Superior pillared clay catalysts for selective catalytic reduction of nitrogen oxides for power plant emission control.
Fe(3+)-, Cr(3+)-, Cu(2+)-, Mn(2+)-, Co(2+)-, and Ni(2+)-exchanged Al2O3-pillared interlayer clay (PILC) or TiO2-PILC catalysts are investigated for the selective catalytic reduction (SCR) of nitric oxide by ammonia in the presence of excess oxygen. Fe(3+)-exchanged pillared clay is found to be the most active. The catalytic activity of Fe-TiO2-PILC could be further improved by the addition of a small amount of cerium ions or cerium oxide. H2O and SO2 increase both the activity and the product selectivity to N2. The maximum activity on the Ce-Fe-TiO2-PILC is more than 3 times as active as that on a vanadium catalyst. Moreover, compared to the V2O5-WO3/TiO2 catalyst, the Fe-TiO2-PILC catalysts show higher N2/N2O product selectivities and substantially lower activities (by approximately 85%) for SO2 oxidation to SO3 under the same reaction conditions. A 100-hr run in the presence of H2O and SO2 for the CeO2/Fe-TiO2-PILC catalyst showed no decrease in activity.
Long
R Q
RQ
Department of Chemical Engineering, University of Michigan, Ann Arbor, USA.
Yang
R T
RT
Zammit
K D
KD
D000397:Air Pollution / Q000032:analysis / Q000517:prevention & control*; D000538:Aluminum Silicates; D002384:Catalysis; D000077215:Clay; D009589:Nitrogen Oxides / Q000737:chemistry*; D010084:Oxidation-Reduction; D011210:Power Plants
D000538:Aluminum Silicates; D009589:Nitrogen Oxides; D000077215:Clay