کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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62603 | 47646 | 2009 | 11 صفحه PDF | دانلود رایگان |
Nickel-based bimetallic catalysts supported on MCM-41 mesoporous molecular sieves (Ni–Ti-, Ni–Mn-, and Ni–Zr–MCM-41) were prepared by direct hydrothermal synthesis. The catalytic properties were tested in methane reforming with CO2. All Zr-promoted catalysts exhibited comparable or enhanced initial catalytic activity as compared to Ni–MCM-41. Adding Zr4+ remarkably improved the long-term stability, whereas decreased lower initial activity and stability were observed for Ti- and Mn-modified catalysts. The addition of Zr4+ enhanced the structural stability and the dispersion of active Ni sites. The strong anchoring effect of Zr4+ and the partial activation of CO2 by Zr4+ contributed to the high catalytic activity and long-term stability. On the contrary, the decoration of Ni clusters with TiOx and MnOx species on Ni–Ti and Ni–Mn catalysts hindered the accessibility of Ni-active centers, thus decreasing their catalytic performance. The partial transformation of amorphous silica matrix into quartz and/or tridymite phases over Ni–Mn, Ni–Ti, and Ni–MCM-41 catalysts also played a negative role on their catalytic stability.
Ni–Zr–MCM-41 catalysts exhibited remarkably enhanced catalytic activity and long-term stability due to the anchoring effect of Zr4+ and partial activation of CO2 by Zr4+.Figure optionsDownload high-quality image (116 K)Download as PowerPoint slide
Journal: Journal of Catalysis - Volume 266, Issue 2, 10 September 2009, Pages 380–390