title: Structural models and atomic distribution of bimetallic nanoparticles as investigated by X-ray absorption spectroscopy.
abstract: In this report, we describe a general methodology to determine the extent of alloying or atomic distribution quantitatively in bimetallic nanoparticles (NPs) by X-ray absorption spectroscopy (XAS). The structural parameters determined in these studies serve as a quantitative index and provide a general route to determine the structural aspects of the bimetallic NPs. We have derived various types of possible structural models based on the extent of alloying and coordination number parameters of bimetallic NPs. We also discussed the nature of homo- and heterometallic interactions in bimetallic NPs based on the extent of alloying. Herein, we use carbon-supported platinum-ruthenium bimetallic nanoparticles to demonstrate the proposed methodology, and this can be extended further to get more insights into the alloying extent or atomic distribution of other bimetallic systems. The results demonstrated in this paper open up methods to determine the atomic distribution of bimetallic NPs, which is an extremely important parameter that strongly influences the physicochemical properties of NPs and their applications.
authors.affiliation: Nanoelectrochemistry Laboratory, Department of Chemical Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan, Republic of China. bjh@mail.ntust.edu.tw
authors.forename: Bing-Joe
authors.initials: BJ
authors.lastname: Hwang
authors.forename: Loka Subramanyam
authors.initials: LS
authors.lastname: Sarma
authors.forename: Jiun-Ming
authors.initials: JM
authors.lastname: Chen
authors.forename: Ching-Hsiang
authors.initials: CH
authors.lastname: Chen
authors.forename: Shou-Chu
authors.initials: SC
authors.lastname: Shih
authors.forename: Guo-Rung
authors.initials: GR
authors.lastname: Wang
authors.forename: Din-Goa
authors.initials: DG
authors.lastname: Liu
authors.forename: Jyh-Fu
authors.initials: JF
authors.lastname: Lee
authors.forename: Mau-Tsu
authors.initials: MT
authors.lastname: Tang