کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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57729 | 47128 | 2008 | 6 صفحه PDF | دانلود رایگان |
Nanocrystalline α-Al2O3 and Ni-modified α-Al2O3 have been prepared by sol–gel and solvothermal methods and employed as supports for Pd catalysts. Regardless of the preparation method used, NiAl2O4 spinel was formed on the Ni-modified α-Al2O3 after calcination at 1150 °C. However, an addition of NiO peaks was also observed by X-ray diffraction for the solvothermal-made Ni-modified α-Al2O3 powder. Catalytic performances of the Pd catalysts supported on these nanocrystalline α-Al2O3 and Ni-modified α-Al2O3 in selective hydrogenation of acetylene were found to be superior to those of the commercial α-Al2O3 supported one. Ethylene selectivities were improved in the order: Pd/Ni-modified α-Al2O3–sol–gel > Pd/Ni-modified α-Al2O3-solvothermal ≈ Pd/α-Al2O3–sol–gel > Pd/α-Al2O3-solvothermal ≫ Pd/α-Al2O3-commerical. As revealed by NH3 temperature program desorption studies, incorporation of Ni atoms in α-Al2O3 resulted in a significant decrease of acid sites on the alumina supports. Moreover, XPS revealed a shift of Pd 3d binding energy for Pd catalyst supported on Ni-modified α-Al2O3–sol–gel where only NiAl2O4 was formed, suggesting that the electronic properties of Pd may be modified.
Journal: Catalysis Today - Volume 131, Issues 1–4, 29 February 2008, Pages 553–558