Study On Controllable Preparation Of High-efficiency Iron-based Oxide And Its Catalytic Performance For CO Reduction Of NO

With the large-scale use of fossil fuels and the rapid development of the transportation industry,air pollution in China has become increasingly serious.Among them,carbon monoxide(CO)and nitrogen monoxide(NO)are two common atmospheric pollutants.Catalytic elimination of CO and NO is a well-recognized and efficient way.The excellent properties of sulfhydryl and iron-based composite oxides in catalysis have been a hot topic for researchers.For Zr02,because it has both basic and acidic sites,it is easy to generate oxygen vacancies,complex and special chemical structure,which makes it have high catalytic performance.Researchers have further expanded their use in catalytic materials by incorporating other atoms or groups into ZrO2 to prevent this from happening.This paper discusses the preparation,physicochemical properties,structural analysis and the effect of Fe0.35(CeZr)x cage-like hollow composite oxide and its supported copper,cobalt and nickel catalysts on CO reduction NO reaction.In addition,the paper focuses on the catalytic performance and composition,structure and properties of the catalyst.relationship through N2 adsorption-desorption(N2-physisorption),X-ray diffraction(XRD),Inductively coupled plasma atomic emission spectrometer(ICP-AES),X ray photoelectron spectroscopy(XPS),Temperature programmed reduction and desorption(H2-TPR),In situ diffuse reflectance Fourier transform infrared spectroscopy(in situ DRIFTS)and NO + CO model reaction.A series of Fe0.35(CeZr)x(X=1,3,5,7,9,10)composite oxides were prepared by template hydrothermal method.The results show that:1.When the molar ratio of Ce to Zr is 5,a uniformly dispersed Fe0.35(CeZr)5 cage-like hollow structure can be prepared by hydrothermal method.2.Fe0.35(CeZr)5 has the largest specific surface area and the lowest reduction temperature.Fe0.35(CeZr)5 has the best activity,the best N2 conversion and selectivity,it can achieve 100%NO conversion at 250 ?,and 100%N2 selectivity at 300 ?.This is mainly due to its optimal reducing ability,large specific surface area and more chemical adsorption of O2-species,and its important reason may be closely related to the synergistic oxygen vacancy effect of Fe2+,Ce3+ and Zr4+.3.Different(Ce:Zr)ratios of Fe0.35(CeZr)x composite oxides have different catalytic properties and can conform to the E-R mechanism to form synergistic oxygen vacancies.A series of M/Fe0.35(CeZr)5(M=Cu,Co,Ni)catalysts with different loadings of 5%were prepared by template hydrothermal method.The characterization results showed that:1.In the load of Cu,Co,Ni,the activity of Cu loading is the best,the reaction temperature can achieve 100%NO conversion at 250 ?,and the selectivity of N2 is 100%at 275 ?.2.The surface synergistic oxygen vacancies play an important role,because CuO can be well dispersed on the surface of the carrier,so the catalyst has the strongest reducing ability and shows the best performance.This is inextricably linked to its structure,oxygen vacancies,surface adsorption oxygen content,and reducing power.High concentrations of synergistic oxygen vacancies enhance their NO conversion and N2 selectivity.3.In the CO + NO reaction,the Cu/Fe0.35(CeZr)5 catalyst follows the E-R reaction mechanism.Finally,to gain a deeper understanding of the interaction of CO and NO probe molecules with the catalyst surface,Finally,in order to find out the interaction between CO and NO probe molecules and the catalyst surface,combined with the characterization results of its physicochemical properties and in situ infrared technology,the CO reduction NO reaction in Fe0.35(CeZr)5 composite oxide was preliminarily proposed.And the reaction mechanism on Cu/Fe0.35(CeZr)5 catalyst.