Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10244606 | Journal of Catalysis | 2005 | 14 Pages |
Abstract
Silica- and alumina-supported nickel phosphide (NixPy) catalysts have been prepared, characterized by bulk and surface sensitive techniques, and evaluated for the hydrodesulfurization (HDS) of thiophene. Series of 30 wt% NixPy/SiO2 and 20 wt% NixPy/Al2O3 catalysts were prepared from oxidic precursors with a range of P/Ni molar ratios by temperature-programmed reduction (TPR) in flowing H2. Oxidic precursors with molar ratios of P/Ni = 0.8 and 2.0 yielded catalysts containing phase-pure Ni2P on the silica and alumina supports, respectively. At lower P/Ni ratios, significant Ni12P5 impurities were present in the NixPy/SiO2 and NixPy/Al2O3 catalysts as indicated by X-ray diffraction. The HDS activities of the NixPy/SiO2 and NixPy/Al2O3 catalysts depended strongly on the P/Ni molar ratio of the oxidic precursors with optimal activities obtained for catalysts containing phase-pure Ni2P and minimal excess P. After 48 h on stream, a Ni2P/SiO2 catalyst was 20 and 3.3 times more active than sulfided Ni/SiO2 and Ni-Mo/SiO2 catalysts, respectively. A Ni2P/Al2O3 catalyst was 2.7 times more active than a sulfided Ni/Al2O3 catalyst but only about half as active as a sulfided Ni-Mo/Al2O3 catalyst.
Related Topics
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Authors
Stephanie J. Sawhill, Kathryn A. Layman, Daniel R. Van Wyk, Mark H. Engelhard, Chongmin Wang, Mark E. Bussell,