PREPARATION METHOD OF Ni ACTIVE SITE-LOADED C-Si AEROGEL CATALYST, AND PRODUCT AND USE THEREOF

Abstract

The present disclosure discloses a method of preparing a Ni active site-loaded C—Si aerogel catalyst, and a product and use thereof, belonging to the technical field of catalyst preparation. The method includes the following steps: (1) dissolving absolute ethanol, trimethoxymethylsilane, cetyltrimethylammonium bromide and HCl in deionized water, conducting hydrolysis to obtain a hydrolyzate, followed by adjusting a pH value of the hydrolyzate to 7 to 8.5, and drying to obtain a C—Si aerogel; and (2) in the absolute ethanol, mixing NiCl.sub.2.6H.sub.2O with the C—Si aerogel obtained in step (1) uniformly, and conducting ultrasonication, impregnation and drying, followed by calcination to obtain the Ni active site-loaded C—Si aerogel catalyst. In the present disclosure, the prepared Ni active site-loaded C—Si aerogel catalyst is capable of conducting catalytic degradation of aromatic volatile organic compounds (VOCs) at room temperature.

Claims

1. A method of preparing a Ni active site-loaded C—Si aerogel catalyst, comprising the steps of: (1) dissolving absolute ethanol, trimethoxymethylsilane and cetyltrimethylammonium bromide in deionized water, adjusting a pH value to 3.5 to 5 with HCl, conducting hydrolysis to obtain a hydrolyzate, adjusting a pH value of the hydrolyzate to 7 to 8.5, and drying to obtain a C—Si aerogel; and (2) in the absolute ethanol, mixing NiCl.sub.2.6H.sub.2O with the C—Si aerogel obtained in step (1) uniformly, and conducting ultrasonication, impregnation and drying, followed by calcination to obtain the Ni active site-loaded C—Si aerogel catalyst.

2. The method according to claim 1, wherein in step (2), mixing the NiCl.sub.2.6H.sub.2O and the C—Si aerogel obtained in the step (1) comprises: mixing the C—Si aerogel obtained in step (1) with the absolute ethanol according to a mass-to-volume ratio of 1 g:10 mL, and stirring evenly to obtain a first solution; mixing the NiCl.sub.2.6H.sub.2O with the absolute ethanol according to a mass-volume ratio of (0.01-0.06) g:10 mL, and stirring evenly to obtain a second solution; and mixing the first solution and the second solution uniformly according to a volume ratio of 1:1.

3. The method according to claim 1, wherein in step (2), the ultrasonication is conducted for 25 min to 35 min.

4. The method according to claim 1, wherein in step (2), the impregnation is conducted at 65° C. to 75° C. for 3 h to 5 h.

5. The method according to claim 1, wherein in step (2), the calcination is conducted at 200° C. to 400° C. for 1.5 h to 3 h with a heating rate of 3° C./min.

6. The method according to claim 1, wherein in step (1), mixing the C—Si aerogel comprises: (a) mixing the deionized water, the absolute ethanol, the trimethoxymethylsilane and the cetyltrimethylammonium bromide at a volume-to-mass ratio of (5-15) mL:(10-20) mL:(4-6) mL:(0.05-0.15) g, stirring well, adjusting the pH value to 3.5 to 5 with HCl, and conducting hydrolysis at 40° C. to 50° C. for 30 min to 60 min to obtain a hydrolyzate; and (b) adjusting the pH value of the hydrolyzate obtained in step (a) to 7 to 8.5, followed by standing at 55° C. to 65° C. for 3.5 h to 4.5 h, and drying to obtain the C—Si aerogel.

7. The method according to claim 6, wherein in step (b), the drying is conducted at 75° C. to 85° C. for 2 h to 2.5 h, then at 95° C. to 105° C. for 2 h to 2.5 h, and finally at 115° C. to 125° C. for 1 h to 1.5 h.

8. A Ni active site-loaded C—Si aerogel catalyst prepared by the method according of claim 1.

9. The Ni active site-loaded C—Si aerogel catalyst according to claim 8, wherein in step (2), mixing the NiCl.sub.2.6H.sub.2O and the C—Si aerogel obtained in the step (1) comprises: mixing the C—Si aerogel obtained in step (1) with the absolute ethanol according to a mass-to-volume ratio of 1 g:10 mL, and stirring evenly to obtain a first solution; mixing the NiCl.sub.2 6H.sub.2O with the absolute ethanol according to a mass-volume ratio of (0.01-0.06) g:10 mL, and stirring evenly to obtain a second solution; and mixing the solution 1 and the solution 2 uniformly according to a volume ratio of 1:1.

10. The Ni active site-loaded C—Si aerogel catalyst according to claim 8, wherein in step (2), the ultrasonication is conducted for 25 min to 35 min.

11. The Ni active site-loaded C—Si aerogel catalyst according to claim 8, wherein in step (2), the impregnation is conducted at 65° C. to 75° C. for 3 h to 5 h.

12. The Ni active site-loaded C—Si aerogel catalyst according to claim 8, wherein in step (2), the calcination is conducted at 200° C. to 400° C. for 1.5 h to 3 h with a heating rate of 3° C./min.

13. The Ni active site-loaded C—Si aerogel catalyst according to claim 8, wherein in step (1), preparing the C—Si aerogel comprises: (a) mixing the deionized water, the absolute ethanol, the trimethoxymethylsilane and the cetyltrimethylammonium bromide at a volume-to-mass ratio of (5-15) mL:(10-20) mL:(4-6) mL:(0.05-0.15) g, stirring well, adjusting the pH value to 3.5 to 5 with HCl, and conducting hydrolysis at 40° C. to 50° C. for 30 min to 60 min to obtain a hydrolyzate; and (b) adjusting the pH value of the hydrolyzate obtained in step (a) to 7 to 8.5, followed by standing at 55° C. to 65° C. for 3.5 h to 4.5 h, and drying to obtain the C—Si aerogel.

14. The Ni active site-loaded C—Si aerogel catalyst according to claim 13, wherein in step (b), the drying is conducted at 75° C. to 85° C. for 2 h to 2.5 h, and then at 95° C. to 105° C. for 2 h to 2.5 h, and finally at 115° C. to 125° C. for 1 h to 1.5 h.

15. Use of the Ni active site-loaded C—Si aerogel catalyst according to claim 8 in catalytic degradation of aromatic volatile organic compounds (VOCs) at room temperature.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In the present disclosure, a plurality of exemplary examples are now described in detail. The detailed description should not be considered as a limitation to the present disclosure, but should be understood as a more detailed description of certain aspects, features, and implement solutions of the present disclosure.

[0028] It should be understood that terms described in the present disclosure are merely used to describe specific embodiments and are not intended to limit the present disclosure. In addition, for a numerical range in the present disclosure, it should be understood that each intermediate value between an upper limit and a lower limit of the range is also specifically disclosed. Each smaller range between any stated value or intermediate value in a stated range and any other stated value or intermediate value in the stated range is also included in the present disclosure. The upper and lower limits of these smaller ranges can independently be included or excluded from the range.

[0029] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art described in the present disclosure. Although the present disclosure describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure. All documents mentioned in this specification are incorporated by reference to disclose and describe methods and/or materials related to the documents. In case of conflict with any incorporated documents, the content of this specification shall prevail.

[0030] It is evident to a person skilled in the art that a plurality of modifications and variations can be made to the specific embodiments of the present specification without departing from the scope or spirit of the present disclosure. Other embodiments derived from the description of the present disclosure will be evident to the skilled person. The specification and examples of the present disclosure are merely exemplary.

[0031] As used herein, “including”, “having”, “containing”, and the like are all open-ended terms, which means including but not limited to.

Example 1

[0032] 1. Preparation of a C—Si Aerogel

[0033] (1) 10 mL of deionized water, 15 mL of absolute ethanol, 5 mL of trimethoxymethylsilane and 0.1 g of cetyltrimethylammonium bromide were added into a 100 mL beaker in turn, followed by stirring uniformly, and the pH value was adjusted to 4 with a 0.1 mol/L HCl to obtain a first solution.

[0034] (2) The first solution was placed in an oil bath pot at 45° C., followed by conducting hydrolysis for 30 min to obtain a hydrolyzate; NH.sub.3.H.sub.2O with a concentration of 1 mol.Math.L.sup.−1 was added dropwise while stirring, followed by adjusting a pH value of the hydrolyzate to 7.5 to obtain a second solution.

[0035] (3) the oil bath pot was heated to 60° C., followed by standing the second solution for 4 h; the second solution was placed in an oven for baking at 80° C., 100° C. and 120° C. for 2 h, 2 h and 1 h, respectively; and the C—Si aerogel was obtained.

[0036] 2. Loading of a Ni Active Site by Impregnation

[0037] (1) 10 mL of the absolute ethanol was added to the beaker containing 1 g of the C—Si aerogel, followed by stirring to obtain a solution 1;

[0038] (2) 10 mL of the absolute ethanol was added to a beaker containing 0.045 g of NiCl.sub.2 6H.sub.2O, followed by stirring to obtain a solution 2;

[0039] (3) the solution 1 and the solution 2 were mixed, followed by conducting ultrasonication for 30 min; a mixture was placed in an oil bath pot for impregnation at 70° C. for 5 h, followed by baking in an oven at 80° C. for 2 h; and

[0040] (4) calcination was conducted at 200° C. for 2 h in a muffle furnace at a heating rate of 3° C./min, to obtain a Ni active site-loaded C—Si aerogel catalyst capable of being used for catalytic degradation of aromatic VOCs at room temperature.

Example 2

[0041] 1. Preparation of a C—Si Aerogel

[0042] (1) 10 mL of deionized water, 15 mL of absolute ethanol, 5 mL of trimethoxymethylsilane and 0.1 g of cetyltrimethylammonium bromide were added into a 100 mL beaker in turn, followed by stirring uniformly, and the pH value was adjusted to 4.5 with a 0.1 mol/L HCl to obtain a first solution.

[0043] (2) The first solution was placed in an oil bath pot at 45° C., followed by conducting hydrolysis for 60 min to obtain a hydrolyzate; NH.sub.3.H.sub.2O with a concentration of 1 mol.Math.L.sup.−1 was added dropwise while stirring, followed by adjusting a pH value of the hydrolyzate to 7.5 to obtain a second solution.

[0044] (3) the oil bath pot was heated to 60° C., followed by standing the second solution for 4 h; the second solution was placed in an oven for baking at 80° C., 100° C. and 120° C. for 2 h, 2 h and 1 h, respectively; and the C—Si aerogel was obtained.

[0045] 2. Loading of a Ni Active Site by Impregnation

[0046] (1) 10 mL of the absolute ethanol was added to the beaker containing 1 g of the C—Si aerogel, followed by stirring to obtain a solution 1;

[0047] (2) 10 mL of the absolute ethanol was added to a beaker containing 0.03 g of NiCl.sub.2.6H.sub.2O, followed by stirring to obtain a solution 2;

[0048] (3) the solution 1 and the solution 2 were mixed, followed by conducting ultrasonication for 30 min; a mixture was placed in an oil bath pot for impregnation at 70° C. for 5 h, followed by baking in an oven at 80° C. for 3 h; and

[0049] (4) calcination was conducted at 300° C. for 2 h in a muffle furnace at a heating rate of 3° C./min, to obtain a Ni active site-loaded C—Si aerogel catalyst capable of being used for catalytic degradation of aromatic VOCs at room temperature.

Example 3

[0050] 1. Preparation of a C—Si Aerogel

[0051] (1) 15 mL of deionized water, 20 mL of absolute ethanol, 6 mL of trimethoxymethylsilane and 0.15 g of cetyltrimethylammonium bromide were added into a 100 mL beaker in turn, followed by stirring uniformly, and the pH value was adjusted to 5 with a 0.1 mol/L HCl to obtain a first solution.

[0052] (2) The first solution was placed in an oil bath pot at 50° C., followed by conducting hydrolysis for 60 min to obtain a hydrolyzate; NH.sub.3.H.sub.2O with a concentration of 1 mol.Math.L.sup.−1 was added dropwise while stirring, followed by adjusting a pH value of the hydrolyzate to 7 to obtain a second solution.

[0053] (3) the oil bath pot was heated to 65° C., followed by standing the second solution for 4.5 h; the second solution was placed in an oven for baking at 85° C., 105° C. and 125° C. for 2 h, 2 h and 1 h, respectively; and the C—Si aerogel was obtained.

[0054] 2. Loading of a Ni Active Site by Impregnation

[0055] (1) 10 mL of the absolute ethanol was added to the beaker containing 1 g of the C—Si aerogel, followed by stirring to obtain a solution 1;

[0056] (2) 10 mL of the absolute ethanol was added to a beaker containing 0.045 g of NiCl.sub.2 6H.sub.2O, followed by stirring to obtain a solution 2;

[0057] (3) the solution 1 and the solution 2 were mixed, followed by conducting ultrasonication for 25 min; a mixture was placed in an oil bath pot for impregnation at 75° C. for 3 h, followed by baking in an oven at 80° C. for 4 h; and

[0058] (4) calcination was conducted at 400° C. for 2 h in a muffle furnace at a heating rate of 3° C./min, to obtain a Ni active site-loaded C—Si aerogel catalyst capable of being used for catalytic degradation of aromatic VOCs at room temperature.

Example 4

[0059] 1. Preparation of a C—Si Aerogel

[0060] (1) 10 mL of deionized water, 15 mL of absolute ethanol, 5 mL of trimethoxymethylsilane and 0.1 g of cetyltrimethylammonium bromide were added into a 100 mL beaker in turn, followed by stirring uniformly, and the pH value was adjusted to 4.5 with a 0.1 mol/L HCl to obtain a first solution.

[0061] (2) The first solution was placed in an oil bath pot at 45° C., followed by conducting hydrolysis for 60 min to obtain a hydrolyzate; NH.sub.3.H.sub.2O with a concentration of 1 mol.Math.L.sup.−1 was added dropwise while stirring, followed by adjusting a pH value of the hydrolyzate to 8 to obtain a second solution.

[0062] (3) the oil bath pot was heated to 60° C., followed by standing the second solution for 4 h; the second solution was placed in an oven for baking at 80° C., 100° C. and 120° C. for 2 h, 2 h and 1 h, respectively; and the C—Si aerogel was obtained.

[0063] 2. Loading of a Ni Active Site by Impregnation

[0064] (1) 10 mL of the absolute ethanol was added to the beaker containing 1 g of the C—Si aerogel, followed by stirring to obtain a solution 1;

[0065] (2) 10 mL of the absolute ethanol was added to a beaker containing 0.06 g of NiCl.sub.2 6H.sub.2O, followed by stirring to obtain a solution 2;

[0066] (3) the solution 1 and the solution 2 were mixed, followed by conducting ultrasonication for 30 min; a mixture was placed in an oil bath pot for impregnation at 70° C. for 5 h, followed by baking in an oven at 80° C. for 3 h; and

[0067] (4) calcination was conducted at 400° C. for 2 h in a muffle furnace at a heating rate of 3° C./min, to obtain a Ni active site-loaded C—Si aerogel catalyst capable of being used for catalytic degradation of aromatic VOCs at room temperature.

Example 5

[0068] 1. Preparation of a C—Si Aerogel

[0069] (1) 5 mL of deionized water, 10 mL of absolute ethanol, 4 mL of trimethoxymethylsilane and 0.05 g of cetyltrimethylammonium bromide were added into a 100 mL beaker in turn, followed by stirring uniformly, and the pH value was adjusted to 3.5 with HCl to obtain a first solution.

[0070] (2) The first solution was placed in an oil bath pot at 45° C., followed by conducting hydrolysis for 40 min to obtain a hydrolyzate; NH.sub.3.H.sub.2O with a concentration of 1 mol.Math.L.sup.−1 was added dropwise while stirring, followed by adjusting a pH value of the hydrolyzate to 8.5 to obtain a second solution.

[0071] (3) the oil bath pot was heated to 55° C., followed by standing the second solution for 3.5 h; the second solution was placed in an oven for baking at 75° C., 95° C. and 115° C. for 2.5 h, 2.5 h and 1.5 h, respectively; and the C—Si aerogel was obtained.

[0072] 2. Loading of a Ni Active Site by Impregnation

[0073] (1) 10 mL of the absolute ethanol was added to the beaker containing 1 g of the C—Si aerogel, followed by stirring to obtain a solution 1;

[0074] (2) 10 mL of the absolute ethanol was added to a beaker containing 0.01 g of NiCl.sub.2 6H.sub.2O, followed by stirring to obtain a solution 2;

[0075] (3) the solution 1 and the solution 2 were mixed, followed by conducting ultrasonication for 25 min; a mixture was placed in an oil bath pot for impregnation at 65° C. for 3 h, followed by baking in an oven at 80° C. for 2 h; and

[0076] (4) calcination was conducted at 300° C. for 1.5 h in a muffle furnace at a heating rate of 3° C./min, to obtain a Ni active site-loaded C—Si aerogel catalyst capable of being used for catalytic degradation of aromatic VOCs at room temperature.

Experimental Example 1

[0077] A calcination temperature of step (4) was set to 150° C., 200° C., 300° C., 400° C., and 450° C., respectively, other operations were the same as those in Example 1, and an optimization experiment was conducted. The experimental results are shown in Table 1. It can be seen from Table 1 that when the calcination temperature is 200° C. to 400° C., the dispersion of Ni active components can be significantly improved, and the particle size of Ni active components can be significantly reduced.

TABLE-US-00001 TABLE 1 Ni active Ni active Calcination component component particle temperature dispersion, % size, % 150° C. 24.9 5.6 200° C. 48.0 2.6 300° C. 53.1 2.2 400° C. 49.3 2.5 450° C. 51.8 2.3

Experimental Example 2

[0078] A volume ratio of absolute ethanol and trimethoxymethylsilane was adjusted to 10:1, 10:2, 10:4, 10:6 and 10:7, respectively, other operations were the same as those in Example 1, and an optimization experiment was conducted. The experimental results are shown in Table 2. It can be seen from Table 2 that: when the volume ratio of absolute ethanol and trimethoxymethylsilane is 10:2, the dispersion of Ni active component begins to be significantly improved, and the particle size of Ni active component also begins to be significantly reduced; when the volume ratio of absolute ethanol and trimethoxymethylsilane is 10:7, the dispersion of Ni active component begins to be decreased, and the particle size of Ni active component also begins to be increased. This shows that when the volume ratio of absolute ethanol and trimethoxymethylsilane is 10:2 to 10:6, the dispersion of Ni active component can be significantly improved, and the particle size of Ni active component can be significantly reduced.

TABLE-US-00002 TABLE 2 Volume ratio of Ni active Ni active absolute ethanol and component component trimethoxymethylsilane dispersion, % particle size, % 10:1 17.8 6.8 10:2 46.2 2.8 10:4 52.7 2.3 10:6 50.9 2.5 10:7 47.6 2.7

Comparative Example 1

[0079] A method was the same as that in Example 1, except that in step (3) of preparation of a C—Si aerogel, drying was conducted at 80° C. for 5 h.

[0080] In the comparative example, the prepared C—Si aerogel has a density of 0.037 g/cm.sup.3 and an average pore size of 1,100 nm.

Comparative Example 2

[0081] A method was the same as that in Example 1, except that in step (3) of preparation of a C—Si aerogel, drying was conducted at 120° C. for 5 h.

[0082] In the comparative example, the prepared C—Si aerogel has a density of 0.031 g/cm.sup.3 and an average pore size of 1,300 nm.

[0083] Table 3 shows the content, dispersion and particle size of Ni active components in the Ni active site-loaded C—Si aerogel catalysts prepared in Example 1-5 and Comparative Example 1-2.

TABLE-US-00003 TABLE 3 Average Density pore Ni active Ni active Ni active of size of component component component C—Si C—Si content, dispersion, particle aerogel, aerogel, Examples % % size, % g/cm.sup.3 nm Example 1 1.57 53.1 2.2 0.008 2600 Example 2 1.32 49.5 2.6 0.009 2300 Example 3 1.18 43.9 2.9 0.010 1900 Example 4 1.22 48.7 2.7 0.095 2000 Example 5 0.86 39.7 3.0 0.014 1700 Comparative 0.71 15.8 6.8 0.037 1100 Example 1 Comparative 0.79 18.2 7.0 0.031 1300 Example 2

[0084] Effect Test

[0085] The catalysts of Examples 1-5 and Comparative Examples 1-2 were installed in a fixed-bed reaction device, and catalytic evaluation was conducted using benzene, toluene and p-xylene as evaluation pollutants of a catalytic reaction. The catalysts were tested in a quartz tube with an inner diameter of 8 mm. The catalytic reaction device has a length of 40 mm, the VOCs have a solubility of 800 mg.Math.m.sup.−3, a space velocity was 70,000 mL.Math.g−1.Math.h.sup.−1, and a reaction temperature was 25° C. The catalytic oxidation was conducted in the presence of oxygen. The results are shown in Table 4. It can be seen from Table 4 that the highly dispersed Ni active site-loaded C—Si aerogel catalysts prepared in Examples 1-5 have a desirable removal effect on the benzene, toluene and p-xylene. Therefore, the catalyst can be used to completely remove the aromatic VOCs at room temperature.

TABLE-US-00004 TABLE 4 Benzene Toluene P-xylene removal rate Removal rate removal rate Examples (%) (%) (%) Example 1  100%  100% 99.8% Example 2 96.3% 92.4% 94.8% Example 3 96.1% 98.3% 95.7% Example 4 98.8% 95.0% 97.5% Example 5 94.7% 86.7% 93.9% Comparative 80.4% 76.7% 78.1% Example 1 Comparative 78.3% 76.0% 75.9% Example 2

[0086] The foregoing embodiments are only intended to describe the preferred implementation of the present disclosure and not intended to limit the scope of the present disclosure. Various alterations and improvements made by a person of ordinary skill in the art based on the technical solution of the present disclosure without departing from the design spirit of the present disclosure shall fall within the protection scope determined by the claims of the present disclosure.