A published article by Mr. Park

게시일: Sep 20, 2012 2:30:35 PM

Hee-Young Park, Sung Jong Yoo, Sang-Young Lee, Hyung Chul Ham, Yung-Eun Sung, Soo-Kil Kim, Seung Jun Hwang, Hyoung-Juhn Kim, EunAe Cho, Dirk Henkensmeier, Suk Woo Nam, Tae-Hoon Lim, Jong Hyun Jang*, “Effect of Se modification on RuSey/C electrocatalyst for oxygen reduction with phosphoric acid”, Electrochemistry Communications, 2013, 47, 46-49. (ELSEVIER, IF:4.859, published date:2013.2).

Abstract

Carbon-supported Se-modified-Ru catalysts (RuSe_y/C) were synthesized, and their phosphate adsorption characteristics were evaluated using electrochemical techniques and in-situ X-ray absorption spectroscopy (XAS). When phosphoric acid was added, the ORR activity of unmodified Ru/C decreased by 26.8% because the active sites were blocked by electrochemical adsorption, as confirmed by CV. However, for RuSe_y/C, the ORR activity was enhanced with phosphoric acid (RuSe_1.56/C: 63.8%), which indicates that the kinetics at each site increased to compensate for the site blocking effect. The XAS results demonstrated that, for RuSe_y/C, phosphoric acid molecules or phosphate anions primarily interacted with Se atoms, and the oxidation state of Ru atoms decreased. Therefore, it was concluded that the enhanced ORR kinetics originated from the decreased oxygen binding energy with larger electrostatic repulsion.

Graphical abstract

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Highlights

► RuSe_y/C showed enhanced ORR activity by 17.8–63.8% with an addition of 10 mM H₃PO₄. ► The addition of 10 mM H₃PO₄ led to the decrease of Ru oxidation state in RuSe_y/C. ► In-situ XAS and cyclic voltammetry suggested interaction between Se and H₃PO₄. ► Electrostatic repulsion between H₃PO₄ and Ru–O_ad likely decreased Ru oxidation state.

Keywords

• Se-modified-Ru catalyst; Oxygen reduction reaction; Phosphoric acid; High temperature-PEMFC