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Kyriienko P.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine | Popovych N.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine | Soloviev S.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine | Orlyk S.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine | Dzwigaj S.,CNRS Surface Science Lab
Applied Catalysis B: Environmental | Year: 2013

Structured silver-alumina catalysts were prepared by the one-step deposition of Al2O3 directly on the surface of cordierite block matrices with subsequent incipient wetness impregnation of Al2O3/cordierite with an AgNO3 aqueous solution. The catalysts were characterized by BET, XRD, XPS and FTIR spectroscopy with CO and pyridine as molecule probe, diffuse reflectance UV-vis, TEM and SEM. The Ag/Al2O3/cordierite catalysts are highly active in SCR of NO with ethanol and butanol and very selective toward N2. The conversion of NO over 0.6%Ag/45%Al2O3/cordierite catalyst reaches the high values of 95-99% already at 250°C and remains at this high level up to 430°C. The optimal silver loading in the silver-alumina catalysts is differing for C2 and C4 alcohols. It is shown that the role of silver in the Ag/Al2O3/cordierite catalyst consists in the modification of both redox and acid-base properties of the catalyst surface. Isolated cations (Ag+) and/or silver nanoclusters (Agn δ+) contain adsorbed oxygen in quantities sufficient only for the partial oxidation of alcohols toward oxygenated compounds, which then reduce NO. © 2013 Elsevier B.V. Source


Popovych N.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine | Kirienko P.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine | Soloviev S.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine | Orlyk S.,Lv Pisarzhevsky Institute Of Physical Chemistry Of The Nas Of Ukraine
Catalysis Today | Year: 2012

The present paper studies effect of silver and alumina loadings on the catalytic activity of Ag/Al 2O 3/cordierite for the selective reduction of NO by ethanol. It is shown that activity of the silver-alumina catalysts depends not only on the loading of components, but also on the surface concentration of silver. High conversion of NO, around 100%, is achieved when the surface concentration of silver is equal to 0.09-0.13 mg/m 2. The Ag/Al 2O 3/cordierite catalyst, as shown by UV-visible diffuse reflectance spectroscopy, under such surface concentration contains silver mainly in the oxidized state (Ag + cations and Ag n δ+ clusters). It is also shown that activity of the structured catalysts with equal silver loading enhances with increasing alumina loading from 18 to 48 wt.%. © 2012 Elsevier B.V. Source

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