Adsorption and Hydrogenation Process of p-Chloronitrobenzene on Au20 Cluster: a DFT Study

摘要

We have systematically investigated the adsorption and hydrogenation process of p-chloronitrobenzene on Au20 cluster using density functional theory (DFT) calculations.The adsorption of two types of all species,vertical adsorption and parallel adsorption,is compared,revealing that former model is more stable than the latter,and all of the species prefer to adsorb at the vertex site.After adsorption,electrons transferred from Au20 cluster to the p-chloronitrobenzene molecule.Almost all hydrogenation processes are exothermic,and the C-Cl bond scissions are considered as the rate-limiting step for both Paths A (p-CNB→ p-CAN→ AN) and B (p-CNB → NB → AN) with the energy barriers of 2.62 and 2.95 eV,respectively.These suggest that the C-Cl bond scission is not easy to occur on Au20 cluster due to the high energy barrier,especially the path B.The p-chloroaniline is the main hydrogenation product catalyzed by Au20.