The effect of the support on the surface composition of PtCu alloy nanocatalysts: In situ XPS and HS-LEIS studies

作     者：黄俊杰 宋艳英 马冬冬 郑燕萍 陈明树 万惠霖 

作者机构：厦门大学化学化工学院固体表面物理化学国家重点实验室醇醚酯化工清洁生产国家工程实验室福建厦门361005 

出 版 物：《Chinese Journal of Catalysis》 (催化学报（英文）)

年 卷 期：2017年第38卷第7期

页      面：1229-1236页

核心收录：

学科分类：081705[工学-工业催化] 08[工学] 0817[工学-化学工程与技术] 

基　　金：supported by the National Basic Research Program of China(973 Program,2013CB933102) the National Natural Science Foundation of China(21273178,21573180,91545204) Xiamen-Zhuoyue Biomass Energy Co.Ltd~~ 

主　　题：PtCu alloy Bimetal catalyst Surface composition Phase diagram In situ XPS-LEIS 

摘      要：Supported PtCu alloys have been broadly applied in heterogeneous catalysis and electrocatalysis owing to their excellent catalytic performance and high CO tolerance. It is important to analyze the outermost surface composition of the supported alloy nanoparticles to understand the nature of the catalytically active sites. In this paper, homogeneous face-centered cubic PtCu nanoparticles with a narrow particle size distribution were successfully fabricated and dispersed on a high-surface-area Ti〇2 powder support. The samples were oxidized and reduced in situ and then introduced into the ultrahigh vacuum chamber to measure the topmost surface composition by high-sensitivity low-energy ion scattering spectroscopy, and to determine the oxidation states of the elements by X-ray photoelectron spectroscopy. The surface composition and morphology, elemental distribu-tion, and oxidation states of the components were found to be significantly affected by the support and treatment conditions. The PtCu is de-alloyed upon oxidation with CuO wetting on the TiO2 sur-face and re-alloyed upon reduction. Phase diagrams of the surface composition and the bulk com-position were plotted and compared for the supported and unsupported materials.