Production method for exhaust gas-purifying catalyst and motor vehicle

摘要

A method for producing an exhaust gas purifying catalyst according to the present invention includes step (a) of preparing a metal oxide support containing zirconium; step (b) of preparing a solution containing rhodium; and step (c) of adding the metal oxide support prepared in the step (a), and ammonium carbonate, ammonium hydrogencarbonate or ammonia water, to the solution prepared in the step (b) to obtain the solution having a pH adjusted to a range of 3.0 or higher and 7.5 or lower. The present invention provides a method capable of producing an exhaust gas purifying catalyst including a metal oxide support containing zirconium and rhodium of a minute particle size which is supported on the metal oxide support at a high degree of dispersion.

主权项

1. A method for producing an exhaust gas purifying catalyst, comprising:
step (a) of preparing a metal oxide support containing zirconium; step (b) of preparing a solution containing rhodium; and step (c) of adding the metal oxide support, and ammonium carbonate or ammonium hydrogencarbonate or ammonia water, to the solution to obtain the solution having a pH adjusted to a range of 3.0 or higher and 7.5 or lower; wherein either the step (c) includes:
substep (c-1 A) of mixing the metal oxide support in the solution; andsubstep (c-2 A) of adding ammonium carbonate, ammonium hydrogencarbonate or ammonia water to the solution containing the rhodium after the substep (c-1 A) to adjust the pH of the solution to a range of 3.0 or higher and 7.5 or lower: or the step (c) includes:
substep (c-1 B) of adding ammonium carbonate, ammonium hydrogencarbonate or ammonia water to the solution containing the rhodium to adjust the pH of the solution to a prescribed range; andsubstep (c-2 B) of mixing the metal oxide support in the solution after the substep (c-1 B); whereinthe prescribed range in the substep (c-1 B) is set such that the pH of the solution becomes a value in a range of 3.0 or higher and 7.5 or lower after the substep (c-2 B) is performed.