High-efficiency hydrogen evolution reaction catalyzed by iron phosphide nanocrystals

Exploring cheap and efficient catalysts to replace platinum-based catalysts for the hydrogen evolution reaction (HER) is essential for hydrogen production. Catalysts based on transition metal phosphides (TMPs) have emerged as greatly promising substitutes for noble-metal catalysts in the HER. Herein, we successfully fabricated iron phosphide ultrafine nanocrystals of ∼8 nm hybridized with carbon black (FeP/C NCs) via a strategy comprising grinding, calcination and phosphidation processes. The as-synthesized FeP/C NCs exhibit excellent catalytic performance for the hydrogen evolution reaction in acidic media, achieving a current density of 10 mA cm−2 at an overpotential of 70 mV and a Tafel slope of 56 mV dec−1. The high activity in the HER was attributed to the abundant active sites owing to the ultra-small and highly dispersive FeP NCs, as well as the good conductivity originating from carbon black. This study provides a cost-effective and scalable approach for the development of efficient HER catalysts.