Reversing Mg suppression effect on Co-site water oxidation of MgCo2O4 based on vanadium-atom electronic affinity synergy with Mg sites toward electronic redistribution

Abstract

Active-site regeneration from d-band-center control engineering and electronic redistribution based on target-atom implantation is of enormous importance for efficient water oxidation. Here, low-activity Co catalytic sites of MgCo₂O₄ are reactivated for large-current (500 mA cm⁻²) and high-efficiency water oxidation through vanadium-atom electronic affinity synergy with Mg sites toward charge rearrangement around Co sites. Interestingly, very little vanadium (1.3 wt%) was implanted into MgCo₂O₄ to achieve atom-scale structure tailoring and electronic redistribution, reversing the Mg suppression effect on Co-site water oxidation of MgCo₂O₄. Vanadium-implantation-tailored MgCo₂O₄ coupled with MgO (V–MgCo₂O₄@MgO) exhibits significantly enhanced oxygen evolution reaction performance, with low overpotentials of 240 and 290 mV for 100 and 500 mA cm⁻², respectively, in 1 M KOH. Operating at 500 mA cm⁻², V–MgCo₂O₄@MgO has good catalytic stability for at least 20 hours. This work constructs excellent catalysts through atomic-level structural regulation and provides a new perspective for the principle of electronic-affinity synergy between V and Mg species toward Co–O bond optimization.