Adsorption of ions at the Au(hkl) - solution interface

Aichen Chen

  • Adsorption of ions at the metal-electrolyte interface belongs to the most important electrochemical and technological processes. The fundamental knowledge about adsorption is important for the understanding and control of technological processes such as corrosion inhibition, electroplating, and electrocatalysis.
  • In my project, I will employ Cyclic Voltammetry, Differential Capacity, Chronocoulometry, Extended X-ray Absorption Fine Structure (EXAFS), and Scanning Tunneling Microscopy (STM) to study the adsorption of ions and their co-adsorption at Au(hkl) surface.

    • The objective of my research is:

    1. to study the effect of surface crystallography of Au (hkl) electrode on the adsorption of anions such as I- and OH- , and co-adsorption of these anions with cations such as Cs+ and Cu2+;
    2. to provide thermodynamic data which characterize adsorption of ions and their coadsorption, for example, charge density, interfacial tension, Gibbs excess, Gibbs energy, and electrosorption valency;
    3. to investigate the differences between adsorption of various anions at the same Au (hkl) - solution interface.

    For example, Zhichao Shi and I have investigated the adsorption of four different anions SO42- , Cl- , Br- and I- at Au(111) surface. The cyclic voltammetry curves and the surface concentration versus potential plots shown below indicate that the strength of anion adsorption at Au(111) surface decreases in the order : I- > Br- > Cl- > SO42- .

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