Oxygen transient behavior

D. Hardacre, C. Seddon, K. R. Compton, R. G. Voltammetry of oxygen in the room-temperature ionic liquids l-ethyl-3-methylimida-zolium bis(triflyl)imide and HexEt3N+ TfiN one-electron reduction to form superoxide. Steady-state and transient behavior in the same cyclic voltammogram resulting from widely different diffusion coefficients of oxygen and superoxide. J. Phys. Chem. A 2003,... 

Figure 17. Plot of the inverse of the steady-state Faradaic efficiency, Ast", of fast step (a) as a function of the polarizing current in terms of the rate of electrochemically supplied oxygen, H2F. Reprinted from J. Electroanal. Chem., G. F6ti, V. Stankovid, 1. Bolzonella, and Ch. Comninellis, Transient Behavior of Electrochemical Promotion of Gas-Phase Catalytic Reactions, (2002), in press, with permission liom Elsevier Science.

Veltkamp R, Warner DS, Domoki F, Brinkhous AD, Toole JF, Busija DW. Hyperbaric oxygen decreases infarct size and behavioral deficit after transient focal cerebral ischemia in rats. Brain Res 2000 853 68-73. 

A group of scientists have studied current transients in biased M-O-M structures.271,300 The general behavior of such a system may be described by classic theoretical work.268,302 However, the specific behavior of current transients in anodic oxides made it necessary to develop a special model for nonsteady current flow applicable to this case. Aris and Lewis have put forward an assumption that current transients in anodic oxides are due to carrier trapping and release in the two systems of localized states (shallow and deep traps) associated with oxygen vacancies and/or incorporated impurities.301 This approach was further supported by others,271,279 and it generally resembles the oxide band structure theoretically modeled by Parkhutik and Shershulskii62 (see. Fig. 37). 

In order to analyze the adsorption behavior of carbon dioxide on silver it was necessary to understand the adsorption behavior of and its reactivity, because the adsorption of CO strongly relatedto the adsorbed oxygen species as will be described later. For this reason, the following transient experiments were purformed. 

Transient kinetic experiments were performed also in the presence of a higher concentration of oxygen, namely 6% v/v. Results collected at different temperatures are displayed in Fig. 37B (symbols) in terms of NH3, NO and N2 outlet concentration traces vs. time ( = 200, 225, 250, 275°C). They are qualitatively similar to those with 2% v/v oxygen feed in Fig. 37A and discussed above. Particularly, two different behaviors of the NO and the N2 concentration traces were again observed when the NH3 feed was opened up/shut down. In the high-T range, monotonic temporal evolutions were observed e.g. at NH3... 

Yakabe, H., Hishinuma, M. and Yasuda, I., Static and transient model analysis on expansion behavior of LaCiO under an oxygen potential gradient, Journal of The Electrochemical Society 147, 2000, 4071. 

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