Surface Proton Conduction of Sm-Doped CeO2-δ Thin Film Preferentially Grown on Al2O3 (0001)

• Published in: Nanoscale research letters Vol. 15; no. 1; p. 42
• Main Authors: Nishioka, D., Tsuchiya, T., Namiki, W., Takayanagi, M., Kawamura, K., Fujita, T., Yukawa, R., Horiba, K., Kumigashira, H., Higuchi, T.
• Format: Journal Article
• Language: English
• Published: New York Springer US 17.02.2020; Springer Nature B.V; SpringerOpen
• Subjects: Aluminum oxide; Cerium oxides; Chemistry and Materials Science; Conduction; EMN Meeting; Lattice vacancies; Low temperature; Magnetron sputtering; Materials Science; Mixed valence state; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; O–H bond; Photoelectric emission; Proton conduction; Protons; Sm-doped CeO2 (SDC); Substrates; Surface proton conduction; Thin film; Thin films; Mixed valence state; SDC; Sm-doped CeO; O–H bond; Thin film; Surface proton conduction
• ISSN: 1931-7573; 1556-276X
• DOI: 10.1186/s11671-020-3267-5

Sm-doped CeO 2- δ (Ce 0.9 Sm 0.1 O 2- δ ; SDC) thin films were prepared on Al 2 O 3 (0001) substrates by radio frequency magnetron sputtering. The prepared thin films were preferentially grown along the [111] direction, with the spacing of the (111) plane ( d 111 ) expanded by 2.6% to compensate for a lattice mismatch against the substrate. The wet-annealed SDC thin film, with the reduced d 111 value, exhibited surface protonic conduction in the low-temperature region below 100 °C. The O1 s photoemission spectrum exhibits H 2 O and OH − peaks on the SDC surface. These results indicate the presence of physisorbed water layers and the generation of protons on the SDC (111) surface with oxygen vacancies. The protons generated on the SDC surface were conducted through a physisorbed water layer by the Grotthuss mechanism.