Density Functional Theory Studies on the C-H Bond Activation of Methane by (CeO2)(m)(m=1-3)

作者：Chen Rongfang; Xia Wensheng^*; Wan Huilin

来源：Chemical Journal of Chinese Universities, 2015, 36(9): 1743-1751.

DOI：10.7503/cjcu20150218

• Ceria
• Methane
• Density functional theory
• Mechanism

Although the rare earth oxide CeO2-based nano-catalysts have exhibited good performances for the activation of C-H of methane at low temperatures, the nature of the active sites and the C-H activation mechanisms are not clear. In this work, we employed the density functional theory(DFT) method to investigate the activation of C-H of CH, and its mechanism at the electroneutral clusters(CeO2)(m)(m=1-3). The results show that the activation of C-H of methane on the clusters obeys the nucleophilic addition modes with the tetra-center structured transition state, in which the electrons are transferred from the clusters to the anti-bonding orbital of CH,, then weakening and activating the C-H of methane. The bridge oxygen sites of the clusters display the higher activity toward the C-H of methane than the terminal oxygen sites, and the threefold bridge sites show the greater activity for C-H activation of methane than the two-fold bridge sites. The charge population of the involved Ce and O atoms in the clusters is closely correlated to their ability toward the C-H activation of methane. In addition, not only decreases the solvation of the clusters the energy barrier for C-H activation of methane, but also makes the activity difference between the active sites of the clusters for C-H activation of methane be smaller.

• 出版日期2015-9-10
• 单位厦门大学