Exploration of highly efficient bifunctional electrocatalysts for optimal hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) has been widely carried out, though it still remains a big challenge. Herein, a hierarchical CoO–Co4N@NiFe-LDH (layered-double-hydroxides) heterostructure electrode anchored on nickel foam (NF) is prepared via a developed three-step hydrothermal–nitridation–electrodeposition pathway. The fabricated CoO–Co4N@NiFe-LDH/NF electrode needs low overpotential values of 66 and 231 mV to supply a current density value of 10 mA cm–2 in aqueous solution of KOH (1 M) for HER and OER, respectively. The Tafel slopes and electrochemical impedance spectroscopy results display favorable reaction kinetics throughout the electrolysis process. Subsequently, an alkaline electrolyzer is assembled with CoO–Co4N@NiFe-LDH/NF, which serves both as the anode and cathode, yielding 10 mA cm–2 with a small voltage of 1.529 V and showing a robust stability for 28 h. Impressively, a urine-mediated electrolysis cell shows efficient catalytic activity as well, allowing to mount the sluggish OER during water splitting. To drive the urine-mediated electrolysis cell containing 0.33 M urea, a low voltage of 1.393 V is required, which is about 136 mV lower compared to the urea-free electrolysis cell. This work presents a solid step for the electrocatalytic generation of hydrogen through water splitting by harvesting low energy.

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Hydrogen is the most promising alternative energy source in the face of energy crisis, and water splitting is a green strategy for hydrogen generation. The oxygen evolution reaction (OER) is the essential half‐reaction in electrochemical water splitting, and thus development and exploration of electrocatalysts with excellent performance are vital to prompt the application of OER. Due to the unique electronic properties of NiTe and strong synergistic interaction between NiTe and FeOOH, NiTe@FeOOH hybrid nanorods were successfully fabricated on Ni foams (NF) by a hydrothermal reaction step and another in‐situ growth step for the first time without consuming any extra energy. The 3D structure of the NiTe@FeOOH/NF was confirmed by powder X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS) and energy dispersive spectrometry (EDS) mapping technologies. Electrochemical measurements showed that the as‐prepared NiTe@FeOOH/NF needs only an overpotential of 241 mV to achieve a current density of 10 mA cm−2 in 1.0 M KOH and requires 1.341 V to drive 10 mA cm−2 in 1 M KOH with a 0.33 M urea, showing excellent long‐term stability. The NiTe@FeOOH/NF as the bifunctional electrocatalyst in an electrolyzer shows high efficiency with a cell voltage of 1.50 V at 10 mA cm−2. This work can provide a new efficient method to construct highly active and cost‐effective OER catalysts.