Nano-cerium oxide and its preparation method

Abstract

The present invention discloses a nano-cerium oxide and a preparation method thereof. The preparation method of nano-cerium oxide comprises the following steps: mixing a cerium source solution, a precipitant solution and a dispersant solution and then precipitating to obtain a precipitate; calcining the precipitate to obtain nano-cerium oxide; the cerium source solution is Ce-containing. 4+ The method comprises a method for preparing nano-cerium oxide by a method comprising: preparing a nano-cerium oxide by a method comprising: a solution containing bicarbonate; a precipitant solution containing bicarbonate; and a dispersant solution containing a first dispersant, wherein the first dispersant comprises one or more of sorbitol, glycerol, lignin sulfonate, and methylcellulose. The nano-cerium oxide prepared by this method has uniform particle size, small primary particle size, is not easily agglomerated, and has a large specific surface area.

Description

Technical Field

[0001] The invention relates to nano cerium oxide and a preparation method thereof. Background Art

[0002] Due to its fine crystal structure, cerium dioxide is widely used as a polishing powder in optical glass, mobile phone covers, integrated circuits, and other fields. Furthermore, CeO2, with its 4f electron structure and rich electronic transition energy levels, is highly sensitive to light absorption, with absorption primarily in the ultraviolet region. The smaller the size, the greater its ability to absorb UV rays. Applying it to the face can prevent sunburn and tanning. Furthermore, because its color is close to skin tone, when blended into cosmetics, it avoids a pale or unnatural appearance and produces a highly effective cosmetic effect. Therefore, nanocerium holds great promise for sun protection in skincare products.

[0003] Currently, nano-cerium oxide can be synthesized using co-precipitation, hydrothermal, sol-gel, electrochemical, and spray pyrolysis methods. The hydrothermal method requires heating the reaction system in the reactor to a critical temperature, placing stringent environmental demands on the powder synthesis environment. This increases synthesis costs and poses risks such as unsafe high-temperature operation. The sol-gel method uses relatively expensive raw materials and requires a long reaction time. The electrochemical method is simple to operate and can produce uniform, non-agglomerated nano-cerium oxide powders, but the electrolysis process is uncontrollable and can result in low yields due to incomplete electrolysis. Nano-powders synthesized by spray pyrolysis appear flaky under an electron microscope, rather than spherical. The co-precipitation method is currently the most widely used method for synthesizing rare earth nano-oxides. Cerium oxide nanoparticles are obtained by reacting a cerium solution with a precipitant, followed by washing, drying, and calcining the precipitate. However, during the precipitation and drying process, nano-cerium powders are prone to agglomeration and uneven particle size due to capillary stress caused by incomplete reaction and water evaporation, hindering their application in downstream applications. Summary of the Invention

[0004] In order to solve the problems of uneven particle size and easy agglomeration of cerium oxide particles prepared in the prior art, a nano-cerium oxide and a preparation method thereof are provided. The nano-cerium oxide prepared by this method has uniform particle size, small primary particle size, is not easy to agglomerate and has a large specific surface area.

[0005] The present invention solves the above technical problems through the following technical solutions.

[0006] The present invention provides a method for preparing nano-cerium oxide, which comprises the following steps: mixing a cerium source solution, a precipitant solution and a dispersant solution and performing precipitation to obtain a precipitate; calcining the precipitate to obtain nano-cerium oxide;

[0007] The cerium source solution contains Ce 4+ of solution;

[0008] The precipitant solution is a solution containing bicarbonate;

[0009] The dispersant solution includes a first dispersant including one or more of sorbitol (NH4PA), glycerol, lignin sulfonate, and methylcellulose.

[0010] In the present invention, preferably, the cerium source solution is a cerium source aqueous solution, the precipitant solution is a precipitant aqueous solution, and the dispersant solution is a dispersant aqueous solution.

[0011] In the present invention, the acidity of the cerium source solution is preferably 0.01-1 mol / L, more preferably 0.02-0.04 mol / L, for example 0.03 mol / L. Acidity refers to the concentration of hydrogen ions in the cerium source solution. Controlling the acidity within 0.02-0.04 mol / L can further accelerate the reaction rate and reduce the primary particle size.

[0012] In the present invention, preferably, the Ce in the cerium source solution 4+ The concentration of Ce in the present invention is 0.1-1.2 mol / L, more preferably 0.6-1.2 mol / L, for example 0.9 mol / L. 4+ Controlling the concentration of 0.6-1.2 mol / L can further reduce the possibility of agglomeration.

[0013] In the present invention, preferably, the cerium source in the cerium source solution is cerium nitrate.

[0014] Wherein, the cerium nitrate is prepared, for example, by mixing nitric acid and cerium carbonate powder, or by mixing nitric acid and cerium oxide powder;

[0015] In the present invention, preferably, the cerium source solution is prepared by the following method: hydrogen peroxide and Ce-containing 3+ The solution is mixed and oxidized to obtain a cerium source solution. Hydrogen peroxide is used as an oxidant to 3+ Oxidized to Ce 4+ , without introducing impurity ions.

[0016] Wherein, the Ce-containing 3+ Ce in solution 3+ The concentration is preferably 0.1-1.2 mol / L, more preferably 0.6-1.2 mol / L, for example 0.9 mol / L.

[0017] The excess coefficient of hydrogen peroxide is preferably 0.1-1.8, more preferably 0.84-1.04. The excess coefficient means the difference between the amount of hydrogen peroxide actually added and the amount of Ce 3+The present invention controls the excess coefficient of hydrogen peroxide to be between 0.84 and 1.04, thereby further forming nano-cerium crystal cells of uniform size and reducing the size of the primary particle size.

[0018] Wherein, the temperature of the oxidation reaction is preferably 40-60°C.

[0019] The oxidation reaction time is preferably more than 30 minutes.

[0020] In the present invention, the concentration of bicarbonate in the precipitant solution is preferably 0.1-2.2 mol / L, more preferably 1.8-2.6 mol / L, for example 2.2 mol / L.

[0021] In the present invention, the precipitant in the precipitant solution is preferably one or more of sodium bicarbonate, ammonium bicarbonate and potassium bicarbonate.

[0022] In the present invention, in the mixed solution formed after the mixing, the excess coefficient of bicarbonate is preferably (1.00-1.16):1, more preferably (1.04-1.16):1, for example, 1.08:1. The excess coefficient of bicarbonate refers to the ratio of the amount of bicarbonate in the mixed solution to the stoichiometric amount of bicarbonate, wherein the stoichiometric amount of bicarbonate is the amount of bicarbonate corresponding to Ce4+ and hydrogen ions in the mixed solution.

[0023] The molar ratio adopted in the present invention is conducive to reducing the generation of accompanying substances such as CeO(CO3)2·H2O, thereby reducing agglomeration, further facilitating the formation of uniform and fine precipitation particles, and increasing the specific surface area and activity of the precipitate.

[0024] In the present invention, the first dispersant preferably includes sorbitol.

[0025] The concentration of sorbitol in the dispersant solution is preferably 0.002-0.05 mol / L, more preferably 0.03-0.05 mol / L. Controlling the concentration of sorbitol in the present invention at 0.03-0.05 mol / L can further enhance the complexation effect and reduce the size of the primary particle size.

[0026] In the present invention, the dispersant solution preferably further includes a second dispersant, which is one or more of citric acid, acrylic resin, polyethylene glycol, and polyacrylic acid. The inventors have discovered through repeated research that the high carbon content and large specific surface area of ​​the second dispersant provide a carbon skeleton for the cerium oxide during the preparation of nano-cerium oxide, thereby facilitating the production of a high specific surface area and fluffy nano-cerium oxide powder.

[0027] Wherein, the sum of the concentrations of the first dispersant and the second dispersant in the dispersant solution is preferably 0.0065-0.05 mol / L.

[0028] In certain preferred embodiments of the present invention, the mixing method is: the cerium source solution and the precipitant solution are introduced into the dispersant solution in parallel.

[0029] In the above embodiment, preferably, the dispersant solution is stirred while the parallel flows are introduced.

[0030] The stirring speed is preferably 200-400 r / min, for example 300 r / min.

[0031] In the above embodiment, the parallel introduction method is preferably to introduce the cerium source solution and the precipitant solution separately through peristaltic pumps.

[0032] In the above embodiment, preferably, the feeding is stopped when the excess coefficient of bicarbonate in the mixed solution formed after mixing is (1.00-1.16):1, more preferably when it is (1.04-1.16):1, and further preferably when it is 1.08:1.

[0033] In the present invention, preferably, the addition rate ratio of the cerium source solution to the precipitant solution is 1:(0.5-3), more preferably 1:(1.9-2.5), for example 1:2 or 1:2.3.

[0034] In the present invention, preferably, the addition rate of the cerium source solution is 10-150 mL / min, for example, 25 mL / min or 100 mL / min.

[0035] In the present invention, preferably, the addition rate of the precipitant solution is 10-250 mL / min, more preferably 15-70 mL / min, even more preferably 40-60 mL / min, for example 47 mL / min, 50 mL / min or 57 mL / min.

[0036] In the present invention, if the addition rate of the cerium source solution and the precipitant solution is too high, the reaction may be incomplete and the particles may be uneven. If the addition rate is too low, the grains will gradually grow and exceed the desired range. The above addition rate range is conducive to maintaining the pH value during the precipitation process.

[0037] In certain specific embodiments of the present invention, the Ce in the cerium source solution is 4+The concentration of is 0.6-1.2 mol / L, the concentration of bicarbonate in the precipitant solution is 1.8-2.6 mol / L, and the addition rate ratio of the cerium source solution and the precipitant solution is 1:(0.5-3).

[0038] In certain specific embodiments of the present invention, the precipitation is performed at room temperature, which has the conventional meaning in the art, i.e., 20-30°C.

[0039] In the present invention, preferably, during the precipitation process, the pH value is 6-10. Within this pH range, the nucleation rate of the precipitate is greater than the growth rate, and cerium oxide powder with a smaller primary particle size can be obtained.

[0040] In the present invention, the calcination temperature is preferably 500-1000°C, more preferably 500-800°C, and even more preferably 500-700°C.

[0041] In the present invention, the calcination time is, for example, 4 hours.

[0042] In the present invention, preferably, the precipitate further comprises a drying step before calcination. The drying step provided before calcination in the present invention can avoid structural collapse or deformation during the calcination process, help form uniform spherical and quasi-spherical particles, and improve dispersibility.

[0043] The drying temperature is preferably 60-120°C, for example 80°C.

[0044] The drying time is, for example, 2 hours.

[0045] Preferably, a washing step is further included before the drying.

[0046] Preferably, the washing comprises a first washing and a second washing, wherein the detergent for the first washing is deionized water and the detergent for the second washing is ethanol. In the present invention, the use of ethanol for washing can further reduce the problem of powder agglomeration.

[0047] The number of times of the first washing can be adjusted according to actual conditions, for example, 2 times.

[0048] The number of times of the second washing can be adjusted according to actual conditions, for example, 2 times.

[0049] Among them, those skilled in the art generally understand that the first washing and the second washing also include a filtering step before each.

[0050] In certain embodiments of the present invention, the precipitate includes cerium carbonate, basic cerium carbonate, cerium sorbitol complex, and cerium carbonate sorbitol complex.

[0051] The present invention also provides nano-cerium oxide prepared by the above-mentioned preparation method of nano-cerium oxide.

[0052] In the present invention, preferably, the primary particle size of the nano-cerium oxide is <100 nm, more preferably, the primary particle size of the nano-cerium oxide is <60 nm, and even more preferably, the primary particle size of the nano-cerium oxide is <30 nm.

[0053] In the present invention, preferably, the bulk density of the nano-cerium oxide is 0.3-0.7 g / cm 3 , more preferably 0.39-0.55g / cm 3 .

[0054] In the present invention, preferably, the D of the nano cerium oxide 50 <2um, more preferably, the D of the nano cerium oxide 50 <1um, further preferably, the D of the nano cerium oxide 50 <0.2um,D 50 It is the particle size corresponding to when the cumulative particle size distribution percentage of nano-cerium oxide powder reaches 50%.

[0055] In the present invention, preferably, the specific surface area of ​​the nano-cerium oxide is greater than 15m 2 / g, more preferably, the specific surface area of ​​the nano cerium oxide is greater than 20m 2 / g, further preferably, the specific surface area of ​​the nano cerium oxide is greater than 30m 2 / g.

[0056] In the present invention, preferably, the shape of the nano-cerium oxide is spherical and / or spherical-like.

[0057] In the present invention, preferably, the Ka of the nano-cerium oxide is less than 2, more preferably, the Ka of the nano-cerium oxide is less than 1.6, and further more preferably, the Ka of the nano-cerium oxide is less than 1.2, wherein Ka is the agglomeration coefficient, Ka=D 50 / D, D is the primary particle size of nanocerium oxide.

[0058] In the present invention, preferably, the R of the nano-cerium oxide is less than 2, more preferably, the R of the nano-cerium oxide is less than 1, and further more preferably, the R of the nano-cerium oxide is less than 0.5, wherein R is the particle size distribution coefficient, R=(D 90 -D 10 ) / D 50 , D 10 D is the particle size corresponding to the cumulative particle size distribution percentage of nano-cerium oxide powder reaching 10%, 90 It is the particle size corresponding to when the cumulative particle size distribution percentage of nano-cerium oxide powder reaches 90%.

[0059] The present invention also provides a nano-cerium oxide, wherein the primary particle size of the nano-cerium oxide is less than 30 nm and the bulk density of the nano-cerium oxide is 0.3-0.7 g / cm 3 , the D of the nano cerium oxide 50 <0.2um, the specific surface area of ​​the nano cerium oxide> 20m 2 / g, the shape of the nano-cerium oxide is spherical and / or quasi-spherical, the Ka of the nano-cerium oxide is less than 1.2, and the R of the nano-cerium oxide is less than 0.5.

[0060] Numerical ranges disclosed herein include all points within that range.

[0061] On the basis of conforming to the common sense in this field, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0062] The reagents and raw materials used in the present invention are commercially available.

[0063] The positive progress effect of the present invention is:

[0064] The preparation method of nano-cerium oxide of the present invention adopts tetravalent cerium ions, which have smaller precipitation cores than trivalent cerium ions during the precipitation process, which is conducive to the formation of nano-cerium unit cells of uniform size; and combined with specific dispersant solution and precipitant solution, it can effectively slow down the formation of precipitation and prevent particle growth and grain agglomeration.

[0065] The nano-cerium oxide provided by the present invention can simultaneously have a low primary particle size, a high specific surface area, a narrow particle size distribution and a low degree of agglomeration.

[0066] In the preferred embodiment of the present invention, the parallel flow precipitation method is adopted, which can further effectively control the reaction process and nucleation rate, help to maintain uniform dispersion of particles throughout the precipitation process, improve precipitation efficiency, reduce agglomeration between the precipitant and the particles, make the precipitation process smoother, simple to make, low cost, and can be produced on a large scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a scanning electron microscope image of Example 22. DETAILED DESCRIPTION

[0068] The present invention is further illustrated by way of examples below, but the present invention is not limited to the scope of the examples. Experimental methods in the following examples where specific conditions are not specified were performed according to conventional methods and conditions, or selected according to the product specifications.

[0069] Examples 1-26 and Comparative Examples 1-3

[0070] Hydrogen peroxide and Ce3+ The solution is mixed and oxidized to obtain a cerium source solution containing Ce 3+ The solution is cerium nitrate solution, and the cerium source solution is Ce 4+ The oxidation reaction temperature is 40-60 ° C, the oxidation reaction time is 30 min; the precipitant is ammonium bicarbonate; wherein, the excess coefficient of hydrogen peroxide in Examples 1-8, Examples 11-26, and Comparative Examples 1-3 is 1.04, the excess coefficient of hydrogen peroxide in Example 9 is 0.44, and the excess coefficient of hydrogen peroxide in Example 10 is 0.84. The excess coefficient means the difference between the amount of hydrogen peroxide actually added and the theoretical amount of Ce 3+ The ratio of the amount of hydrogen peroxide required for complete oxidation.

[0071] A cerium source solution and a precipitant solution are introduced into a dispersant solution in parallel through a peristaltic pump for mixing. When the excess coefficient of bicarbonate in the mixed solution reaches a set value, the feeding is stopped and precipitation is carried out at room temperature to obtain a precipitate. While the dispersant solution is introduced in parallel, the stirring speed is 300 r / min. The precipitate includes cerium carbonate, basic cerium carbonate, cerium sorbitol complex and cerium carbonate sorbitol complex.

[0072] The flow rate of the cerium source solution was 25 mL / min, and the flow rate of the precipitant solution, the excess coefficient of bicarbonate and other parameters are listed in Table 1. During the precipitation process, the pH value was 6-10.

[0073] The precipitate is filtered, washed for a first time, washed for a second time, dried, and calcined in sequence to obtain spherical and / or quasi-spherical nano-cerium oxide, which is the product. The first washing is performed twice with deionized water, the second washing is performed twice with ethanol, the drying temperature is 80° C., the drying time is 2 hours, and the calcination time is 4 hours.

[0074] The nano-cerium oxide prepared in Comparative Example 1 is in the form of flakes.

[0075] The specific parameters of Examples 1-26 and Comparative Examples 1-3 are listed in Table 1.

[0076] Among them, in Example 24, sorbitol is replaced by glycerol, and the sorbitol concentration in the dispersant solution of Example 24 corresponding to Table 1 is the concentration of glycerol in the dispersant solution; in Example 25, sorbitol is replaced by sodium lignin sulfonate, and the sorbitol concentration in the dispersant solution of Example 25 corresponding to Table 1 is the concentration of sodium lignin sulfonate in the dispersant solution; in Example 26, sorbitol is replaced by methylcellulose, and the sorbitol concentration in the dispersant solution of Example 26 corresponding to Table 1 is the concentration of methylcellulose in the dispersant solution.

[0077] Among them, the precipitant in Comparative Example 2 is ammonium carbonate, and the bicarbonate concentration in the precipitant of Comparative Example 2 corresponding to Table 1 is the concentration of carbonate in the precipitant; the precipitant in Comparative Example 3 is oxalic acid, and the bicarbonate concentration in the precipitant of Comparative Example 3 corresponding to Table 1 is the concentration of oxalate in the precipitant.

[0078] Table 1

[0079]

[0080]

[0081] It should be noted that the addition rate of the cerium source solution, the drying temperature and time are conventional choices in the industry, and the above ranges are not tested and verified in the examples.

[0082] Effect Example 1

[0083] The nano-cerium oxide prepared in Examples 1-26 and Comparative Examples 1-3 was tested as follows:

[0084] (1) Primary particle size D test: The particle size image is obtained by field emission scanning electron microscopy, and the average particle size measured by Nano Measurer is the primary particle size.

[0085] (2) Bulk density test: The bulk density is measured using the Scott volumetric method, which is the bulk density of the powder after it freely fills a standard container.

[0086] The model of the Scott bulk density tester is FS4-2, manufactured by Beijing Zhonghui Tiancheng Technology Co., Ltd. The specific operating steps of the Scott volumetric method are as follows:

[0087] A: Before use, check whether the Scott capacity meter is normal. If any abnormality is found, it should be handled promptly.

[0088] B: Place the container on a horizontal workbench, turn on the electronic balance, place the container on the balance, and adjust the zero point;

[0089] C: Place the standard sieve on the container and evenly distribute the nano-cerium oxide powder in the container;

[0090] D: After scraping the surface of the nano-cerium oxide powder with a scraper, put the nano-cerium oxide powder on the screen of the upper combined funnel and let it flow into the distribution box freely or by external force;

[0091] E: The powder alternately passes through four glass plates with an inclination angle of 25 degrees and a square funnel in the distribution box, and finally falls freely from the funnel hole at a certain height to fill the cup;

[0092] F: Use a cleaning brush to remove the remaining metal powder in the container, then place the container on a balance and measure the mass of the container (M2);

[0093] G: Calculate the bulk density of the powder using the following formula: bulk density = (M1-M2) / V, where M1 is the total mass of the container and powder, and V is the volume of the container.

[0094] (3) Specific surface area test: Use a fully automatic rapid specific surface area meter for testing.

[0095] (4)D 50 、D 10 and D 90 Test: D 50 D is the particle size corresponding to the cumulative particle size distribution percentage of nano-cerium oxide powder reaching 50%, 10 D is the particle size corresponding to the cumulative particle size distribution percentage of nano-cerium oxide powder reaching 10%, 90 D is the particle size corresponding to when the cumulative particle size distribution percentage of nano-cerium oxide powder reaches 90%; 50 、D 10 and D 90 The volume distribution of the particle size is obtained by a laser scattering particle size distribution analyzer, the model of the laser scattering particle size distribution analyzer is LA-960, and the manufacturer is HORIBA Scientific Instruments.

[0096] The agglomeration coefficient Ka is calculated using the following formula: Ka = D 50 / D. The agglomeration coefficient Ka reflects the agglomeration degree of nano-cerium oxide powder. The closer Ka is to 1, the smaller the agglomeration degree is.

[0097] The particle size distribution coefficient R is calculated using the following formula: R = (D 90 -D 10 ) / D 50 The particle size distribution coefficient R reflects the particle size distribution range of nano-cerium oxide powder. The smaller R is, the narrower the particle size distribution is.

[0098] The above test results are listed in Table 2 below:

[0099] Table 2

[0100]

[0101]

[0102] The scanning electron microscope image of Example 22 is as follows: Figure 1 As shown, the black bold line segments in the figure represent the primary particle sizes of the two particles respectively.

[0103] According to the results of Comparative Example 1, no hydrogen peroxide was added in Comparative Example 1, the powder had a flaky morphology, and the primary particle size (ie, the primary particle size) was too high, at 469.74 nm.

[0104] The precipitants in Comparative Examples 2 and 3 were carbonate and oxalic acid, respectively, which affected the primary particle size of the powder synthesis and could not synthesize cerium oxide powder with a primary particle size of nanometers.

[0105] According to the results of Example 1 and Example 2, the acidity of the cerium source solution affects the technical effect. If the acidity of the cerium source solution is too high, the ionized bicarbonate ions may react with hydrogen ions first, and the probability of reacting with tetravalent cerium ions is lower. The nucleation rate of the powder is lower than the growth rate, and the primary particle size is larger.

[0106] According to Examples 17-19, the concentration of sorbitol is 0.03-0.05 mol / L, which is more conducive to the realization of the technical effect. If the concentration of sorbitol is too low, there are fewer hydroxyl groups, which may be unfavorable for the reaction with Cr. 4+ The complexation occurs.

[0107] According to the results of Example 18 and Examples 24-26, selecting sorbitol as the first dispersant can further reduce the primary particle size and the degree of powder agglomeration.

Claims

1. A method for preparing nano-cerium oxide, characterized in that: mixing a cerium source solution, a precipitant solution, and a dispersant solution and performing precipitation to obtain a precipitate; and calcining the precipitate to obtain nano-cerium oxide; The cerium source solution contains Ce 4+ of solution; The precipitant solution is a solution containing bicarbonate; The dispersant solution includes a first dispersant, wherein the first dispersant includes one or more of sorbitol, glycerol, lignin sulfonate, and methylcellulose; The dispersant solution further includes a second dispersant, which is one or more of citric acid, acrylic resin, polyethylene glycol and polyacrylic acid.

2. The method for preparing nano-cerium oxide according to claim 1, wherein: The cerium source solution is a cerium source aqueous solution, the precipitant solution is a precipitant aqueous solution, and the dispersant solution is a dispersant aqueous solution; and / or, the acidity of the cerium source solution is 0.01-1 mol / L; And / or, Ce in the cerium source solution 4+ The concentration is 0.1-1.2 mol / L; And / or, the cerium source in the cerium source solution is cerium nitrate.

3. The method for preparing nano-cerium oxide according to claim 2, wherein: The acidity of the cerium source solution is 0.02-0.04 mol / L.

4. The method for preparing nano-cerium oxide according to claim 3, wherein: The acidity of the cerium source solution is 0.03 mol / L.

5. The method for preparing nano-cerium oxide according to claim 2, wherein: The Ce in the cerium source solution 4+ The concentration is 0.6-1.2mol / L.

6. The method for preparing nano-cerium oxide according to claim 5, wherein: The Ce in the cerium source solution 4+ The concentration is 0.9 mol / L.

7. The method for preparing nano-cerium oxide according to claim 2, wherein: The cerium nitrate is prepared by mixing nitric acid and cerium carbonate powder, or by mixing nitric acid and cerium oxide powder.

8. The method for preparing nano-cerium oxide according to claim 1, wherein: The cerium source solution is prepared by the following method: hydrogen peroxide and Ce-containing 3+ and the solution thereof and subjected to oxidation reaction to obtain a cerium source solution.

9. The method for preparing nano-cerium oxide according to claim 8, wherein: The Ce-containing 3+ Ce in solution 3+ The concentration is 0.1-1.2mol / L.

10. The method for preparing nano-cerium oxide according to claim 9, characterized in that: The Ce-containing 3+ Ce in solution 3+ The concentration is 0.6-1.2mol / L.

11. The method for preparing nano-cerium oxide according to claim 10, characterized in that: The Ce-containing 3+ Ce in solution 3+ The concentration is 0.9 mol / L.

12. The method for preparing nano-cerium oxide according to claim 8, characterized in that: The excess coefficient of the hydrogen peroxide is 0.1-1.

8.

13. The method for preparing nano-cerium oxide according to claim 12, wherein: The excess coefficient of the hydrogen peroxide is 0.84-1.

04.

14. The method for preparing nano-cerium oxide according to claim 8, characterized in that: The temperature of the oxidation reaction is 40-60°C.

15. The method for preparing nano-cerium oxide according to claim 8, characterized in that: The oxidation reaction time is more than 30 minutes.

16. The method for preparing nano-cerium oxide according to claim 1, wherein: The concentration of the bicarbonate in the precipitant solution is 0.1-2.2 mol / L; and / or, the precipitant in the precipitant solution is one or more of sodium bicarbonate, ammonium bicarbonate and potassium bicarbonate; And / or, in the mixed solution formed after the mixing, the excess coefficient of bicarbonate is (1.00-1.16): 1, wherein the excess coefficient of bicarbonate means the ratio of the amount of bicarbonate in the mixed solution to the amount of bicarbonate in the stoichiometric amount, wherein the amount of bicarbonate in the stoichiometric amount is Ce in the mixed solution. 4+ The amount of bicarbonate corresponding to the hydrogen ion.

17. The method for preparing nano-cerium oxide according to claim 16, wherein: The concentration of the bicarbonate in the precipitant solution is 1.8-2.6 mol / L.

18. The method for preparing nano-cerium oxide according to claim 17, wherein: The concentration of the bicarbonate in the precipitant solution is 2.2 mol / L.

19. The method for preparing nano-cerium oxide according to claim 16, wherein: In the mixed solution formed after the mixing, the excess coefficient of bicarbonate is (1.04-1.16):

1.

20. The method for preparing nano-cerium oxide according to claim 19, wherein: In the mixed solution formed after the mixing, the excess coefficient of bicarbonate is 1.08:

1.

21. The method for preparing nano-cerium oxide according to claim 1, wherein: The first dispersant includes sorbitol.

22. The method for preparing nano-cerium oxide according to claim 21, wherein: The concentration of sorbitol in the first dispersant is 0.002-0.05 mol / L.

23. The method for preparing nano-cerium oxide according to claim 22, wherein: The concentration of sorbitol in the first dispersant is 0.03-0.05 mol / L.

24. The method for preparing nano-cerium oxide according to claim 21, wherein: The sum of the concentrations of the first dispersant and the second dispersant in the dispersant solution is 0.0065-0.05 mol / L.

25. The method for preparing nano-cerium oxide according to claim 1, wherein: The mixing method is: the cerium source solution and the precipitant solution are flowed into the dispersant solution in parallel.

26. The method for preparing nano-cerium oxide according to claim 25, wherein: The dispersant solution is stirred while the parallel flow is introduced.

27. The method for preparing nano-cerium oxide according to claim 26, wherein: The stirring speed is 200-400 r / min.

28. The method for preparing nano-cerium oxide according to claim 27, wherein: The stirring speed is 300 r / min.

29. The method for preparing nano-cerium oxide according to claim 25, wherein: The parallel introduction method is to introduce the cerium source solution and the precipitant solution respectively through peristaltic pumps.

30. The method for preparing nano-cerium oxide according to claim 25, wherein: When the excess coefficient of bicarbonate in the mixed solution formed after mixing is (1.00-1.16):1, the feeding is stopped.

31. The method for preparing nano-cerium oxide according to claim 30, wherein: When the excess coefficient of bicarbonate in the mixed solution formed after mixing is (1.04-1.16):1, the feeding is stopped.

32. The method for preparing nano-cerium oxide according to claim 31, wherein: When the excess coefficient of bicarbonate in the mixed solution formed after mixing is 1.08:1, the feeding is stopped.

33. The method for preparing nano-cerium oxide according to claim 25, wherein: The addition rate ratio of the cerium source solution to the precipitant solution is 1:(0.5-3).

34. The method for preparing nano-cerium oxide according to claim 33, wherein: The addition rate ratio of the cerium source solution to the precipitant solution is 1:(1.9-2.5).

35. The method for preparing nano-cerium oxide according to claim 34, wherein: The addition rate ratio of the cerium source solution to the precipitant solution is 1:2 or 1:2.

3.

36. The method for preparing nano-cerium oxide according to claim 25, wherein: The cerium source solution is added at a rate of 10-150 mL / min.

37. The method for preparing nano-cerium oxide according to claim 36, wherein: The addition rate of the cerium source solution is 25 mL / min or 100 mL / min.

38. The method for preparing nano-cerium oxide according to claim 25, wherein: The addition rate of the precipitant solution is 10-250 mL / min.

39. The method for preparing nano-cerium oxide according to claim 38, wherein: The addition rate of the precipitant solution is 15-70 mL / min.

40. The method for preparing nano-cerium oxide according to claim 39, wherein: The addition rate of the precipitant solution is 40-60 mL / min.

41. The method for preparing nano-cerium oxide according to claim 40, wherein: The addition rate of the precipitant solution is 47 mL / min, 50 mL / min or 57 mL / min.

42. The method for preparing nano-cerium oxide according to claim 25, wherein: The Ce in the cerium source solution 4+ The concentration of is 0.6-1.2 mol / L, the concentration of bicarbonate in the precipitant solution is 1.8-2.6 mol / L, and the addition rate ratio of the cerium source solution and the precipitant solution is 1:(0.5-3).

43. The method for preparing nano-cerium oxide according to claim 1, wherein: During the precipitation process, the pH value is 6-10; and / or, the calcination temperature is 500-1000° C.; And / or, the calcination time is 4h; And / or, the precipitate further comprises a drying step before calcining; And / or, when the first dispersant includes sorbitol, the precipitate includes cerium carbonate, basic cerium carbonate, cerium sorbitol complex, and cerium carbonate sorbitol complex.

44. The method for preparing nano-cerium oxide according to claim 43, wherein: The calcination temperature is 500-800°C.

45. The method for preparing nano-cerium oxide according to claim 44, wherein: The calcination temperature is 500-700°C.

46. ​​The method for preparing nano-cerium oxide according to claim 43, wherein: The drying temperature is 60-120°C.

47. The method for preparing nano-cerium oxide according to claim 46, wherein: The drying temperature is 80°C.

48. The method for preparing nano-cerium oxide according to claim 43, wherein: The drying time is 2 hours.

49. The method for preparing nano-cerium oxide according to claim 43, wherein: The method further includes a washing step before the drying.

50. The method for preparing nano-cerium oxide according to claim 49, wherein: The washing includes a first washing and a second washing, wherein the detergent for the first washing is deionized water, and the detergent for the second washing is ethanol.

51. A nano-cerium oxide, characterized in that The nano-cerium oxide is prepared by the preparation method of nano-cerium oxide according to any one of claims 1 to 50.

52. The nano-cerium oxide according to claim 51, wherein The primary particle size of the nano-cerium oxide is less than 100 nm; And / or, the bulk density of the nano-cerium oxide is 0.3-0.7 g / cm 3 ; And / or, the D of the nano cerium oxide 50 <2um; And / or, the specific surface area of ​​the nano-cerium oxide is greater than 15m 2 / g; And / or, the shape of the nano-cerium oxide is spherical and / or spherical-like; And / or, the Ka of the nano-cerium oxide is less than 2; And / or, R of the nano-cerium oxide is less than 2.

53. The nano-cerium oxide according to claim 52, wherein The primary particle size of the nano-cerium oxide is less than 60 nm.

54. The nano-cerium oxide according to claim 53, wherein The primary particle size of the nano-cerium oxide is less than 30 nm.

55. The nano-cerium oxide according to claim 52, wherein The bulk density of the nano-cerium oxide is 0.39-0.55 g / cm 3 .

56. The nano-cerium oxide according to claim 52, wherein The D of the nano cerium oxide 50 <1um.

57. The nano-cerium oxide according to claim 56, wherein The D of the nano cerium oxide 50 <0.2um.

58. The nano-cerium oxide according to claim 52, wherein The specific surface area of ​​the nano cerium oxide is greater than 20m 2 / g.

59. The nano-cerium oxide according to claim 58, wherein The specific surface area of ​​the nano cerium oxide is greater than 30m 2 / g.

60. The nano-cerium oxide according to claim 52, characterized in that The Ka of the nano-cerium oxide is less than 1.

6.

61. The nano-cerium oxide according to claim 60, wherein The Ka of the nano-cerium oxide is less than 1.

2.

62. The nano-cerium oxide according to claim 52, wherein The R of the nano-cerium oxide is less than 1.

63. The nano-cerium oxide according to claim 62, wherein The R of the nano-cerium oxide is less than 0.5.

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