Performance analysis of transition metal oxides on glassy carbon electrode for improved electrochemical water splitting

In response to the global demand for sustainable energy sources, this research explores the modification of glassy carbon electrodes with nickel oxide (NiO), cobalt oxide (CoO), zirconium oxide (ZrO₂), and manganese oxide (MnO₂) for improved electrochemical water splitting. A wet-chemical precipitation approach yielded metal oxides via a basic solution, producing distinct morphologies as revealed by SEM. XRD analysis confirmed the crystalline nature of the synthesized materials. FTIR spectra demonstrated characteristic absorption bands, affirming the formation of metal oxides. The three-electrode system employed platinum wire, Ag/AgCl, and glassy carbon electrodes for cyclic voltammetry, revealing synergistic effects in combined metal oxide modifications. The modified electrodes exhibited increased current density and distinctive redox peaks, indicating enhanced electrocatalytic activity. Cyclic voltammograms, recorded at various scan rates, elucidated the diffusion-controlled electrochemical processes on the modified electrodes. Active surface areas were estimated using the Randles-Sevcik equation, with NiO-modified electrode demonstrating superior electrochemical characteristics, showcasing 0.0209 cm². Furthermore, diffusion coefficients were calculated to assess electrocatalytic efficiency, and NiO exhibited the highest values, signifying maximum diffusion efficiency among the studied catalysts, with 9.11 × 10⁻⁵ cm²s⁻¹. Reproducibility and stability studies confirmed the electrodes’ reliability, showcasing minimal variation in anodic peak currents. Overall, these metal oxide-modified glassy carbon electrodes present promising candidates for efficient and stable electrochemical water splitting applications.