How the Porous Transport Layer Interface Affects Catalyst Utilization and Performance in Polymer Electrolyte Water Electrolysis

Carl Weber, Jacob Wrubel, Lorenz Gubler, Guido Bender, Salvatore De Angelis, Felix Buchi

Research output: Contribution to journalArticlepeer-review

5 Scopus Citations

Abstract

Cost reduction and fast scale-up of electrolyzer technologies are essential for decarbonizing several crucial branches of industry. For polymer electrolyte water electrolysis, this requires a dramatic reduction of the expensive and scarce iridium-based catalyst, making its efficient utilization a key factor. The interfacial properties between the porous transport layer (PTL) and the catalyst layer (CL) are crucial for optimal catalyst utilization. Therefore, it is essential to understand the relationship between this interface and electrochemical performance. In this study, we fabricated a matrix of two-dimensional interface layers with a well-known model structure, integrating them as an additional layer between the PTL and the CL. By characterizing the performance and conducting an in-depth analysis of the overpotentials, we were able to estimate the catalyst utilization at different current densities, correlating them to the geometric properties of the model PTLs. We found that large areas of the CL become inactive at increasing current density either due to dry-out, oxygen saturation (under the PTL), or the high resistance of the CL away from the pore edges. We experimentally estimated the water penetration in the CL under the PTL to be ≈20 μm. Experimental results were corroborated using a 3D-multiphysics model to calculate the current distribution in the CL and estimate the impact of membrane dry-out. Finally, we observed a strong pressure dependency on performance and high-frequency resistance, which indicates that with the employed model PTLs, a significant gas phase accumulates in the CL under the lands, hindering the distribution of liquid water. The findings of this work can be extrapolated to improve and engineer PTLs with advanced interface properties, helping to reach the required target goals in cost and iridium loadings.

Original languageAmerican English
Pages (from-to)34750-34763
Number of pages14
JournalACS Applied Materials and Interfaces
Volume15
Issue number29
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Published by American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-87267

Keywords

  • active catalyst layer
  • catalyst utilization
  • hydrogen
  • interface PTL/CL
  • iridium loading
  • PEM electrolysis
  • polymer electrolyte water electrolysis
  • porous transport layer

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