Gas Phase Synthesis of Au Clusters Deposited on Titanium Oxide Clusters and Their Reactivity with CO Molecules
Gas Phase Synthesis of Au Clusters Deposited on Titanium Oxide Clusters and Their Reactivity with CO Molecules
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DOI：
10.1021/jp202125g
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发表时间：
2011-10-27
影响因子：
2.9
通讯作者：
Mafune, Fumitaka
中科院分区：
文献类型：
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作者：
Himeno, Hidenori;Miyajima, Ken;Mafune, Fumitaka
钛氧化物簇在气相中形成的激光烧蚀的钛棒在氧气的存在下，在He气体。不仅形成了化学计量比的钛氧化物团簇Ti（n）O（2n+x）（+）（n = 1-22和x = 1-3），而且还形成了非化学计量比的钛氧化物团簇Ti（n）O（2n + x）（+）。氧原子的含量很大程度上取决于氧的分压。利用激光烧蚀法在Ti（n）O（2n+x）团簇上制备了金团簇Au（m）（m = 1-4）。Au（m）Ti（n）O（2n+x）（+）的形成是由电子从Au（m）转移到Ti（n）O（2n+x）（+）。用质谱法研究了Au（m）Ti（n）O（2n+x）（+）团簇离子与CO的反应性。发现Ti（n）O（2n-1）（+）上的Au（m）比Ti（n）O（2n+x）（+）（x = 0和1）上的活性低。另外，当Au（m）（m = 1和3）在化学计量的氧化钛（x = 0）上时，反应性最高，而当Au（2）在富氧的氧化钛（x = 1）上时，反应性也高。用密度泛函方法研究了Au（m）Ti（n）O（2n+x）（+）的几何结构对反应活性的影响.
Titanium oxide clusters were formed in the gas phase by the laser ablation of a Ti rod in the presence of oxygen in a He gas. Not only stoichiometric but also nonstoichiometric titanium oxide clusters, Ti(n)O(2n+x)(+) (n = 1-22 and x = 1-3), were formed. The content of oxygen atoms depends strongly on a partial pressure of oxygen. Gold clusters, Au(m) (m = 1-4), were generated by the laser ablation, which were then deposited on Ti(n)O(2n+x) clusters. The formation of Au(m)Ti(n)O(2n+x)(+) follows electron transfer from Au(m) to Ti(n)O(2n+x)(+.) The reactivity of Au(m)Ti(n)O(2n+x)(+) cluster ions with CO was examined for different m, n, and x by the mass spectrometry. It was found that Au(m) on Ti(n)O(2n-1)(+) are less reactive than those on the other Ti(n)O(2n+x)(+) (x = 0 and 1). In addition, the reactivity is highest when Au(m) (m = 1 and 3) is on the stoichiometric titanium oxide (x = 0), whereas the reactivity is also high when Au(2) is on the oxygen-rich titanium oxide (x = 1). The reactivity was found to relate to geometrical structures of Au(m)Ti(n)O(2n+x)(+), which were studied by density functional calculations.