Intermetallic ferric nickel silicide alloy derived from magadiite by magnesiothermic reaction as bifunctional electrocatalyst for overall water splitting

Abstract

As the cleanest energy source, hydrogen energy is regarded as the most promising fuel. Water electrolysis, as the primary means of hydrogen production, has constantly been the focus of attention in the energy conversion field. Developing eco-friendly, cheap, safe and efficient catalysts for electrochemical water splitting (EWS) is the key challenge. Herein, the intermetallic silicide alloy is first synthesized via a facile magnesiothermic reduction and employed as bifunctional electrocatalysts for EWS. Ferric-nickel silicide (denoted as FeNiSi) alloy is designed and shows a good electrocatalytic performance for EWS. The lattice distortions of FeNiSi enhance the electrocatalytic activity. Besides, the porous structure affords more active sites and improves the reaction kinetics. As a consequence, FeNiSi delivers an excellent performance with overpotential of 308 mV for oxygen evolution reaction (OER) and 386 mV for hydrogen evolution reaction (HER) at 10 mA·cm−2 in 1 M KOH. The stability structure of intermetallic silicide achieves an outstanding durability with an unchanged potential of 1.66 V for overall water splitting at 10 mA·cm−2 for 15 h. This work not only provides a facile method for the synthesis of intermetallic silicide with considerable porous structures, but also develops the potential of intermetallic silicide alloy as bifunctional electrocatalysts for EWS, which opens up a new avenue for the design and application of intermetallic silicide alloy.

Keywords

• bimetallic silicide
• magadiite
• magnesiothermic reduction
• bifunctional electrocatalyst
• overall water splitting