Study On Catalytic Oxidation Of Formaldehyde By Silver-based Supported Catalysts

Indoor air pollution is threatening human health,formaldehyde is one of the main indoor pollutants,with high toxicity,long release years and other characteristics.Living in the environment containing formaldehyde for a long time will cause harm to human health,so how to remove indoor formaldehyde pollution has become one of the focus of social attention.Of the many methods for removing formaldehyde,catalytic oxidation technology can convert formaldehyde into harmless H2O and CO2,at lower temperature,which is the most promising method for formaldehyde purification at present.Ag is cheaper in noble metals and has good catalytic performance.Therefore,the application of Ag based catalysts in catalytic oxidation of formaldehyde has attracted much attention.The CeO2-Al2O3?Co-MOF?Co-Mn-MOF was prepared as the support by hydrothermal synthesis and the active components Ag loaded on the support by impregnation.The types of the support,the molar ratio of the Co/Mn,the content of the Ag and the influence on the catalytic activity of the catalyst were examined.The catalyst was characterized by physical adsorption-desorption techniques(BET),X-ray diffraction(XRD),hydrogen temperature programmed reduction(H2-TPR),oxygen temperature programmed desorption(O2-TPD)and the following conclusions were drawn:1?The CeO2-Al2O3 oxide supports were prepared by hydrothermal synthesis,the active components were loaded by impregnation Ag,and the effect of Ag content on the catalytic oxidation performance was investigated.The results show that when the content of Ag is 1%,1%Ag/CeO2-Al2O3 can completely transform formaldehyde at 60? temperature,showing better catalytic activity than 0.5%Ag/CeO2-Al2O3 and 2%Ag/CeO2-Al2O3.2?The Co-MOF?Co-Mn-MOF support was prepared by hydrothermal synthesis.the active components ag impregnated onto the support to obtain a series of Co3O4?Co-Mn-9:1?Co-Mn-7:3?%Ag/Co-Mn-9:1?1%Ag/Co-Mn-7:3 catalysts.The results showed that when the molar ratio of Co/Mn was 9:1 and the content of Ag was 1%,the 1%prepared could completely oxidize formaldehyde to H2O and CO2 at 80?.H2-TPR?O2-TPD characterization showed that the catalyst possessed low reduction performance and abundant surface reactive oxygen species,which enhanced the catalytic activity.The interaction between Co3O4 and MnOx enhances the low temperature reduction performance of the catalyst.