-density single-atom reactive centers on a few-layer (7 × 7)-PtTe_2–x superstructure. Compared with pristine Pt(111), PtTe₂, and (2 × 2)-PtTe_2–x, (7 × 7)-PtTe_2–x exhibits superior HER performance owing to its substantially increased density of undercoordinated Pt sites, alongside exceptional catalytic stability when operating at high current densities. First-principles calculations confirm that multiple types of undercoordinated Pt sites on (7 × 7)-PtTe_2–x exhibit favorable hydrogen adsorption Gibbs free energies, and remain active upon increasing hydrogen coverage. Furthermore, (7 × 7)-PtTe_2–x possesses nontrivial band topologies with robust edge states, suggesting potential enhancements for HER. Our findings are expected to advance TMD-based catalysts and exploration of topological materials in catalysis.

中文翻译：

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具有周期性碲空位的二维拓扑碲化物超结构，可实现高效和稳健的催化


过渡金属硫化物 （TMD） 固有惰性基平面中的缺陷工程，涉及硫属空位的引入，代表了通过暴露高密度催化金属单原子位点来增强催化活性的关键方法。然而，在硫族元素空位之间实现单原子极限间距以形成有序的超结构对于在 TMD 上创建均匀分布的高密度金属单原子位点仍然具有挑战性，可与碳负载单原子催化剂 （SAC） 相媲美。在这里，我们推出了一种用于析氢反应 （HER） 的基于 TMD 的高效拓扑催化剂，它在几层 （7 × 7）-PtTe _2-x 超结构上具有高密度单原子反应中心。与原始 Pt（111）、PtTe₂ 和 （2 × 2）-PtTe _2-x 相比，（7 × 7）-PtTe _2-x 表现出卓越的 HER 性能，因为它的配位不足的 Pt 位点的密度大大增加，并且在高电流密度下运行时具有出色的催化稳定性。第一性原理计算证实，（7 × 7）-PtTe _2-x 上的多种类型的配位不足的 Pt 位点表现出良好的氢吸附吉布斯自由能，并在氢覆盖率增加时保持活性。此外，（7 × 7）-PtTe _2-x 具有具有稳健边缘态的非平凡能带拓扑结构，表明 HER 具有潜在的增强功能。我们的研究结果有望推动基于 TMD 的催化剂和催化中拓扑材料的探索。