Engineering Ir-based catalysts for high current density applications in proton exchange membrane water electrolyzers

Abstract

The proton exchange membrane water electrolyzers (PEMWEs) are promising for the conversion and storage of renewable energy. Understanding the performance and durability of PEMWEs is crucial for engineers and researchers aiming to enhance the market adoption of this technology. Despite their potential, PEMWEs encounter challenges in large-scale and long-term deployment due to high costs and durability concerns in acidic environments. This review delves into the activation and degradation mechanisms of PEMWE components during the oxygen evolution reaction (OER), underscoring the importance of developing efficient PEMWE systems for industrial-scale hydrogen production. We explore recent advancements in engineering Ir-based catalysts for acidic OER, identifying existing gaps for practical application. A detailed overview of various modification techniques for Ir-based catalysts, such as electronic structure engineering, morphology engineering, and support engineering, is presented. Additionally, the critical influence of catalyst coating methods on membrane electrode assembly is discussed. The review also covers performance degradation in PEMWEs, detailing the degradation sources of anode catalysts, membranes, and bipolar plates. By analyzing degradation causes and mechanisms, we highlight effective strategies to enhance component longevity. Moreover, we expand our focus towards the industrialization of PEMWEs operating at high current density. Concluding with an outlook on unresolved challenges, this review offers promising directions for future research aimed at realizing practical PEMWE systems.