Synergistic Interlayer and Defect Engineering in VS2 Nanosheets toward Efficient Electrocatalytic Hydrogen Evolution Reaction

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2018-03, Vol.14 (9), p.n/a
• Main Authors: Zhang, Junjun, Zhang, Chenhui, Wang, Zhenyu, Zhu, Jian, Wen, Zhiwei, Zhao, Xingzhong, Zhang, Xixiang, Xu, Jun, Lu, Zhouguang
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Defects; Density functional theory; Electrocatalysts; Free energy; hydrogen evolution reaction; Hydrogen evolution reactions; Hydrogen-based energy; interlayer expansion; Interlayers; Nanosheets; Nanotechnology; Platinum; Slope stability; transition‐metal dichalcogenides; VS2
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201703098

A simple one‐pot solvothermal method is reported to synthesize VS2 nanosheets featuring rich defects and an expanded (001) interlayer spacing as large as 1.00 nm, which is a ≈74% expansion as relative to that (0.575 nm) of the pristine counterpart. The interlayer‐expanded VS2 nanosheets show extraordinary kinetic metrics for electrocatalytic hydrogen evolution reaction (HER), exhibiting a low overpotential of 43 mV at a geometric current density of 10 mA cm−2, a small Tafel slope of 36 mV dec−1, and long‐term stability of 60 h without any current fading. The performance is much better than that of the pristine VS2 with a normal interlayer spacing, and even comparable to that of the commercial Pt/C electrocatalyst. The outstanding electrocatalytic activity is attributed to the expanded interlayer distance and the generated rich defects. Increased numbers of exposed active sites and modified electronic structures are achieved, resulting in an optimal free energy of hydrogen adsorption (∆GH) from density functional theory calculations. This work opens up a new door for developing transition‐metal dichalcogenide nanosheets as high active HER electrocatalysts by interlayer and defect engineering. VS2 nanosheets featuring rich defects and an expanded (001) interlayer spacing as large as 1.00 nm are synthesized by a solvothermal method and demonstrate extraordinary kinetic metrics for the hydrogen evolution reaction. The electrocatalytic activity enhancement is attributed to the optimal free energy of hydrogen adsorption (∆GH) based on the molecular simulation.