1D Co₆Mo₆C‐Based Heterojunctional Nanowires from Pyrolytically “Squeezing” PMo₁₂/ZIF‐67 Cubes for Efficient Overall Water Electrolysis

Abstract The bi‐transition‐metal interstitial compounds (BTMICs) are promising for water electrolysis. The previous BTMICs are usually composed of irregular particles. Here, this work shows the synthesis of novel 1D Co₆Mo₆C‐based heterojunction nanowires (1D Co/Co₆Mo₆C) with diameters about 50 nm and a length‐to‐diameter ratio about 20 for efficient water electrolysis. An interesting growth process based on pyrolytically “squeezing” PMo₁₂ (Phosphomolybdic acid)/ZIF‐67 (Zeolitic Imidazolate Framework‐67) cube precursor is demonstrated. The “squeezing” growth is related to the role of Mo species for isolating Co species. A series of tests and theoretical calculation show the mutual regulation of Co and Mo to optimize the electronic structure, accelerating H₂O dissociation and the reduction kinetics of H⁺. Additionally, the nanowires provide pathways for electron transfer and the transmission of reactants. Consequently, the 1D Co/Co₆Mo₆C exhibits high activity for hydrogen evolution reaction (η₁₀ of 31 mV) and oxygen evolution reaction (η₁₀ of 210 mV) in 1 m KOH. The electrolytic cell based on 1D Co/Co₆Mo₆C requires a low voltage of 1.43 V to drive 10 mA cm⁻². The catalyst also exhibits good HER performance in 1 m phosphate‐buffered saline solution, exceeding Pt/C at a current density >42 mA cm⁻².