Potentiodynamic electrochemical impedance spectroscopy: lead underpotential deposition on tellurium

Effects of anions on the underpotential deposition behavior of Cu on polycrystalline Pt

The process of Cu underpotential deposition (UPD) on polycrystalline Pt (pc Pt) has been investigated by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques using (bi)sulfate and perchlorate (with/without the addition of a small amount of NaCl) as supporting electrolytes, respectively. The results showed that the adsorption capacity of the anions influences both the reversibility and charge transfer resistance (R_ct) of Cu UPD reactions on pc Pt. With a negative shift of the applied potential, R_ct of the (bi)sulfate system decreases monotonously, whereas R_ct of the perchlorate system (with/without Cl⁻ ions) decreases at first and then increases. Cu UPD on pc Pt follows Langmuir-type adsorption and two-dimensional nucleation/growth mechanisms. The specific adsorption anions ((bi)sulfate and chloride ions) can not only enhance the Cu UPD process by decreasing R_ct, but also favor instantaneous 2D nucleation and subsequent grain growth. Finally, the possible deposition mechanisms of the Cu UPD process in the presence of specific adsorption anions were proposed.

Effects of anions on underpotential deposition behavior of Cu at polycrystalline Pt has been investigated by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy techniques.

Cyclic voltammetry as a sensitive method for in situ probing of chemical transformations in quantum dots

Cyclic voltammetry revealed processes responsible for the pH effect on the chemical stability of aqueous thiol-capped CdTe quantum dots.

Electrochemical impedance spectroscopy

This review describes recent advances in electrochemical impedance spectroscopy (EIS) with an emphasis on its novel applications to various electrochemistry-related problems. Section 1 discusses the development of new EIS techniques to reduce measurement time. For this purpose, various forms of multisine EIS techniques were first developed via a noise signal synthesized by mixing ac waves of various frequencies, followed by fast Fourier transform of the signal and the resulting current. Subsequently, an entirely new concept was introduced in which true white noise was used as an excitation source, followed by Fourier transform of both excitation and response signals. Section 2 describes novel applications of the newly developed techniques to time-resolved impedance measurements as well as to impedance imaging. Section 3 is devoted to recent applications of EIS techniques, specifically traditional measurements in various fields with a special emphasis on biosensor detections.