A bio-inspired molecular water oxidation catalyst for renewable hydrogen generation: An examination of salt effects

Robin Brimblecombe, Miriam Rotstein, Annette Koo, G. Charles Dismukes, Gerhard F. Swiegers, Leone Spiccia

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


Most transport fuels are derived from fossil fuels, generate greenhouse gases, and consume significant amounts of water in the extraction, purification, and/or burning processes. The generation of hydrogen using solar energy to split water, ideally from abundant water sources such as sea water or other non-potable sources, could potentially provide an unlimited, clean fuel for the future. Solar, electrochemical water splitting typically combines a photoanode at which water oxidation occurs, with a cathode for proton reduction to hydrogen. In recent work, we have found that a bioinspired tetra-manganese cluster catalyzes water oxidation at relatively low overpotentials (0.38 V) when doped into a Nafion proton conduction membrane deposited on a suitable electrode surface, and illuminated with visible light. We report here that this assembly is active in aqueous and organic electrolyte solutions containing a range of different salts in varying concentrations. Similar photocurrents were obtained using electrolytes containing 0.0 - 0.5 M sodium sulfate, sodium Perchlorate or sodium chloride. A slight decline in photocurrent was observed for sodium Perchlorate but only at and above 5.0 M concentration. In acetonitrile and acetone solutions containing 10% water, increasing the electrolyte concentration was found to result in leaching of the catalytic species from the membrane and a decrease in photocurrent. Leaching was not observed when the system was tested in an ionic liquid containing water, however, a lower photocurrent was generated than observed in aqueous electrolyte. We conclude that immersion of the membrane in an aqueous solution containing an electrolyte concentration of 0.05 - 0.5M represent good conditions for operation for the cubium/Nafion catalytic system.

Original languageEnglish
Title of host publicationSolar Hydrogen and Nanotechnology IV
Publication statusPublished - 2009
EventSolar Hydrogen and Nanotechnology IV - San Diego, CA, United States
Duration: Aug 3 2009Aug 6 2009

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherSolar Hydrogen and Nanotechnology IV
CountryUnited States
CitySan Diego, CA


  • Hydrogen
  • Manganese cubane catalyst
  • Photocatalysis
  • Photosystem ii
  • Salt effects
  • Water oxidation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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