Rare-earth-manganese/cerium-zirconium-based composite compound, method for preparing same and use thereof

Patent metadata

Field	Value
Publication number	US-2022184583-A1
Application number	US-202017422691-A
Country	US
Kind code	A1
Filing date	Sep 4, 2020
Priority date	Sep 4, 2019
Publication date	Jun 16, 2022
Grant date	—

Abstract

The present invention discloses a rare-earth-manganese/cerium-zirconium-based composite compound, a method for preparing the same, and a use thereof. The composite compound is of a core-shell structure with a general formula expressed as: A RE c B a O b -(1-A)Ce x Zr (1-x-y) M y O 2-z , wherein 0.1≤A≤0.3, preferably 0.1≤A≤0.2; a shell layer has a main component of rare-earth manganese oxide with a general formula of RE c Mn a O b , wherein RE is a rare-earth element or a combination of more than one rare-earth elements, and B is Mn or a combination of Mn and a transition metal element, 1≤a≤8, 2≤b≤18, and 0.25≤c≤4; and a core has a main component of cerium-zirconium composite oxide with a general formula of Ce x Zr (1-x-y) M y O 2-z , wherein M is one or more non-cerium rare-earth elements, 0.1≤x≤0.9, 0≤y≤0.3, and 0.01≤z≤0.3. The composite compound enhances an oxygen storage capacity of a cerium-zirconium material through an interface effect, thereby increasing a conversion rate of a nitrogen oxide.

First claim

1 . A rare-earth-manganese/cerium-zirconium-based composite compound, wherein
the composite compound is of a core-shell structure, with a general formula expressed as: A RE c B a O b -(1-A) Ce x Zr (1-x-y) M y O 2-z , wherein 0.1≤A≤0.3; a shell layer has a main component of rare-earth manganese oxide with a general formula of RE c B a O b , wherein RE is a rare-earth element or a combination of more than one rare-earth elements, B is Mn or a combination of Mn and a transition metal element, 1≤a≤8, 2≤b≤18, and 0.25≤c≤4; and a core has a main component of cerium-zirconium composite oxide with a general formula of Ce x Zr (1-x-y) M y O 2-z , wherein M is at least one selected from a group consisting of a non-cerium rare-earth element and a transition metal element, 0.1≤x≤0.9, 0≤y≤0.3, and 0.01≤z≤0.3.

2 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein a mass of the Mn element in the shell layer is 70-98 wt % of a total mass of the Mn element in the rare-earth-manganese/cerium-zirconium-based composite compound.

3 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein cerium in the cerium-zirconium composite oxide has composite valence states of trivalence and tetravalence, and tetravalent cerium accounts for 60-90 wt % of the total amount of cerium.

4 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein 1≤a≤3, 2≤b≤8, and preferably, the shell layer is a compound of a mullite-type structure.

5 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 4 , wherein a mass of the Mn element in the shell layer is 70-95 wt % of a total mass of the Mn element in the rare-earth-manganese/cerium-zirconium-based composite compound.

6 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein
the rare-earth element RE in the rare-earth manganese oxide comprises one or more selected from a group consisting of lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, and yttrium; M in the cerium-zirconium composite oxide is one or more selected from a group consisting of lanthanum, praseodymium, neodymium, yttrium, samarium, europium, gadolinium, holmium, erbium, thulium, ytterbium, hafnium, aluminum, and barium.

7 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein the shell layer further contains one or more selected from a group consisting of a hydroxide, a carbonate and a basic carbonate, with a content of 0.01-1 wt %.

8 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein
the rare-earth manganese oxide is doped with the transition metal element which is one or more selected from a group consisting of iron, tungsten, molybdenum, nickel, cobalt, vanadium, and titanium; and a mass of the transition metal element is 0.01%-10% of a mass of the rare-earth manganese oxide, wherein the mass of the transition metal element is based on the self-mass of the transition metal element, and the mass of the rare-earth manganese oxide is based on the mass of the rare-earth manganese oxide before the transition metal element is doped.

9 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein an oxygen storage capacity of the rare-earth-manganese/cerium-zirconium-based composite compound is not less than 800 umol-O 2 /g.

10 . The rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein a particle size D50 is 1-m.

11 . A method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , comprising:
reacting a mixed raw material containing a divalent manganese source, a rare-earth source, and a cerium-zirconium composite oxide to obtain the rare-earth-manganese/cerium-zirconium-based composite compound.

12 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 11 , wherein said reacting the mixed raw material containing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide specifically comprises the following steps:
preparing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide according to a stoichiometric ratio of a final product; and adding a mixed solution containing the divalent manganese source and the rare-earth source to the cerium-zirconium composite oxide for reaction, and after the reaction is completed, drying, calcining and pulverizing a resultant to obtain the rare-earth-manganese/cerium-zirconium-based composite compound.

13 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 12 , wherein the divalent manganese source in the mixed solution has a concentration of 2-4 mol/L, with a molar weight of the divalent manganese source based on a molar weight of a manganese element; and
the rare-earth source in the mixed solution has a concentration of 0.5-2 mol/L, with a molar weight of the rare-earth source based on a molar weight of the rare-earth element.

14 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein the mixed solution containing the divalent manganese source and the rare-earth source has a volume accounting for 70-150% of a pore volume of the cerium zirconium composite oxide.

15 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein the reaction occurs under the following specific conditions:
the reaction occurs under stirring; a reaction temperature is 15-45° C.; and reaction duration is 5-20 min.

16 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 11 , wherein said reacting the mixed raw material containing the manganese source, the rare-earth source and the cerium-zirconium composite oxide specifically comprises the following steps:
preparing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide according to a stoichiometric ratio of a final product; and adding a precipitant and an oxidant sequentially to a mixed slurry containing the divalent manganese source, the rare-earth source and the cerium-zirconium composite oxide for reaction, and after the reaction is completed, washing, drying, calcining and pulverizing a resultant to obtain the rare-earth-manganese/cerium-zirconium-based composite compound.

17 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 16 , wherein the precipitant is at least one selected from a group consisting of sodium hydroxide, ammonia water, ammonium bicarbonate or potassium hydroxide.

18 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein the precipitant has an amount of substance accounting for 5-90% of a stoichiometric amount required to precipitate a manganese element and a rare-earth element in the slurry.

19 . The method for preparing the rare-earth-manganese/cerium-zirconium-based composite compound according to claim 1 , wherein the precipitant is added to the mixed slurry in a form of a precipitant solution; and
the precipitant in the precipitant solution has a conc

Assignees

• Grirem Advanced Mat Co Ltd
• Rare Earth Functional Mat Xiongan Innovation Center Co Ltd
• Grirem Hi Tech Co Ltd

Inventors

• Huang Xiaowei
• Zhang Yongqi
• Li Hongwei
• Zhai Zhizhe
• Zhong Qiang
• Zhang He
• Cui Meisheng
• Hou Yongke
• Wang Hao
• Feng Zongyu

Classifications

• B01D2255/206

  Rare earth metals · CPC title

• B01D2255/407

  Zr-Ce mixed oxides · CPC title

• B01D2255/2073

  Manganese · CPC title

• B01D2255/2065

  Cerium · CPC title

• B01D53/9427

  for removing nitrous oxide · CPC title