FeS₂ Nanoparticles Embedded in Reduced Graphene Oxide toward Robust, High-Performance Electrocatalysts

Developing low-cost, highly efficient, and robust earth-abundant electrocatalysts for hydrogen evolution reaction (HER) is critical for the scalable production of clean and sustainable hydrogen fuel through electrochemical water splitting. This study presents a facile approach for the synthesis of nanostructured pyrite-phase transition metal dichalcogenides as highly active, earth-abundant catalysts in electrochemical hydrogen production. Iron disulfide (FeS₂) nanoparticles are in situ loaded and stabilized on reduced graphene oxide (RGO) through a current-induced high-temperature rapid thermal shock (≈12 ms) of crushed iron pyrite powder. FeS₂ nanoparticles embedded in between RGO exhibit remarkably improved electrocatalytic performance for HER, achieving 10 mA cm⁻² current at an overpotential as low as 139 mV versus a reversible hydrogen electrode with outstanding long-term stability under acidic conditions. The presented strategy for the design and synthesis of highly active earth-abundant nanomaterial catalysts paves the way for low-cost and large-scale electrochemical energy applications.