Water Reduction by a p-GaInP2 Photoelectrode Stabilized by an Amorphous TiO2 Coating and a Molecular Cobalt Catalyst

John Turner, James Young, Nathan Neale, Yong Yan, Kenneth Steirer, Jing Gu

Research output: Contribution to journalArticlepeer-review

212 Scopus Citations

Abstract

Producing hydrogen through solar water splitting requires the coverage of large land areas. Abundant metal-based molecular catalysts offer scalability, but only if they match noble metal activities. We report on a highly active p-GaInP2 photocathode protected through a 35-nm TiO2 layer functionalized by a cobaloxime molecular catalyst (GaInP2-TiO2 -cobaloxime). This photoelectrode mediates H2 production with a current density of ∼9 mA cm-2 at a potential of 0 V versus RHE under 1-sun illumination at pH 13. The calculated turnover number for the catalyst during a 20-h period is 139,000, with an average turnover frequency of 1.9 s-1. Bare GaInP2 shows a rapid current decay, whereas the GaInP2-TiO2 -cobaloxime electrode shows ≤5% loss over 20 min, comparable to a GaInP2-TiO2-Pt catalyst particle-modified interface. The activity and corrosion resistance of the GaInP2-TiO2-cobaloxime photocathode in basic solution is made possible by an atomic layer-deposited TiO2 and an attached cobaloxime catalyst.

Original languageAmerican English
Pages (from-to)456-460
Number of pages5
JournalNature Materials
Volume15
Issue number4
DOIs
StatePublished - 1 Apr 2016

Bibliographical note

Publisher Copyright:
© 2016 Macmillan Publishers Limited. All rights reserved.

NREL Publication Number

  • NREL/JA-5900-64559

Keywords

  • cobaltoxime catalysts
  • p-GaInP2 photoelectrode
  • photoelectrochemical
  • solar-photochemistry
  • stabilization
  • titanium dioxide
  • turnover frequency
  • turnover number

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