A new route to the shape-controlled synthesis of nano-sized γ-alumina and Ag/γ-alumina for selective catalytic reduction of NO in the presence of propene

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• 作者：Driss Mrabet ; Manh-Hiep Vu ; Serge Kaliaguine ; ^{serge.kaliaguine@gch.ulaval.ca" class="auth_mail" title="E-mail the corresponding author} ; Trong-On Do ; ^{Trong-On.Do@gch.ulaval.ca" class="auth_mail" title="E-mail the corresponding author}
• 关键词：γ-Nanoalumina ; Nanocrystals ; γ-Nanoalumina based Ag catalysts ; Selective catalytic reduction ; NO ; C3H6
• 刊名：Journal of Colloid and Interface Science
• 出版年：2017
• 出版时间：1 January 2017
• 年：2017
• 卷：485
• 期：Complete
• 页码：144-151
• 全文大小：1886 K

文摘

We report a new route for the direct synthesis of γ-alumina nanocrystals with size and shape control in the presence of oleylamine as the capping agent. Their morphology can be controlled from nanospheres to nanorods by simply tuning a proper amount of concentrated nitric acid (67%) in the synthetic mixture. The as-made nanoparticle products after calcination show γ-alumina nano-size with unique porosity and high specific surface area and retained morphology. The XRD patterns of these calcined samples exhibit broad diffraction lines which are characteristic of nanocrystal size of γ-alumina.

This synthesis procedure has been extended to the one-pot synthesis of nano-alumina based Ag catalysts with spherical and rod-shaped nano-alumina morphologies. Selective catalytic reduction (SCR) of NO with C₃H₆ over these catalysts was investigated. The results were compared to those of the conventional Ag/γ-Al₂O₃ and γ-nanoalumina alone. These nano-alumina based Ag catalysts exhibit excellent NO reduction activity in the presence of C₃H₆. Even in the presence of large oxygen concentration (15%), N₂ yields as high as ∼90% at quite low temperature (∼350 °C) have been achieved. The significantly high catalytic activity of this new type of nanocatalysts can also be attributed to their high surface area and good dispersion of silver species in the alumina matrix as well as the synergism and new properties that arise at the silver-nanoalumina interface.