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Title: Discovery of true electrochemical reactions for ultrahigh catalyst mass activity in water splitting

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 uniformly with 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 exhibit more than 50 times higher mass activity than conventional catalyst-coated membranes in PEMECs. In conclusion, 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.
Authors:
 [1] ;  [2] ;  [3] ;  [3] ;  [3] ;  [4] ;  [5] ;  [2]
  1. Univ. of Tennessee, Knoxville, TN (United States). Space Inst., Dept. of Mechanical, Aerospace, and Biomedical Engineering
  2. Univ. of Tennessee, Knoxville, TN (United States). Space Inst., Dept. of Mechanical, Aerospace, and Biomedical Engineering.
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
  4. National Renewable Energy Lab. (NREL), Golden, CO (United States)
  5. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical, Aerospace, and Biomedical Engineering.
Publication Date:
Report Number(s):
NREL/JA-4A00-67493
Journal ID: ISSN 2375-2548
Grant/Contract Number:
AC36-08GO28308; FE0011585; AC05-00OR22725
Type:
Accepted Manuscript
Journal Name:
Science Advances
Additional Journal Information:
Journal Volume: 2; Journal Issue: 11; Journal ID: ISSN 2375-2548
Publisher:
AAAS
Research Org:
National Renewable Energy Lab. (NREL), Golden, CO (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Sciences (CNMS); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center (FEERC); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Transportation Research Center (NTRC)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; electrochemical reactions; catalyst mass activity; hydrogen; water splitting; electrolyzer; high-speed visualization; microscale reaction; transparent proton exchange membrane electrolyzer cell; well-tunable liquid/gas diffusion layers; catalyst deposition; 36 MATERIALS SCIENCE
OSTI Identifier:
1334398
Alternate Identifier(s):
OSTI ID: 1337486