Method for producing composite oxide and composite oxide catalyst

Abstract

Provided are a method for producing a composite oxide and the composite oxide, which finds use as an easy-to-handle catalyst material having a high reforming rate of hydrocarbon to hydrogen even when oxidized. The method includes the steps of: (a) preparing a Ce aqueous solution not less than 80 mol % of which Ce ions are tetravalent, and a Zr aqueous solution containing Zr ions; (b1) mixing the Zr aqueous solution and a portion of the Ce aqueous solution to prepare a mixed aqueous solution (X1); (c1) hydrothermally processing solution (X1); (b2) adding the remainder of the Ce aqueous solution prepared in step (a) to a colloidal solution (Y1) of a composite salt obtained from step (c1) to prepare a colloidal solution (Y2) of a composite salt; (c2) hydrothermally processing solution (Y2) obtained from step (b2); (d) mixing a colloidal solution (Y3) of a composite salt obtained from step (c2) with an alkaline solution and a surfactant to prepare a precipitate; and (e) calcining the precipitate.

Dependencies are inferred from the claim text.