Corrosion‐Resistant Copper Surfaces via Electrochemically‐Reduced Graphene Oxide Deposition

Abstract A single‐step electrochemical approach was developed to deposit electrochemically‐reduced graphene oxide (ERGO) films on copper substrates by reducing graphene oxide (GO) in an aqueous electrolyte. The ERGO coatings were thoroughly characterized using miscellaneous physicochemical and electrochemical techniques. The corrosion resistance of ERGO‐coated copper was evaluated using Tafel polarization measurements in a 3.5% NaCl solution. The ERGO layer significantly enhanced the corrosion resistance of copper, reducing the corrosion rate from 0.01038 mm/year (bare Cu) to 0.001118 mm/year (ERGO‐coated Cu), achieving a 90% reduction in corrosion rate. Additionally, the polarization resistance ( R p ) increased from 32.44 kΩ (bare Cu) to 2426.7 kΩ (ERGO‐coated Cu), indicating a substantial improvement in charge transfer resistance. The superior corrosion protection was attributed to the ERGO film's ability to act as a diffusion barrier, limiting direct exposure of the copper surface to the corrosive environment. However, its protective efficacy was influenced by defect density and porosity, which allowed some electrolyte penetration. FESEM analysis revealed that the ERGO coating evolved from initial cluster formation to a compact, entangled structure at extended deposition times, with a film thickness of 4 µm (1 min deposition) to 18 µm (200 min deposition). These findings underscore ERGO's potential as a cost‐effective, scalable, and moderately efficient protective coating for corrosion‐resistant applications.