Light-Assisted CO₂ Conversion on Electrodeposited Cu₂O-Based Composite Layers

Light-assisted electrochemical conversion of carbon dioxide is widely investigated as a potential pathway toward sustainable energy and carbon utilization technologies. Cu₂O-based materials remain central to these studies due to their ability to facilitate complex CO₂ reduction processes. In this contribution, we focus on the relationship between electrodeposition conditions and the photoelectrocatalytic performance of copper-based composite layers during light-assisted CO₂ conversion. The composite layers were prepared by electrodeposition from alkaline electrolytes based on copper(II) lactate complexes, containing dispersed reduced graphene oxide (rGO). The layers were electrodeposited at different potentials in order to optimize their selectivity and efficiency toward ethylene formation. The electrodeposited layers were examined under dark and under illumination in CO₂-saturated aqueous electrolytes to assess the influence of synthesis parameters on their photoelectrochemical performance in the conversion of CO₂ to hydrocarbons. The analysis highlights qualitative trends linking electrodeposition conditions with changes in the photoelectrochemical performance of the obtained layers. Differences observed between materials obtained at varied deposition potentials point to the role of material composition in the modification of charge-transfer processes during light-assisted CO₂ reduction. The presence of rGO further contributes to modulation of the photoelectrochemical response, indicating its influence on interfacial charge transport under illuminated conditions. The results emphasize electrodeposition as a versatile method of synthesis of composite layers for PEC CO₂ conversion. Obtained results provide insight into how controlled adjustment of electrodeposition parameters can guide the design of materials for light-assisted electrochemical CO₂ conversion.