论文标题
PT7/氧化铝模型催化剂的SN调节：碳沉积和增强的热稳定性
Sn-modification of Pt7/alumina model catalysts: Suppression of carbon deposition and enhanced thermal stability
论文作者
论文摘要
原子层沉积过程用于通过SN添加PT7簇沉积之前和之后通过SN添加来修改尺寸选择的PT7/Alumina模型催化剂。表面科学方法用于探测SN调节对簇的电子性质，反应性和形态的影响。 SN添加是在簇沉积之前或之后的，发现强烈影响烯烃模型，乙烯的结合特性，改变结合位点的数量和类型，并抑制分解，从而导致催化剂的碳沉积和中毒。模型系统上的密度功能理论PT4SN3/氧化铝表明，SN和PT原子混合在一起，形成了合金簇，具有从SN到PT的大量电子转移。 SN的存在还使所有可接收的结构都封闭壳，从而使乙烯仅通过π键与单个Pt原子结合。在反复的乙烯温度编程反应实验中，SN修饰的催化剂非常稳定，这表明SN的存在还降低了亚纳米群体接受热烧结的趋势。
An atomic layer deposition process is used to modify size-selected Pt7/alumina model catalysts by Sn addition, both before and after Pt7 cluster deposition. Surface science methods are used to probe the effects of Sn-modification on the electronic properties, reactivity, and morphology of the clusters. Sn addition, either before or after cluster deposition, is found to strongly affect the binding properties of a model alkene, ethylene, changing the number and type of binding sites, and suppressing decomposition leading to carbon deposition and poisoning of the catalyst. Density functional theory on a model system, Pt4Sn3/alumina, shows that the Sn and Pt atoms are mixed, forming alloy clusters with substantial electron transfer from Sn to Pt. The presence of Sn also makes all the thermally accessible structures closed shell, such that ethylene binds only by π-bonding to a single Pt atom. The Sn-modified catalysts are quite stable in repeated ethylene temperature programmed reaction experiments, suggesting that the presence of Sn also reduces the tendency of the sub-nano-clusters to undergo thermal sintering.
