Sulfonic acid (SO3H) functionalized two-dimensional MoS2 nanosheets for electrocatalytic hydrogen generation
Singh, Vivek Kumar; Mukherjee, Bratindranath; Assa Aravindh, S.; Das, Santanu (2022-10-22)
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Sisältö avataan julkiseksi: 22.10.2024
Singh, Vivek Kumar
Mukherjee, Bratindranath
Assa Aravindh, S.
Das, Santanu
Elsevier
22.10.2022
Singh, V. K., Mukherjee, B., Assa Aravindh, S., & Das, S. (2023). Sulfonic acid (So3h) functionalized two-dimensional MoS2 nanosheets for electrocatalytic hydrogen generation. Applied Surface Science, 609, 155354. https://doi.org/10.1016/j.apsusc.2022.155354
https://creativecommons.org/licenses/by-nc-nd/4.0/
© 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/(opens in new tab/window)
https://creativecommons.org/licenses/by-nc-nd/4.0/
© 2022. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/(opens in new tab/window)
https://creativecommons.org/licenses/by-nc-nd/4.0/
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:oulu-202312183889
https://urn.fi/URN:NBN:fi:oulu-202312183889
Tiivistelmä
Abstract
We report the sulfonic acid (–SO3H) functionalized two-dimensional (2D) molybdenum disulfide (MoS2) nanosheet with significantly enhanced physical and electrochemical properties as an efficient electrocatalyst for hydrogen evolution reaction (HER). The functionalized 2D-nanosheet shows enhanced electrocatalytic performance than the pristine one. We obtained overpotential as low as ∼82 mV (ƞ10) along with a very low Tafel slope ∼57 mV dec-1 and excellent stability (12 h) in functionalized MoS2. We also found that, with increasing the % of functional group, -SO3H molecules were intercalated through the MoS2 layers resulting in the increase in interlayer spacing from 6.1 Å to 9.4 Å. The intercalated 2D-MoS2 nanosheets with expanded interlayer distance further enhance the surface area, charge-transfer sites, and surface adsorption–desorption by lowering the ΔGH (i.e., the energy barrier of hydrogen adsorption/desorption), thereby accelerating the Volmer step of hydrogen evolution. Finally, density functional theory (DFT) calculations show significant changes in the electronic structure of the functionalized 2D-MoS2 with a considerable shift in the total density of states (DOS) as compared to its pristine counterpart. The DFT calculations reveal that hybridizations occur between the SO3H and p and d states of the S and Mo, which propel the valence band maximum towards higher energies, thus, leading to the narrowing of the bandgap of MoS2. Such changes in electronic properties further reduce work function and facilitate redox-mediated charge-transfer, thereby, enhancing the electrocatalytic activity for HER.
We report the sulfonic acid (–SO3H) functionalized two-dimensional (2D) molybdenum disulfide (MoS2) nanosheet with significantly enhanced physical and electrochemical properties as an efficient electrocatalyst for hydrogen evolution reaction (HER). The functionalized 2D-nanosheet shows enhanced electrocatalytic performance than the pristine one. We obtained overpotential as low as ∼82 mV (ƞ10) along with a very low Tafel slope ∼57 mV dec-1 and excellent stability (12 h) in functionalized MoS2. We also found that, with increasing the % of functional group, -SO3H molecules were intercalated through the MoS2 layers resulting in the increase in interlayer spacing from 6.1 Å to 9.4 Å. The intercalated 2D-MoS2 nanosheets with expanded interlayer distance further enhance the surface area, charge-transfer sites, and surface adsorption–desorption by lowering the ΔGH (i.e., the energy barrier of hydrogen adsorption/desorption), thereby accelerating the Volmer step of hydrogen evolution. Finally, density functional theory (DFT) calculations show significant changes in the electronic structure of the functionalized 2D-MoS2 with a considerable shift in the total density of states (DOS) as compared to its pristine counterpart. The DFT calculations reveal that hybridizations occur between the SO3H and p and d states of the S and Mo, which propel the valence band maximum towards higher energies, thus, leading to the narrowing of the bandgap of MoS2. Such changes in electronic properties further reduce work function and facilitate redox-mediated charge-transfer, thereby, enhancing the electrocatalytic activity for HER.
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