| 초록 |
Among the contaminants commonly encountered in readily available fuels, sulfur compounds can dramatically reduce the catalytic activity of Ni-based anode of solid oxide fuel cell (SOFC). Enhancing the sulfur tolerance is therefore an important issue for design of SOFC anode. In this study, the mechanism of interactions between H2S and Ni or Ni-based bimetallic alloy surfaces (Cu/Ni, Rh/Ni, Pd/Ni, Ag/Ni, Pt/Ni, Au/Ni) was elucidated by density functional theory calculations. To investigate the mechanism of sulfur poisoning on the surfaces, we assumed the process of H2S dissociation into two sequential steps: H2S* → HS* + H → S* + H* + H*. We examined the dissociation of H2S on (111) and (211) surfaces, which are the representative of flat and step surfaces, respectively, to mimic nanoparticle catalysts. Our results showed that Ni-based bimetallic alloy surface has higher sulfur-tolerance than pure Ni surface. In addition, Ni(211) has a lower barrier for H2S dissociation, compare to Ni(111). From this study, we suggest the principles of design for SOFC anode materials with high sulfur-tolerance. |
