Han Wenqian, Liu Zihan, Pan Yanbo, Guo Guannan, Zou Jinxiang, Xia Yan, Peng Zhenmeng, Li Wei, Dong Angang
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai, 200433, China.
Department of Chemical and Biomolecular Engineering, University of Akron, Akron, OH, 44325, USA.
Adv Mater. 2020 Jul;32(28):e2002584. doi: 10.1002/adma.202002584. Epub 2020 Jun 3.
Fine-tuning strain and vacancies in 2H-phase transition-metal dichalcogenides, although extremely challenging, is crucial for activating the inert basal plane for boosting the hydrogen evolution reaction (HER). Here, atomically curved 2H-WS nanosheets with precisely tunable strain and sulfur vacancies (S-vacancies) along with rich edge sites are synthesized via a one-step approach by harnessing geometric constraints. The approach is based on the confined epitaxy growth of WS in ordered mesoporous graphene derived from nanocrystal superlattices. The spherical curvature imposed by the graphitic mesopores enables the generation of uniform strain and S-vacancies in the as-grown WS nanosheets, and simultaneous manipulation of these two key parameters can be realized by simply adjusting the pore size. In addition, the formation of unique mesoporous WS @graphene van der Waals heterostructures ensures the ready access of active sites. Fine-tuning the WS layer number, strain, and S-vacancies enables arguably the best-performing HER 2H-WS electrocatalysts ever reported. Density functional theory calculations indicate that compared with strain, S-vacancies play a more critical role in enhancing the HER activity.
在二硫化物相过渡金属二卤化物中微调应变和空位，尽管极具挑战性，但对于激活惰性基面以促进析氢反应（HER）至关重要。在此，通过利用几何约束的一步法合成了具有精确可调应变和硫空位（S空位）以及丰富边缘位点的原子弯曲的二硫化钨（2H-WS）纳米片。该方法基于在由纳米晶体超晶格衍生的有序介孔石墨烯中WS的受限外延生长。石墨介孔施加的球形曲率能够在生长的WS纳米片中产生均匀的应变和S空位，并且通过简单地调节孔径就可以实现这两个关键参数的同时调控。此外，独特的介孔WS@石墨烯范德华异质结构的形成确保了活性位点易于接近。微调WS层数、应变和S空位可实现有史以来报道的性能最佳的HER 2H-WS电催化剂。密度泛函理论计算表明，与应变相比，S空位在增强HER活性方面起着更关键的作用。
