Rhodium Sulfide Catalysts for HER/HOR in H2-Br2 Fuel Cells

Rhodium Sulfide Catalysts for HER/HOR in H2-Br2 Fuel Cells

Jahangir Masud^a, Jack Walter^a, Trung Van Nguyen^a*, Guangyu Lin^b, Nirala Singh^c, Eric McFarland^c, Horia Metiu^d_, Myles Ikenberry^e, Keith  Hohn^e, Chun-Jern Pan^f and Bing-Joe Hwang^f

^a Department of Chemical & Petroleum Engineering

The University of Kansas

Lawrence, KS, USA

^b TVN Systems, Inc.

Lawrence, KS, USA

^c Department of Chemical Engineering

University of California

Santa Barbara, USA

^d Department of Chemistry and Biochemistry

University of California

Santa Barbara, USA

^e Department of Chemical Engineering

Kansas State University

KS, USA

^f Department of Chemical Engineering

National Taiwan University of Science and Technology, Taipei, Taiwan

^*Corresponding Author: cptvn@ku.edu

Abstract

There has been growing interest in the hydrogen bromine (H₂-Br₂) fuel cell system for electrical energy storage because of its high round-trip conversion efficiency and low costs. The present H₂-Br₂ fuel cells use platinum as a catalyst for the HER/HOR at the hydrogen electrode. While this catalyst is highly active, it is susceptible to poisoning by bromine. Here, we demonstrate a Pt-free Rh_xS_y/C catalyst which exhibits high activity and stability in Br₂/HBr solution.

The synthesis procedure for rhodium sulfide on carbon support (Rh_xS_y/C) catalyst can be found in the patent by Allen et al. [1]. The carbon supported catalysts (Rh:C =1:4) were prepared by heating the precursor Rh₂S₃ phase under flowing argon in a quartz furnace tube for 1 hr at several fixed temperatures. These different heat treated catalysts were tested in HBr and Br₂ solutions to determine their HER/HOR activity and stability. The catalyst was also characterized using SEM/EDX, TEM/EDX, XRD and XPS for morphology, elemental chemical compositions, rhodium sulfide phases and particle size. Figure 1 shows a TEM image of one of the samples.

Fig.1: TEM image of a prepared Rh_xS_y/C catalyst.

Reference

1. Allen, R.J, Gulla, A.F., “Synthesis of noble metal, sulphide catalysts in a sulfide ion-free aqueous environment”, U.S. Patent 6,967,185, 22 Nov, 2005.

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.

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