Electrochemical Surface Interrogation of a MoS2 Hydrogen-Evolving Catalyst: In Situ Determination of the Surface Hydride Coverage and the Hydrogen Evolution Kinetics

Hyun S. Ahn; Allen J. Bard

doi:10.1021/acs.jpclett.6b01276

Electrochemical Surface Interrogation of a MoS₂ Hydrogen-Evolving Catalyst: In Situ Determination of the Surface Hydride Coverage and the Hydrogen Evolution Kinetics

Hyun S. Ahn, Allen J. Bard

Research output: Contribution to journal › Article › peer-review

46 Citations (Scopus)

Abstract

The hydrogen evolution reaction (HER) on an electrodeposited a-MoS₂ electrode was investigated by a surface-selective electrochemical titration technique by application of surface interrogation scanning electrochemical microscopy. In a mildly acidic (pH 4.6) environment, the saturated surface hydride coverage of MoS₂ was determined to be 31%, much higher than that expected for a crystalline nanoparticle. The HER rate constant of a surface molybdenum atom was measured for the first time in situ to be 3.8 s^-1 at a 600 mV overpotential. At high Mo-H coverages, a change in the nature of the active sites was observed upon consumption of Mo-H by HER.

Original language	English
Pages (from-to)	2748-2752
Number of pages	5
Journal	Journal of Physical Chemistry Letters
Volume	7
Issue number	14
DOIs	https://doi.org/10.1021/acs.jpclett.6b01276
Publication status	Published - 2016 Jul 21

Bibliographical note

Publisher Copyright:
© 2016 American Chemical Society.

All Science Journal Classification (ASJC) codes

General Materials Science
Physical and Theoretical Chemistry

Access to Document

10.1021/acs.jpclett.6b01276

Cite this

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title = "Electrochemical Surface Interrogation of a MoS2 Hydrogen-Evolving Catalyst: In Situ Determination of the Surface Hydride Coverage and the Hydrogen Evolution Kinetics",

abstract = "The hydrogen evolution reaction (HER) on an electrodeposited a-MoS2 electrode was investigated by a surface-selective electrochemical titration technique by application of surface interrogation scanning electrochemical microscopy. In a mildly acidic (pH 4.6) environment, the saturated surface hydride coverage of MoS2 was determined to be 31%, much higher than that expected for a crystalline nanoparticle. The HER rate constant of a surface molybdenum atom was measured for the first time in situ to be 3.8 s-1 at a 600 mV overpotential. At high Mo-H coverages, a change in the nature of the active sites was observed upon consumption of Mo-H by HER.",

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AB - The hydrogen evolution reaction (HER) on an electrodeposited a-MoS2 electrode was investigated by a surface-selective electrochemical titration technique by application of surface interrogation scanning electrochemical microscopy. In a mildly acidic (pH 4.6) environment, the saturated surface hydride coverage of MoS2 was determined to be 31%, much higher than that expected for a crystalline nanoparticle. The HER rate constant of a surface molybdenum atom was measured for the first time in situ to be 3.8 s-1 at a 600 mV overpotential. At high Mo-H coverages, a change in the nature of the active sites was observed upon consumption of Mo-H by HER.

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