Ultrafast Microwave Quasi-Solid-State Construction of Os-OsP₂ with Enhanced Interfacial Spillover for Seawater-Based Anion Exchange Membrane Electrolyzers

Abstract

Developing cost-effective hydrogen evolution reactions (HER) catalysts to replace Pt/C in alkaline seawater media remains a critical challenge. Therefore, the osmium-osmium phosphide (Os-OsP₂) catalyst is reported with a heterogeneous junction through ultrafast (20 s) microwave quasi-solid approach for seawater-splitting under industrial-grade current density. Experimental and theoretical analysis reveal that the Os-OsP₂ interface optimizes electronic structure: osmium (Os) sites accelerate water dissociation by lowering the d-band center, while OsP₂ promotes hydrogen desorption via interfacial spillover, collectively reducing the HER energy barrier. In addition, the catalyst requires only 1.74 V to reach 1 A cm⁻² and owns high price activity in the anion exchange membrane water electrolyzer, surpassing commercial Pt/C by 23% in efficiency under identical conditions. Furthermore, it exhibits robust HER activity across a wide pH range and exceptional durability over 100 h in alkaline seawater. Economic evaluation highlights its superior cost activity (85.6 A dollar⁻¹), 90-fold higher than Pt/C, with hydrogen production costs ($0.86 GGE⁻¹) undercutting the U.S. DOE target. This study provides feasible guidance for the development of high-performance, cost-effective catalysts for scalable hydrogen production from seawater.