Effect Of Perovskite-type Supports On Soot Oxidation Of Copper Catalysts

Diesel particulate matter?PM,mainly containing soot?,undesired by-products of diesel engines in combustion process,have been recognized among the top threads to environment and human health which has driven research focusing on solutions.Copper catalyst has showed excellent catalytic activity,and is a potential substitution for noble metal.And support is an important factor on the catalytic activity of metal oxide catalysts.In this study,we focus on the supports of copper catalysts,the physic-chemical properties of supports and copper catalysts are characterized by XRD,SEM,TEM,ICP-MS,Raman,and N2-adsorption-desorption isotherm.The catalytic activity of copper catalysts for soot combustion were studied by TPO and H2-TPR.the effect of three kind of supports?Ba Al2O3,BaTiO₃ and Fe₃O₄@BaTiO₃?on soot combustion of cooper catalysts were also studied and the main conclusion are listed as followed:1.A stabilized alumina,containing Ba and a titanium-based mixed oxide,also containing Ba were prepared and used as copper supports.Denoted as Ba Al2O3,BaTiO₃,Cu/BaTiO₃ and Cu/Ba Al2O3.2.The catalytic activity of Cu/BaTiO₃ and Cu/Ba Al2O3 on soot combustion were compared,though the two supports could not contribute directly to catalytic activity of copper catalysts,for they have little catalytic activity,but they affect the catalytic activity of copper.Tm of Cu/BaTiO₃ is decreased by 32 °C and 41 °C compared with that of Cu/Ba Al2O3 under O₂ and O₂/NOX,respectively.the reduction temperature of Cu/Fe₃O₄@BaTiO₃?271 °C?is lower than that of Cu/BaTiO₃?305 °C?under H2,indicating copper is more easily reduced when supported on BaTiO₃.However,the BET surface area is only 9 m2/g which will restrict the development of metal oxides catalysts.3.Fe₃O₄@BaTiO₃ core/shell microspheres were synthesized by a hydrothermal-annealing approach.The specific surface area of Fe₃O₄@BaTiO₃ support is much larger?44 m2/g?than that of BaTiO₃ support.And two kinds of copper catalysts?Cu/Fe₃O₄@BaTiO₃ and Cu/BaTiO₃?were prepared.4.The catalytic activity of Cu/Fe₃O₄@BaTiO₃ and Cu/BaTiO₃ on soot combustion were compared,though the two supports could not contribute directly to catalytic activity of copper catalysts,for they have little catalytic activity,but they affect the catalytic activity of copper.Tm of Cu/Fe₃O₄@BaTiO₃ is decreased by 32 °C and 56 °C compared with that of Cu/BaTiO₃ under O₂ and O₂/NOX,respectively.The reduction temperature of Cu/Fe₃O₄@BaTiO₃?305 °C?is lower than that of Cu/BaTiO₃?388 °C?,indicating copper is more easily reduced when supported on Fe₃O₄@BaTiO₃ under H2.Fe₃O₄ has excellent catalytic activity for soot combustion,but covered by a BaTiO₃ layer,the ability of catalysis is feeble under O₂ gas flow.