Manipulating the d- and p-Band centers of amorphous alloys by variable composition for robust oxygen evolution reaction

Abstract

Amorphous electrocatalysts display several unique advantages in electricity-driven water splitting compared to their crystalline analogs, but understanding their structure–activity relationships remains a major challenge. Herein, we show that the d- and p-electronic states of amorphous Ni-Fe-B can be subtly manipulated by varying the Ni and Fe contents. The optimal Ni-Fe-B alloy exhibits a high performance in the oxygen evolution reaction (OER), as supported by its impressive stability (no clear degradation after 100 h) and considerably lower overpotential compared to those of its crystalline analogs. Based on theoretical calculations, different Ni and Fe contents can cause significant shifts in the d-band levels of Ni and Fe and the p-band level of B, thus altering the OER activity. Additionally, the energy difference between the d- and p-band centers (ΔEad-p) may be an effective index for use in reflecting the structure–activity relationship of an amorphous Ni-Fe-B alloy in the OER. An amorphous Ni-Fe-B alloy with a smaller ΔEad-p displays a higher intrinsic activity. This study supplies a unique direction for use in constructing the structure–activity relationships of amorphous electrocatalysts by revealing the role of ΔEad-p, which promotes fundamental research and the practical application of amorphous electrocatalysts.