Kinetic Study of Hydrogen Evolution Reaction over Strained MoS2 with Sulfur Vacancies Using Scanning Electrochemical Microscopy

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• 作者：Hong Li ; Minshu Du ; Michal J. Mleczko ; Ai Leen Koh ; Yoshio Nishi ; Eric Pop ; Allen J. Bard ; Xiaolin Zheng
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：April 20, 2016
• 年：2016
• 卷：138
• 期：15
• 页码：5123-5129
• 全文大小：488K
• 年卷期：0
• ISSN：1520-5126

文摘

Molybdenum disulfide (MoS₂), with its active edge sites, is a proposed alternative to platinum for catalyzing the hydrogen evolution reaction (HER). Recently, the inert basal plane of MoS₂ was successfully activated and optimized with excellent intrinsic HER activity by creating and further straining sulfur (S) vacancies. Nevertheless, little is known about the HER kinetics of those S vacancies and the additional effects from elastic tensile strain. Herein, scanning electrochemical microscopy was used to determine the HER kinetic data for both unstrained S vacancies (formal potential E_v⁰ = −0.53 V_Ag/AgCl, electron-transfer coefficient α_v = 0.4, electron-transfer rate constant k_v⁰ = 2.3 × 10^–4 cm/s) and strained S vacancies (E_sv⁰= −0.53 V_Ag/AgCl, α_sv = 0.4, k_sv⁰ = 1.0 × 10^–3 cm/s) on the basal plane of MoS₂ monolayers, and the strained S vacancy has an electron-transfer rate 4 times higher than that of the unstrained S vacancy. This study provides a general platform for measuring the kinetics of two-dimensional material-based catalysts.