Exploring Electrodeposition of Copper Oxide Nanomaterials and Self-Assembled Monolayer Formation from Aliphatic and Aromatic Thiols

Abstract

The superhydrophobic modification of Cu₂O electrodes has shown great promise in enhancing CO₂ reduction due to the formation of a triple phase boundary at the surface, allowing high concentrations of CO₂, which is not achievable in typical aqueous media. Herein, a two-step study is undertaken to investigate and optimize hydrophobic modification of electrodeposited Cu₂O nanomaterial electrodes. First, the electrochemical deposition potentials are altered in equivalent electrolyte conditions, which is found to alter the size of the deposited nanomaterials and the corresponding electrode surface roughness. Second, the electrodes are soaked in thiol-containing solutions containing a range of both aromatic and aliphatic thiols to achieve chemically modified self-assembled monolayers (SAMs) on the electrode surfaces. The surface and morphological properties of the electrodeposited electrodes are assessed with scanning electron microscopy, laser confocal, and atomic force microscopy (AFM) imaging. Confocal and AFM also allow the determination of the surface roughness of the electrodes at both the microscale and the nanoscale. The presence of SAM-modification is determined by X-ray photoelectron spectroscopy, and water contact angles are also measured on the nonthiol-modified and thiol-modified electrodes, and the contact angle is found to increase from 70°–100° to 130°–140°, close to superhydrophobic levels of contact angles.