Substituent effects on cobalt diglyoxime catalysts for hydrogen evolution

Brian H. Solis, Sharon Hammes-Schiffer

Research output: Contribution to journalArticlepeer-review

Abstract

The design of efficient, robust, and inexpensive hydrogen evolution catalysts is important for the development of renewable energy sources such as solar cells. Cobalt diglyoxime complexes, Co(dRgBF 2) 2 with substituents R, are promising candidates for such electrocatalysts. The mechanism for hydrogen production requires a series of reduction and protonation steps for various monometallic and bimetallic pathways. In this work, the reduction potentials and pK a values associated with the individual steps were calculated for a series of substituents. The calculations revealed a linear relation between the reduction potentials and pK a values with respect to the Hammett constants, which quantify the electron donating or withdrawing character of the substituents. Additionally, the reduction potentials and pK a values are linearly correlated with each other. These linear correlations enable the prediction of reduction potentials and pK a values, and thus the free energy changes along the reaction pathways, to assist in the design of more effective cobaloxime catalysts.

Original languageEnglish (US)
Pages (from-to)19036-19039
Number of pages4
JournalJournal of the American Chemical Society
Volume133
Issue number47
DOIs
StatePublished - Nov 30 2011

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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