Advancements in Non-Precious Electrocatalysts for Alkaline Water Electrolysis: Mechanistic Insights and Industrial Application Challenges

Alkaline water electrolysis (AWE) is a promising pathway for gigawatt-scale green hydrogen production; however, its widespread deployment is constrained by high overpotentials, catalyst instability, and insufficient durability. This review systematically assesses recent advances (20202024) in non-precious electrocatalysts for AWE based on peer-reviewed literature from Web of Science, emphasizing industrially relevant benchmarks including current densities 500 mAcm, durability > 500 h, and compatibility with intermittent operation. Transition metal phosphides (e.g., CoP/NC) exhibit Pt-like hydrogen evolution activity ( 45 mV) through d-band center modulation, although validation at high current densities remains limited. For oxygen evolution, anion-intercalated NiFe-LDH and self-reconstructing chalcogenides (e.g., FeCoS) achieve overpotentials below 250 mV at 10 mAcm, yet their long-term stability under fluctuating renewable energy input has not been established. Heterojunction bifunctional systems (e.g., NiS/MoO) enable overall water splitting at cell voltages below 1.65 V, but scalable and cost-effective synthesis strategies are still underdeveloped. Remaining challenges include elucidating atomic-scale reconstruction mechanisms, establishing standardized testing protocols under industrial conditions (6 M KOH, 80 C), and ensuring resilience against grid volatility. Future progress is expected to rely on in situ interfacial characterization, accelerated durability tests under intermittent cycling, and modular electrode engineering, which collectively could drive hydrogen production costs toward $2 per kilogram.