Abstract
Size-selected molybdenum sulfide (MoSx) nanoclusters obtained by magnetron sputtering and gas condensation on glassy carbon substrates are typically sulfur-deficient (x = 1.6 ± 0.1), which limits their crystallinity and electrocatalytic properties. Here we demonstrate that a sulfur-enriching method, comprising sulfur evaporation and cluster annealing under vacuum conditions, significantly enhances their activity towards the hydrogen evolution reaction (HER). The S-richness (x = 4.9 ± 0.1) and extended crystalline order obtained in the sulfur-treated MoSx nanoclusters lead to consistent 200 mV shifts to lower HER onset potentials, along with two-fold and more-than 30-fold increases in turnover frequency and exchange current density values respectively. The high mass activities (∼111 mA mg−1 @ 400 mV) obtained at ultra-low loadings (∼100 ng cm-2, 5% surface coverage) are comparable to the best reported MoS2 catalysts in the literature.
Original language | English |
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Pages (from-to) | 84-91 |
Number of pages | 8 |
Journal | Applied Catalysis B: Environmental |
Volume | 235 |
Early online date | 27 Apr 2018 |
DOIs | |
Publication status | Published - 5 Nov 2018 |
Keywords
- Hydrogen evolution
- Magnetron sputtering deposition
- Molybdenum sulfide
- Nanoclusters
- Sulfur-rich
ASJC Scopus subject areas
- Catalysis
- General Environmental Science
- Process Chemistry and Technology