Efficient oxygen evolution using Ni@C catalysts: electrochemical optimization and long-term stability

Abstract

Effective electrocatalysis is vital for advancing renewable energy technology, and the study of hybrid nanomaterials has great potential to improve catalytic performance. A composite design like metallic nickel, onion-like carbon nanoparticles, and Ni@C nanocomposite (Ni@C) was proposed, produced by an easy solvent-free methodology at low temperatures. The produced nanocomposite was verified using Raman, FT-IR (Fourier Transform Infrared Spectra), FE-SEM (Field Emission-Scanning Electron Microscopy), UV–Vis (Ultraviolet Visible spectra), TGA (Thermal Gravimetric Analysis), and XRD (X-ray Diffraction). XRD characterization uses the Debye–Scherrer formula to determine the crystalline size of to produced Ni, C, and Ni@C, which are approximately 28.6, 0.7, and 25.1 nm, respectively. The fabricated Ni@C nanocomposite exhibited consistent XRD patterns and Raman spectra, indicating the preservation of crystallinity and carbon structure. FTIR and Raman spectra with the same wavelength verify the produced Ni@C. The mass loss of the substance was examined by using TGA analysis. FE-SEM analysis revealed morphological features suggesting that the Ni nanoparticles are embedded within an onion-like carbon matrix. The Ni@C nanocomposite showed excellent OER performance with a low overpotential of 210 mV at 10 mA cm⁻², a Tafel slope of 69.5 mV dec⁻¹, and impressive stability for 16 h at about 88% Faradaic efficiency, demonstrating the synergistic effect of nickel and the carbon matrix on catalytic efficiency and durability. Above all, results demonstrate that the synthesized nanocomposite at low temperatures shows a high performance of electrocatalytic activity for Oxygen Evolution Reaction (OER).

Graphical abstract