title: Atomic origins of the high catalytic activity of nanoporous gold.
abstract: Distinct from inert bulk gold, nanoparticulate gold has been found to possess remarkable catalytic activity towards oxidation reactions. The catalytic performance of nanoparticulate gold strongly depends on size and support, and catalytic activity usually cannot be observed at characteristic sizes larger than 5 nm. Interestingly, significant catalytic activity can be retained in dealloyed nanoporous gold (NPG) even when its feature lengths are larger than 30 nm. Here we report atomic insights of the NPG catalysis, characterized by spherical-aberration-corrected transmission electron microscopy (TEM) and environmental TEM. A high density of atomic steps and kinks is observed on the curved surfaces of NPG, comparable to 3-5 nm nanoparticles, which are stabilized by hyperboloid-like gold ligaments. In situ TEM observations provide compelling evidence that the surface defects are active sites for the catalytic oxidation of CO and residual Ag stabilizes the atomic steps by suppressing {111} faceting kinetics.
authors.affiliation: WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan. tfujita@wpi-aimr.tohoku.ac.jp
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fujita
authors.forename: Pengfei
authors.initials: P
authors.lastname: Guan
authors.forename: Keith
authors.initials: K
authors.lastname: McKenna
authors.forename: Xingyou
authors.initials: X
authors.lastname: Lang
authors.forename: Akihiko
authors.initials: A
authors.lastname: Hirata
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
authors.forename: Tomoharu
authors.initials: T
authors.lastname: Tokunaga
authors.forename: Shigeo
authors.initials: S
authors.lastname: Arai
authors.forename: Yuta
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Nobuo
authors.initials: N
authors.lastname: Tanaka
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Ishikawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Asao
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Yamamoto
authors.forename: Jonah
authors.initials: J
authors.lastname: Erlebacher
authors.forename: Mingwei
authors.initials: M
authors.lastname: Chen