Investigating the oxidative synthesis of copper oxide nanowires: Wettability and photoelectrochemical insights

•Growth of copper oxide nanowires on copper foil by thermal oxidation in ambient environments: air, oxygen, and argon.•The contact angles in oxygen and argon synthesized samples were found to be 32.6° and 101.6°, respectively.•Photocurrent density of samples synthesized in air, argon, and oxygen was 1.02, 1.4, and 1.8 mA/cm², respectively.•We propose an inexpensive way to tune the wettability and PEC performance of copper foil by thermal treatment. In this report, we fabricated the copper oxide nanowires by thermally oxidizing copper foil in different ambient environments such as: air, argon, and oxygen. The as-synthesized samples showed very low reflectance properties, and the contact angle measurements revealed a wide range of contact angles, ranging from 32.6° to 101.6°. The difference in the wettability behavior was attributed to the varying proportions of cupric and cuprous oxide in the growth process, as well as the existence of oxygen vacancies. The presence of the adsorbed hydroxyl groups on the surface was found to greatly influence the hydrophilicity of the surface. Furthermore, the synthesized samples were tested as photoelectrochemical water-splitting electrodes to assess their performance. The photocurrent density of samples synthesized in air, argon, and oxygen was 1.02, 1.4, and 1.8 mA/cm2, respectively. The results showed that samples synthesized in an oxygen environment showed a lower charge transfer resistance at the electrode-electrolyte interface with the highest shift in flat band potential. The study demonstrates a cost-effective method to modify wetting properties and enhance the photoelectrochemical performance of the copper foil. [Display omitted]