ZIF-Derived Carbon Nanoarchitecture as a Bifunctional pH-Universal Electrocatalyst for Energy-Efficient Hydrogen Evolution

Abstract

Development of nonprecious metal-based electrocatalysts supporting hydrogen evolution reaction (HER) in the entire pH range has gained significant importance for harvesting green and renewable energy. Herein, we developed a novel electrocatalyst based on 3D carbon nanoarchitecture hybrid, which consists of CoP nanoparticles (CoP NPs) embedded into N-doped carbon nanotubes (NCNT), grafted on carbon polyhedron (CoP/NCNT-CP) that was prepared by carbonization and low-temperature phosphatization treatment of cobalt-based zeolite imidazole framework (ZIF). Benefiting from the strong synergistic effect and unique 3D structure, the CoP/NCNT-CP hybrid loaded on Ni foam exhibited excellent electrocatalytic HER performance in base with a low overpotential of 165 mV at a current density of 10 mA cm–2, which is competitive with the previously reported Co-based hybrid electrocatalysts. Furthermore, the CoP/NCNT-CP also demonstrated high HER electrocatalytic activities in both neutral and acidic conditions with the overpotentials of 203 and 305 mV at the current density of 10 mA cm–2. Additionally, the bifunctional CoP/NCNT-CP electrode simultaneously acted as an anode for hydrazine oxidation reaction (HzOR) and a cathode for HER. Excellent catalytic performance was demonstrated in base conditions with a low cell potential of 0.89 V at 10 mA cm–2, which was much lower than the voltage of overall water splitting (1.91 V) at the same current density.