Promotion effect of H2 on the low temperature activity of the selective reduction of NO by light hydrocarbons over Ag/Al2O3

New Insights into the Active Surface Species of Silver Alumina Catalysts in the Selective Catalytic Reduction of NO

“…1,9,[11][12][13][14] The lack of certainty on the type of the active site is due to the complex nature of the SCR reaction, 1,15 the mobility of silver species under reaction condition, 3,16 and the influence of temperature and gas-phase composition on the formed surface species. 17 Hydrocarbons are used as reducing agents for the SCR reaction (HC-SCR) with silver alumina catalysts, and in the past decades the use of several different hydrocarbons, ranging from short-chain hydrocarbons, such as propane 2,7,12,18 and propene, 11,19 to long-chain hydrocarbons such as octane, 15,20,21 decane, 17 and real diesel fuel, 22 has been studied. The structure of the hydrocarbon only influences the activity of the catalysts; increasing the number of carbons and the linearity of the carbon chain increases the activity of the catalyst but does not affect its selectivity.…”

The role of Ag O Al entities in adsorption of NCO species and reduction of NO

“…[12,13]. For HC-SCR over Ag/Al 2 O 3 , it has been accepted that silver (Ag) and support Al must interact strongly with each other to guarantee high activity in NO x reduction.…”

Promotional Effect of Titanium on the Catalytic Performance of Anodic Alumina Supported Silver Catalyst for the Selective Reduction of NO with Propene

“…In the last decade, Ag-based alumina catalyst was considered one of the most promising de-NO x catalysts, and was extensively investigated using methane (Keshavaraja et al, 2000), propene (Jen, 1998;Meunier et al, 1999Meunier et al, , 2001Martínez-Arias et al, 2000), propane (Angelidis and Kruse, 2001;Satokawa et al, 2001Satokawa et al, , 2003, long paraffins (Shimizu et al, 2000(Shimizu et al, , 2001 and alcohols (Miyadera, 1993;Masuda et al, 1996;Bion et al, 2003) as reductants, due to its relatively high and durable de-NO x activity even in the presence of SO 2 and water, moderate operating temperature window and inexpensive preparation cost.…”

“…This activated hydrocarbon was proposed to react with nitrates on the catalyst surface to form organic nitrate intermediates, and finally lead to nitrogen and carbon oxides (Shimizu et al, 2001;Furusawa et al, 2003;He et al, 2003;Sato et al, 2003). In SCR of NO with propene, oxygenated hydrocarbons adsorbed on the catalyst surface (acetate) were detected by in situ Fourier-Transform infrared (FTIR) spectroscopy (Satokawa et al, 2003). The isocyanate (-NCO) species from the reaction between oxygenated hydrocarbons and adsorbed NO x species were detected by situ diffuse reflectance infrared Fourier-Transform (DRIFT) spectroscopy and presumed to be key reaction intermediates (Bion et al, 2003).…”

“…The isocyanate (-NCO) species from the reaction between oxygenated hydrocarbons and adsorbed NO x species were detected by situ diffuse reflectance infrared Fourier-Transform (DRIFT) spectroscopy and presumed to be key reaction intermediates (Bion et al, 2003). In addition, the absence of appreciable activity of Ag/alumina at low temperatures was ascribed to the inhibition of active sites due to adsorbed nitrates (Meunier et al, 1999;Shimizu et al, 2001;Furusawa et al, 2003;Satokawa et al, 2003).…”