Morphological-modulated FeNi-based amorphous alloys as efficient alkaline water splitting electrocatalysts

Abstract

The rational design of high-performance earth-abundant bifunctional electrocatalysts is highly appealing in electrocatalytic water splitting. Herein, a hybrid morphological-modulation strategy is investigated, which integrates etching treatment with surface strain engineering and can be used as a facile and scalable approach to fabricate efficient FeNi-based amorphous electrocatalysts for alkaline water splitting. In comparison with the as-spun sample, the etched amorphous FeNiCoMoP sample displays superior electrocatalytic performance toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Further, the electrocatalytic activity of this etched material is significantly improved through the pretreatment of surface strain engineering, which is mainly ascribed to the harmonized electron-modulation of multi-metal amorphous alloys and enhancement in surface areas caused by unique micro-holes architecture as well as the strain-induced positive shift of binding energy. The hybrid morphological-modulated sample (namely, FNCMP-S-20) exhibits advanced alkaline HER and OER performance as evidenced by low overpotentials of 146 mV and 205 mV, respectively, to deliver a current density of 10 mA cm−2. Furthermore, a two-electrode electrolyzer constructed by FNCMP-S-20 is shown a remarkably low cell voltage of 1.59 V along with excellent stability of 12 h operating at 10 mA cm−2 for overall water splitting performances.