Methods and systems are provided for an emissions aftertreatment device. In one example, the emissions aftertreatment device may include a catalyst and a high entropy oxygen storage material formed of at least five metal oxides in equal molar proportions. The at least five metal oxides includes one or more rare earth metals as well as other metals with similar chemical properties as the rare earth metals.

Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is Ce.sub.xZr.sub.1-x-yM.sub.yO.sub.2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol %, and y is 0-20 mol %.

Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is Ce.sub.xZr.sub.1-x-yM.sub.yO.sub.2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol %, and y is 0-20 mol %.

Mixed metal oxide catalysts capable of catalyzing hydrogenation of carbon dioxide to methanol reaction are disclosed, as well as a method for producing methanol from carbon dioxide and hydrogen. The mixed metal oxide catalysts include copper (Cu), and M.sup.1 and M.sup.2 oxides. M.sup.1 can be zinc (Zn), zirconium (Zr), or cerium (Ce), or any combination thereof, and M.sup.2 can be yttrium (Y), barium (Ba), rubidium (Rb), terbium (Tb), strontium (Sr), or molybdenum (Mo), or any combination thereof, with the proviso that M.sup.2 is not Y when the mixed metal oxide catalyst is [Cu/Zn/M.sup.2]0.sub.n or [Cu/Zr/M]0.sub.n, where n is determined by the oxidation states of the other elements.

Mixed metal oxide catalysts capable of catalyzing hydrogenation of carbon dioxide to methanol reaction are disclosed, as well as a method for producing methanol from carbon dioxide and hydrogen. The mixed metal oxide catalysts include copper (Cu), and M.sup.1 and M.sup.2 oxides. M.sup.1 can be zinc (Zn), zirconium (Zr), or cerium (Ce), or any combination thereof, and M.sup.2 can be yttrium (Y), barium (Ba), rubidium (Rb), terbium (Tb), strontium (Sr), or molybdenum (Mo), or any combination thereof, with the proviso that M.sup.2 is not Y when the mixed metal oxide catalyst is [Cu/Zn/M.sup.2]0.sub.n or [Cu/Zr/M]0.sub.n, where n is determined by the oxidation states of the other elements.

Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is Ce.sub.xZr.sub.1-x-yM.sub.yO.sub.2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol %, and y is 0-20 mol %.

Provided are a cerium-zirconium composite oxide, a preparation method therefor and application of a catalyst. The cerium-zirconium composite oxide has a composite phase structure, and comprises a cerium oxide phase and a cerium-zirconium solid solution phase, or consists of two or more cerium-zirconium solid solution phases with different crystal structures and different chemical compositions, wherein the chemical formula of the cerium-zirconium solid solution phase is Ce.sub.xZr.sub.1-x-yM.sub.yO.sub.2, where M is at least one selected from the group consisting of a rare earth element other than cerium, a transition metal element and an alkaline earth metal element, x is 15-85 mol %, and y is 0-20 mol %.

An exhaust gas purifying catalyst of the present invention includes: a first metal oxide selected from the group of praseodymium oxide, terbium oxide, and a combination thereof; a second metal oxide that is neodymium oxide; a third metal oxide that is zirconia or a combination of zirconia and ceria; and a fourth metal oxide selected from the group of lanthanum oxide, yttrium oxide, barium oxide, calcium oxide, strontium oxide, silicon oxide and a combination thereof.

An exhaust gas purifying catalyst of the present invention includes: a first metal oxide selected from the group of praseodymium oxide, terbium oxide, and a combination thereof; a second metal oxide that is neodymium oxide; a third metal oxide that is zirconia or a combination of zirconia and ceria; and a fourth metal oxide selected from the group of lanthanum oxide, yttrium oxide, barium oxide, calcium oxide, strontium oxide, silicon oxide and a combination thereof.

Methods and systems are provided for an emissions aftertreatment device. In one example, the emissions aftertreatment device may include a catalyst and a high entropy oxygen storage material formed of at least five metal oxides in equal molar proportions. The at least five metal oxides includes one or more rare earth metals as well as other metals with similar chemical properties as the rare earth metals.