Abstract: It is of essential importance to exploit electrocatalysts with excellent performance for anodic reactions in electrochemical water splitting, such as oxygen evolution reaction (OER) and urea oxidation reaction (UOR). Herein, we delicately constructed a coaxial nanocable-like structure containing Cu foam-supported CuO NWs as core and Ni(OH)₂@FeOOH heterogeneous nanosheets as a porous sheath (i.e., CuO@Ni(OH)₂@FeOOH NWs/CF). The particular architecture with 1D nanoarray frameworks in-situ grown on 3D conductive substrate and hierarchical microstructure ensures the adequate exposure of the active sites, facilitative electron/mass transfer, and high structural stability. Combined experimentation and DFT calculation demonstrate that Ni(OH)₂ and CuO in the hybrid served as active metal ions and scaffold for providing a fast electron conducting path, respectively. Meanwhile, FeOOH acted as an inductive agent to attract charge reorganization of adjacent Ni sites, thus modulating the electron structure and optimizing the d-band centers. Strengthened by the above desirable characteristics, CuO@Ni(OH)₂@FeOOH NWs/CF exhibited superior electrocatalytic activities towards both OER and UOR with a small overpotential of 310 mV and low potential of 1.37 V at 100 mA cm^-2, respectively, as well as the expected electrocatalytic stability. This work affords a way to design highly active catalysts via constructing heterojunctions for various applications.

Key words: Oxygen evolution reaction, Urea oxidation reaction, Self-supported electrode, Nanoarray, Interfacial interaction