Investigation Of Oxygen Storage Catalysts LnO₂-ZrO₂(Ln=Tb, Pr)

Severe air pollution in metropolitan cities due to the emission of noxious automobile exhaust gases becomes critical international concern. One essential drive to effectively eliminate the air pollution of our homeland country is to develop nationally-authorized, cutting-edge catalysts and catalytic technology in conferring substantial purification of in-land automobile exhaust. For this purpose, (LnO₂)_x-(ZrO₂)_1-x (Ln=Ce,Pr,Tb) oxygen storage catalysts were synthesized using a self-developed, so called"supersonically diffusion-controlled precipitation"method. The physical and chemical process of the catalysts forming solid solution has been investigated using thermal gravimetry (TG) and differential scanning calirometry (DSC). The crystalline structure of the catalysts has been studied via XRD. Oxygen storage capacity (OSC), catalytic activity (light-off) and thermal durability have been assessed using a flow micro-reactor and mass spectroscopy. And the electrical conductivity properties were tested.(CeO₂)_x-(ZrO₂)_1-x fresh solid solution with the largest storage of oxygencorresponding to the elements (CeO₂) 0.6-(ZrO₂) 0.4 comparison, (PrO₂)_0.8-(ZrO₂)_0.2 and (TbO₂)_0.9-(ZrO₂)_0.1 are the largest reservoir of oxygen. The aged storage materials (PrO₂)_x-(ZrO₂)_1-x, and (TbO₂)_x-(ZrO₂)_1-x (x = 0.4-0.8) are super than the oxygen reservoir (CeO₂) 0.6-( ZrO₂) 0.4 . (PrO₂)_x-(ZrO₂)_1-x, and (TbO₂)_x-(ZrO₂)_1-x (x = 0.7,0.8) show that the ageing of its higher oxygen storage of the special attributes. Its thermal stability are super than the traditional oxygen storage materials.Adsorption-desorption experiment results showed that the samples of fresh and processed the aging (PrO₂)_x-(ZrO₂)_1-x, and (TbO₂)_x-(ZrO₂)_1-x are bigger than the (CeO₂) x-(ZrO₂)_1-x of adsorption-desorption rate and the absorption and desorption .The storage of oxygen, adsorption-desorption experiment, thermal stability, activity and anti-ageing properties of the test showed that, (PrO₂)_x-(ZrO₂)_1-x, and (TbO₂) x-(ZrO₂)_1-x show a better performance than (CeO₂)_x-(ZrO₂)_1-x .And they can replace the traditional three - catalytic material (CeO₂)_x-(ZrO₂)_1-x as important candidate materials.Oxygen storage catalytic material 1 wt% Pt-(LnO₂)_0.4-(ZrO₂)_0.6 (Ln = Ce, Pr, Tb), in addition to fresh (PrO₂)_0.4-(ZrO₂)_0.6 and aged (TbO₂)_0.4-(ZrO₂)_0.6 showed poor activity of CH , both fresh and other aged state of activity are better than (CeO₂)_0.4-(ZrO₂)_0.6.Through the exchange of oxygen storage of the impedance test the materials of oxygen storage, transmission, adsorption / desorption, and oxidation / reduction and oxygen storage capacity of lattice defects and non-chemical science than the corresponding mutual relations are resolved. This will not only solve the forefront of this academic key scientific problems, as well as ternary catalytic materials and technology to the development of a new road. The results showed that the oxygen storage reaction from the sample of the grain within the lattice defects, and oxygen is the desorption reaction from the grain boundary surface defects began.