Dynamics of Photocatalytic Hydrogen Production in Aqueous Dispersions of Monolayer-Rich Tungsten Disulfide

Jeremy Dunklin, Hanyu Zhang, Jao Van De Lagemaat, Ye Yang, Jun Liu

Research output: Contribution to journalArticlepeer-review

26 Scopus Citations

Abstract

Two-dimensional tungsten disulfide (WS2) is an emerging semiconducting photocatalyst featuring high optical absorption, carrier mobility, and catalytic activity toward hydrogen evolution. While characterization of its optical and electrocatalytic properties has advanced, less is known about its ultrafast carrier dynamics and intrinsic photocatalytic activity in aqueous systems producing hydrogen. This work removed extraneous variables often found in photoelectrochemical systems, thereby allowing the intrinsic proton reduction rate for monolayer-rich WS2 nanosheets to be estimated via transient absorption lifetimes and a developed kinetic scheme. Addition of a hole scavenger, ascorbic acid (AA), resulted in a 3-fold increase in carrier lifetimes following photoexcitation. Longer electron lifetimes with AA yielded a 14-fold increase in hydrogen production. An intrinsic proton reduction rate constant was extracted that may be extended to any photoelectrochemical or electrochemical hydrogen evolution scheme involving small, monolayer-rich WS2 catalysts. This represents an important step in better understanding catalytic systems utilizing TMD catalysts.

Original languageAmerican English
Pages (from-to)2223-2229
Number of pages7
JournalACS Energy Letters
Volume3
Issue number9
DOIs
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© 2018 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-71560

Keywords

  • photocatalysts
  • photoelectrochemical systems
  • semiconductors
  • solar-photochemistry
  • tungsten disulfide

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