Structural functional design of catalysts for conversion of nitrogen(I, II) oxides

Selective Reduction of No By C3 and C8 Alkanes Over Silver Catalysts on Structured Al2O3/Cordierite Supports

“…Neutralization of nitrogen oxides in the exhaust gases of diesel and lean-burn gasoline engines with a high oxygen content is an important problem for environmental catalysis [1,2]. Silver-alumina catalysts have been widely investigated for the selective catalytic reduction (SCR) of nitrogen oxides by the C 3 -C 10 hydrocarbons that are products from incomplete combustion of the fuel [3-6].…”

“…The optimum content of Ag was higher during reduction with octane (0.5 wt.%) than with propane (0.3 wt.%). The role of the silver involves formation not only of oxidation-reduction centers but also of additional Lewis acid centers at which activation of the reagents (NO and C n H m ) occurs.Neutralization of nitrogen oxides in the exhaust gases of diesel and lean-burn gasoline engines with a high oxygen content is an important problem for environmental catalysis [1,2]. Silver-alumina catalysts have been widely investigated for the selective catalytic reduction (SCR) of nitrogen oxides by the C 3 -C 10 hydrocarbons that are products from incomplete combustion of the fuel [3-6].…”

“…1, curve 3)]. This may indicate that the limiting stage of the process includes a stage with activation of the reducing agent by cleavage of the C n H 2n+1 -H bond [2]. Table 1 shows the conversion of NO in SCR at Ag/46%Al 2 O 3 /cordierite catalysts with various silver contents at the temperature corresponding to the maximum achievable conversion (495°C during reduction with propane, 360°C with octane).…”

Effect of Structural, Size, and Acid Characteristics of Hierarchical BEA and MOR Zeolites on Their Activity in the Catalytic Reduction of N2O and no by Propylene

“…Mesophase materials containing crystalline nanoparticles of various structural types (MFI, MTW, BEA, MRE) were obtained using a similar approach [8,9]. Such zeolite materials, which are often named hierarchical, differ in their adsorption characteristics from ordinary 3D zeolites and, in particular, have a well-developed external surface and greater accessibility of the active sites, which leads to high catalytic activity in acid-base and redox reactions [10].There is considerable present work underway on the development of new operationally-stable catalytic systems for the removal of nitrogen oxides by their reduction to molecular nitrogen in an oxygen-enriched medium (selective catalytic reduction or SCR) as an efficient method for the elimination of NO x emissions [11][12][13]. The search is underway to find catalysts and elucidate the conditions for the combined reduction of N 2 O and NO by light hydrocarbons.…”

“…The search is underway to find catalysts and elucidate the conditions for the combined reduction of N 2 O and NO by light hydrocarbons. Moisture-resistant indium-containing catalysts have been proposed for the reduction of nitrogen oxides (NO x ) in a highly-moist oxidizing atmosphere [14,15].The acidity of the surface of both zeolite and oxide catalysts, in particular, zirconium oxide catalysts, is important for obtaining SCR activity [12,16]. The effect of the acid properties of the surface of zeolite and aluminum oxide catalysts containing indium oxide and cobalt oxide on the activity in deNO x reactions has been studied by various workers [13,17,18].…”