title: Mechanism of N2O formation during the low-temperature selective catalytic reduction of NO with NH3 over Mn-Fe spinel.
abstract: The mechanism of N2O formation during the low-temperature selective catalytic reduction reaction (SCR) over Mn-Fe spinel was studied. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and transient reaction studies demonstrated that the Eley-Rideal mechanism (i.e., the reaction of adsorbed NH3 species with gaseous NO) and the Langmuir-Hinshelwood mechanism (i.e., the reaction of adsorbed NH3 species with adsorbed NOx species) both contributed to N2O formation. However, N2O selectivity of NO reduction over Mn-Fe spinel through the Langmuir-Hinshelwood mechanism was much less than that through the Eley-Rideal mechanism. The ratio of NO reduction over Mn-Fe spinel through the Langmuir-Hinshelwood mechanism remarkably increased; therefore, N2O selectivity of NO reduction over Mn-Fe spinel decreased with the decrease of the gas hourly space velocity (GHSV). As the gaseous NH3 concentration increased, N2O selectivity of NO reduction over Mn-Fe spinel increased because of the promotion of NO reduction through the Eley-Rideal mechanism. Meanwhile, N2O selectivity of NO reduction over Mn-Fe spinel decreased with the increase of the gaseous NO concentration because the formation of NH on Mn-Fe spinel was restrained. Therefore, N2O selectivity of NO reduction over Mn-Fe spinel was related to the GHSV and concentrations of reactants.
authors.affiliation: School of Environmental and Biological Engineering, Nanjing University of Science and Technology , Nanjing 210094, People's Republic of China.
authors.forename: Shijian
authors.initials: S
authors.lastname: Yang
authors.forename: Shangchao
authors.initials: S
authors.lastname: Xiong
authors.forename: Yong
authors.initials: Y
authors.lastname: Liao
authors.forename: Xin
authors.initials: X
authors.lastname: Xiao
authors.forename: Feihong
authors.initials: F
authors.lastname: Qi
authors.forename: Yue
authors.initials: Y
authors.lastname: Peng
authors.forename: Yuwu
authors.initials: Y
authors.lastname: Fu
authors.forename: Wenpo
authors.initials: W
authors.lastname: Shan
authors.forename: Junhua
authors.initials: J
authors.lastname: Li
mesh_terms: D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D003080:Cold Temperature; D007501:Iron / Q000737:chemistry*; D008277:Magnesium Oxide / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D009609:Nitrous Oxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: C111130:spinell; D009569:Nitric Oxide; D008277:Magnesium Oxide; D008345:Manganese; D000641:Ammonia; D007501:Iron; D009609:Nitrous Oxide; D000537:Aluminum Oxide