Enhanced hydrogen evolution reaction activity of hydrogen-annealed vertical MoS nanosheets
Molybdenum disulfide (MoS 2 ) is a promising electrocatalyst for hydrogen evolution reaction (HER), but only edges and S-vacancies are catalytic active sites for the HER. Therefore, it is crucial to increase edge sites and S-vacancies for enhancing the HER activity of MoS 2 . Here, we report an enha...
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Published in | RSC advances Vol. 8; no. 26; pp. 14369 - 14376 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
17.04.2018
|
Online Access | Get full text |
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Summary: | Molybdenum disulfide (MoS
2
) is a promising electrocatalyst for hydrogen evolution reaction (HER), but only edges and S-vacancies are catalytic active sites for the HER. Therefore, it is crucial to increase edge sites and S-vacancies for enhancing the HER activity of MoS
2
. Here, we report an enhanced HER activity of MoS
2
by combing vertical nanosheets and H
2
annealing. Compared to horizontal MoS
2
nanosheets, pristine vertical MoS
2
nanosheets showed better HER activity due to a larger amount of edges. H
2
annealing further enhanced the HER activity of vertical MoS
2
nanosheets remarkably. Scanning electron microscopy (SEM), X-ray photoelectron spectra (XPS) and electrochemical impedance spectroscopy (EIS) were used to elucidate the enhanced HER activity by H
2
annealing. SEM images showed that H
2
annealing roughened the MoS
2
edges, leading to more edge sites. XPS data revealed the smaller S : Mo ratio after H
2
annealing, meaning more S-vacancies. Meanwhile, EIS measurements showed that charge transfer was accelerated by H
2
annealing. These findings elaborated the H
2
annealing induced enhancement of the HER activity, which were further confirmed by the subsequent re-sulfurization experiment.
Vertical configuration and H
2
annealing enhanced the hydrogen evolution reaction activity of MoS
2
nanosheets. |
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Bibliography: | 2 samples. See DOI Electronic supplementary information (ESI) available: XPS data of Mo 3d region for the re-sulfurized MoS 10.1039/c8ra01147h calculation of onset overpotential, cathodic polarization curves of three H annealed MoS |
ISSN: | 2046-2069 |
DOI: | 10.1039/c8ra01147h |