Effect of Areal Parameter of Sputtered Cu Layers on C₂ Products for CO₂ Electroreduction

The CO2 electrochemical reduction (CO2ER) to produce valuable multicarbon products represents a promising approach for enhancing CO2 conversion. While previous research has investigated the impact of Cu electrode surface topography on C2 production, it is important to note that other parameters were also altered concurrently with changes in roughness. To isolate the specific effect of surface texture on CO2 electroreduction, this study prepared Cu layers with varying textures using the sputtering method with a varied sputtering time. To characterize the surface features of the sputtered Cu layers, the developed interfacial area ratio (Sdr), known as areal parameter, was introduced, with the aim of correlating it with C2 product selectivity. The results of this study indicate that the improved selectivity of C2 products can be attributed to higher Sdr values, primarily due to a rougher and finer surface texture that increases the local concentration of CO and OH–. This research underscores the significance of surface topography and offers perspectives for designing efficient Cu electrodes for the CO2ER.