Modification of copper surface with palladium/platinum via galvanic displacement in ionic liquid for enhancing electrochemical nitrate reduction activities

Galvanic displacement in an ionic liquid was utilized to deposit palladium (Pd) or platinum (Pt) onto a copper (Cu) surface. Compared to water and conventional organic solvents, the relatively high viscosity of ionic liquids offers a distinct advantage in controlling the modification process, as the reduced mass transfer leads to a slower and more manageable displacement rate. This control is crucial; excessive deposition of Pd or Pt on the Cu surface can result in diminished, rather than enhanced, electrochemical nitrate reduction activity. Cu surfaces modified with an appropriate amount of Pd or Pt exhibited improved electrochemical performance toward both nitrate (NO₃⁻) and nitrite (NO₂⁻) reduction. This enhancement is likely attributed to the increased porosity induced during the galvanic displacement process, as well as synergistic effects between Pd/Pt and Cu. Overall, galvanic displacement in ionic liquids represents a practical and effective strategy for the synthesis of Cu-based electrocatalysts for electrochemical nitrate reduction.