Construction of amorphous Fe0.95S1.05 nanorods with high electrocatalytic activity for enhanced hydrogen evolution reaction

Abstract Amorphous catalysts with abundant defects are attractive for electrocatalytic water splitting. In this work, amorphous Fe0.95S1.05 (a-FeS) nanorods are synthesized by a facile solvothermal method using octylamine solvent and employed as a low-cost and highly active electrocatalyst towards efficient hydrogen evolution reaction (HER). The capped octylamine molecules are responsible for formation of the amorphous structure. The disordered atomic arrangement with plenty of unsaturated atoms endows the a-FeS nanorods with extensive defects as exposed catalytic sites. Compared with the crystalline Fe0.95S1.05 (c-FeS) nanorods, the a-FeS nanorods exhibit a larger electrochemical active surface area and more remarkable catalytic activity. Consequently, excellent HER performance of a small Tafel slope of 43 mV dec−1, a low overpotential of 67 mV at the current density of 10 mA cm−2, and a long operation stability of 80 h is achieved for a-FeS. This work demonstrates the best catalytic activity for hydrogen generation among iron sulfide-based catalysts to date.