Nitrogen-Doped Cobalt Nanoparticles Anchored Porous Carbon Nanorods for Efficient Electrocatalytic Water Splitting

The effective application of nonprecious electrocatalysts for water splitting is constrained by slow kinetics and inferior durability compared to noble metals. Here, we introduce a scalable electrospinning-carbonization strategy to fabricate cobalt nanoparticles anchored in nitrogen-doped carbon nanorods with cobalt metal organic framework (Co-MOF)/polyacrylonitrile (PAN) precursors. By adjusting the Co-MOF/PAN ratio, we attained meticulous regulation of nanorod diameter, porosity, and cobalt dispersion, with Co@CNR-II (0.6:1) achieving the most favorable architecture. Synchrotron X-ray absorption spectroscopy and X-ray photoelectron spectroscopy jointly reveal that synergistic Co–Co–N x coordination is the predominant active motif. Complementary density functional theory calculations indicate that cobalt incorporation reduces the band gap, improves conductivity, and facilitates charge transfer, whereas water adsorption and reaction pathway simulations show enhanced H 2 O interaction and diminished energy barriers compared to commercial Pt/C. This nanorod architecture facilitates fast electron and mass transport with numerous active sites, resulting in low overpotentials of 62 mV for the hydrogen evolution reaction and 339 mV for the oxygen evolution reaction at 10 mA cm –2 . In a two-electrode setup, it attained 10 mA cm –2 at 1.66 V with remarkable 210 h stability, confirming efficient overall water splitting. This study proposes a stable and scalable design concept for cobalt-based catalysts, enhancing the development of economical and durable bifunctional electrocatalysts for sustainable hydrogen production.