标题：Atomic Observation of Catalysis-Induced Nanopore Coarsening of Nanoporous Gold
作者：Takeshi Fujita;Tomoharu Tokunaga;Ling Zhang;Dongwei Li;Luyang Chen;Shigeo Arai;Yuta Yamamoto;Akihiko Hirata;Nobuo Tanaka;Yi Ding
作者机构：[Fujita, T] Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan, PRESTO, JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-00 更多
通讯作者地址：[Fujita, T]Tohoku Univ, Adv Inst Mat Res, Sendai, Miyagi 9808577, Japan.
关键词：CO oxidation;heterogeneous catalyst;environmental transmission electron microscopy;nanoporous metal;In situ TEM
摘要：Dealloyed nanoporous metals have attracted much attention because of their excellent catalytic activities toward various chemical reactions. Nevertheless, coarsening mechanisms in these catalysts have not been experimentally studied. Here, we report in situ atomic-scale observations of the structural evolution of nanoporous gold during catalytic CO oxidation. The catalysis-induced nanopore coarsening is associated with the rapid diffusion of gold atoms at chemically active surface steps and the surface segregation of residual Ag atoms, both of which are stimulated by the chemical reaction. Our observations provide the first direct evidence that planar defects hinder nanopore coarsening, suggesting a new strategy for developing structurally stable and highly active heterogeneous catalysts.