Design,Synthesis And Characterization Of Cerium-Copper Composite Catalysts For NH₃-SCR Reaction

Nitrogen oxides（NO_x）as one of the products in the course of energy use today that is unavoidable and harmful.The use of catalytic techniques such as ammonia selective catalytic reduction（NH₃-SCR）for its harmless conversion treatment has important socio-economic,environmental protection value.However,the traditional V₂O₅-WO₃（MoO₃）/TiO₂ catalyst has some shortcomings such as poor adaptability,easy loss of vanadium and pollution,it is urgent to develop new catalysts.In this paper,Focusing on the copper-based catalysts that have attracted the attention of domestic and foreign countries and combine with the efficient use of rare earth resources which is the key requirements of industrial development in China,we designed and synthesized two series of cerium-copper composite oxide catalysts.XRD,XPS,SEM,H₂-TPR,NH₃-TPD,with sulfur and without sulfur for SCR reaction were used to study the structural characteristics of the two catalysts and the catalytic properties of NH₃-SCR.The effects of physical and chemical properties of compound oxides on the low temperature and sulfur content of NH₃-SCR were investigated.The typical samples with good performance（suitable for sulfur-resistant selectivity in the suitable temperature range）were screened,Patent of preparation of New Copper-Cerium Composite Oxide Material can be obtained.The details are as follows:（1）（CeO_x）_mCuO composite oxide catalyst was prepared by coprecipitation method.It was found that the Ce/Cu molar composition such as（CeO_x）_0.25CuO in the sample was calcined at 350-450 ^oC,and Ce could be doped into CuO The lattice thus produces the appropriate Cu⁺and Ce³⁺highly active species or sites in the catalyst surface layer to improve the redox and acid center distribution properties of the catalyst.Under 250-350 ^oC and in the presence of 200 ppm SO₂,100%of the selective catalytic conversion can be achieved,and this performance can be maintained by 50hours of continuous testing,these results show that the preparation of the composition of a simple structure and excellent performance of sulfur（CeO_x）_mCuO composite oxide catalyst was prepared,related work was published.（2）Based on the above work,in order to further improve the utilization efficiency of rare earth element Ce,a new method for the preparation of Ce-Cu on copper oxide substrate was proposed by using the redox substitution reaction between tetravalent Ce and monovalent Cu.A series of samples were prepared and used for NH₃-SCR reaction.It was found that the addition of Ce to CuO surface and the introduction of a small amount of Ce at 1.6 wt.%resulted in an appropriate amount of Cu⁺and Ce（III）activity on the catalyst surface（95%）of NO in the presence of240-360 ^oC and 200 ppm SO₂,indicating that this method take the efficient use of Ce and to achieve high performance Ce-Cu Composite materials design and preparation of new methods into account,related research will be submitted,and has submitted two invention patent applications.