Electrospun IrP2-carbon nanofibers for hydrogen evolution reaction in alkaline medium

Platinum-group metals are the most promising catalysts choice for hydrogen evolution reaction (HER) due to their good catalytic stability and optimum Gibbs free energy for hydrogen adsorption and desorption. However, high cost restricts their industrial application. To lower price, the most commonly used method is to reduce noble metals' dosage. Herein, iridium (Ir) and its diphosphide (IrP2) based on one-dimensional carbon nanofibers (CNFs) are easily fabricated by electrospinning and following calcination, and then are applied as efficient catalysts for HER. Both Ir-CNFs and IrP2-CNFs show excellent HER performances with overpotentials of 22 mV and 19 mV under the current density of 10 mA cm-2 in alkaline medium, respectively. The experimental results are further proved by density function theory (DFT) calculations, in which IrP2 (2 0 0) shows better HER kinetics than Ir (1 1 1) with lower water adsorption and hydrogen evolution energies. This work presents a simple method to prepare Ir-CNFs and IrP2-CNFs and provides a new feasibility for design and synthesis of efficient and stable HER catalysts.