Transition metal dichalcogenides such as molybdenum disulfides (MoS<sub>2</sub>) and tungsten disulfides (WS<sub>2</sub>) have been extensively studied as a potential catalyst for hydrogen production. So far, the primary consideration has been on tuning the hydrogen adsorption free energy at the catalytic site in order to improve the electrocatatlyic activity for hydrogen evolution reaction (HER). Equally important, however, is the electron transport within the catalyst and electron transfer at the catalyst/electrode interface. Here, we will discuss the important role that the catalyst/electrode interface plays as a rate limiting step in HER. HER measurements were performed on isolated nanodevices based on single-crystalline transition metal dichalcogenide nanoflakes.  Nanodevices allow accurate measurements of the number density and the types of catalytic sites, the electrical properties of the catalyst, and the contact resistance between the catalyst and the electrode.  Our results show that aligning the Fermi levels at the catalyst/electrode interface is critical for HER.

Role of electron transfer in hydrogen evolution reaction of 2D transition metal dichalcogenides

254th National Meeting (2017)

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