二氧化铈上钯团簇成熟机制的理论研究

Su Ya-Qiong, Liu Jin-Xun, Filot Ivo A W, Hensen Emiel J M

Laboratory of Inorganic Materials Chemistry, Schuit Institute of Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.

Chem Mater. 2017 Nov 14;29(21):9456-9462. doi: 10.1021/acs.chemmater.7b03555. Epub 2017 Oct 13.

We carried out density functional theory calculations to investigate the ripening of Pd clusters on CeO(111). Starting from stable Pd clusters ( = 1-21), we compared how these clusters can grow through Ostwald ripening and coalescence. As Pd atoms have mobility higher than that of Pd clusters on the CeO(111) surface, Ostwald ripening is predicted to be the dominant sintering mechanism. Particle coalescence is possible only for clusters with less than 5 Pd atoms. These ripening mechanisms are facilitated by adsorbed CO through lowering barriers for the cluster diffusion, detachment of a Pd atom from clusters, and transformation of initial planar clusters.

我们进行了密度泛函理论计算，以研究CeO(111)上钯团簇的熟化过程。从稳定的钯团簇（n = 1 - 21）出发，我们比较了这些团簇如何通过奥斯特瓦尔德熟化和聚结进行生长。由于钯原子在CeO(111)表面的迁移率高于钯团簇，预计奥斯特瓦尔德熟化是主要的烧结机制。只有对于含少于5个钯原子的团簇，颗粒聚结才有可能。吸附的CO通过降低团簇扩散、钯原子从团簇脱离以及初始平面团簇转变的势垒，促进了这些熟化机制。