Study On Application Of V₂O₅/TiO₂&La_1-XCe_XCoO₃ Catalysts On Diesel Engine Exhaust

The application of catalytic technique with La_1-xCe_xCoO₃ catalysts of perovskite type structure and V₂O₅/TiO₂ catalysts on diesel engine exhaust was discussed in this paper. Simulative diesel emission was introduced through pure gases mixed in this research. The principle and reaction mechanism of nitrogen oxides (NO_x),total hydrocarbon compound (THC) from the diesel exhaust through catalysis were focused, which maked foundation for practical Selective Catalytic Reduction(SCR) catalysis on diesel emission in the future.A series of La_1-xCe_xCoO₃ catalysts were synthesized with citric acid method, during which the catalysts with particle diameters that scatters in the domain of 90 and 200nm was prepared, and the BET values of the catalysts range from 8 to 13 m²/g. And V₂O₅/TiO₂ catalysts were prepared by dipping. The structure and component of the catalysts were studied by means of X-ray diffraction (XRD), transmission electron microscope (TEM) and X-Ray Photoelectron Spectrometer (XPS). The results indicate that La_1-xCe_xCoO₃ is single perovskite phase in the case of x≤0.2,and when x>0.2,Co3O4 appears in the catalysts sample and increased the increase of x.Study of catalytic property for removal of NO_x, THC and CO from diesel exhaust was carried out by using temperature-programmed reaction (TPR). The results show that the pure LaCoO3 granule has higher (>30%) reductive ability between 250 to 450℃. It has great oxidated activity, which enhances as soon as the temperature rises.The selective reduction of NO_x was carried out by LaCoO3 and V₂O₅/TiO₂ catalysts. The results indicate that the catalysis have good selectivity and catalysis for the removal NO_x from diesel engine. And the high catalytic performance of Mo-V-O/TiO₂ catalysts originated from the high redox capcacity of vanadium molybdate phase.