Surfactant-assisted copper electrodeposition: role of SDS on nucleation kinetics, surface area, and catalytic activity for CO2 reduction
摘要
This study reports the nucleation and growth of copper onto glassy carbon in an acidic solution in the presence of sodium dodecyl sulphate. Various influencing factors were examined, including the concentration of copper ions, nature of the cation of the background electrolyte, concentration of sodium dodecyl sulphate, temperature, and pH. The monovalent cations of the background electrolyte increased the average radius of the copper deposits in the order of lithium < sodium < ammonium < potassium and the electrodeposited copper nanoparticles demonstrated electrocatalytic activity in the electrochemical reduction of carbon dioxide. In the presence of sodium dodecyl sulphate, the nucleation mechanism changes from instantaneous to progressive. Under an applied potential of – 0.50 V for 20 min at pH = 1.5 and 40 °C, the presence of sodium dodecyl sulphate induced a distinct change in the surface morphology of copper deposits, as observed by scanning electron microscopy, transitioning from a nubby structure to dendritic crystal growth. Linear sweep voltammetry and electrochemical impedance spectroscopy indicated that the active surface of the copper electrodeposited in the presence of sodium dodecyl sulfate increased significantly with temperature. The catalyst deposited at 70°Cshowed the lowest charge transfer resistance of 75.3 Ω, a Tafel Slope of 239 mV dec−1, and the highest double-layer capacitance of 14.9 microfarads. Furthermore, lead underpotential deposition analysis confirmed an increase inelectroactive surface area, copperdeposited at 70 °C exhibited 14-fold active surface area compared to the smooth surface of polycrystalline copper. These findings indicate that copper electrodeposited in the presence of sodium dodecyl sulphate has potential as a material for the electrochemical reduction of carbon dioxide.
Graphical abstract