Proton-Exchange Membrane Electrolysis for Green Hydrogen Production: Fundamentals, Cost Breakdown, and Strategies to Minimize Platinum-Group Metal Content in Hydrogen Evolution Reaction Electrocatalysts

Green hydrogen (H2 ) has emerged as a promising energy carrier for decarbonizing the industrial, building, and transportation sectors. However, current green H2 production technologies face challenges that limit cost reduction and scaling up. Platinum-group metals (PGMs), including platinum and iridium, present exceptional electrocatalytic properties for water splitting, but their high cost is a significant barrier. This directly impacts the overall cost of electrolyzers, thus increasing green H2 production costs. The present work covers the fundamentals of water electrolysis, the currently available technologies, focusing on proton-exchange membrane electrolyzers, and the critical role of electrocatalysts, discussing potential strategies for reducing the PGM content and, consequently, decreasing green H2 cost.