Low-Iridium Catalysts with High Atom Utilization for Acidic Oxygen Evolution Reaction: Design Strategies, Controllable Synthesis, and Mechanisms

Hydrogen energy represents a key pillar of future integrated clean energy systems, with proton exchange membrane water electrolysis (PEMWE) enabling vital electricity-to-hydrogen conversion. However, widespread adoption is constrained by prohibitive production costs. Specifically, anodic iridium catalysts are pivotal for sustaining high energy efficiency under harsh operating regimes, yet they remain a primary cost driver. Currently, analyses prioritizing the maximization of intrinsic iridium atom utilization are limited. This review examines low-iridium strategies, encompassing dealloying, morphology engineering, single-atom/cluster, and support engineering configurations. Distinctively, we correlate controllable synthesis protocols with acidic oxygen evolution mechanisms to construct an iterative “design-synthesis-mechanism” framework. By leveraging deep mechanistic insights to enhance design efficiency, this work aims to expedite the development of cost-effective, high-performance catalysts for industrial-scale water electrolysis and green energy transitions.