Molybdenum sulfide within a metal-organic framework for photocatalytic hydrogen evolution from water

Hyunho Noh, Ying Yang, Sol Ahn, Aaron W. Peters, Omar K. Farha, Joseph T. Hupp

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

A representative metal-organic framework, NU-1000, was functionalized with MoSx. The previously determined crystal structure of the material, named MoSx-SIM, consists of monometallic Mo(IV) ions with two sulfhydryl ligands. The metal ions are anchored to the framework by displacing protons presented by the-OH/-OH2 groups on the Zr6 node. As shown previously, the MOF-supported complexes are electrocatalytic for hydrogen evolution from acidified water. The earlier electrocatalysis results, together with the nearly ideal formal potential of the Mo(IV/II) couple (i.e., nearly coincident with that of the hydrogen couple), and the physical proximity of UV-absorbing MOF linkers to the complexes, suggested to us that the linkers might behave photosensitizers for catalyst reduction, and subsequently, for H2 evolution from water. To our surprise, MoSx-SIM, when UV-illuminated in an aqueous buffer at near-neutral pH, displays a biphasic photocatalytic response: an initially slow rate of reaction, i.e. 0.56 mmol g-1 h-1, followed by an increase to 4 mmol g-1 h-1. Ex-situ catalyst examination revealed that nanoparticulate MoSx suspended within the reaction mixture is the actual catalyst. Thus, photo-assisted restructuring and detachment of the catalyst or pre-catalyst from the MOF node appears to be necessary for the catalyst to reduce water at neutral pH.

Original languageEnglish
Pages (from-to)H3154-H3158
JournalJournal of the Electrochemical Society
Volume166
Issue number5
DOIs
Publication statusPublished - 2019

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Renewable Energy, Sustainability and the Environment
  • Surfaces, Coatings and Films
  • Electrochemistry
  • Materials Chemistry

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