Improved RhxSy/C Catalyst Structure for Higher HOR/HER Activity

Abstract

With the development of distributed energy resources such as wind and solar power, there has been growing interest in electrical energy storage. The hydrogen-bromine (H2-Br2) reversible fuel cell system serves as one of the promising technologies because of its high round-trip conversion efficiency and low cost. For the highly corrosive HBr/Br2 environment, alternative catalysts to platinum, which was shown to be rapidly corroded and poisoned in this environment, is needed for the HER/HOR reactions at the hydrogen electrode. RhxSy catalysts have been found to be stable in the HBr/Br2 environment. Even though existing RhxSy catalysts show high specific HER activity, which makes these catalysts suitable for HBr or HCl electrolysis, their specific HOR activities are not satisfactory for the H2-Br2reversible fuel cell system [1, 2]. Recently, we have found a way to develop an optimal RhxSy catalyst structure that results in higher specific HER/HOR activity, as shown in Figure 1. This presentation will discuss the approach used and the characteristics and performance of this catalyst. References J. Masud, T.V. Nguyen, N. Singh, E. McFarland, M. Ikenberry, K. Hohn, C.J. Pan, and B.J. Hwang, J. Electrochem. Soc., 162 (4) F455-F462 (2015).A. Ivanovskaya, N. Singh, R.F. Liu, H. Kreutzer, J. Baltrusaitis, T.V. Nguyen, H. Metiu, and E. McFarland, Langmuir, 29 , 480-492 (2013). Acknowledgements The work presented herein was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E), U.S. Department of Energy, under Award Number DE-AR0000262 and the National Science Foundation under Grant No. EFRI-1038234. Figure 1