The Role of Intrinsic Defects in Electrocatalytic Activity of Monolayer VS2 Basal Planes for the Hydrogen Evolution Reaction

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• 作者：Yang Zhang ; Xiaoshuang Chen ; Yan Huang ; Chong Zhang ; Feng Li ; Haibo Shu
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 26, 2017
• 年：2017
• 卷：121
• 期：3
• 页码：1530-1536
• 全文大小：525K
• ISSN：1932-7455

文摘

Two-dimensional VS₂ nanomaterials have emerged as highly efficient and inexpensive electrocatalysts for the hydrogen evolution reaction (HER), and the further improvement of their HER performance depends on the understanding of the catalytic mechanism and activity in various pristine and defective structures. Here, structural stability, electronic properties, and HER activity of monolayer VS₂ nanosheets with various intrinsic point defects are studied by using first-principles calculations. Compared to the most-studied 2H-phase MoS₂ basal plane, both 2H- and 1T-phase VS₂ basal planes exhibit superior catalytic activity due to their metallic properties. With the introduction of intrinsic point defects onto VS₂ basal planes, we find that there are four types of stable defects in the 2H phase (i.e., S_ad, S_vac, V_ad, and V_S) and three types of stable defects in the 1T phase (i.e., S_ad, S_vac, and V_ad). Moreover, the formation of S_vac, V_ad, and V_S structures in the 2H phase and V_ad in the 1T phase can enhance the HER activity of basal planes, which implies that the synthesis of VS₂ nanosheets at the V-rich condition facilitates the achievement of high HER performance. The HER activity of pristine and defective VS₂ structures can be well understood by a Fermi-abundance model that is also suitable to describe a broad class of electrocatalytic HER systems. This work provides a deep insight into the HER activity of single-layer VS₂ and the guidance for synthesizing highly active electrocatalysts in transition-metal dichalcogenides.