Unlocking dual functionality: novel Ag-doped CuCo2O4 for electro-catalytic and photochemical oxidation reactions

The design and development of novel materials for dual electrocatalytic and photochemical applications are of high interest due to their widespread applications in energy and organic transformations. Here, we report the fabrication of CuCo₂O₄ (thereafter named CCO) and 10% Ag-doped CuCo₂O₄ (Ag_0.1Cu_0.9Co₂O₄; thereafter named Ag–CCO) nanomaterials via the co-precipitation method and their characterization by UV-Vis, powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), BET, XPS, TGA, and EDX studies. The Ag–CCO catalyst demonstrated excellent efficiency in the electrochemical water oxidation reaction (WOR)/oxygen evolution reaction (OER) and photocatalytic oxidation of alcohols, anilines, and methylene blue (MB). The Ag–CCO material showed superior catalytic activity compared to CCO for both the electrocatalytic WOR and photochemical oxidation reactions. For WOR, Tafel slopes of 60.8 and 39.2 mV dec⁻¹ are found for the CCO and Ag–CCO, respectively. The lower Tafel slope (39.2 mV dec⁻¹) and high current density made the Ag–CCO an ideal catalyst for water splitting. On the other hand, the Ag–CCO material also displayed photocatalytic activity in the selective oxidation of alcohols to carbonyl compounds and oxidative azo-coupling of anilines to aromatic azos in good to excellent yields. In addition, Ag–CCO also exhibited efficient charge transfer activity and facilitated efficient hot electron transfer in MB, resulting in Azure A, Azure B, Azure C, and thionine over time. Meanwhile, CCO was found to be inefficient in transferring hot electrons.