Electrochemical quartz microbalance

Despite H/D kinetic isotope studies, application of modern techniques such as atomic force microscopy (AFM), electrochemical mass spectrometry (EMS) [60], and electrochemical quartz microbalance (EQCM), the mechanism of electroless nickel and cobalt, whatever reducing agent is involved, continues to be the subject of much discussion and varying opinions. 

Daujotis et al. [32] have described the use of electrochemical quartz microbalance for the quantitative studies on monolayer adsorption on working mercury electrodes. Mercury was deposited on Pt at negative potentials (—0.4 to —0.5 V versus AgjAgCljKClgat)- In order to avoid undesirable transformation of mercury into, for example, larger droplets, the thickness of mercury film could not exceed 20 nm. Then, the linear dependence of the frequency change on the added mass was achieved. Applicability of such an electrode for EQCM measurements has been demonstrated by performing electroreduction of Pb(II) and T1(I), as an example. 

Figure 15 Modified Pourbaix diagram for Ti02 illustrating the origins of pH-dependent band energetics and the pH-independent back-ET kinetics for covalently anchored dye species. The open circles are experimentally determined values of Ecb (combined electrochemical quartz microbalance and reflectance measurements). The driving force for the overall back reaction [coupled electron and proton transfer cf. Eqs. (10) and (11) for analogous reactions at Sn02] is pH dependent, but the driving force for the back ET in isolation [cf. Eq. (10)] is pH independent. (Data from Ref. 78.)...

As already mentioned, the principle of electroneutrality must be fulfilled in charged polymers. Consequently, in freshly prepared p-doped polymers, anions must compensate the positive charges within the polymeric chains. However, spectroelectrochemical studies [114], electrochemical quartz microbalance (EQMC) measurements [115], and SIMS and XPS measurements [116] on the mechanism of ion transport during charging and discharging of conducting polymers prove that discharging involves not only the expulsion of... 

Two additional electrochemical techniques, electrochemical quartz microbalance, EQCM and scanning atomic force electrochemical microscopy, can be mentioned. EQCM is based on the piezoelectric properties of quartz and permits the user to evaluate mass changes occurring on an electrode supported over a quartz lamina. 

Mechanical investigations, for example, gravimetric measurements with the electrochemical quartz microbalance. Measurements of elasticity and deformation, for example, by indentation or by the film deflection method. 

The electrochemical quartz microbalance (EQCM) is a powerful measuring technique commonly used by electrochemists as weU by scientists coming from other fields, like physicists and biologists. One can find descriptions of the EQCM technique and of its applications in textbooks dealing with fundamentals of electrochemistry [1 ]. This fact proves the importance of this technique within the electrochemical scientific community. 

Wudy F, Stock C, Gores HI (2009) Measurement methods electrochemical quartz microbalance. In Encyclopedia of electrochemical powCT sources, vol 3. Elsevier, Oxford, UK, pp 660-672... 

Henderson Ml, Hillman AR, Vieil E, Lopez C (1998) Combined electrochemical quartz microbalance (EQCM) and probe beam defection (PBD) validation of the technique by a study of silver ion mass transport. J Electroanal Chem 458 241-248 Henderson MJ, Hillman AR, Vieil E (1999) Ion and solvent transfer discrimination at a poly(o-toluidine) film exposed to HC104 by combined electrochemical quartz crystal microbalance (EQCM) and probe beam deflection (PBD). J Phys Chem B 103 8899-8907 Henderson MJ, French H, Hillman AR, Vieil E (1999) A combined EQCM and probe beam defection study of salicylate ion transfer at a polypyrrole modified electrode. Electrochem Solid State Lett 2(12) 631-633... 

Zar bska K, Skompska M (2011) Electrodeposition of CdS from acidic aqueous thiosulfate solution— invesitigationof the mechanism by electrochemical quartz microbalance technique. Electrochim Acta 56 5731... 

Toluidine Potentiostatic Au,SCE, 0.5 M H2SO4 Electrochemical quartz microbalance, capacity measurements 69... 

Henderson et al. [468] studied the behavior of Poll in an acidic perchloric acid solution with probe beam deflection and electrochemical quartz microbalance (EQMB) [468]. The degree of film hydration affected the relative contributions of protons and anions during the first redox cycle. During further cycles, a proton contribution was observed at electrode potentials around the first redox peak in the CV. During the second redox peak, electroneutrality was established by proton expulsion. 

EQMB, EQCM Electrochemical quartz microbalance ERS Electroreflectance spectroscopy... 

The growth of the polymer film can be followed by cyclic voltammetry since the current peaks related to the polymer redox transformations increase as more and more polymer is deposited. The increase of the surface mass can be detected by using an -> electrochemical quartz microbalance. Such an example is shown in the Figure. In this experiment the positive potential limit of cycling was gradually decreased in order to avoid overoxidation of the polyaniline (PANl) formed. It does not affect the rate of polymerization, i.e., the film growth, since the electrooxidation of aniline is an autocatalytic process. 

A. Bund and S. Neudeck. 2004. Effect of the solvent and the anion on the dop-ing/dedopingbehaviorofpoly(3,4-ethylenedioxythiophene)filmsstudiedwith the electrochemical quartz microbalance. / Phys Chem B 108(46) 17845-17850. A. Bund and R. Peipmann. 2008. Application of PEDOT layers for the electro-gravimetric detection of sulphate and phosphate in aqueous media. Electrochim Acta 53(ll) 3772-3778. 

C. Gabrielli, M. Keddam, F. Minouflet, and H. Perrot, Investigation of the anodic behaviour of iron in, sulfuric acid medium by the electrochemical quartz microbalance under ac regime. Mater. Sci. Forum, 185-188 631 (1995). 

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