Preparation Of Metal Oxide Catalyst And Investigation Of Its Catalytic Properties For The Selective Reduction Of NO

With the significant increase of automobile quantity, the pollution caused by automobile exhaust has become more and more severe, especially for the NO_x, it not only will result in the formation of photochemistry smoke, acid rain and the human body breath endanger, but also will destroy the ecological environment, as well as bring the serious influence on the mankind's life and production. The traditional three-way catalyst would be ineffective under lean-burn condition, therefore, researching a new type of catalyst for automobile exhaust purification becomes the current topic that many scholars pay much attention to.Two kinds of catalysts have been studied in this thesis: one is Cu/La/SO₄^2-/Al₂O₃ catalyst that has high catalytic activity and thermal stability, which was prepared by modified γ -Al₂O₃ carrier with SO₄^2- followed by addition of La and loading with Cu²⁺ afterward; The other is Cu/SO₄^2-/La₂O₃-ZrO₂-Al₂O₃ catalyst that prepared bymodified La₂O₃ZrO₂-Al₂O₃ composite support with SO₄^2- followed by loading with Cu²⁺. Meanwhile, the structure and property of catalysts have been investigated by using the catalysts performances and the results of characterization. The results are showed as follows:1 .The SO₄^2- modification can facilitate an increase of the acidity on the surface of the catalyst, and improve the catalytic activity of catalysts effectively. Meanwhile, the addition of La promoter could greatly increase the thermal stability and reducibility of the catalyst, and could restrain the formation of CuAl₂O₄ sharp stone availably, thus expand the operation temperature window clearly.2. The property of La₂O₃-ZrO₂-Al₂O₃ composite support made by hydrothermal synthesis was better than the singleness carriers. The addition of ZrC>2 contributed mainly to the increase of the catalytic activity in low temperature of the title catalysts, whilst the addition of La₂O₃ contributed mainly to the enhancement of the thermal stability of the catalyst.3. After the SO₄^2- modification, the SO₄^2- was able to combine with Zr to form a chelate bidentate state which could largely facilitate an increase of the acid quantity...