Developing stable and efficient electrocatalysts for the oxygen reduction reaction (ORR) is crucial for energy storage and conversion. In this study, highly active cobalt oxide (Co3O4) and reduced graphene oxide/cobalt oxide (rGO/Co3O4) nanocomposite electrocatalysts were synthesized using a simple co-precipitation method and a modified Hummer’s method (for preparing rGO). The physical and electrochemical properties were characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis), Thermogravimetric Analysis (TGA), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). XRD confirmed the successful synthesis of Co3O4 and rGO/Co3O4 nanoparticles. The Co3O4 retained its cubic spinel crystalline structure after rGO incorporation, with an additional diffraction peak corresponding to rGO. This confirms the presence of rGO and suggests that Co3O4 maintains its original structure in the composite. SEM revealed spherical Co3O4 nanoparticles with clustered rGO, while FTIR confirmed the presence of rGO in the Co3O4 matrix. TGA demonstrated enhanced thermal stability in rGO/Co3O4 compared to pure Co3O4. BET analysis showed a slight increase in surface area due to rGO incorporation. The energy bandgap of Co3O4 was found to be 1.92 eV with a sub-bandgap energy of 1.54 eV, whereas the rGO/Co3O4 nanocomposite exhibited a slightly reduced bandgap of 1.85 eV and sub-bandgap energy of 1.53 eV. CV measurements revealed that rGO/Co3O4 had superior specific capacitance (463 F g−1 at 5 mV s−1) compared to pure Co3O4 (330 F g−1) in a 0.1 M Na2SO4 electrolyte solution. EIS analysis indicated that the rGO/Co3O4 electrode exhibited lower charge transfer resistance, suggesting that rGO enhances the electrochemical activity and charge transport of Co3O4. These findings demonstrate the synergistic effect of rGO on Co3O4, highlighting the potential of the rGO/Co3O4 nanocomposite as an efficient electrocatalyst for energy storage and conversion application.

Developing active and stable rGO/Co₃O₄ nanocomposite electrocatalyst for oxygen reduction reaction

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发表日期：

2025年5月9日

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Girmaye Ambissa Begaw,
Ababay Ketema Worku,
Delele Worku Ayele,
Temesgen Atnafu Yemata

摘要

Developing stable and efficient electrocatalysts for the oxygen reduction reaction (ORR) is crucial for energy storage and conversion. In this study, highly active cobalt oxide (Co₃O₄) and reduced graphene oxide/cobalt oxide (rGO/Co₃O₄) nanocomposite electrocatalysts were synthesized using a simple co-precipitation method and a modified Hummer’s method (for preparing rGO). The physical and electrochemical properties were characterized using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet-Visible Spectroscopy (UV-Vis), Thermogravimetric Analysis (TGA), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS). XRD confirmed the successful synthesis of Co₃O₄ and rGO/Co₃O₄ nanoparticles. The Co₃O₄ retained its cubic spinel crystalline structure after rGO incorporation, with an additional diffraction peak corresponding to rGO. This confirms the presence of rGO and suggests that Co₃O₄ maintains its original structure in the composite. SEM revealed spherical Co₃O₄ nanoparticles with clustered rGO, while FTIR confirmed the presence of rGO in the Co₃O₄ matrix. TGA demonstrated enhanced thermal stability in rGO/Co₃O₄ compared to pure Co₃O₄. BET analysis showed a slight increase in surface area due to rGO incorporation. The energy bandgap of Co₃O₄ was found to be 1.92 eV with a sub-bandgap energy of 1.54 eV, whereas the rGO/Co₃O₄ nanocomposite exhibited a slightly reduced bandgap of 1.85 eV and sub-bandgap energy of 1.53 eV. CV measurements revealed that rGO/Co₃O₄ had superior specific capacitance (463 F g⁻¹ at 5 mV s⁻¹) compared to pure Co₃O₄ (330 F g⁻¹) in a 0.1 M Na₂SO₄ electrolyte solution. EIS analysis indicated that the rGO/Co₃O₄ electrode exhibited lower charge transfer resistance, suggesting that rGO enhances the electrochemical activity and charge transport of Co₃O₄. These findings demonstrate the synergistic effect of rGO on Co₃O₄, highlighting the potential of the rGO/Co₃O₄ nanocomposite as an efficient electrocatalyst for energy storage and conversion application.

Developing active and stable rGO/Co3O4 nanocomposite electrocatalyst for oxygen reduction reaction

摘要

Developing active and stable rGO/Co₃O₄ nanocomposite electrocatalyst for oxygen reduction reaction