Electrochemical crystal adsorption studies

Uchida H, Ikeda N, Watanahe M. 1997. Electrochemical quartz crystal microhalance study of copper ad-atoms on gold electrodes. Part II. Further discussion on the specific adsorption of anions from the solutions. J Electroanal Chem 424 5-12. 

Below, we describe two examples that illustrate electrochemical applications of STM. Other topics that can be studied by solution-phase STM include surface reconstructions of single crystals, adsorption of molecules, and anodic dissolution [59,60]. 

Jia, X., Xie, Q., Zhang, Y., Yao, S. (2007). Simultaneous quartz crystal microbalance-electrochemical impedance spectroscopy study on the adsorption of anti-human immunoglobulin G and its immunoreaction at nanomaterial-modified Au electrode surfaces. Anal. Sci., 23, 689-696. 

Among the ex situ methods that can be employed in surface analysis, low-energy electron diffraction (LEED) and x-ray photoelectron spectroscopy (XPS) can give the crystal structure and the nature of the surface ad-layers after the electrochemical and adsorption experiments as explained in this chapter [31,32]. Among the in situ non-electrochemical techniques, the radiotracer method [33] gives information about the adsorbed quantities however, infrared spectroscopy in FTIR mode [34] allows the identity of the bonding of the adsorbed molecules, and finally ellipsometry [35] makes possible the study of extremely thin films. Recently, some optical methods such as reflectance, x-ray diffraction, and second harmonic generation (SHG) [36] have been added to this list. 

Fig.1 Electrochemical quartz crystal microbalance schematic of the three-electrode setup used for carrying out the electropolymerization/adsorption studies presented later in this chapter. This figure was reprinted with permission from [71]...

In addition to the information on the adsorbed anion, this methodology provides detailed information on the potential-dependent behavior of solvent and supporting electrolyte molecules present in the electrochemical interfaces. Adsorption of HSO /SOl-, CIO4, CN on both single crystal and polycrystalline surfaces (Pt, Au) were studied. ... 

SAMs are generating attention for numerous potential uses ranging from chromatography [SO] to substrates for liquid crystal alignment [SI]. Most attention has been focused on future application as nonlinear optical devices [49] however, their use to control electron transfer at electrochemical surfaces has already been realized [S2], In addition, they provide ideal model surfaces for studies of protein adsorption [S3]. 

Dynamics of Crystal Growth hi the preceding section we illustrated the use of a lattice Monte Carlo method related to the study of equilibrium properties. The KMC and DMC method discussed above was applied to the study of dynamic electrochemical nucleation and growth phenomena, where two types of processes were considered adsorption of an adatom on the surface and its diffusion in different environments. 

Gao, G., Y. Wurm et al. (1997). Electrochemical quartz crystal microbalance, voltammetry, spectroelectrochemical, and microscopic studies of adsorption behavior for (7E,7 Z)-diphenyl-7,7 -diapocarotene electrochemical oxidation product. J. Phys. Chem. B 101 2038-2045. 

Electrochemical quartz crystal microbalance (EQCM) has been used [65] to study adsorption/desorption of iodide on Au(lll) electrodes. The coverages obtained at different potentials were quite close to those estimated from STM images and SXS measurements. 

Jusys and Bruckenstein [84] have used electrochemical quartz crystal microbalance to study adsorption/desorption of perchlorate and perrhenate ions on a bare polycrystalline Au electrode. The change in the equivalent mass was undoubtedly assigned to the adsorption of both anions in the double-layer region of Au electrode. 

Adsorption of glutathione on a gold electrode has been studied [310] using electrochemical quartz crystal impedance, electrochemical impedance spectroscopy, and CV. 

Pb UPD on polycrystalline An electrode in 0.1 M perchloric acid solution has been studied by Henderson et al. [484]. In this study, CV, electrochemical quartz crystal microbalance (EQCM), and probe beam deflection methods have been used. It has been found that Pb UPD proceeds in three steps. The first step comprised water ejection from the gold surface. This step was followed by metal UPD accompanied by the removal of the adsorbed OH. Also, Zeng and Bruckenstein have studied UPD and adsorption of Pb on pc-Au electrodes, applying XPS and TOF-SIMS method in case of 0.1 M NaCl electrolyte [485], and EQCM in case of 0.1 M NaCl04 and 0.1 M NaCl electrolytes [486]. In the presence of chloride anions, the adsorption of Pb—Cl complex has been found. 

Shi et al. [68] have studied iodine adsorption on Ag using atomic-resolution electrochemical scanning turmehng microscopy (ECSTM) method. Distinctly different iodine adlayer structures and surface diffusion behavior were observed on mechanically polished pc-Ag in comparison with those obtained on single-crystal electrodes. 

Underpotential deposition (UPD) is the electrochemical adsorption and (partial) reduction of a submonolayer or monolayer of cations on a foreign metal substrate at potentials more positive than the reversible potential of the deposited metal [141]. The UPD phenomenon is used in many fundamental and applied studies because it offers a means of controlling coverages during electrodeposition in a very concise manner. Until recently, most of the information obtained about the structure of the overlayers deposited on single crystal surfaces has come from indirect means such as current-voltage analysis or by analysis of the deposited films after transfer to a UHV chamber [141]. 

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