Design Principles of Electrocatalysts for Industrial‐Scale Water Electrolysis

ABSTRACT Electrocatalytic water splitting is central to the emerging hydrogen economy, yet its translation from laboratory discovery to industrial deployment remains constrained by the absence of catalytic systems that can sustain ampere‐level current densities with high efficiency, durability and acceptable cost. This Review presents a principle‐driven framework for the rational design of electrocatalysts for industrial‐scale water electrolysis, beginning with the fundamentals of hydrogen production, the persistent lab‐to‐industry gap and the technical barriers associated with high‐current operation. Descriptor‐guided design concepts for hydrogen and oxygen evolution are first examined to clarify how electronic structure governs catalytic activity, followed by a systematic overview of transition‐metal‐based electrocatalysts and the major strategies used to regulate their performance, including defect, doping, high‐entropy, phase, strain and heterostructure engineering, reconstruction, support, built‐in electric fields and surface micro‐environment modulation. These advances are further distilled into four overarching design principles for ampere‐scale catalysis: intrinsic active‐site and electronic‐structure engineering, mass‐transport optimization, robust catalyst–support integration and durability under extreme operating conditions. State‐of‐the‐art cathodic, anodic, bifunctional and seawater‐compatible systems are then assessed alongside integrated electrolyser platforms. Finally, operando characterization methods and industrial translation challenges, including scalability, device integration, long‐term stability and policy alignment, are discussed to outline a roadmap toward truly industrial electrocatalysts.