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

Superhydrophobic modification of Cu₂O electrodes has shown great promise to enhance CO₂ reduction due to the formation of a triple phase boundary at the surface, allowing high concentrations of CO₂ not achievable in typical aqueous media. Here we undertake a two-step study to investigate and optimize hydrophobic modification of electrodeposited Cu₂O nanomaterial electrodes. Firstly, the electrochemical deposition potentials were altered in equivalent electrolyte conditions, which was found to alter the size of the deposited nanomaterials and the corresponding electrode surface roughness. Secondly, the electrodes were 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 were assessed with scanning electron microscopy (SEM), laser confocal, and atomic force microscopy (AFM) imaging. Confocal and AFM also allowed the determination of the surface roughness of the electrodes at both the microscale and the nanoscale. The presence of SAM-modification was determined by X-ray photoelectron spectroscopy (XPS) and water contact angles were also measured on the non-thiol modified and thiol modified electrodes, and found the contact angle to increase from 70 – 100° to 130 – 140°, close to superhydrophobic levels of contact angles.