The Anodic Oxidation of Copper Amalgam and Polycrystalline Copper Electrodes in LiOH Solution

Abstract

The anodie behavior of copper in lithium hydroxide solution was investigated at room temperature under controlled potential conditions. The electrodes were either saturated copper amalgams or small polycrystalline wires. Particular attention was focused on the copper (I) region. Two layerplanes of Cu~O were formed at anodic overpotentials following the dissolution of copper (I) hydroxy complexes on the COl~per amalgam electrodes. Some novel data are reported concerning the nucleation of holes in these layers during the reverse reaction. Behavior analogous to that of the amalgam electrodes was observed on the polycrystalline electrodes, except that a thick layer of Cu20 was also formed On top of the previously formed layer-planes. A model is proposed for the growth of this thick layer, and it is demonstrated that this model also describes the galvanostatic data acquired by earlier workers.* Electrochemical Society Active Member. ** Electrochemical Society Student Member.

Initial stages of anodic oxidation of polycrystalline copper electrodes in alkaline solution

“…1) with a potential negative to the peak due to formation of Cu20 (peak 2). Peak 3 is generally associated with formation of Cu(II) species [11,13,19,20]. Peaks 4 and 5 correspond to the Cu(II)/Cu(III) redox couple [11,19].…”

“…Recently, Fletcher et al [20] have reported cyclic voltammetry measurements on polycrystalline copper electrodes in 0.1 mol dm -3 LiOH. They concluded that the first anodic process is dissolution of Cu(I).…”

Characterization of anodic films formed on copper in 0.1M borax solution

“…The potential scan in the negative direction shows two well defined cathodic peaks at À0.385 V (Peak 3) and À0.665 V (Peak 4). Peak 1 has been associated with the formation of Cu 2 O film [3][4][5]11,13] and Peaks 2a and 2b have been related with the formation and growth of CuO, Cu(OH) 2 film [1,[4][5][6]9] until reaching a duplex structure of the oxide layer represented by Cu 2 O/CuO,Cu(OH) 2 [6,8,9] Peak 3 has been attributed to the electroreduction of a Cu (II) oxide outer layer to Cu 2 O and Peak 4 has been associated with the electroreduction of Cu 2 O to Cu.…”

“…Although it is a relatively noble metal, copper reacts easily with aqueous oxygen containing environments resulting in the formation of different oxides. It has been demonstrated that in alkaline solutions the passivation layer is built from a simple Cu 2 O structure over which an outer film constituted by a CuO, Cu(OH) 2 structure may be formed, depending on solution pH and electrode potential [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The formation processes of these structures are also accompanied by the production of soluble species of Cu(I) and Cu(II) [2,10,11,15].…”

Metallization of Iron Powders by Autocatalytic Copper Plating Process

“…Paunovic [2] and Bindra [3] had investigated the role of sulphur containing compounds in electroless copper plating process. The performance of copper in aqueous solution [4,5], alkaline media [6,7], and in lithium batteries [8] have been reported by many researchers. According to Hung et al [9], Baskaran et al [10], and Ohno [11], thiourea and Saccharin were used as exaltants in electroless nickel plating.…”