A Graded Catalytic-Protective Layer for an Efficient and Stable Water-Splitting Photocathode

John Turner, Chuanxiao Xiao, James Young, Mowafak Al-Jassim, Nathan Neale, Jing Gu, Jeffery Aguiar, Suzanne Ferrere, Kenneth Steirer, Yong Yan

Research output: Contribution to journalArticlepeer-review

136 Scopus Citations


Achieving solar-to-hydrogen efficiencies above 15% is key for the commercial success of photoelectrochemical water-splitting devices. While tandem cells can reach those efficiencies, increasing the catalytic activity and long-term stability remains a significant challenge. Here we show that annealing a bilayer of amorphous titanium dioxide (TiO x) and molybdenum sulfide (MoS x) deposited onto GaInP 2 results in a photocathode with high catalytic activity (current density of 11 mA cm 2 at 0 V versus the reversible hydrogen electrode under 1 sun illumination) and stability (retention of 80% of initial photocurrent density over a 20 h durability test) for the hydrogen evolution reaction. Microscopy and spectroscopy reveal that annealing results in a graded MoS x /MoO x /TiO 2 layer that retains much of the high catalytic activity of amorphous MoS x but with stability similar to crystalline MoS 2. Our findings demonstrate the potential of utilizing a hybridized, heterogeneous surface layer as a cost-effective catalytic and protective interface for solar hydrogen production.

Original languageAmerican English
Article numberArticle No. 16192
Number of pages8
JournalNature Energy
Issue number2
StatePublished - 13 Jan 2017

Bibliographical note

Publisher Copyright:
© 2017 Macmillan Publishers Limited, part of Springer Nature. All rights reserved.

NREL Publication Number

  • NREL/JA-5900-67483


  • catalytic activity
  • graded MoSx/MoOx/TiO2 layer
  • photocathodes
  • protective interface
  • solar-photochemistry
  • water-splitting


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