EXAFS-XANES evidence of in situ cesium reduction in Cs-Ru/C catalysts for ammonia synthesis.
EXAFS-XANES evidence of in situ cesium reduction in Cs-Ru/C catalysts for ammonia synthesis.
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DOI：
10.1021/ic2001656
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发表时间：
2011-03
影响因子：
4.6
通讯作者：
I. Rossetti;L. Sordelli;P. Ghigna;S. Pin;M. Scavini;L. Forni
中科院分区：
文献类型：
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作者：
I. Rossetti;L. Sordelli;P. Ghigna;S. Pin;M. Scavini;L. Forni
我们在这里提出了一个X射线吸收光谱（XAS）调查的本地化学秩序和电子结构的Cs和Ba，促进剂的Ru/C催化剂的氨合成，吸引了人们的兴趣，因为大大提高了生产率。的作用的促进剂仍然在很大程度上是不清楚的，虽然间接的证据，铯部分减少已经获得了这个和其他团体。我们的XAS分析与原位H（2）还原直接支持部分Cs还原促进Ru/C催化剂，取决于Ru的存在和对载体的石墨化程度。在还原样品中观察到Ba相对于Cs的更高配位，而没有证据表明周围环境中存在重原子（Ru、Cs和Ba）。由于铯的强正电性，其部分还原的直接实验证据对于其他应用也具有突出的意义。
We present here a X-ray absorption spectroscopy (XAS) investigation on the local chemical order and electronic structure of Cs and Ba, promoters of the Ru/C catalysts for ammonia synthesis that attracted interest because of highly increased productivity. The role of the promoters is still largely unclear, although indirect evidence for Cs partial reduction has been obtained by this and other groups. Our XAS analysis with in situ H(2) reduction directly supports the partial Cs reduction in the promoted Ru/C catalysts, depending on the presence of Ru and on the graphitization degree of the support. Higher coordination of Ba was observed with respect to Cs in the reduced samples, without evidence of heavy atoms (Ru, Cs, and Ba) in the surroundings. Because of the strong electropositive nature of Cs, direct experimental evidence of its partial reduction is of outstanding significance also for other applications.