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.
authors.affiliation: Center for Electrochemistry, Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Hyun S
authors.initials: HS
authors.lastname: Ahn
authors.affiliation: Center for Electrochemistry, Department of Chemistry, The University of Texas at Austin , Austin, Texas 78712, United States.
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Bard