Copper oxygen reduction

In analyzing the polarization data, it can be seen that the cathodic reaction on the copper (oxygen reduction) quickly becomes diffusion controlled. However, at potentials below -0.4 V, hydrogen evolution begins to become the dominant reaction, as seen by the Tafel behavior at those potentials. At the higher anodic potentials applied to the steel specimen, the effect of uncompensated ohmic resistance (IRohmk) can be seen as a curving up of the anodic portion of the curve. 

A striking example of the interaction of solution velocity and concentration is given by Zembura who found that for copper in aerated 0-1 N H2SO4, the controlling process was the oxygen reduction reaction and that up to 50°C, the slow step is the activation process for that reaction. At 75 C the process is now controlled by diffiision, and increasing solution velocity has a large effect on the corrosion rate (Fig. 2.5), but little effect at temperatures below 50 C. This study shows how unwise it is to separate these various... 

J. of Electro-analytical Chemistry, 471 116- 125 King, F., Quinn, M. J., Litke, C. D., 1995. Oxygen reduction on copper in neutral NaCl solution. Journal of Electro-analytical Chemistry, 385(1) 45 - 55 Kneer, E. A., 1997. Electrochemical measurements during the CMP of Tungsten thin films. J. Electrochem. Soc., 144 3041 - 3049... 

Rand, D. A., 1975. Oxygen reduction on sulphide minerals, part III comparisson of activity of various copper, iron, lead, nickle mineral electrodes. Electrochemistry and Interfacial Electrochemistry, 60 265 - 275... 

Different chemical environments surrounding the T1 copper result in different redox potentials. Fungal laccases demonstrate the highest potential, close to the equilibrium potential of oxygen reduction in their respective pH regions (see Table 1). Laccases, however, are anion sensitive, with deactivation involving dissociation of T2 copper from the active site of the enzyme. Alternative copper oxidases such as bilirubin oxidase and ceruloplasmin ° ... 

Adsorption inhibitors act by forming a film on the metal surface. The action of traditional oil-based red lead paint formulations presumably involves the formation of soaps and the precipitation of complex ferric salts that reinforce the oxide film. There has been substantial interest in recent years in development of replacements for lead-based and chromate-based inhibitor systems. Adsorption inhibitors based on pol3rmers have been of particular interest. In this volume, Johnson et al. and Eng and Ishida discuss inhibitors for copper 2-undecylimidazole is shown to be effective in acid media, where it suppresses the oxygen reduction reaction almost completely. Polyvlnyllmidazoles are shown to be effective oxidation inhibitors for copper at elevated temperatures. Also in this volume, Chen discusses the use of N-(hydroxyalkyl)acrylamide copolymers in conjunction with phosphate-orthophosphate inhibitor systems for cooling systems. 

Azole compounds, poly-N-vinylimidazole (PVI-1) and 2-undecylimidazole (UDI), are studied as alternative inhibitors to benzotriazole (BTA) for copper corrosion in aqueous systems using electrochemical techniques. It is shown that UDI, either as a cast film or dissolved in solution at concentrations as low as 7 X inhibits oxygen reduction on... 

The influence of the central atom is shown in Fig. 14. In all the chelates we have studied, this influence is strong. The compounds with iron as central atom show the greatest activity, followed by cobalt, nickel and copper. This is shown by comparing monomeric Pc, TAA and TDAP. The activity of NiPc, CuPc and CuTAA is so small that potentials below 600 mV are measured even with a load of 30 mA/g catalyst. With TDAP, the Cu complex is more active than the Ni complex. The Fe complex of TAA, which would have been particularly interesting, was unfortunately not available. These observations indicate that oxygen reduction proceeds at the central atom of the chelate. 

Mukherjee A. Smirnov V. V. Land M. P. Brown D. E. Shepard E. M. Dooley D. M. Roth J. P. Inner-sphere mechanism for molecular oxygen reduction catalyzed by copper amine oxidases. J. Am. Chem. Soc. 2008, 130, 9459-9473. 

The phenomenon of bioelectrical catalysis with direct electron transfer from electrode to enzyme active site was primarily observed in the study of electrochemical oxygen reduction in the presence of a copper-containing oxidase - laccase, adsorbed on electrodes of different origins. This work was developed with peroxidase and hydrogenase application as the working components [2],... 

Dealuminification. Recent investigations have shown the importance of the dealloying of S-phase (Al2CuMg) particles on the corrosion of aluminum aircraft alloys, specifically aluminum alloy 2024-T3. In 2024-T3, the S-phase particles represent approximately 60% of the particle population. These particles are of the order of 1 pm diameter, with a separation of the order of 5 pm representing an surface area fraction of 3%.56 The selective removal of aluminum and magnesium from these particles leaves behind a porous copper particle that becomes the preferential site for oxygen reduction.57, (Corcoran)5... 

Passive layers on copper and its alloys, which have technological relevance in corrosion, have been investigated in studies of oxygen reduction. Balakrishnan and Venkatesan [448] reported a two-step reduction of oxygen via peroxide on copper(I) surface oxides in neutral solutions. 

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