title: Application of mixed oxide catalysts to the removal of lean NOx and N2O using transient-mode cyclic operations.
abstract: The storage and reduction of NO and N2O in the presence of excess O2 have been investigated over two mixed oxide catalysts. The catalysts, which were prepared via coprecipitation of solutions of mixed metal nitrates, followed by calcination, were found to have plenty storage capacities for nitrogen oxides. The storage and reduction performances varied with the catalyst composition and the duration of cycle time: the AlCoPd (1/1/0.05) mixed oxide catalyst exhibited higher efficiency for NO, and an AlCoFe (1/1/2) mixed oxide catalyst exhibited higher efficiency for N2O. The adsorptions of NO and N2O onto the mixed oxide catalysts progressed without an oxidation step, and the adsorptivity of NO surpassed that of O2. The mixed oxides showed spinel structures with sizes of 10-100 nm, and with well-developed mesopores that were formed by the evaporation of H2O and CO2 from layered double hydroxide (LDH) precursors. The storage and reduction of lean NOx and N2O over the mixed oxide catalysts were carried out via cyclic operations in a transient mode at 300 degrees C and at space velocities of around 30,000 h(-1). The removal efficiency of the cyclic operations generally increased with reduced adsorption cycle time, and reached 90% for NOx and N2O with the respective catalysts.
authors: Department of Industrial Chemistry, Sangmyung University, Seoul 110-743, Korea.
authors: Xiaoshan
authors: X
authors: Peng
authors: Ki-Seon
authors: KS
authors: Yang
authors: Kil Sang
authors: KS
authors: Chang