2009年5月11日 · An analysis of the XANES (Au-L 3) spectra has revealed mainly Au 3+ cations located on the oxide matrix surface in distorted octahedral coordination for the catalysts reduced at 150 °C. For the catalysts reduced at 300 °C, a highly distorted metallic gold species has been mainly found, within the method limitation.

2017年3月1日 · Operando XAFS analyses show the mixtures of Au and NiO are easily reduced to bimetallic nano-particles. The Au atoms promote the release of oxygen from nearby NiO within the cluster. Au-Ni bimetallic clusters were identified as possible automobile catalysts that do not contain a platinum-group metal (PGM).

2012年6月1日 · In this study, we measured the valence state and speciation of the Au that was removed from Au (III)–chloride solutions by non-metabolizing common soil bacteria: the Gram-positive species Bacillus subtilis, and the Gram-negative species Pseudomonas putida. We conducted the XAFS experiments as a function of pH at two different Au loadings.

2007年5月12日 · Formation mechanisms of metal particles (gold (Au) particles) in an aqueous ethanol solution of HAuCl 4 with poly (N -vinyl-2-pyrrolidone) (PVP) by the photoreduction method were investigated by UV−vis, transmission electron microscopy (TEM), and in situ and ex situ X-ray absorption fine structure (XAFS) analysis.

2005年6月3日 · Au/zeolite catalysts prepared with a deposition−precipitation method were characterized with quick XAFS (QXAFS) in combination with IR. The data were correlated with the catalytic performance in the CO−O 2 reaction conducted at 273 K. On the basis of the XANES analysis of Au loaded on H−Y, the deposited Au 2 O 3 was observed at the initial stage.

Using state-of-the-art beamlines, we demonstrate how X-ray absorption ne structure fi (XAFS) techniques are now able to provide accurate structural information on nano-sized colloidal Au solutions at mM concentrations. This study demonstrates: (i) the size of Au colloids can be accurately Received 14th March 2019 Accepted 11th May 2019

2009年11月1日 · 通过 EXAFS 研究了通过不同程序和一系列模型系统 Au/Si (100)、Au/Si (111) 制备的一系列 Au/Al2O3 催化剂，这些催化剂的平均 Au 粒径（从 2 nm 到 30 nm）不同和 XANES 技术。 对于通过不同方法制备的所有样品，与块状材料相比，未检测到金的电子态发生明显变化。 在我们研究的检测范围内（周围原子的百分之几），未在 Au 原子周围检测到氧原子。 随着负载的金颗粒尺寸的减小，观察到金-金键长和第一壳金-金配位数逐渐减少，德拜-沃勒因子增加。 …

Artemis 对 XAFS 数据拟合是重点也是难点，通过拟合可以得到配位数N、原子间距离R、无序度s. 、能量原点的位移ΔE0等结构参数。 本次介绍内容包含四部分： 1、利用Artemis程序进行 EXAFS 拟合的一般步骤. 2、Artemis拟合的基本流程. 3、Artemis数据拟合基本操作. 4、拟合结果合理性判断. 1、利用Artemis程序进行EXAFS拟合的一般步骤. Artemis: the goddess of the hunt, an apt metaphor doing EXAFS analysis. 输入文件为不加权的EXAFS振荡函数χ (k)； Artemis本身不能 …

同步辐射吸收谱是一种基于X射线吸收的谱学技术，当同步辐射光源照射到样品上时，样品中的原子会吸收能量，产生电子跃迁。 XAFS主要包括两个部分：近边区（XANES，X-ray Absorption Near-Edge Structure）和扩展边（EXAFS，Extended X-ray Absorption Fine Structure）。 1. 近边区（XANES）：XANES反映了原子吸收边的精细结构，可以提供吸收原子的电子结构信息，如价态、对称性、轨道占据等。 2. 扩展边（EXAFS）：EXAFS反映了吸收原子周围配位原子的信 …

2009年5月11日 · An analysis of the XANES (Au-L3) spectra has revealed mainly Au 3+ cations located on the oxide matrix surface in distorted octahedral coordination for the catalysts reduced at 150 °C. For the catalysts reduced at 300 °C, a highly distorted metallic gold species has been mainly found, within the method limitation.