Ni-modulated Co–N4 electronic configuration enables high-current-density oxygen evolution

MOF-derived NiCo/NPC electrocatalyst was constructed with tailored M-N 4 coordination environments. • Ni incorporation regulated Co electronic structures for accelerated oxygen evolution reaction. • DFT calculations elucidated the electronic modulation mechanism and optimized OER energetics. The development of efficient, low-cost, and scalable oxygen evolution reaction (OER) catalysts is crucial for practical water electrolysis. Herein, a MOF-derived NiCo/NPC electrocatalyst containing predominantly atomically dispersed Co–N 4 /Ni–N 4 sites is prepared by controlled Ni incorporation into ZIF-67-derived porous carbon. The optimized 50% NiCo/NPC exhibits an overpotential of 207 mV at 10 m⋅A cm⁻ 2 , a Tafel slope of 51.6 mV⋅dec⁻ 1 , and stable operation for over 100 h, outperforming Co/NPC and commercial RuO 2 . Aberration-corrected HAADF-STEM directly visualizes atomically dispersed Co and Ni species, while synchrotron X-ray absorption spectroscopy confirms the Co–N 4 coordination environment and reveals that Ni incorporation modifies the electronic environment of the Co sites. Density functional theory calculations further show that Ni incorporation shifts the Co d -band center toward the Fermi level and lowers the energy barrier of the rate-determining step, accounting for the enhanced OER activity. In an anion exchange membrane water electrolyzer, the catalyst delivers current densities of 1000 and 4000 mA ⋅cm⁻ 2 at 2.02 and 2.46 V, respectively. This work provides an effective strategy for improving the OER performance of MOF-derived electrocatalysts through regulating the electronic structure of Co active sites. Download: Download high-res image (186KB) Download: Download full-size image Ni-doped ZIF-67 is converted via pyrolysis into morphology-retained Co–N 4 and Ni–N 4 single-atom active sites embedded in N-doped porous carbon (NiCo/NPC). Benefiting from the Ni-induced electronic modulation of Co active sites, together with the enhanced conductivity of the carbon framework, the catalyst achieves efficient and durable OER performance with a low overpotential.