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<p>Iridium-based catalysts supported on corrosion-resistant metal oxides such as TiO₂ are promising candidates for the oxygen evolution reaction in proton exchange membrane water electrolyzers (PEMWEs). However, the inherently poor electronic conductivity of oxide supports can limit catalyst performance, especially at low Ir loadings. In this study, we systematically investigate the relationship between Ir loading, electronic conductivity, and electrochemical activity in Ir-TiO₂ catalysts. Through structural characterization, electrochemical analysis, and impedance spectroscopy, we demonstrate that insufficient Ir loading leads to isolated nanoparticles and poor interparticle electron transport, which cannot be fully corrected by conventional iR compensation methods. Electrochemical impedance spectroscopy reveals that the increased charge transfer resistance at OER potentials is strongly coupled with limited electronic conductivity. The introduction of conductive carbon additives restores activity in low-loading systems, confirming the importance of continuous conductive networks. Our findings highlight a critical design principle: the need to balance Ir utilization and electron transport to maximize catalytic activity. This work provides a practical framework for diagnosing and overcoming conductivity-related limitations in low-Ir electrocatalyst systems for PEMWE applications<b>.</b></p>

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Revealing the Impact of Electronic Conductivity on Iridium-Loaded TiO₂ Catalysts for Efficient Proton Exchange Membrane Water Electrolysis

  • 期刊论文

  • 发表日期：

    2025年6月24日

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  • Wonchul Park,
  • Jongmin Lee,
  • Baeck B. Choi,
  • Ji Hyun Um,
  • Dong Young Chung

摘要

Iridium-based catalysts supported on corrosion-resistant metal oxides such as TiO₂ are promising candidates for the oxygen evolution reaction in proton exchange membrane water electrolyzers (PEMWEs). However, the inherently poor electronic conductivity of oxide supports can limit catalyst performance, especially at low Ir loadings. In this study, we systematically investigate the relationship between Ir loading, electronic conductivity, and electrochemical activity in Ir-TiO₂ catalysts. Through structural characterization, electrochemical analysis, and impedance spectroscopy, we demonstrate that insufficient Ir loading leads to isolated nanoparticles and poor interparticle electron transport, which cannot be fully corrected by conventional iR compensation methods. Electrochemical impedance spectroscopy reveals that the increased charge transfer resistance at OER potentials is strongly coupled with limited electronic conductivity. The introduction of conductive carbon additives restores activity in low-loading systems, confirming the importance of continuous conductive networks. Our findings highlight a critical design principle: the need to balance Ir utilization and electron transport to maximize catalytic activity. This work provides a practical framework for diagnosing and overcoming conductivity-related limitations in low-Ir electrocatalyst systems for PEMWE applications.