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Please use this identifier to cite or link to this item: http://hdl.handle.net/10119/10719

Title: High-resolution spectroscopy (XPS, 1^H MAS solid-state NMR) and DFT investigations into Ti-modified Phillips CrO_x/SiO_2 catalysts
Authors: Cheng, Ruihua
Xu, Chen
Liu, Zhen
Dong, Qi
He, Xuelian
Fang, Yuwei
Terano, Minoru
Hu, Yatao
Pullukat, Thomas J.
Liu, Boping
Keywords: Phillips CrO_x/SiO_2 catalyst
X-ray photoelectron spectroscopy
1^H magic-angle-spin solid state nuclear magnetic resonance
Density functional theory
Issue Date: 2010-06-16
Publisher: Elsevier
Magazine name: Journal of Catalysis
Volume: 273
Number: 2
Start page: 103
End page: 115
DOI: 10.1016/j.jcat.2010.05.002
Abstract: Ti-modified Phillips catalyst is a most important industrial catalyst widely used in ethylene polymerization, but the mechanism still remains mysterious. In this work, Ti-modified Phillips catalysts were characterized by high-resolution X-ray photoelectron spectroscopy (XPS) and 1^H magic-angle-spin solid-state nuclear magnetic resonance (1^H MAS solid-state NMR) combined with density functional investigations on the effects of Ti-modification on promotion of polymerization activity, and regulation of microstructures of the polymer chains. XPS data revealed Ti-modification caused increase of electron-deficiency and photo-stability of the surface chromate species. 1^H NMR provided the first direct evidence of surface residual Ti–OH groups. Modeling results rationalized well the effects of Ti-modification on promotion of polymerization activity, extension of molecular weight distribution (MWD) to lower MW region, improvement of the distribution of inserted co-monomer and enhancement of 2,1-insertion in regioselectivity of Phillips catalysts. It was the first time the Ti-modification on Phillips catalysts were theoretically elucidated.
Rights: NOTICE: This is the author's version of a work accepted for publication by Elsevier. Ruihua Cheng, Chen Xu, Zhen Liu, Qi Dong, Xuelian He, Yuwei Fang, Minoru Terano, Yatao Hu, Thomas J. Pullukat, Boping Liu, Journal of Catalysis, 273(2), 2010, 103-115, http://dx.doi.org/10.1016/j.jcat.2010.05.002
URI: http://hdl.handle.net/10119/10719
Material Type: author
Appears in Collections:c10-1. 雑誌掲載論文 (Journal Articles)

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