Dual Doping of N and F on Co₃O₄ to Activate the Lattice Oxygen for Efficient and Robust Oxygen Evolution Reaction.

Abstract

The oxygen evolution reaction (OER) is a pivotal process in numerous renewable energy conversion technologies. However, its sluggish intrinsic kinetics and intricate transfer process impede the efficient conversion of energy. Activating the lattice oxygen mechanism (LOM) is of paramount importance to break through the theoretical scaling relationship and boost the oxygen evolution catalytic activity. In this contribution, N and F are successfully introduced into Co₃O₄ simultaneously as heteroatoms via a controllable plasma strategy to modulate the covalency property of metal-oxygen. Theoretical simulations and experiment results demonstrated that the covalency of the cobalt-oxygen bond is significantly enhanced under the synergistic effect of N and F, successfully triggering the LOM pathway and facilitating the OER process. The N, F-Co₃O₄ composite displays an impressive OER performance, exhibiting a low overpotential of 254 mV at 10 mA cm^-2 and remarkable stability at 20, 150, and 400 mA cm^-2. In addition, The N, F-Co₃O₄ also exhibits a low overpotential of 285 mV at 20 mA cm^-2 in 1 m KOH + 0.5 m NaCl solution, and remarkable performance on overall water splitting. This work offers profound insights into the OER mechanism and a crucial strategy for enhancing the electrocatalytic activity of spinel oxides.