Alloying-Triggered Phase Engineering of NiFe System via Laser-Assisted Al Incorporation for Full Water Splitting.

ABSTRACT

It is challenging to design one non-noble material with balanced bifunctional performance for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) for commercial sustainability at a low cost since the different electrocatalytic mechanisms are not easily matchable for each other. Herein, a self-standing hybrid system Ni18 Fe12 Al70 , consisting of Ni2 Al3 and Ni3 Fe phases, was constructed by laser-assisted aluminum (Al) incorporation towards full water splitting. It was found that the incorporation of Al could effectively tune the morphologies, compositions and phases. The results indicate that Ni18 Fe12 Al70 delivers an extremely low overpotential to trigger both HER (η100 =188 mV) and OER (η100 =345 mV) processes and maintains a stable overpotential for 100 h, comparable to state-of-the-art electrocatalysts. The synergistic effect of Ni2 Al3 and Ni3 Fe alloys on the HER process is confirmed based on theoretical calculation.