CN116550358A - N-carbon@Ag-void@SiO 2 Preparation method and application of nano catalyst with yolk-eggshell structure - Google Patents

N-carbon@Ag-void@SiO 2 Preparation method and application of nano catalyst with yolk-eggshell structure Download PDF

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CN116550358A
CN116550358A CN202310321594.5A CN202310321594A CN116550358A CN 116550358 A CN116550358 A CN 116550358A CN 202310321594 A CN202310321594 A CN 202310321594A CN 116550358 A CN116550358 A CN 116550358A
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sio
yolk
void
carbon
apf
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潘明旺
赵娜娜
袁金凤
潘志成
张广林
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Hebei University of Technology
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    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/24—Nitrogen compounds
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    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00—Catalysts, in general, characterised by their form or physical properties
    • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
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Abstract

The invention relates to an N-carbon@Ag-void@SiO 2 A preparation method and application of a nano catalyst with a yolk-eggshell structure. The method firstly prepares the 3-aminophenol formaldehyde resin microsphere @ SiO 2 Core-shell structured nanoparticles, then Ag in the medium + By SiO 2 A shell layer in contact with amino groups on the surface of the 3-APF, wherein Ag is added under the condition of no additional reducing agent + In situ reduction to Ag nanoThe particles were immobilized on the 3-APF surface. Finally, for the Ag-loaded 3-APF@Ag@SiO 2 The core-shell structure nano particles are carbonized, and the Ag nano particles migrate along with the shrinkage of the core part in the carbonization process due to the coordination effect of N atoms on the core, so that N-carbon@Ag-void@SiO is finally formed 2 Egg yolk-eggshell structured nanocatalysts. The invention omits the complex template removing process, has simple method and low cost, and is suitable for large-scale preparation.

Description

N-carbon@Ag-void@SiO 2 Preparation method and application of nano catalyst with yolk-eggshell structure
Technical Field
The invention belongs to the field of catalysis, in particular to an N-carbon@Ag-void@SiO 2 A preparation method and application of a nano catalyst with a yolk-eggshell structure.
Background
The nano particle with the yolk-eggshell structure has the unique structural characteristics that: the shell layer with mesoporous, the size-adjustable cavity and the movable core are favored by researchers in the field of catalysis. According to the structure, the noble metal nano particles are encapsulated in the shell, so that the problem of agglomeration of the noble metal nano particles in the catalysis process is solved, and the recycling rate of the noble metal is improved; the existence of the other cavity makes the surrounding environment of the noble metal nano particles relatively uniform, and more active sites can be exposed in the catalytic process, so that the catalytic efficiency of the noble metal nano particles is improved. Based on the advantages of the yolk-eggshell structure catalyst in the catalysis field, by loading smaller noble metal nano particles on the core/shell of the structure, more catalytic active sites can be exposed while the advantages of the yolk-eggshell structure serving as the catalyst are maintained, the utilization rate of noble metal is improved, and meanwhile, the catalytic activity of the noble metal nano particles is improved.
At present, the nano-catalyst with the yolk-eggshell structure is generally coated layer by layer, and then a template is removed through dissolution or calcination to obtain a cavity, so that the nano-particle catalyst with the yolk-eggshell structure is prepared. Chinese patent CN 110405200A discloses a method for preparing au@hollow carbon nano composite nano particles. By SiO 2 As a sacrificial template, siO is first applied 2 Coating Au nano particles, coating the composite particles with a polychloromethylstyrene compound, and sequentially carbonizing and removing SiO 2 And (5) obtaining the Au@hollow carbon nanocomposite after the template. For the purpose ofImproves the utilization rate of noble metal, and Chen Zhe et al prepares Pd@SiO with noble metal loaded on the shell by using carbon nano particles as a template 2 Nanoparticle catalysts (chem. Comm.46 (2010) 6524-6526.). Firstly, pd nano particles are loaded on carbon nano particles, then a silicon dioxide shell is coated outside the particles, and finally the core is removed by calcination, thus obtaining Pd@SiO with noble metal loaded on the shell 2 A nano-reactor. In the preparation of the nano catalyst with the yolk-eggshell structure, the use of the sacrificial template clearly causes the defects of complex preparation flow, high cost and the like. Therefore, the research on the preparation method of the nano catalyst with the yolk-eggshell structure, which has simple method and low cost, has important research significance.
Disclosure of Invention
The invention aims at overcoming the defects existing in the prior art and provides an N-carbon@Ag-void@SiO 2 A preparation method and application of a nano catalyst with a yolk-eggshell structure. The method firstly prepares the 3-aminophenol formaldehyde resin microsphere @ SiO 2 (3-APF@SiO 2 ) Core-shell structured nanoparticles. Then Ag in the medium + By SiO 2 A shell layer in contact with amino groups on the surface of the 3-APF, wherein Ag is added under the condition of no additional reducing agent + Reduced to Ag nano particles in situ and fixed on the surface of 3-APF. Finally, for the Ag-loaded 3-APF@Ag@SiO 2 The core-shell structure nano particles are carbonized, and the Ag nano particles migrate along with the shrinkage of the core part in the carbonization process due to the coordination effect of N atoms on the core, so that N-carbon@Ag-void@SiO is finally formed 2 Egg yolk-eggshell structured nanocatalysts. The method omits a complex template removing process, is simple, has low cost and is suitable for large-scale preparation. N-carbon@Ag-void@SiO 2 The nano catalyst with the yolk-eggshell structure is applied to the catalytic degradation of the p-nitrophenol, the p-nitrophenol can be completely degraded within 22min, and the corresponding catalyst conversion frequency (TOF) is 137.1/h.
The technical scheme of the invention is as follows:
N-carbon@Ag-void@SiO 2 The preparation method of the nano catalyst with the yolk-eggshell structure comprises the following steps:
the materials are composed of the following components in proportion:
step (1): according to the proportion of the raw materials, 3-aminophenol is dissolved in a mixed solution of distilled water, absolute ethyl alcohol and ammonia water, formaldehyde is added to react for 0.5 to 1.5 hours, 3-aminophenol formaldehyde resin microspheres (3-APF) are prepared, CTAB is added into the system to stir for 5 to 15 minutes, TEOS is added, and the reaction is continued for 20 to 30 hours, thus obtaining 3-APF@SiO 2 Core-shell structured nanoparticle emulsions;
step (2): the obtained 3-APF@SiO 2 Carrying out hydrothermal reaction on the core-shell structure nanoparticle emulsion at 100-130 ℃ for 0.5-24h; after cooling to room temperature, agNO is added 3 Magnetically stirring the ethanol solution of (2), and reacting for 6-10h at room temperature; obtaining 3-APF@Ag@SiO after centrifugal separation 2 Core-shell structured nanoparticles;
step (3): the obtained 3-APF@Ag@SiO 2 Carbonizing the core-shell structure nanoparticle at 500-550deg.C for 2-4 hr to obtain N-carbon@Ag-void@SiO 2 Egg yolk-eggshell structured nanocatalysts.
The AgNO 3 The mass concentration range of the ethanol solution is 0.01-0.03%;
the mass concentration of the ammonia water is 25-30%;
the mass concentration of the formaldehyde solution is 30-40%.
In the step (1), the stirring speed is 230-300rpm, and the reaction temperature is 35-40 ℃;
N-Carbon-void@SiO 2 the diameter of the nano-particle with the yolk-eggshell structure is 389-538nm.
N-Carbon@Ag-void@SiO 2 The particle size of the Ag nano particles in the nano particles with the yolk-eggshell structure is 8-25nm.
N-Carbon@Ag-void@SiO 2 The thickness of the nano particle shell material with the yolk-eggshell structure is 30-42nm.
The N-carbon@Ag-void@SiO prepared by the preparation method 2 Yolk-eggshellThe application of the structural nano catalyst. For use in NaBH 4 The catalytic degradation of the p-nitrophenol is realized under the condition of reducing agent.
The invention has the substantial characteristics that:
the invention breaks through the traditional method of preparing the nano-particle catalyst with the yolk-eggshell structure by coating layer by layer and removing the template, and provides a method of preparing the nano-particle catalyst with the yolk-eggshell structure by using the thinking of 'shipbuilding in bottle' (namely, firstly preparing the nano-particle with the core-shell structure and then loading the metal in the core part).
The beneficial effects of the invention are as follows:
(1) The invention prepares N-carbon@Ag-void@SiO by using the thinking of carrying Ag nano particles in' shipbuilding in bottle 2 The nano catalyst with the yolk-eggshell structure has the advantages of simple process, low cost and high yield, and is easy for mass production;
(2) The N-carbon@Ag-void@SiO prepared by the preparation method provided by the invention 2 The nano particles with the yolk-eggshell structure have the characteristics of uniform particle size (PDI=0.298), adjustable particle size (415-610 nm), high Ag load (0.805%), and the like, and have good application prospects in the catalysis field;
(3) Based on structural advantages, the N-carbon@Ag-void@SiO prepared by the method 2 The nano catalyst with the yolk-eggshell structure realizes the maximum utilization of noble metal and has good recycling stability. The catalyst shows excellent catalytic performance (TOF=137.1/h) in the catalytic degradation of the p-nitrophenol.
Drawings
FIG. 1 is a schematic diagram of the preparation of N-carbon@Ag-void@SiO from example 1 2 A flow chart of a nano catalyst with a yolk-eggshell structure.
FIG. 2 is a schematic diagram of the preparation of 3-APF@Ag@SiO from example 1 2 TEM photograph of core-shell structured nanoparticles.
FIG. 3 is a schematic diagram of the preparation of N-carbon@Ag-void@SiO from example 1 2 SEM photograph of the yolk-eggshell structured nanocatalyst.
FIG. 4 is a schematic diagram of the preparation of N-carbon@Ag-void@SiO from example 1 2 Yolk-eggXRD pattern of the shell structured nanocatalyst.
FIG. 5 shows N-Carbon-void@SiO prepared in examples 2-5 at 3-aminophenol loadings of 0.5g, 0.6g, 0.7g, 0.8g, respectively 2 SEM photograph of yolk-eggshell structure.
FIG. 6 shows N-Carbon-void@SiO prepared in examples 2-5 at 3-aminophenol loadings of 0.5g, 0.6g, 0.7g, 0.8g, respectively 2 TEM photograph of yolk-eggshell structure.
FIG. 7 is an SEM photograph of a sample obtained in example 6 without CTAB.
Fig. 8 is an SEM photograph of a sample prepared in example 7 without ammonia participating in the coating process.
Fig. 9 is a TEM photograph of example 8 failed to successfully load Ag nanoparticles.
FIG. 10 is a schematic diagram of the preparation of N-carbon@Ag-void@SiO from example 1 2 The nano catalyst with yolk-eggshell structure can catalyze and degrade p-nitrophenol to generate an ultraviolet absorption spectrum of p-aminophenol with time dependence.
FIG. 11 is a schematic diagram showing the preparation of N-carbon@Ag-void@SiO of example 1 2 The effect diagram of the recycling application of the nano catalyst with the yolk-eggshell structure for degrading p-nitrophenol into p-aminophenol is shown.
Detailed Description
Example 1.
(1) Ultrasonically dissolving 0.7g of 3-aminophenol into a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) and adding 0.73g of formaldehyde solution (37 wt%) to react for 1h at the reaction temperature of 35 ℃ and the rotating speed of 300rpm to prepare 3-APF, adding 0.51g of CTAB into the system, stirring for 10min, adding 2.36g of TEOS, and continuously reacting for 24h to obtain 3-APF@SiO 2 Core shell nanoparticle emulsion (67.7 mL).
(2) 19.13g (20 mL) of 3-APF@SiO 2 The core-shell structure nanoparticle emulsion is reacted for 24 hours at 130 ℃ in a polytetrafluoroethylene-lined hydrothermal reaction kettle. Cooling to room temperature, adding 15.79g of 0.02% silver nitrate ethanol solution, magnetically stirring at room temperature for reaction for 8h, and centrifuging to obtain core-loaded Ag 3-APF@Ag@SiO 2 Core-shell structured nanoparticles. For a pair ofThe sample at this time was subjected to TEM test, see fig. 2. The Ag nano particles are obviously supported on the core with the core-shell structure.
(3) 3-APF@Ag@SiO 2 Carbonizing the core-shell structure nano particles in a tubular furnace at 550 ℃ for 2 hours to obtain N-carbon@Ag-void@SiO 2 Egg yolk-eggshell structured nanocatalysts. The prepared samples were subjected to TEM and XRD tests, see fig. 3 and 4. It is evident from the figure that the nanoparticles are uniformly supported on the core of the yolk-eggshell structure, and the supported nanoparticles are Ag nanoparticles.
The process flow chart of the preparation process is shown in figure 1.
Example 2.
(1) Ultrasonically dissolving 0.5g of 3-aminophenol in a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) at a reaction temperature of 35 ℃ and a rotating speed of 300rpm, adding 0.73g of formaldehyde solution (37 wt%) to react for 1h to prepare 3-APF, adding 0.51g of CTAB to the system, stirring for 10min, adding 2.36g of TEOS, and continuing to react for 24h to obtain 3-APF@SiO 2 Core-shell structured nanoparticle emulsions.
(2) 19.07g of 3-APF@SiO 2 The core-shell structure nanoparticle emulsion is reacted for 24 hours at 130 ℃ in a polytetrafluoroethylene-lined hydrothermal reaction kettle, and solidified 3-APF@SiO is obtained after centrifugal separation 2 Core-shell structured nanoparticles.
(3) Curing 3-APF@SiO 2 Carbonizing the core-shell structure nano particles in a tubular furnace at 550 ℃ for 2 hours to obtain N-Carbon-void@SiO 2 Yolk-eggshell structured nanoparticles.
Example 3.
(1) Ultrasonically dissolving 0.6g of 3-aminophenol into a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) and adding 0.73g of formaldehyde solution (37 wt%) to react for 1h at the reaction temperature of 35 ℃ and the rotating speed of 300rpm to prepare 3-APF, adding 0.51g of CTAB into the system, stirring for 10min, adding 2.36g of TEOS, and continuously reacting for 24h to obtain 3-APF@SiO 2 Core-shell structured nanoparticle emulsions.
(2) 19.09g of 3-APF@SiO 2 Core-shell knotThe structured nanoparticle emulsion reacts for 24 hours at 130 ℃ in a polytetrafluoroethylene-lined hydrothermal reaction kettle, and solidified 3-APF@SiO is obtained after centrifugal separation 2 Core-shell structured nanoparticles.
(3) Curing 3-APF@SiO 2 Carbonizing the core-shell structure nano particles in a tubular furnace at 550 ℃ for 2 hours to obtain N-Carbon-void@SiO 2 Yolk-eggshell structured nanoparticles.
Example 4.
(1) Ultrasonically dissolving 0.7g of 3-aminophenol into a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) and adding 0.73g of formaldehyde solution (37 wt%) to react for 1h at the reaction temperature of 35 ℃ and the rotating speed of 300rpm to prepare 3-APF, adding 0.51g of CTAB into the system, stirring for 10min, adding 2.36g of TEOS, and continuously reacting for 24h to obtain 3-APF@SiO 2 Core-shell structured nanoparticle emulsions.
(2) 19.13g of 3-APF@SiO 2 The core-shell structure nanoparticle emulsion is reacted for 24 hours at 130 ℃ in a polytetrafluoroethylene-lined hydrothermal reaction kettle, and solidified 3-APF@SiO is obtained after centrifugal separation 2 Core-shell structured nanoparticles.
(3) Curing 3-APF@SiO 2 Carbonizing the core-shell structure nano particles in a tubular furnace at 550 ℃ for 2 hours to obtain N-Carbon-void@SiO 2 Yolk-eggshell structured nanoparticles.
Example 5.
(1) Ultrasonically dissolving 0.8g of 3-aminophenol into a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) and adding 0.73g of formaldehyde solution (37 wt%) to react for 1h at the reaction temperature of 35 ℃ and the rotating speed of 300rpm to prepare 3-APF, adding 0.51g of CTAB into the system, stirring for 10min, adding 2.36g of TEOS, and continuously reacting for 24h to obtain 3-APF@SiO 2 Core-shell structured nanoparticle emulsions.
(2) 19.14g of 3-APF@SiO 2 The core-shell structure nanoparticle emulsion is reacted for 24 hours at 130 ℃ in a polytetrafluoroethylene-lined hydrothermal reaction kettle, and solidified 3-APF@SiO is obtained after centrifugal separation 2 Core-shell structured nanoparticles.
(3) Curing 3-APF@SiO 2 Carbonizing the core-shell structure nano particles in a tubular furnace at 550 ℃ for 2 hours to obtain N-Carbon-void@SiO 2 Yolk-eggshell structured nanoparticles.
SEM and TEM tests were performed on the samples prepared in examples 2-5:
SEM photograph of the sample is shown in FIG. 5, TEM photograph is shown in FIG. 6, the addition amount of 3-aminophenol is changed, the prepared nano particles with yolk-eggshell structure all show uniform hollow spheres, and the prepared N-Carbon-void@SiO is prepared as the addition amount of 3-aminophenol is increased 2 The particle size of the nano particles with the yolk-eggshell structure is increased (389-538 nm). Therefore, N-carbon@Ag-void@SiO with different particle sizes can be prepared by changing the adding amount of 3-aminophenol 2 Egg yolk-eggshell structured nanocatalysts.
Comparative example 1.
The difference from example 4 is that CTAB was not added in this example
0.7g of 3-aminophenol is dissolved in a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) by ultrasonic method, 0.73g of formaldehyde solution (37 wt%) is added to react for 1h at the reaction temperature of 35 ℃ and the rotating speed of 300rpm to prepare 3-APF, and then 2.36g of TEOS is added to the system to continue the reaction for 24h. The prepared sample was subjected to SEM test, and SEM photograph is shown in fig. 7. The results show that only a portion of the silica particles deposited on the 3-APF without the CTAB addition did not completely coat it. This phenomenon occurs mainly because in silica coated 3-APF experiments, CTAB self-assembles at the 3-APF surface with the hydrophobic end extending towards the 3-APF and the amino (i.e. hydrophilic) end extending towards the reaction medium. Thereby leading the surface of the 3-APF to have positive charge and attracting silicon dioxide with negative charge to nucleate and grow on the surface of the silicon dioxide to generate the 3-APF@SiO with complete coating 2 Core-shell structured nanoparticles.
Comparative example 2.
The difference from example 4 is that no ammonia is involved in the silica coating of the 3-APF.
(1) 0.7g of 3-aminophenol is ultrasonically dissolved in a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) and 0.73g of formaldehyde solution (37 wt%) is added for reaction for 1 hour under the conditions of a reaction temperature of 35 ℃ and a rotating speed of 300rpm, so as to prepare the 3-APF nanoparticle emulsion.
(2) The resulting 3-APF nanoparticle emulsion was centrifuged (8000 rpm) with water and ethanol 1:1 in a mixed solution of 15.79g of absolute ethanol and 45.00g of distilled water, 0.51g of CTAB was added to the system and stirred for 10 minutes, then 2.36g of TEOS was added, and the reaction was carried out for 24 hours. SEM testing was performed on the samples produced, see fig. 8 for SEM photographs. The results show that in the silica coated 3-APF experiment, no ammonia water is added, most of the silica self-nucleates in the medium and is partially deposited on the surface of the 3-APF. This is mainly because ammonium ions ionized from ammonia water are adsorbed on the surface of 3-APF during the process of coating the 3-APF with silicon dioxide, thereby attracting negatively charged silicon dioxide to nucleate and grow on the surface of the 3-APF. Without the addition of ammonia, the silica could not be completely deposited on the 3-APF surface, resulting in incomplete coating.
From example 4, comparative example 1, comparative example 2 we show that the positive charge on the 3-APF and the negative charge on the silica are attracted to each other by 3-APF@SiO 2 The main reason for successful preparation of core-shell structured nanoparticles.
Comparative example 3.
The difference from example 1 is that the 3-APF@SiO prepared in step (1) is 2 The core-shell structured nano particles are directly loaded with Ag without high-temperature hydrothermal treatment.
(1) Ultrasonically dissolving 0.7g of 3-aminophenol into a mixed solution of 15.79g of absolute ethyl alcohol, 45.00g of distilled water and 0.18g of ammonia water (28 wt%) and adding 0.73g of formaldehyde solution (37 wt%) to react for 1h at the reaction temperature of 35 ℃ and the rotating speed of 300rpm to prepare 3-APF, adding 0.51g of CTAB into the system, stirring for 10min, adding 2.36g of TEOS, and continuously reacting for 24h to obtain 3-APF@SiO 2 Core-shell structured nanoparticle emulsions.
(2) To 19.13g of 3-APF@SiO 2 15.79g of ethanol solution of silver nitrate with mass fraction of 0.02% is added into the core-shell structure nanoparticle emulsion, and the mixture is magnetically stirred at room temperature for reaction for 8 hours. The sample at this point was subjected to TEM testing, see fig. 9. At the moment, the Ag nano particles are not successfully loaded on the 3-APF@SiO 2 The core-shell structure composite particles are arranged between the core and the shell. This phenomenon occurs mainly because of the 3-APF@SiO which has not been subjected to hydrothermal treatment 2 In the core-shell nano particles, the core and the shell are tightly bonded, and no position is available for loading the Ag nano particles. Whereas hydrothermally treated 3-APF@SiO 2 The core-shell structured nanoparticle has small pits on the core surface, and the structure provides a position for Ag loading. As a matter of course, the hydrothermal treatment is that Ag nano particles are successfully loaded on 3-APF@SiO 2 The main reason for the surface of the core-shell structure.
Example 9.
N-Carbon@Ag-void@SiO prepared in example 1 was evaluated using a catalytic reduction reaction of p-nitrophenol as a model reaction 2 Performance of nano-catalyst with yolk-eggshell structure. 0.3mL of freshly prepared NaBH 0.2mol/L 4 The solution was added to a mixed solution of 0.3mL of a 0.01mol/L p-nitrophenol solution and 3mL of deionized water, and 0.2mL of N-carbon@Ag-void@SiO with a mass fraction of 0.04% was added at room temperature 2 The degradation process was monitored by means of an ultraviolet spectrophotometer (absorbance at 402nm of the reaction system was measured every 2 min). The result shows that the catalyst can completely degrade the p-nitrophenol in 22min, and the corresponding catalytic degradation process is shown in figure 10. The yolk-eggshell catalyst after centrifugal separation is subjected to a cyclic catalytic performance test, and as shown in figure 11, the five-time catalytic degradation effect can still be kept above 90%.
The catalyst shows excellent catalytic performance (TOF=137.1/h) in the catalytic degradation of the p-nitrophenol, and the catalytic effect of the catalyst on reducing the p-nitrophenol is compared with that of different Ag-based catalysts, and is shown in table 1.
TABLE 1 comparison of catalytic Effect of different Ag-based catalysts for reduction of p-nitrophenols
The above examples illustrate that composite particles of yolk-eggshell structure of different particle sizes can be obtained by varying the amount of 3-aminophenol added. And 3-APF@SiO 2 Shell mesoporous and storage of amino groups on coreThe main reason is that Ag nanoparticles can be loaded in situ in the core part.
In summary, the invention provides an N-carbon@Ag-void@SiO 2 The nano catalyst with yolk-eggshell structure has adjustable particle size, ag can be stably loaded, and p-nitrophenol can be efficiently catalyzed and degraded. The method for preparing the catalyst is simple, has low cost, has a large-scale industrialized application prospect, is expected to be applied to catalysis of various chemical reactions in the catalysis field, and provides a new method and a new idea for preparing the catalyst with a novel structure.
The invention is not a matter of the known technology.

Claims (5)

1. N-carbon@Ag-void@SiO 2 The preparation method of the nano catalyst with the yolk-eggshell structure is characterized by comprising the following steps:
the materials are composed of the following components in proportion:
step (1): according to the proportion of the raw materials, 3-aminophenol is dissolved in a mixed solution of distilled water, absolute ethyl alcohol and ammonia water, formaldehyde is added to react for 0.5 to 1.5 hours, 3-aminophenol formaldehyde resin microspheres (3-APF) are prepared, CTAB is added into the system to stir for 5 to 15 minutes, TEOS is added, and the reaction is continued for 20 to 30 hours, thus obtaining 3-APF@SiO 2 Core-shell structured nanoparticle emulsions;
step (2): the obtained 3-APF@SiO 2 The core-shell structure nanoparticle emulsion is subjected to hydrothermal reaction for 0.5 to 24 hours at the temperature of 100 to 130 ℃, and AgNO is added according to the raw material proportion after the mixture is cooled to room temperature 3 Magnetically stirring the ethanol solution of (2), and reacting for 6-10h at room temperature; obtaining 3-APF@Ag@SiO after centrifugal separation 2 Core-shell structured nanoparticles;
step (3): the obtained 3-APF@Ag@SiO 2 Carbonizing the core-shell structure nanoparticle at 500-550deg.C for 2-4 hr to obtain N-carbon@Ag-void@SiO 2 Egg yolk-eggshell structured nanocatalysts.
2. The N-carbon@Ag-void@SiO of claim 1 2 The preparation method of the nano catalyst with the yolk-eggshell structure is characterized in that in the step (1), the stirring speed is 230-300rpm, and the reaction temperature is 35-40 ℃.
3. The N-carbon@Ag-void@SiO of claim 1 2 The preparation process of nanometer catalyst in yolk-eggshell structure features that the nanometer catalyst is N-Carbon-void@SiO 2 The diameter of the nano particles with the yolk-eggshell structure is 389-538nm;
N-Carbon@Ag-void@SiO 2 the particle size of Ag nano particles in the nano particles with yolk-eggshell structures is 8-25nm;
N-Carbon@Ag-void@SiO 2 the thickness of the nano particle shell material with the yolk-eggshell structure is 30-42nm.
4. The N-carbon@Ag-void@SiO of claim 1 2 The preparation method of the nano catalyst with the yolk-eggshell structure is characterized in that the AgNO 3 The mass concentration range of the ethanol solution is 0.01-0.03%;
the mass concentration of the ammonia water is 25-30%;
the mass concentration of the formaldehyde solution is 30-40%.
5. The N-carbon@Ag-void@SiO prepared by the method of claim 1 2 The application of the nano catalyst with the yolk-eggshell structure is characterized in that the nano catalyst is used for preparing NaBH (sodium silicate-polyethylene glycol) catalyst 4 The catalytic degradation of the p-nitrophenol is realized under the condition of reducing agent.
CN202310321594.5A 2023-03-29 2023-03-29 N-carbon@Ag-void@SiO 2 Preparation method and application of nano catalyst with yolk-eggshell structure Pending CN116550358A (en)

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