Selective catalytic reduction of NOx by C2H5OH over Ag/Al2O3/cordierite: Effect of the surface concentration of silver

The present paper studies effect of silver and alumina loadings on the catalytic activity of Ag/Al2O3/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/Al2O3/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(delta+) 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.%. (c) 2012 Elsevier B.V. All rights reserved.