The exploration and design of highly active, low-cost, transition metal-based electrocatalysts are crucial for large-scale green hydrogen production. Here, the heterostructure of oxygen-coordinated cobalt single atoms with O-doped carbon and CoO nanowires (Co-O-C-O/CoO/CF) is constructed for efficient and stable HER at industrial current densities. Benefiting from the synergistic effect of O doping and CoO nanowires, Co-O-C-O/CoO/CF exhibits extremely low overpotentials of 24.8, 229, and 239 mV to achieve current densities of 10, 500, and 1000 mA cm−2 in 1.0 M KOH solution, respectively, and operates stably for 1000 h at 1000 mA cm−2. Additionally, when coupled with NiFe-LDH in a self-assembled electrolyzer, it delivers a high current density of 1000 mA cm−2 at 1.97 V, along with outstanding stability, outperforming Pt/C||NiFe-LDH and most reported electrolyzers. Density functional theory (DFT) calculations reveal that the optimized d-band center and binding strength of H* and OH* intermediates for Co-O-C-O/CoO/CF lower the energy barrier of the rate-determining step. This work provides a new pathway for engineering Co-based catalysts for green hydrogen production at industrial current densities.
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