摘要:
Processes for manufacturing porous ceramic honeycomb articles are disclosed. The processes include mixing a batch of inorganic components with processing aids to form a plasticized batch. The batch of inorganic components include talc having dpt50≦̸10 μm, a silica-forming source having dps50≦̸20 μm, an alumina-forming source having a median particle diameter dpa50 of less than or equal to 10.0 μm, and a pore former having dpp50≦̸20 μm. The plasticized batch is formed into a green honeycomb article and fired under conditions effective to form a porous ceramic honeycomb article comprising a cordierite crystal phase and having a microcrack parameter (Nb3) of from about 0.05 to about 0.25. After firing, the green honeycomb article the porous ceramic honeycomb article is exposed to a microcracking condition, which increases the microcrack parameter (Nb3) by at least 20%.
摘要:
A catalyst comprising palladium supported on a titania-alumina extrudate is disclosed. The extrudate comprises at least 80 wt% titania and 0.1 to 15 wt% alumina. A palladium catalyst prepared from the titania-alumina extrudate has significantly higher crush strength. Its catalytic performance in vinyl acetate production is improved.
摘要:
A wall-flow filter comprises a catalyst for converting oxides of nitrogen in the presence of a reducing agent, which wall-flow filter comprising an extruded solid body comprising: 10-95% by weight of at least one binder/matrix component; 5-90% by weight of a zeolitic molecular sieve, a non-zeolitic molecular sieve or a mixture of any two or more thereof; and 0-80% by weight optionally stabilized ceria, which catalyst comprising at least one metal, wherein: the at least one metal is present throughout the extruded solid body alone or in combination with: is also present in a higher concentration at a surface of the extruded solid body; is also carried in one or more coating layer(s) on a surface of the extruded solid body; or both.
摘要:
A honeycomb structure 20 is provided with a partition portion 22 constituting a plurality of cells 23 serving as flow paths of a fluid. This honeycomb structure 20 includes electrode portions 32 which are disposed as parts of the partition portion 22 and which have a SiC phase, an oxide phase containing a Si oxide, an Al oxide, and an alkaline-earth metal oxide, and a metal phase containing metal Si and metal Al, where the proportion of metal Al relative to the total amount of metal Si and metal Al is 0.001 percent by mole or more and 20 percent by mole or less and a heat generation portion 34 which is a part of the partition portion 22 and which has a volume resistivity higher than that of the electrode portion 32. This honeycomb structure is obtained by forming an impregnation base material containing metal Si and metal Al and an alkaline-earth metal compound on a part of the surface of a honeycomb base material having a SiC phase and an oxide phase containing a Si oxide and impregnating metal Si and metal Al into pores of the honeycomb base material through heating in an inert gas atmosphere.