Electrochemical water splitting presents an optimal approach for generating hydrogen ( H2), a highly promising alternative energy source. Nevertheless, the slow kinetics of the electrochemical oxygen evolution reaction (OER) and the exorbitant cost, limited availability, and susceptibility to oxidation of noble metal-based electrocatalysts have compelled scientists to investigate cost-effective and efficient electrocatalysts. Bimetallic nanostructured materials have been demonstrated to exhibit improved catalytic performances for the oxygen evolution reaction (OER). Herein, we report carbon aerogel (CA) decorated with different molar ratios of Fe and Ni with enhanced OER activity. Microwave irradiation was involved as a novel strategy during the synthesis process. Inductively coupled plasma mass spectrometry (ICP-MS), X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscope (SEM), Energy dispersive X-ray spectroscopy (EDAX spectra and EDAX mapping), Transmission Electron Microscope (TEM), High-Resolution Transmission Electron Microscope (HR-TEM), and Selected Area Electron Diffraction (SAED) were used for physical characterizations of as-prepared material. Electrochemical potential towards OER was examined through cyclic voltammetry (CV), chronoamperometry, and electrochemical impedance spectroscopy (EIS). The FeNi/CA with optimized molar ratios exhibits low overpotential 377 mV at 10 mAcm− 2, smaller Tafel slope (94.5 mV dec− 1), and high turnover frequency (1.09 s− 1 at 300 mV). Other electrocatalytic parameters were also calculated and compared with previously reported OER catalysts. Additionally, chronoamperometric studies confirmed excellent electrochemical stability, as the OER activity shows minimal change even after a stability test lasting 3600 s. Moreover, the bimetallic (Fe and Ni) carbon aerogel exhibits faster catalytic kinetics and higher conductivity than the monometallic (Fe), which was observed through EIS investigation. This research opens up possibilities for utilizing bi- or multi-metallic anchored carbon aerogel with high conductivities and exceptional electrocatalytic performances in electrochemical energy conversion.

Carbon aerogel supported Ni–Fe catalysts for superior oxygen evolution reaction activity
    Abstract
    1 Introduction
    2 Experimental
        2.1 Materials
        2.2 Synthesis of carbon aerogel (CA)
        2.3 Synthesis of FeCA and Ni–FeCA catalysts
    3 Characterization
        3.1 Physical characterizations
        3.2 Electrochemical characterizations
        3.3 Electrode modification
    4 Results and discussion
        4.1 Physical characterizations
        4.2 Electrochemical characterization
            4.2.1 Calculation of kinetic parameters
            4.2.2 Determination of active surface area
            4.2.3 Stability test
            4.2.4 Electrochemical impedance spectroscopy (EIS)
    5 Conclusions
    Acknowledgements 
    References

• Muhammad Asim(Department of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan)
• Akbar Hussain(Department of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan)
• Meryem Samancı(Faculty of Engineering, Department of Chemical Engineering, Atatürk University, Erzurum 25240, Turkey)
• Naveed Kausar Janjua(Department of Chemistry, Quaid-I-Azam University, Islamabad 45320, Pakistan)
• Ayşe Bayrakçeken(Faculty of Engineering, Department of Chemical Engineering, Atatürk University, Erzurum 25240, Turkey, Department of Nanoscience and Nanoengineering, Atatürk University, Erzurum 25240, Turkey) Corresponding author