Perovskites As Alternative Catalysts for Solid Oxide Fuel Cell Anodes: Effect of Dopants

Perovskites as  alternative catalysts for solid oxide fuel cell anodes:  Effect of dopants

Hyunkyu Choi, Umit S. Ozkan*

The Ohio State University

Heterogeneous Catalysis Research Group

Department of Chemical and Biomolecular Engineering

Solid oxide fuel cells (SOFCs) show great potential for effectively generating clean power from a variety of fuels. Current state of the art anode catalysts based on Ni catalysts supported on yittria-stabilized zirconia (Ni/YSZ) deactivate in the presence of coal-derived gas because they are highly susceptible to coking and sulfur poisoning. These processes decrease the anodic reaction rates, lower the power densities, and lead to instability during long time operation. Therefore, the development of carbon and sulfur tolerant as well as highly active materials suitable for anodes is essential to bring coal-gas fed SOFC systems closer to wide-spread application.

Ongoing research in our group examines developing perovskite-type catalysts by incorporating cerium to the doped-lanthanum ferrites. The materials are prepared by sol gel techniques. The present work studies the kinetics of the hydrocarbon fuel oxidation reaction, the resistance to carbon coking and sulfur poisoning, the formation of oxygen vacancies, and the bulk and surface chemistry of cerium-doped perovskites. The phase transformation of these materials are characterized using in-situ X-ray diffraction (XRD). The activity as well as stability of these catalysts in the presence of H₂S is studied with time-on-stream reaction experiments for various anode reactions. Oxygen nonstoichiometry, an indicator of oxygen vacancies, is vitally important for the diffusion of the oxide ion to react in the three-phase boundary (TPB) and is determined by thermogravimetric analysis.  Surface sites are probed using methanol adsorption and diffuse reflectance infrared Fourier Transform (DRIFT) spectroscopy.

Session : Novel catalytic materials I

*Presenting author

331 Koffolt Laboratory
140 West Nineteenth Avenue

Columbus, OH 43210

Phone:  614-292-4993

Fax: 614-292-3769

Email: choi.508@osu.edu

Umit S. Ozkan

333A Koffolt Laboratory
140 West Nineteenth Avenue

Columbus, OH 43210

Phone:  614-292-6623

Fax: 614-292-3769

Email: ozkan@chbmeng.ohio-state.edu