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Exploring bifunctional electrocatalysts for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), which combine the features of effective electrocatalytic activity, high electrical conductivity, and superior stability, remains a significant challenge for rechargeable Zn–air batteries (ZABs). Herein, we report a material, selenium (Se)-doped CoSe2 embedded in carbon nanofibers (CNFs) (denoted as Se–CoSe2/CNFs), which was synthesized as a bifunctional electrocatalyst for ZABs via electrospinning combined with in situ growth of Zeolitic Imidazolate Framework-67 strategy, followed by carbonization and a facile selenization process. The as-synthesized Se–CoSe2/CNF electrode exhibits satisfactory electrochemical performance in an alkaline environment with a low overpotential of 325 mV at 10 mA cm−2 toward OER and a half-wave potential of 0.80 V for ORR. Remarkably, the Se–CoSe2/CNF catalyst-based ZAB shows a peak power density of 149.4 mW cm−2 and the voltage window barely changes after 180 h of cycling at 5 mA cm−2, which proves its great potential application for advanced bifunctional electrocatalysis in ZABs. [ABSTRACT FROM AUTHOR]

In this study, carbon nanofibers (CNFs) embedding molybdenum carbide (Mo 2 C)/cobalt (Co)-molybdenum (Mo) bimetallic carbide heterostructure electrocatalysts (denoted as A-B/CNFs) were prepared via electrospinning and high-temperature carbonization. Owing to the synergistic interaction between Co 6 Mo 6 C 2 and Mo 2 C components, the catalyst activity is improved. Furthermore, the rich mesoporous structure and electrical conductivity of CNFs, accelerate the reaction kinetics. As a result, the optimized Co 6 Mo 6 C 2 -Mo 2 C/CNFs-1 has excellent bifunctional electrocatalytic activity. With the current density of 10 mA cm−2, the hydrogen evolution reaction (HER) overpotential is only 94 mV, and the oxygen evolution reaction (OER) overpotential is 295 mV in an alkaline electrolyte. Building an alkaline electrolyzer with Co 6 Mo 6 C 2 -Mo 2 C/CNFs-1 as the anode and cathode electrodes requires a low cell voltage of only 1.66 V to achieve the current density of 10 mA cm−2, while maintaining ideal durability. This research offers a versatile and effective approach to creating bimetallic-based monolithic hydrolysis electrocatalysts. [Display omitted] • Co 6 Mo 6 C 2 -Mo 2 C/CNFs were synthesized through a two-step method. • Co 6 Mo 6 C 2 -Mo 2 C/CNFs-1 exhibited bifunctional activity for water splitting. • Overpotentials of HER and OER are 94 mV and 295 mV to deliver 10 mA cm−2. • A cell voltage of only 1.66 V was needed for overall water splitting. [ABSTRACT FROM AUTHOR]

Carbon nanofiber-based amorphous cobalt oxide (CoxOy/CNFs) embedded with Ag have been prepared by a simple electrospinning technique followed by heat treatment. Because the composite material prepared by this method showed good flexibility, addition of a conductive agent and binder is not required for use as an electrode material in supercapacitors. The Co-Ag/CNFs composite materials exhibited remarkably improved electrical conductivity and specific capacitance with good cycling stability in comparison with electrodes based on CoxOy/CNFs, owing to the presence of Ag; For instance, the Co-Ag/CNFs(2) composite electrode exhibited specific capacitance of 698 F g−1 at 1 A g−1 and good cycling stability with ∼ 81.1% capacitance retention over 3000 cycles. The composite materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD) analysis, Raman spectra, and thermogravimetric analysis (TGA), confirming successful combination of the amorphous cobalt oxide and silver metal element with the carbon nanofibers. [ABSTRACT FROM AUTHOR]