Preparation And Properties For Selective Catalytic Reduction Of NO In The Presence Of Oxygen, Of Ti-pillared Montmorillonite Mesoporous Solid Acid Catalysts

Because high degree of NO_X emitted to the atmosphere from combustion sources contributes to acid rain and smog formation, it has become a major concern in air pollution, and catalytic decomposition and reduction of NO_X has been studied extensively. Recently, more stringent regulations have been imposed to lower the emission of contaminative hydrocarbon, carbon oxides and nitric oxides. All of these pollutants including NO_X can be minimized by operating combustion engines on the high are fruel ratio. In such highly oxidizing condition, the activity of conventional three-way catalysis, which is used to eliminate HC, CO and NO_X would be diminished totally. To search for new catalysts or methods to deal with the increased NO concentration from the lean-burn engines has become a challenge in this field.In this paper, a Sol-Gel method that can be used to control the quantity of Ti was applied to prepare mesoporous pore Ti-Pillared montmorillon using natrium montmorillonite as matrix and tetra-n-butyl titanate as resource of Ti. Ti-PILM was then treated with SO₄^2- and Ce to obtain Ce/SO₄^2-/Ti-PILM as support to prepare Cu/Ce/SO₄^2-/Ti-PILM via loading Cu²⁺. XRD, DTA, IR, BET, NH₃-TPD, Py-IR, FT-IR and XPS techniques were used to characterize the relation of structure and performances. And the effects of synthesized conditions were investigated for the selective reduction of NO by propene (C₃H₆). The results were as following:(1) The catalyst was modified by SO₄^2-, and the chelate ligand structure was formed. The appearance of the chelate ligand structure of solid acid on the surface of catalysts increased acid amount greatly and Bronsted acid sites. The results of activity test indicated that the conversion rate of NO could be greatly enhanced by modified Ti-PILM with SO₄^2-.(2) It was obviously influenced the structure and performances that the catalysts introducted Ce. The results of structural test indicated that the introduction of Ce enhanced not only thermal stability but also its reduction efficacy of copper. The activity and thermal stability of catalysts were improved.(3) The polycationic titanium solution could insert into the layers ofmonlmorillonile effectively. The surface area of catalysts was increased remarkably alter pillared, and the mesoporous pore was formed whose size mainly ranged from 3 to 7 nm. The uniformity of mesoporous pore was improved, and the size of mesoporous pore was about 4 nm after modified by SO4"" and Ce.