|Toward a Unified Identification of Ti Location in the MFI Framework of High-Ti-Loaded TS-1: Combined EXAFS, XANES, and DFT Study|
|Dong JC(董俊才); Zhu HL(朱海亮); Wang Y(王研); An PF(安鹏飞); Liang YX(梁雅翔); Guo ZY(郭志英); Chen DL(陈栋梁); Doug, JC; Zhu, HL; Xiang, YJ; Wang, Y; An, PF; Gong, Y; Lang, YX; Qiu, LM; Zheng, AG; Peng, XX; Lin, M; Xu, GT; Guo, ZY; Chen, DL
|发表期刊||JOURNAL OF PHYSICAL CHEMISTRY C
|摘要||Titanium silicalite-1 (TS-1) has been shown to be a heterogeneous catalyst with remarkable efficiency and selectivity; however, the nature of the active Ti site in the MFI framework remains elusive. Here we report combined experimental and theoretical research on Ti distribution in the 12 crystallographically distinct T sites of the MFI framework in high-Ti-loaded TS-1 (2.7 wt % in TiO2). Using a multishell fit to extended X-ray absorption fine structure, we show that T4 is the most populated site, in marked contrast to the preferential substitution sites and the definitely excluded sites assumed hitherto by diffraction studies. The identification is supported by a good agreement between calculated and experimental X-ray absorption near-edge structure studies and by full periodic density functional theory (DFT) computation. In spite of having the identical most favored site, the preference order for the remaining sites predicted by DFT does not fully match the experimental results. This suggests that Ti distribution in the resulting TS-1 framework is positively correlated with the thermodynamic stability of pure material but can be affected by other factors such as interdefects. These new insights may facilitate the bottom-up design of new zeolites with tailored catalytic performance and studies on mechanisms of various oxidation reactions.|
; POWDER NEUTRON-DIFFRACTION
; SILICALITE CHARACTERIZATION
; DEFECTIVE SILICALITES
; TITANIUM SILICALITE-1
; TITANOSILICATE TS-1
; IR SPECTROSCOPY
; ZEOLITE TS-1
; Nanoscience & Nanotechnology
; Materials Science, Multidisciplinary
Dong JC,Zhu HL,Wang Y,et al. Toward a Unified Identification of Ti Location in the MFI Framework of High-Ti-Loaded TS-1: Combined EXAFS, XANES, and DFT Study[J]. JOURNAL OF PHYSICAL CHEMISTRY C,2016,120(36):20114-20124.
董俊才.,朱海亮.,王研.,安鹏飞.,梁雅翔.,...&Chen, DL.(2016).Toward a Unified Identification of Ti Location in the MFI Framework of High-Ti-Loaded TS-1: Combined EXAFS, XANES, and DFT Study.JOURNAL OF PHYSICAL CHEMISTRY C,120(36),20114-20124.
董俊才,et al."Toward a Unified Identification of Ti Location in the MFI Framework of High-Ti-Loaded TS-1: Combined EXAFS, XANES, and DFT Study".JOURNAL OF PHYSICAL CHEMISTRY C 120.36(2016):20114-20124.