Materials Transactions Online

Materials Transactions, Vol.46 No.05 (2005) pp.1058-1063
© 2005 The Japan Institute of Metals

Dynamical Desorption Process of Oxygen on Platinum by Using a Gas Controllable H2 | H+Electrolyte | Pt Cell

Kunio Matsuda1, and Shuji Harada2

1Graduate School of Science & Technology, Niigata University, Niigata 950-2181, Japan
2Faculty of Engineering, Niigata University, Niigata 950-2181, Japan

The dynamical desorption process of oxygen on platinum was investigated by an electrochemical method. By using a gas controllable H2 | H+electrolyte | Pt cell, the value of electromotive force (EMF) has been measured as a function of lapse of time after an oxygen adsorbing treatment on the Pt electrode. The time dependence of EMF value has been classified into three stages. In the base stage, the value of EMF was discussed on the oxygen concentration on the Pt electrode. The 1st stage was interpreted by using the electrochemical theory on a diffusion model. The 2nd stage has been analyzed by using a random desorption model. The behavior of EMF was in good agreement with these models. From above analyses, the activation energy of oxygen diffusion process and the adsorption energy of oxygen on the Pt electrode were evaluated. The inflection point as a boundary point of the 1st to 2nd stage was related to the dynamical desorption process of oxygen.

(Received 2005/1/21; Accepted 2005/3/30; Published 2005/5/15)

Keywords: oxygen, platinum, desorption, adsorption, electromotive force, electrochemical method, fuel cell, gas controllable cell, diffusion, electrode

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