Direct observation of fractional change of niobium ionic species in a solution by means of X-ray absorption fine structure spectroscopy

被引：13

作者：

Kubouchi, Yuta

Hayakawa, Shinjiro ^{[1
]}

Namatame, Hirofumi ^{[2
]}

Hirokawa, Takeshi

机构：

[1] Hiroshima Univ, Dept Appl Chem, Grad Sch Engn, Higashihiroshima, Hiroshima 7398527, Japan

[2] Hiroshima Univ, Hiroshima Synchrotron Radiat Ctr, Higashihiroshima, Hiroshima 7390046, Japan

来源：

X-RAY SPECTROMETRY | 2012年 / 41卷 / 04期

关键词：

XAFS; L3-edge; niobium; DFT calculation; solution; OXIDE CATALYSTS; METAL-COMPOUNDS; XANES; TRANSITION; TEMPERATURE; SPECTRA; SILICA;

D O I：

10.1002/xrs.2390

中图分类号：

O433 [光谱学];

学科分类号：

0703 ; 070302 ;

摘要：

Local coordination of niobium oxalate in oxalic acid solutions was investigated by Nb L3-edge X-ray absorption near edge structure (XANES) spectroscopy that was sensitive to the coordination environment of X-ray absorbing atoms. The Nb L3-edge XANES spectra were measured from solutions of difference pH, and the solution was composed of different molar fractions of NbO(C2O4)2H2O- and NbO(C2O4)33-. The lower energy shift of the spectral peak was observed with the lower pH that was attributed to the greater fraction of NbO(C2O4)2H2O-. The spectral shape was different from those of reference samples representing tetrahedral and octahedral coordination, and the lower symmetry of niobium site was confirmed. The XANES spectra of two ionic species were simulated with the density functional theory calculations, and the mixture of these spectra demonstrated the peak shift caused by the change of solution pH. Copyright (c) 2012 John Wiley & Sons, Ltd.

引用

页码：259 / 263

页数：5

共 21 条

[1] Structural Analysis of Group V, VI, and VII Metal Compounds by XAFS [J].