title: Observation of Surface Coverage-Dependent Surface-Enhanced Raman Scattering and the Kinetic Behavior of Methylene Blue Adsorbed on Silver Oxide Nanocrystals.
abstract: We report the study of surface-enhanced Raman scattering (SERS) and photocatalytic reactions of methylene blue (MB) adsorbed on cubic silver oxide (c-Ag2O) nanocrystals. The SERS activities of MB observed on c-Ag2O are surface coverage-dependent. According to the SERS selection rules, the strong intensities of the C-S-C and C-N-C bending modes imply that the MB molecules are adsorbed on the c-Ag2O surface with a near-perpendicular position. On the other hand, if these modes are weak, MB assumes a near-parallel position to the c-Ag2O surface. Under the "perpendicular" condition, the photocatalytic reaction rate of MB observed on c-Ag2O surfaces is first order at a high surface coverage, whereas under the "parallel" condition, the observed rate is zero order at a low surface coverage. The SERS intensity trends and the kinetic behavior of MB on c-Ag2O are correlated.
authors.affiliation: Department of Chemistry, Chung Yuan Christian University , Zhongli District, Taoyuan City 32023, Taiwan.
authors.forename: Hsiang-Ling
authors.initials: HL
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Chung Yuan Christian University , Zhongli District, Taoyuan City 32023, Taiwan.
authors.forename: Zen-Hung
authors.initials: ZH
authors.lastname: Yang
authors.affiliation: Department of Chemistry, Chung Yuan Christian University , Zhongli District, Taoyuan City 32023, Taiwan.
authors.forename: Szetsen
authors.initials: S
authors.lastname: Lee