COATED COMPOSITE CONTAINING Al₂O₃-CeO₂/ZrO₂, AND METHOD FOR PRODUCTION THEREOF

摘要

FIELD: chemistry.;SUBSTANCE: present invention relates to composite material having coating from metal oxides, which includes a base consisting of a mixture of stabilized La phase Al₂O₃ and phases of mixed oxides Ce/Zr/RE₂O₃, and a method of producing a composite material having a metal oxide coating. Coated composite material containing Al/Ce/Zr for use as a catalyst support for cleaning exhaust gases includes a calcinated base containing Al/Ce/Zr, wherein the base consists of two phases: stabilized La phase Al₂O₃ and phases of mixed oxides Ce/Zr/RE₂O₃, wherein both phases form a homogeneous mixture, wherein the calcined base containing Al/Ce/Zr is characterized by the presence of a pore volume of more than 0.2 ml/g (according to DIN 66133) and the pore radius distribution, having a maximum in range of 50 Å to 200 Å (according to DIN 66133), the base contains a metal oxide coating comprising one or more components selected from the group consisting of CeO₂, ZrO₂, mixed cerium/zirconium oxides and one or more rare-earth metal oxide, other than cerium, and where metal oxide coating is at least 1 wt. % to 50 wt. % of coated composite material containing Al/Ce/Zr, and where the Al/Ce/Zr-containing base in the coated composite material is characterized by the ratio of the intensity of the characteristic reflections of gamma-aluminum oxide at 2θ ≈ 67° and characteristic reflections of Ce/Zr solid solution at 2θ ≈ 29°, normalized % by weight Al₂O₃, equal to or greater than 1. Method includes steps of: i) obtaining a base material containing Al/Ce/Zr, wherein base is obtained from an aluminum oxide precursor boehmite crystal structure, having crystallite size measured with reflex (020), in range from 4 nm to 40 nm; wherein the base consists of two phases - stabilized La phase Al₂O₃ and phases of mixed oxides Ce/Zr/RE₂O₃, wherein both phases form a homogeneous mixture; ii) calcining a base containing Al/Ce/Zr to obtain a calcined base containing Al/Ce/Zr; wherein the calcined base containing Al/Ce/Zr is also characterized by the pore space volume of more than 0.2 ml/g and the pore radius distribution maximum within range of 50 Å to 200 Å; iii) impregnating a calcined base containing Al/Ce/Zr, a metal oxide precursor containing precursors of oxides of alkali-earth elements, transition metals or rare-earth metals, such that the metal oxide precursor forms a coating based on, wherein metal oxide forms from 1 wt. % by 50 wt. % of coated composite material containing Al/Ce/Zr, as a result of which coating is applied on base; and iv) calcination of the impregnated base so that the metal oxide coating is applied onto the base to form a coating material containing Al/Ce/Zr, wherein the metal oxide coating after calcination ranges from 1 wt. % to 50 wt. % of coated composite material containing Al/Ce/Zr.;EFFECT: technical result is improved coating for composite material containing Al/Ce/Zr, having high thermal stability.;15 cl, 4 dwg, 9 tbl, 8 ex