AC Impedance Investigation of Copper in Acid Solution

Abstract

Many aspects of the electrochemistry of copper in aqueous acid solution are dominated by the presence of low coverage, high energy, metastable surface states which constitute surface active sites. Such states undergo quasireversible redox transitions within the double-layer region, and these species play a vital role in electrocatalytic and electrodeposition processes in the case of this electrode system. In the present work this aspect of copper electrochemistry is explored using alternating current impedance techniques and one of the main conclusions drawn is that there are often important aspects of surface electrochemistry that can only be rationalized in terms of the unusual properties of the active, highly defective, state of the surface.

Tuning Electrochemical Bistability by Surface Area Blocking in the Cathodic Deposition of Copper

“…They are related to two limiting steps which compete simultaneously and are affected by the applied voltage—high frequencies describe activation control, whereas low frequencies describe mass transport control. 57 In the latter, the Warburg impedance shows a decreasing imaginary component, resulting in the observed trend 58 (Figure 4a, black line). It has been also ascribed that low-frequency loops are strongly dependent of the growth mode of copper deposits.…”

“…Figure a shows that the process has distinct time scales with the presence of two semicircles, one at higher and another at lower frequencies. They are related to two limiting steps which compete simultaneously and are affected by the applied voltagehigh frequencies describe activation control, whereas low frequencies describe mass transport control . In the latter, the Warburg impedance shows a decreasing imaginary component, resulting in the observed trend (Figure a, black line).…”

Catalytic and Electrocatalytic Hydrogenation of Nitroarenes

“…For example, the atoms or clusters that are metastable on the surface of Cu act as a reversible redox mediator and can be used in electrocatalytic reduction systems such as nitrobenzene. 75 However, it is more typical to apply soluble redox mediators in the bulk solution. By this means, it can usually avoid the direct reduction of the reactant on the electrode surface to improve the selectivity, and on the other hand, the reaction conditions are milder and favorable to reduce the overpotential.…”

Study the Mettalic Finishing and Corrosion Control Processes for Carbon Steel over Head Pipes Using Polymer Molecules

“…However steel suffers from corrosion in electrolytes because of the presence of cementite in its structure [3,4]. Cementite [Fe 3 C] which does not form solid solution with iron [Fe] and hence leads to steel corrosion through the formation of a multitude of microscopic galvanic cells of the type : Fe / Electrolyte /Fe 3 C (Cementite) To protect steel structures against corrosion different techniques are used such as cathodic protection, anodic protection, coating and the use of inhibitors [4][5][6][7]. Inhibitors are materials that may be injected into the system.…”