Preparation And Characterization Of DeNO_x Catalysts With CO As Reducing Agent

NOx is one of the main air pollutants. The decomposition of NOx has received growing interest because of its environmental effect. The SCR offers an attractive alternative method to reduce industrial NOx emission. Metallic oxide catalyst with TiO2 as carriers is a kind of catalytical materials with higher catalytic activities. Hexaaluminates is a kind of catalytical materials with high thermal stability and higher catalytic activities. In this thesis, the preparation methods of the two kinds of catalysts and theirs activities for SCR-DeNOx were studied.The impregnation methods was employed to prepare metallic oxide catalysts with TiO2 as carriers. The co-precipitation methods was employed to prepare Sr-hexaaluminate catalysts. The catalysts were characterized by means of XRD, BET, TPR, SEM, TG-DTA etc. The performance of the catalysts was investigated by miniature fixed bed reactor with CO+NO as model reaction.Effect of calcination temperature, calcination time, loading factor on the structure and catalytic activities of metallic oxide catalysts were investigated with NiO/TiO2 as model sample. The best calcination temperature is 550℃, the best calcination time is 4 h, The best loading factor is 12%. Effect of calcination temperature, calcination time, on the structure and catalytic activities of Sr-hexaaluminate catalysts were investigated with SrMnAl11O19-δas model sample. The best calcination temperature is 1200℃, the best calcination time is 4h.Lots of metallic oxides were loaded on nano-TiO2.Their structure and catalytic activities were investigated. The metallic oxide catalysts with dual-active component were prepared by the metallic oxide expressed well. Their structure and catalytic activities were investigated. The results showed when active component was Fe2O3,NiO,Cr2O3 or CuO, the conversion of NO was high. The Fe2O3-Cr2O3/TiO2 catalysts expressed smaller larger specific surface area, high thermal stability and higher catalytic activities.In this thesis, Sr-hexaaluminate catalysts were substituted by lots of metallic element. The structure and catalytic activities of substituted hexaaluminate catalysts were investigated. All the catalysts SrMAl11O19-δ(M= Cu, Co, Zn, Fe, Ni, Cr, Zr, Ce) were prepared by the co-precipitation method. The catalysts SrMAl11O19-δ(M= Cu, Co, Fe, Ni, Cr) were found the formation of the crystal phase of hexaaluminates after samples were calcinated at 1200℃for 4 hours. The catalysts SrMAl11O19-δ(M= Cu, Fe, Cr) expressed high catalytic activities. The catalysts SrMAl11O19-δwere prepared. The results showed crystal phase of hexaaluminates would be broken by excessive metallic element.The catalysts SrMNAl10O19-δ(M, N= Mn, Cd, Co, Cu, Fe, Ni, Zn, Zr, Cr, Y) were prepared by the co-precipitation method. In the catalysts substituted by composite metal, the catalysts SrMnFeAl11O19-δ, SrMnCuAl11O19-δ, SrMnCoAl11O19-δ, SrMnCrAl11O19-δ, SrMnNiAl11O19-δ, SrFeCuAl11O19-δ, SrCuCoAl11O19-δ, were found the formation of the crystal phase of hexaaluminates after samples were calcinated at 1200℃for 4 hours; the catalysts SrMnFeAl11O19-δ, SrMnCuAl11O19-δ, SrMnCoAl11O19-δ, SrFeCuAl11O19-δ, SrCuCoAl11O19-δ, expressed high catalytic activities. Then the catalysts SrMnxFe1-xAl11O19-δ, SrFexCo1-xAl11O19-δ, SrFexCo1-xAl11O19-δ, SrFexCu1-xAl11O19-δ, SrMnxCo1-xAl11O19-δ, SrCuxCo1-xAl11O19-δwere prepared. Their structure and catalytic activities were investigated. The results showed SrMnxFe1-xAl11O19-δcatalysts expressed smaller larger specific surface area, high thermal stability and higher catalytic activities.