Current Trends of Iridium-Based Catalysts for Oxygen Evolution Reaction in Acidic Water Electrolysis

The proton exchange membrane water electrolysis (PEMWE) powered by renewable electricity offers a facile route for clean hydrogen production. The oxygen evolution reaction (OER) at the anode plays a major role in affecting the overall device efficiency due to its sluggish OER kinetics. Thus, it remains a challenge to develop robust and active catalysts for OER in acid media for efficient PEMWE. Currently, iridium (Ir)-based materials, such as mono- and multimetallic Ir, Ir-based oxides, pyrochlore iridate oxides, and Ir-based perovskites, are the most promising OER catalysts in acid media for PEMWEs. Extensive research has been conducted to enhance the specific activity of Ir species to make cost-effective. The present review aims to provide the recent progress on addressing the long-term durability issue of Ir-based catalyst for OER in acidic conditions, aspiring to inspire the researchers to design highly efficient and stable Ir-based catalysts. Moreover, the detailed OER mechanism along with the dissolution nature of Ir species is discussed and summarized. Finally, the status, challenges, and prospects for the development of Ir-based OER catalysts are discussed.