title: Mechanisms of enhanced sulfur tolerance on samarium (Sm)-doped cerium oxide (CeO2) from first principles.
abstract: The role of samarium (Sm) 4f states and Sm-perturbed O 2p states in determining the sulfur tolerance of Sm-doped CeO2 was elucidated by using the density functional theory (DFT) + U calculation. We find that the sulfur tolerance of Sm-doped CeO2 is closely related to the modification of O 2p states by the strong interaction between Sm 4f and O 2p states. In particular, the availability of unoccupied O 2p states near the Fermi level is responsible for enhancing the sulfur tolerance of Sm-doped CeO2 compared to the pure CeO2 by increasing the activity of the surface lattice oxygen toward sulfur adsorption, by weakening the interaction between Sm-O, and by increasing the migration tendency of the subsurface oxygen ion toward the surface.
authors.affiliation: Fuel Cell Research Center, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791, Republic of Korea. hchahm@kist.re.kr.
authors.forename: Dong-Hee
authors.initials: DH
authors.lastname: Lim
authors.forename: Hee Su
authors.initials: HS
authors.lastname: Kim
authors.forename: Sung Pil
authors.initials: SP
authors.lastname: Yoon
authors.forename: Jonghee
authors.initials: J
authors.lastname: Han
authors.forename: Chang Won
authors.initials: CW
authors.lastname: Yoon
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Choi
authors.forename: Suk Woo
authors.initials: SW
authors.lastname: Nam
authors.forename: Hyung Chul
authors.initials: HC
authors.lastname: Ham