title: Catalytic reduction of NOx with NH3 over different-shaped MnO2 at low temperature.
abstract: MnO(2) nanotubes, nanorods, and nanoparticles were prepared using a hydrothermal method, after which the different activities for selective catalytic reduction (SCR) of nitrogen oxides (NO(x)) were compared. MnO(2) nanorods performed the highest activity for reduction of NO(x) under a gas hourly space velocity of 36,000 h(-1) with conversion efficiencies of above 90% between 250 and 300 °C; it also had the highest removal efficiency of 98.2% at 300 °C. From the analysis of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption, and temperature-programmed reduction, we can ascribe the high activity of MnO(2) nanorods to low crystallinity, more lattice oxygen, high reducibility, and a large number of strong acid sites. The apparent activation energy of the SCR reaction on the surface of nanorods was calculated to be 20.9 kJ/mol, which favored the reaction better than the other catalysts.
authors.affiliation: State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Zheda Road 38, Hangzhou 310027, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Tian
authors.forename: Hangsheng
authors.initials: H
authors.lastname: Yang
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Fan
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D003080:Cold Temperature; D017895:Manganese Compounds / Q000737:chemistry*; D043942:Nanotubes / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*
chemical_list: D017895:Manganese Compounds; D009589:Nitrogen Oxides; D010087:Oxides; D000641:Ammonia; C016552:manganese dioxide