Magnetic graphene vacancies: atomic-scale O2 scissors mediated by antiferromagnetic exchange interaction–spin-orbit selective coupling effects

Abstract

The serious corrosion of electrode caused by hydrogen peroxide (H₂O₂) generated by noble metal catalyst through two-electron path is the key bottleneck of large-scale application of fuel cell. Based on the study of the structure–activity relationship between defect size and oxygen reduction reaction (ORR) activity of graphene, a strategy is proposed to use the single-atom vacancy (SAV) of graphene to induce electrons to preferentially fill the antibonding orbital (π*_p) of oxygen (O₂) and achieve four-electron path selectivity far exceeding conventional carbon defects via Yeager-type adsorption. Among them, a new mechanism of electron transfer induced by the magnetic properties of SAV and O₂ (spin inversion induced by antiferromagnetic exchange and selective injection of the same spin orbitals (p_z-π*_p)) is the key to realize the strong electron transfer and shear of O₂. In thermodynamic analysis, the magnetic SAV has the lowest ORR overpotential (0.26 V) and the highest *OOH desorption barrier, showing a unique four-electron path selectivity. The above results will provide new insights into the electron transfer mechanism of magnetic materials and fill the theoretical gap of magnetism in the development of atomic scale construction of graphene defects, non-metallic catalysts for fuel cells, and corrosion resistance technology.