Roughness Factors of Electrodeposited Nanostructured Copper Foams

Area of Science:

• Electrochemistry
• Materials Science
• Nanotechnology

Background:

• Copper-based electrocatalysts are vital for CO2 and nitrate electroreduction.
• Three-dimensional nanostructured electrodes offer enhanced charge transfer and mass transport.
• Accurate determination of the real surface area (RSA) of high-surface-area copper electrodes is often overlooked.

Purpose of the Study:

• To investigate the roughness factors of electrodeposited copper foams.
• To demonstrate the applicability of lead underpotential deposition (UPD) for determining the RSA of copper deposits with hierarchical porosity.
• To optimize experimental conditions for accurate RSA estimation, minimizing diffusion and background current limitations.

Main Methods:

• Fabrication of electrodeposited copper foams using the hydrogen bubble dynamic template technique.
• Utilizing underpotential deposition (UPD) of lead (Pb) for RSA determination.
• Systematic exploration of lead ion concentration, stirring rate, scan rate, deposition time, and solution pH to optimize measurement conditions.

Main Results:

• Optimized Pb UPD protocol accurately estimates RSA for copper deposits with hierarchical porosity.
• Roughness factors as high as 400 were determined for 100 µm thick copper foams.
• This corresponds to a specific surface area of approximately 6 m²·g⁻¹.

Conclusions:

• Lead UPD is a reliable method for quantifying the RSA of nanostructured copper electrocatalysts.
• The developed protocol provides accurate surface area measurements for materials with complex porosity.
• This method can be extended to estimate the RSA of other copper-based electrocatalytic materials.