Abstract
We report the electrochemical hydrogen evolution reaction (HER) of two-dimensional metallic transition metal dichalcogenides (TMDs). TMTe2 (TM: Mo, W, and V) single crystals were synthesized and characterized by optical microscopy, X-ray diffraction, and electrochemical measurements. We found that TMTe2 acts as a HER-active catalyst due to the inherent catalytic activity of its basal planes. Among the three metallic TMTe2, VTe2 shows the best HER performance with an overpotential of 441 mV and a Tafel slope of 70 mV/dec. It is 668 mV and 137 mV/dec for MoTe2 and 692 mV and 169 mV/dec for WTe2. Even though VTe2 has the lowest values in the exchange current density, the active site density, and turn-over-frequency (TOF) among the three TMTe2, the lowest charge transfer resistance (RCT) of VTe2 seems to be critical to achieving the best HER performance. First-principles calculations revealed that the basal-plane-active HER performance of metallic TMDs can be further enhanced with some Te vacancies. Our study paves the way to further study of the inherent catalytic activity of metallic 2D materials for active hydrogen production.
Highlights
IntroductionHydrogen energy is receiving tremendous attention as it is regarded as the most promising eco-friendly and renewable energy to replace the carbon emission energies such as fossil fuels [1,2,3,4]
Hydrogen energy is receiving tremendous attention as it is regarded as the most promising eco-friendly and renewable energy to replace the carbon emission energies such as fossil fuels [1,2,3,4].To produce high purity hydrogen gas, electrochemical water splitting has been frequently used with noble metal-based electrocatalysts [5]
We found that clean surfaces of TMTe2 behaved as hydrogen evolution reaction (HER)-active surfaces due to the inherent catalytic activity of their basal planes
Summary
Hydrogen energy is receiving tremendous attention as it is regarded as the most promising eco-friendly and renewable energy to replace the carbon emission energies such as fossil fuels [1,2,3,4]. To produce high purity hydrogen gas, electrochemical water splitting has been frequently used with noble metal-based electrocatalysts [5]. Much research has focused on the development of new types of the electrocatalysts, combining lower amounts of noble metals with earth-abundant materials for economy and efficient hydrogen production [6,7]. For a high number of active sites, the periodic arrangement of the catalytic active sites in the 2D plane can be a challenging theme for an efficient hydrogen evolution reaction (HER)
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