XAFS and HAADF STEM combined characterization for size regulated Ni nanocluster catalyst and its unique size dependence for water gas shift reaction
XAFS and HAADF STEM combined characterization for size regulated Ni nanocluster catalyst and its unique size dependence for water gas shift reaction
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DOI：
10.1016/j.apcata.2014.03.031
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发表时间：
2014-05
影响因子：
5.5
通讯作者：
Hirotake Kitagawa;N. Ichikuni;H. Okuno;Takayoshi Hara;S. Shimazu
中科院分区：
文献类型：
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作者：
Hirotake Kitagawa;N. Ichikuni;H. Okuno;Takayoshi Hara;S. Shimazu
X射线吸收精细结构（XAFS）和高角度环形暗场扫描透射电子显微镜（HAADF STEM）都被应用于氧化铝上的尺寸调节的Ni纳米簇催化剂的表征。XAFS分析表明，在我们的胶体衍生催化剂中没有形成NiAl_2O_4。Ni-Ni的配位数变化范围很大，表明尺寸可控的Ni纳米簇催化剂的制备已经实现。HAADF STEM分析表明，即使在673 K下H2还原后，Ni纳米簇催化剂的粒度分布也很窄。观察到扭曲的颗粒，并且扭曲的颗粒的比例随着簇尺寸的减小而增加。以水煤气变换反应考察了催化剂的催化性能。负载型Ni纳米簇催化剂的活性具有火山状的尺寸依赖性。
X-ray absorption fine structure (XAFS) and high angle annular dark field scanning transmission electron microscopy (HAADF STEM) were both applied to a characterization of the size regulated Ni nanocluster catalyst on alumina. XAFS analysis showed that NiAl2O4was not formed in our colloid derived catalyst. The wide variety of coordination number (CN) for Ni–Ni indicated the achievement of the size regulated Ni nanocluster catalyst preparation. HAADF STEM analysis showed narrow size distribution of Ni nanocluster catalyst even after H2reduction at 673 K. Distorted particles were observed and the ratio of distorted particles increased with decrease in the cluster size. Water gas shift reaction was carried out to investigate the catalysis. Volcano-shaped size dependence was observed for the activity of supported Ni nanocluster catalyst.