Discovery of True Electrochemical Reactions for Ultrahigh Catalyst Mass Activity in Water Splitting

Johney Green, Jingke Mo, Zhenye Kang, Scott Retterer, David Cullen, Todd Toops, Matthew Mench, Feng-Yuan Zhang

Research output: Contribution to journalArticlepeer-review

170 Scopus Citations


Better understanding of true electrochemical reaction behaviors in electrochemical energy devices has long been desired. It has been assumed so far that the reactions occur across the entire catalyst layer (CL), which is designed and fabricated uniformlywith catalysts, conductors of protons and electrons, and pathways for reactants and products. By introducing a state-of-the-art characterization system, a thin, highly tunable liquid/gas diffusion layer (LGDL), and an innovative design of electrochemical proton exchange membrane electrolyzer cells (PEMECs), the electrochemical reactions on both microspatial and microtemporal scales are revealed for the first time. Surprisingly, reactions occur only on the CL adjacent to good electrical conductors. On the basis of these findings, new CL fabrications on the novel LGDLs exhibitmore than 50 times highermass activity than conventional catalyst-coated membranes in PEMECs. This discovery presents an opportunity to enhance the multiphase interfacial effects, maximizing the use of the catalysts and significantly reducing the cost of these devices.

Original languageAmerican English
Article numbere1600690
Number of pages7
JournalScience Advances
Issue number11
StatePublished - 2016

Bibliographical note

Publisher Copyright:
© 2016 The Authors, some rights reserved.

NREL Publication Number

  • NREL/JA-4A00-67493


  • catalyst deposition
  • catalyst mass activity
  • electrochemical reactions
  • electrolyzer
  • high-speed visualization
  • hydrogen
  • microscale reaction
  • transparent proton exchange membrane electrolyzer cell
  • water splitting
  • well-tunable liquid/gas diffusion layers


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