Über die bei verschiedenen stationären Überspannungswerten auf Edelmetallelektroden adsorbierten, mittels Ladekurven bestimmbaren Wasserstoffmengen

124

Section: Xo Io ~D ~O Bx/~"mentioning

confidence: 99%

Recent Advances in the Science of Electrocatalysis

Yeager

1981

124

“…The formation and dissolution of an oxide film on platinum are phenomena well known to electrochemists (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13). The oxide film may be formed chemically (1)(2)(3)(4)(5) or electrochemically (1,4,(6)(7)(8)(9)(10)(11)(12) and may be formed or removed either chemically (1)(2)(3)13) or electrochemically (1, 3, 6-8, 10, 11, 13). Young (14) has thoroughly reviewed the literature on this subject.…”

mentioning

confidence: 99%

Formation and Dissolution of Platinum Oxide Film: Mechanism and Kinetics

Feldberg

Enke²,

Bricker

1963

106

Oxide film formation on a smooth platinum electrode in perchloric acid solution has been studied as a function of potential, current, time, and electrode history, using constant current and controlled potential techniques. Anodic film formation proceeds through two, single electron steps: a slow step followed by a fast (reversible) one. During film reduction the fast step occurs first, followed by the slow step. In the case of constant current reduction the slow step does not occur, and the film is exactly half-reduced. Complete reduction requires several hours at a controlled potential. Three electrode states are thus clearly defined: oxidized, half-reduced (active), and completely reduced or clean. A single kinetic equation quantitatively relates the current, potential, and time parameters, predicts the initial rate of opencircuit potential decay following film formation, and strongly suggests that the oxide is a chemisorbed film.

“…It has been well substantiated that a surface oxidation occurs on a platinum electrode which is functioning as an anode in water solutions (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17). The surface oxide thus formed on platinum has the unusual ability to transfer charge from the metal to a reactant in the solution without an appreciable increase in the thickness of the film.…”

mentioning

confidence: 99%

The Electrolytic Formation and Dissolution of Oxide Films on Platinum

Laitinen¹,

Enke²

1960

167

105

The extent of surface oxidation of a smooth platinum electrode and the electrode capacitance were measured for various conditions of anodization. The electrolytic formation of the surface platinum oxide is shown to be a highly irreversible reaction. A mechanism which involves a hydroxyl radical intermediate of the oxygen evolution reaction is proposed for the surface oxide formation reaction. This mechanism is supported by the shapes of the anodic and cathodic charging curves on platinum and the interrelationships of the electrode potential, the electrode capacitance, and the extent of surface oxidation. From these same interrelationships it was also concluded that the steady‐state evolution of oxygen occurs on a surface which has at least one atom of oxygen per surface platinum atom and that the rate‐determining step in the oxygen evolution reaction is the electrolytic discharge of oxygen‐containing radicals which are adsorbed on the electrode surface. The surface oxide is reduced at potentials several hundred millivolts cathodic to the potential required to form the oxide. The reduction of the surface oxide is shown to be a first order reaction. The rate of the reduction increases with increasingly cathodic electrode potential.