Catalyst support for purification of exhaust gas, catalyst for purification of exhaust gas using the same, and method for producing the catalyst support for purification of exhaust gas

摘要

A catalyst support for purification of exhaust gas includes a porous composite metal oxide, the porous composite metal oxide containing alumina, ceria, and zirconia and having an alumina content ratio of from 5 to 80% by mass, wherein after calcination in the air at 1100° C. for 5 hours, the porous composite metal oxide satisfies a condition such that standard deviations of content ratios (as at % unit) of aluminum, cerium and zirconium elements are each 19 or less with respect to 100 minute areas (with one minute area being 300 nm in length×330 nm in width) of the porous composite metal oxide, the standard deviation being determined by energy dispersive X-ray spectroscopy using a scanning transmission electron microscope equipped with a spherical aberration corrector.

主权项

1. A catalyst support for purification of exhaust gas comprising a porous composite metal oxide, the porous composite metal oxide containing alumina, ceria, and zirconia and having an alumina content ratio of from 5 to 80% by mass,
wherein the porous composite metal oxide is produced by: introducing independently a first raw material solution and a second raw material solution directly into a region in which a shear rate is from 1000 to 200000 sec−1, and homogeneously mixing the raw material solutions to obtain a colloidal solution of metal compounds, the first raw material solution containing an aluminum ion, a cerium ion, and a zirconium ion, and the second raw material solution containing a high-molecular dispersant having a weight average molecular weight of from 3000 to 15000, adjusting a pH of the colloidal solution to between 3 and 5, degreasing the colloidal solution after the pH adjustment or a suspension of metal compounds which is obtained by adding an organic amine to the colloidal solution after the pH adjustment, and then subjecting the solution or the suspension to heat treatment at from 700 to 1050° C. in an oxidizing atmosphere, to obtain the porous composite metal oxide, and wherein after calcination in air at 1100° C. for 5 hours, the porous composite metal oxide satisfies a condition such that standard deviations of content ratios (as at % unit) of aluminum, cerium and zirconium elements are each 19 or less with respect to 100 minute areas (with one minute area being 300 nm in length×330 nm in width) of the porous composite metal oxide, the standard deviation being determined by energy dispersive X-ray spectroscopy using a scanning transmission electron microscope equipped with a spherical aberration corrector.