Ultrastable molybdenum disulfide-based electrocatalyst for hydrogen evolution in acidic media

Yunxing Zhao, Jeemin Hwang, Michael T. Tang, Hoje Chun, Xingli Wang, Hu Zhao, Karen Chan, Byungchan Han, Pingqi Gao, Hong Li*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Despite the incredible success in reducing the overpotential of nonprecious catalysts for acidic hydrogen evolution reaction (HER) in the past few years, the stability of most platinum-free electrocatalysts is still poor. Here, we report an ultrastable electrocatalyst for acidic HER based on two-dimensional (2D) molybdenum disulfide (MoS2) doped with trace amount of palladium (<5 μg cm-2), which creates sulfur vacancies (S-vacancies). The optimized catalyst shows stable operation over 1000 h at 10 mA cm-2 with overpotential of 106 mV. The MoS2 catalyst is stabilized on a defective vertical graphene support, where the strong interaction at the 2D-2D interface increases the adhesion between the catalyst and the support. Palladium (Pd) doping generates rich sulfur vacancies in MoS2 that have a twofold role: (1) increasing hydrogen adsorption energy, which enhances activity; and (2) further increasing the adhesion between graphene support and defective MoS2, and thus enhancing stability. Complementary theoretical studies reveal the reaction pathways for substitutional doping, where the Mo-vacancy sites are prior to be doped by Pd. Our work thus offers a strategy for making stable, efficient, and earth-abundant HER catalysts with strong potential to replace platinum for PEM electrolysis.
Original languageEnglish
Article number227998
JournalJournal of Power Sources
Volume456
Number of pages9
ISSN0378-7753
DOIs
Publication statusPublished - 2020

Keywords

  • Vertical graphene network
  • MoS2 electrocatalyst
  • 2D-2D interface
  • Acidic HER
  • Palladium doping mechanism
  • Long-term stability

Cite this

Zhao, Y., Hwang, J., Tang, M. T., Chun, H., Wang, X., Zhao, H., Chan, K., Han, B., Gao, P., & Li, H. (2020). Ultrastable molybdenum disulfide-based electrocatalyst for hydrogen evolution in acidic media. Journal of Power Sources, 456, [227998]. https://doi.org/10.1016/j.jpowsour.2020.227998