Hydrogen chemisorption on Al2O3-supported gold catalysts
Hydrogen chemisorption on Al2O3-supported gold catalysts
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DOI：
10.1021/jp051660z
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发表时间：
2005-08-04
影响因子：
3.3
通讯作者：
van Bokhoven, JA
中科院分区：
文献类型：
--
作者：
Bus, E;Miller, JT;van Bokhoven, JA
氢解离吸附在Au/Al 2 O3催化剂中的金颗粒上，通过原位X-射线吸收光谱，化学吸附和H/D交换实验的组合证明。这种氢的化学吸附引起了An L-3和L-2 X射线吸收近边结构的变化。角和边缘位置上的金原子解离氢，其不溢出到面位点。因此，每个表面金原子吸附的氢原子的平均数随着颗粒尺寸的减小而增加。随着温度的升高，负载金的吸氢量增加或保持不变，而铂的吸氢量则减少。此外，在H/D交换实验中，Au/Al 2 O3的活性随温度的升高而增强。因此，氢在金上的解离和吸附被激活。
Hydrogen is dissociatively adsorbed on the gold particles in Au/Al2O3 catalysts, as demonstrated by a combination of in-situ X-ray absorption spectroscopy, chemisorption, and H/D exchange experiments. This chemisorption of hydrogen induces changes in the An L-3 and L-2 X-ray absorption near-edge structures. The gold atoms on corner and edge positions dissociate the hydrogen, which does not spill over to the face sites. Therefore, the average number of adsorbed hydrogen atoms per surface gold atom increases with decreasing particle size. With temperature, the hydrogen uptake by supported gold increases or remains constant, whereas it decreases for platinum. Furthermore, in H/D exchange experiments, the activity of Au/Al2O3 increases strongly with temperature. Thus, the dissociation and adsorption of hydrogen on gold is activated.