Enhanced Fe 3d delocalization and moderate spin polarization in Fe Ni atomic pairs for bifunctional ORR and OER electrocatalysis

Charge and spin manipulations of electrons are considered to be of great significance in boosting the catalytic activity of MNC electrocatalysts. However, to the best of our knowledge, most current studies focus only on the charge engineering, the interplay between spin and charge is not well understood, and the simultaneous manipulation of both charge and spin remains challenging. Herein, we show that the cooperative interplay between charge itineration and spin-polarization of electrons has a profound impact on the catalytic behavior through density functional theory (DFT) calculations for the first time. Following this concept, we report a Fe-Ni atomic pair as a superior bifunctional catalyst for high performance ORR and OER, with a very small potential difference (ΔE) of 0.691 V. We confirm that the coexistence of Fe 3d itinerant charge and moderate spin polarization (magnetic moment: 1.48 μB) is responsible for the superior functional catalytic activity for the FeNi atomic pairs.