Nanoscale characterization of acid properties of heteropolyacids by scanning tunneling microscopy and tunneling spectroscopy

被引：33
|
作者：
Kaba, MS
Barteau, MA
Lee, WY
Song, IK [1 ]
机构：
[1] Kangnung Natl Univ, Dept Ind Chem, Kangnung 210702, Kangwondo, South Korea
[2] Seoul Natl Univ, Dept Chem Engn, Kwanak Ku, Seoul 151742, South Korea
[3] Univ Delaware, Dept Chem Engn, Ctr Catalyt Sci & Technol, Newark, DE 19716 USA
来源：
APPLIED CATALYSIS A-GENERAL | 2000年 / 194卷
基金：
美国国家科学基金会;
关键词：
heteropolyacid; acid property; scanning tunneling microscopy; pyridine interaction; negative differential resistance;
D O I：
10.1016/S0926-860X(99)00361-0
中图分类号：
O64 [物理化学（理论化学）、化学物理学];
学科分类号：
070304 ; 081704 ;
摘要：
Nanoscale characterization of the acid properties of H3PMo12-xWxO40 (x = 0, 3, 6, 9, 12) was carried out by scanning tunneling: microscopy (STM) and tunneling spectroscopy, Pyridine binding with the acid sites of heteropolyacids (HPAs) was reflected in both the STM images and FT IR spectra of these materials: All the HPAs investigated formed well-ordered monolayer arrays on highly oriented pyrolytic graphite (HOPG) before and after pyridine adsorption. Exposure to pyridine increased the lattice constants of the two-dimensional HPA arrays by ca; 6:Exposure to pyridine also shifted the negative differential resistance (NDR) peak voltages of HPAs to less negative values in the::tunneling spectroscopy measurements. The NDR shifts of HPAs obtained before and after pyridine adsorption were correlated:with acid properties of HPAs for the first time, suggesting that tunneling spectra measured by STM could serve to fingerprint acid properties of HPAs. (C) 2000 Elsevier Science B.V. All rights reserved.
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页码：129 / 136
页数：8
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