Grain boundary and surface-doped rare earth manganese-zirconium composite compound and preparation method and use thereof

Patent metadata

Field	Value
Publication number	US-2024390878-A1
Application number	US-202418796186-A
Country	US
Kind code	A1
Filing date	Aug 6, 2024
Priority date	Feb 14, 2022
Publication date	Nov 28, 2024
Grant date	—

Abstract

Disclosed are a grain boundary and surface-doped rare earth manganese-zirconium composite compound as well as a preparation method and use thereof. A rare earth manganese oxide with a special structure is formed at grain boundary and surface of a rare earth zirconium-based oxide by a grain boundary doping method so as to increase oxygen defects at the grain boundary and the surface, thereby increasing the amount of active oxygen, improving the catalytic activity of the rare earth manganese-zirconium composite compound, inhibiting high-temperature sintering of the rare earth manganese-zirconium composite compound, and improving the NO catalytic oxidation capability. When the rare earth manganese-zirconium composite compound is applied to a catalyst, the consumption of noble metal can be greatly reduced.

First claim

What is claimed is:

1 . A grain boundary and surface-doped rare earth manganese-zirconium composite compound, wherein the rare earth manganese-zirconium composite compound has a chemical formula of RE a Mn b Zr c L d M e O (2-δ) D β , RE is a rare earth element, M and L are cation doped elements, and D is an anion doped element;
wherein 0.1≤a≤0.5, 0.05≤b≤0.4, 0.2≤c≤0.8, 0≤d≤0.2, 0≤e≤0.2, 0≤δ≤0.1, 0≤β≤0.1, a+b+c+d+e=1.

2 . The grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , wherein the grain boundary and surface of the rare earth manganese-zirconium composite compound contain one or more of doping elements M, L and D.

3 . The grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , wherein the doping elements M, L and D are in the form of one or more of oxides, nitrogen-containing compounds, fluorides, phosphates and sulfates at the grain boundary and surface of the rare earth manganese-zirconium composite oxide.

4 . The grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , wherein the RE comprises one or a combination of more than one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y and Sc;
preferably, RE is one or a combination of more than one of La, Ce, Pr, Nd, Sm, Eu, Gd and Y.

5 . The grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , wherein the cation doping element M comprises a transition metal, preferably one or a combination of more than one of Fe, Co, Ni, Cu, Zn, V, Ti, Cr, Mo, W, Hf and Nb; the cation doping element L comprises alkaline earth metal and one or a combination of more than one of Ga, Al, Si and Sn, and the alkaline earth metal is preferably one or a combination of more than one of Ba, Sr, Mg and Ca; and the doping element D comprises one or a combination of more than one of anions N, P, F and S.

6 . The grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , wherein the total amount of +3 and +4 valence states of Mn at the surface and grain boundary of the rare earth manganese-zirconium composite compound accounts for more than 80% of all valence states of Mn; preferably, greater than 90%.

7 . The grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , wherein the rare earth manganese-zirconium composite compound comprises a core-shell structure, the core comprises rare earth and zirconium elements, and the shell comprises rare earth and manganese elements.

8 . The grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , wherein the rare earth manganese-zirconium composite compound comprises rare earth zirconium-based oxide with an element gradient distribution structure.

9 . A preparation method of the grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 , comprising the following steps:
S1, mixing a mixed salt aqueous solution of Zr and RE or a mixed salt aqueous solution of Zr, RE, L and D with an alkaline solution in a required stoichiometric ratio, carrying out precipitation reaction, and filtering, washing, drying and roasting to obtain rare earth zirconium-based oxide containing RE and L; S2, mixing a mixed salt aqueous solution of Mn and RE or a mixed salt aqueous solution of Mn, RE, M and D in the required stoichiometric ratio with the rare earth zirconium-based oxide obtained in step S1 to obtain a composite compound wet material; S3, performing one or two heat treatments on the composite compound wet material obtained in step S2; and S4, performing one or two calcinations on the material obtained in step S3 to obtain the grain boundary and surface-doped rare earth manganese-zirconium composite compound.

10 . The method according to claim 9 , wherein the doping element D is added in one or both of steps S1 and S2; the doping element D is added in the form of one or a combination of more than one of nitrate, fluoride, phosphate and sulfate, preferably one or a combination of more than one of nitrate and sulfate.

11 . The method according to claim 9 , wherein the manganese source in the mixed salt aqueous solution in step S1 and step S2 comprises one or a combination of more than one of chloride, nitrate, sulfate and acetate, preferably manganese nitrate; the zirconium source comprises one or a combination of more than one of oxychloride, nitrate, sulfate, acetate and citrate, preferably zirconyl nitrate; the salt aqueous solution of M, L, and RE comprises one or a combination of more than one of liquid salt of chloride, nitrate, sulfate, acetate, citrate, and amino acid salt, and organosilicon compound, preferably nitrate.

12 . The method according to claim 9 , wherein the alkaline solution comprises at least one of magnesium bicarbonate, urea and hydroxide, carbonate or bicarbonate of at least one of elements ammonium, sodium and potassium, preferably at least one of sodium hydroxide, urea, ammonia water and ammonium bicarbonate.

13 . The method according to claim 9 , wherein pH value in the precipitation process of step S1 is controlled at 4.5-14, preferably 5-11; pH value at the end of precipitation is controlled at 8-13, preferably 9-11; and temperature during the precipitation is 0-120° C., preferably 20-80° C.

14 . The method according to claim 9 , wherein the roasting of the rare earth zirconium-based oxide is performed at a temperature of 500-1000° C. for 1-20 h; preferably, the roasting is performed at a temperature of 600-900° C. for 2-10 h.

15 . The method according to claim 9 , wherein the heat treatment is performed at a temperature of 100-500° C. for 2-30 h; preferably, the heat treatment is performed at a temperature of 150-300° C. for 6-12 h.

16 . The method according to claim 9 , wherein the calcination is performed at a temperature of 400-1000° C. for 1-20 h; preferably, the calcination is performed at a temperature of 500-900° C. for 3-10 h.

17 . The method according to claim 9 , wherein the rare earth manganese-zirconium composite compound after post-treatment has a particle size D50 of less than 15 μm, preferably less than 10 um.

18 . The method according to claim 9 , wherein the rare earth manganese oxide with perovskite, spinel or mullite structure is formed on the surface and grain boundary of the rare earth zirconium-based oxide after calcination.

19 . Use of the grain boundary and surface-doped rare earth manganese-zirconium composite compound according to claim 1 in the fields of motor vehicle exhaust purification, industrial waste gas treatment and catalytic combustion.

Assignees

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

Inventors

• Zhang Yongqi
• Huang Xiaowei
• Zhao Weixin
• Peng Xinlin
• Zhao Zheng
• Hou Yongke
• Zhai Zhizhe
• Zhong Qiang

Classifications

• B01J23/34 Primary

  Manganese · CPC title

• B01J23/8892

  Manganese · CPC title

• B01J37/035

  Precipitation on carriers · CPC title

• B01J35/505

  with a non-spherical or unspecified core-shell structure · CPC title

• B01J35/398

  Egg yolk like · CPC title