Reversing the Tradeoff between Rate and Overpotential in Molecular Electrocatalysts for H2 Production

Christina M. Klug, Allan Jay P. Cardenas, R Morris Bullock, Molly O'Hagan, Eric Wiedner

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

A longstanding challenge in molecular electrocatalysis is to design catalysts that break away from the tradeoff between rate and overpotential arising from electronic scaling relationships. Here we report an inversion of the rate-overpotential correlation through system-level design of [Ni(PR 2NR2)2]2+ electrocatalysts for the production of H2. The overpotential is lowered by an electron-withdrawing ligand, while the turnover frequency is increased by controlling the catalyst structural dynamics, using both ligand design and solvent viscosity. The cumulative effect of controlling each of these system components is an electrocatalyst with a turnover frequency of 70000 s-1 and an overpotential of 230 mV, corresponding to a 100-fold rate enhancement and a 170 mV reduction in overpotential in comparison to the parent nickel catalyst. Molecular Tafel plot analysis reveals that the new catalysts reported here are substantially more efficient than other leading molecular electrocatalysts for the production of H2.

Original languageEnglish
Pages (from-to)3286-3296
Number of pages11
JournalACS Catalysis
Volume8
Issue number4
DOIs
Publication statusPublished - Apr 6 2018

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Keywords

  • Electrocatalysis
  • hydrogen
  • nickel
  • overpotential
  • proton relay
  • scaling relation
  • viscosity

ASJC Scopus subject areas

  • Catalysis

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