title: Structural evolution of NiAu nanoparticles under ambient conditions directly revealed by atom-resolved imaging combined with DFT simulation.
abstract: From an economic point of view, the structural stability of noble-transition bimetallic catalysts is as significant as their well-studied catalytic efficiency. The structural evolution and corresponding dynamics of NiAu bimetallic nanoparticles under ambient conditions are investigated using in situ Cs-corrected STEM and DFT calculations. During oxidization, the Au component promotes dissociation of oxygen and initiates Ni oxidization, which simultaneously drives the migration of Au atoms, thus yielding multi-shell structures (denoted by Ni@Au@NiO). The subsequent hydrogen reduction induces surface reconstruction, forming fcc-NiAu clusters. After several cycles of catalyzing CO oxidization, both inverse Au segregation and Ni recrystallization occur, which are ascribed to exothermic excitation. The results of this study can help researchers understand the evolutionary behaviors of the bimetallic nanoparticles under ambient conditions as well as optimize the structural design of bimetallic catalysts.
authors.affiliation: School of Physical Electronics and Institute of Fundmental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, China. weiliu@uestc.edu.cn xtzu@uestc.edu.cn.
authors.forename: Xia
authors.initials: X
authors.lastname: Xiang
authors.forename: Jinlan
authors.initials: J
authors.lastname: Nie
authors.forename: Kai
authors.initials: K
authors.lastname: Sun
authors.forename: Li
authors.initials: L
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Johannes
authors.initials: J
authors.lastname: Schwank
authors.forename: Shifa
authors.initials: S
authors.lastname: Wang
authors.forename: Mian
authors.initials: M
authors.lastname: Zhong
authors.forename: Fei
authors.initials: F
authors.lastname: Gao
authors.forename: Xiaotao
authors.initials: X
authors.lastname: Zu