Coating Effects of Sm0.2Ce0.78M0.02O2- δ (M=Ni, Co, Pd, NiCo) Layer on Ni/YSZ Anode for Internal Dry Reforming in Solid Oxide Fuel Cells

Abstract

Internal dry reforming of methane (DRM) in solid oxide fuel cells (SOFCs) has environmental advantages because CH4 and CO2 are considered as two major greenhouse gases causing global warming. Carbon coking, however, can be major drawback in the DRM via pyrolysis of methane and Boudouard reaction. In this study, Sm0.2Ce0.78M0.02O3- δ (SCM, M=Ni, Co, Pd, NiCo) was investigated to minimize carbon coking and to improve the catalytic activity for internal DRM in SOFCs. Samarium doped ceria (Ce0.8Sm0.2O2- δ) has been widely used in SOFCs due to the excellent ionic conductivity and the mixed ionic and electronic conductivity (MIEC). To improve the catalytic activity of Ce0.8Sm0.2O2- δ, Ni, Co, Pd, and NiCo alloy were substituted into the Ce. The SCM phase was stable in internal DRM condition. The morphology and compositions are analyzed with XRD, SEM, TEM, XPS, etc. Sm0.2Ce0.78Ni0.01Co0.01O2- δ(SCNC) showed excellent DRM results with over 90% in CH4 and CO2 conversion and close to 1 in H2/CO selectivity at 800oC. The carbon deposition of SCNC catalysts was minimized. In addition, power density of SCNC-coated Ni/YSZ anode was improved with 2.3 times higher in CH4/CO2 fuel conditions comparing to that of Ni/YSZ anode.