title: Catalytically active Au-O(OH)x-species stabilized by alkali ions on zeolites and mesoporous oxides.
abstract: We report that the addition of alkali ions (sodium or potassium) to gold on KLTL-zeolite and mesoporous MCM-41 silica stabilizes mononuclear gold in Au-O(OH)x-(Na or K) ensembles. This single-site gold species is active for the low-temperature (<200°C) water-gas shift (WGS) reaction. Unexpectedly, gold is thus similar to platinum in creating -O linkages with more than eight alkali ions and establishing an active site on various supports. The intrinsic activity of the single-site gold species is the same on irreducible supports as on reducible ceria, iron oxide, and titania supports, apparently all sharing a common, similarly structured gold active site. This finding paves the way for using earth-abundant supports to disperse and stabilize precious metal atoms with alkali additives for the WGS and potentially other fuel-processing reactions.
authors.affiliation: Department of Chemical and Biological Engineering, Tufts University, MA 02155, USA.
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, WI 53706, USA.
authors.forename: Sha
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Chemical and Biological Engineering, Tufts University, MA 02155, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, WI 53706, USA.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Herron
authors.affiliation: Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Ye
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA.
authors.forename: Lawrence F
authors.initials: LF
authors.lastname: Allard
authors.affiliation: X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA.
authors.forename: Sungsik
authors.initials: S
authors.lastname: Lee
authors.affiliation: School of Chemical and Biomolecular Engineering, University of Sydney, NSW 2006, Australia.
authors.forename: Jun
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Chemical and Biological Engineering, University of Wisconsin-Madison, WI 53706, USA.
authors.forename: Manos
authors.initials: M
authors.lastname: Mavrikakis
authors.affiliation: Department of Chemical and Biological Engineering, Tufts University, MA 02155, USA. maria.flytzani-stephanopoulos@tufts.edu.
authors.forename: Maria
authors.initials: M
authors.lastname: Flytzani-Stephanopoulos