Electrochemical Surface Interrogation of a MoS2 Hydrogen-Evolving Catalyst

In Situ Determination of the Surface Hydride Coverage and the Hydrogen Evolution Kinetics

Hyun Seo Ahn, Allen J. Bard

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17 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 languageEnglish
Pages (from-to)2748-2752
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume7
Issue number14
DOIs
Publication statusPublished - 2016 Jul 21

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interrogation
Hydrides
hydrides
Hydrogen
catalysts
Catalysts
Kinetics
kinetics
hydrogen
selective surfaces
titration
molybdenum
Molybdenum
reaction kinetics
Titration
Reaction rates
microscopy
Rate constants
nanoparticles
Microscopic examination

All Science Journal Classification (ASJC) codes

  • Materials Science(all)

Cite this

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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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