Reusable nano core-shell structure mimic enzyme material and preparation method thereof
阅读说明：本技术 一种可复用纳米核-壳结构模拟酶材料及其制备方法 (Reusable nano core-shell structure mimic enzyme material and preparation method thereof ) 是由 王建芝 徐晗 余洪亮 于 2021-08-19 设计创作，主要内容包括：本发明提供了一种可复用纳米核-壳结构模拟酶材料及其制备方法,所述制备方法包括步骤：取铁源和铵源,加入到溶剂中超声搅拌,得到混合液A,将所述混合液A在第一预设条件下反应,磁分离后洗涤、干燥,得到磁性纳米铁；将所述磁性纳米铁与锰源、铵源在去离子水中超声搅拌,得到混合液B,将所述混合液B在第二预设条件下进行反应,磁分离后洗涤、干燥,得到可复用纳米核-壳结构模拟酶材料。本发明制备工艺简单、原料简单易得且对生物和环境友好,可适用于工业化大规模生产,且制得的产品具有可磁分离和循环使用的特性,再生循环使用中依然保持极高的酶活力,具有广阔应用前景。(The invention provides a reusable nano core-shell structure mimic enzyme material and a preparation method thereof, wherein the preparation method comprises the following steps: adding an iron source and an ammonium source into a solvent, performing ultrasonic stirring to obtain a mixed solution A, reacting the mixed solution A under a first preset condition, performing magnetic separation, washing, and drying to obtain magnetic nano iron; and ultrasonically stirring the magnetic nano iron, a manganese source and an ammonium source in deionized water to obtain a mixed solution B, reacting the mixed solution B under a second preset condition, washing and drying after magnetic separation to obtain the reusable nano core-shell structure mimic enzyme material. The preparation method is simple in preparation process, simple and easily available in raw materials, friendly to organisms and environment, and suitable for industrial large-scale production, and the prepared product has the characteristics of magnetic separation and recycling, still keeps extremely high enzyme activity in regeneration recycling, and has wide application prospect.)
1. A preparation method of a reusable nano core-shell structure mimic enzyme material is characterized by comprising the following steps:
s1, adding an iron source and an ammonium source into a solvent, performing ultrasonic stirring to obtain a mixed solution A, reacting the mixed solution A under a first preset condition, performing magnetic separation, washing, and drying to obtain magnetic nano iron;
s2, ultrasonically stirring the magnetic nano iron, a manganese source and an ammonium source in deionized water to obtain a mixed solution B, reacting the mixed solution B under a second preset condition, washing after magnetic separation, and drying to obtain the reusable nano core-shell structure mimic enzyme material.
2. The method of claim 1, wherein the iron source in step S1 comprises ferric nitrate or ferric trichloride, the ammonium source comprises one of ammonium persulfate, ammonium oxalate, tetrabutylammonium bromide and methylethylenediamine, and the solvent comprises one of methanol, ethanol and ethylene glycol.
3. The method according to claim 1, wherein the mass ratio of the iron source to the ammonium source in step S1 is 1: 0.2 to 1: within the range of 0.8.
4. The method as claimed in claim 2, wherein the first preset condition of step S1 includes a reaction temperature ranging from 200 ℃ to 400 ℃ and a reaction time ranging from 10h to 20 h.
5. The method according to any one of claims 1 to 4, wherein the second predetermined condition of step S2 includes a reaction temperature in a range of 120 ℃ to 200 ℃ and a reaction time in a range of 1h to 2 h.
6. The method according to claim 5, wherein the mass ratio of the magnetic nano-iron, the manganese source and the ammonium source in step S2 is 1: 66: 92 to 1: 17: within 23.
7. The method of claim 6, wherein the source of manganese comprises one of manganese sulfate, manganese nitrate, and manganese chloride.
8. A reusable nano core-shell structure mimic enzyme material, which is prepared by the preparation method of the reusable nano core-shell structure mimic enzyme material according to any one of claims 1 to 7.
Technical Field
The invention relates to the technical field of electrolytic water catalytic hydrogen evolution, in particular to a reusable nano core-shell structure mimic enzyme material and a preparation method thereof.
Background
The natural enzyme has high catalytic activity, strong specificity for the combination of substrates, andand has relatively mild conditions, however, the catalytic activity of the enzyme is very sensitive to changes in environmental conditions, is easy to denature and digest, and reduces the stability of the enzyme, and the inherent defects greatly limit the practical application potential of the natural enzyme. Scientists have been working for many years to develop artificial enzyme analogs with similarities to the natural enzymes to construct more stable and more readily available biomimetic enzyme systems. With the development of nanotechnology in recent years, some new nanomaterials are successfully prepared and proved to have the property of simulating enzyme, such as FeS and Co3O4AgPd, etc., which can be in H2O2When existing, the material shows high-efficiency catalytic performance, and the material is actually applied to the related medical fields such as catalysts.
Manganese dioxide nanoparticle MnO2NPs have the advantages of controllable structure, easy ion conversion and the like, and have wide application in the aspects of catalysis, biosensors, energy storage and the like. In addition, when nano-microsphere MCs are processed into nano-sized thin films and then subjected to catalytic experiments, excellent enzyme activity is also exhibited. Based on the characteristic of high catalytic activity, the manganese dioxide microsphere (MnO) modified by bovine serum albumin2MCs) have been put to practical use for detecting H2O2And (4) concentration.
However, manganese dioxide microspheres (MnO)2MCs) are complex in preparation and application, expensive in price and incapable of realizing MnO2The controllable growth of the crystal structure is not suitable for industrial production.
Disclosure of Invention
In view of the above, the invention aims to overcome the defects of the prior art, and provides a reusable nano core-shell structure mimic enzyme material and a preparation method thereof, so as to solve the problems of complex process, low catalytic efficiency and high price of the existing manganese dioxide microsphere nano mimic enzyme material in practical application.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
a preparation method of a reusable nano core-shell structure mimic enzyme material comprises the following steps:
s1, adding an iron source and an ammonium source into a solvent, performing ultrasonic stirring to obtain a mixed solution A, reacting the mixed solution A under a first preset condition, performing magnetic separation, washing, and drying to obtain magnetic nano-Fe3O4 NPs；
S2, mixing the magnetic nano-iron Fe3O4NPs, a manganese source and an ammonium source are ultrasonically stirred in deionized water to obtain a mixed solution B, the mixed solution B is reacted under a second preset condition, and the mixed solution B is washed and dried after magnetic separation to obtain the reusable nano core-shell structure mimic enzyme material Fe3O4@MnO2 MCM。
Optionally, the iron source of step S1 includes ferric nitrate or ferric trichloride, and the ammonium source includes ammonium persulfate (NH)4)2S2O8Ammonium oxalate (NH)4)2C2O4Tetrabutylammonium bromide C16H36BrN and methylethylenediamine C3H12N2Wherein the solvent comprises one of methanol, ethanol and ethylene glycol.
Optionally, in step S1, the mass ratio of the iron source to the ammonium source is in the range of 1: 0.2 to 1: within the range of 0.8.
Optionally, the first preset condition of step S1 includes a reaction temperature in the range of 200 ℃ to 400 ℃ and a reaction time in the range of 10h to 20 h.
Optionally, the second preset condition of step S2 includes a reaction temperature in the range of 120 ℃ to 200 ℃ and a reaction time in the range of 1h to 2 h.
Optionally, in step S2, the mass ratio of the magnetic nano-iron to the manganese source to the ammonium source is 1: 66: 92 to 1: 17: within 23.
Optionally, the source of manganese comprises one of manganese sulfate, manganese nitrate and manganese chloride.
The invention also aims to provide a reusable nano core-shell structure mimic enzyme material which is prepared by the preparation method of the reusable nano core-shell structure mimic enzyme material.
Compared with the prior art, the reusable nano core-shell structure mimic enzyme material and the preparation method thereof provided by the invention have the following advantages:
(1) the invention realizes MnO under the conditions of high temperature and high pressure by a hydrothermal method2Controlled growth of crystalline structure, with simple MnO2MCs exhibit a needle-like structure, Fe3O4@MnO2The flower-like structure on the surface of the MCM is a three-dimensional structure, and the structure can expose more active sites and provide more contact areas for catalytic reaction, so that the catalytic performance of the material is improved; further, Fe3O4NPs have unique superparamagnetism and similar catalytic activity to natural enzymes, can still maintain higher catalytic activity under wider acid-base conditions and temperature intervals, and can regulate the catalytic activity by changing surface groups, particle structures and the like.
(2) The preparation method is simple in preparation process, simple and easily available in raw materials, friendly to organisms and environment, and suitable for industrial large-scale production, and the prepared product has the characteristics of magnetic separation and recycling, still keeps extremely high enzyme activity in regeneration recycling, and has wide application prospect.
Drawings
In order to more clearly illustrate the technical solutions of the present invention or the prior art, the drawings needed for the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and those skilled in the art can also obtain other drawings according to the drawings without creative efforts.
FIG. 1 is Fe as described in example 1 of the present invention3O4Transmission electron microscopy images of NPs;
FIG. 2 is Fe as described in example 2 of the present invention3O4XRD spectrum of NPs;
FIG. 3 is Fe as described in example 2 of the present invention3O4@MnO2XRD pattern of MCM;
FIG. 4 is Fe as described in example 4 of the present invention3O4@MnO2A characterization plot of the catalytic effect of the pH of MCM;
FIG. 5 is the bookFe described in inventive example 43O4@MnO2A characterization plot of the catalytic effect of temperature of MCM;
FIG. 6 is Fe according to example 4 of the present invention3O4@MnO2Repeatability characterization of the MCM;
FIG. 7 is Fe according to example 4 of the present invention3O4@MnO2H of MCM2O2Characterization graph of catalytic effect of content.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below.
In the description of the present invention, it should be noted that the terms "first" and "second" mentioned in the embodiments of the present invention are only used for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.
In the description of embodiments of the present application, the description of the term "some embodiments" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. Throughout this specification, the schematic representations of the terms used above do not necessarily refer to the same implementation or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
It should be noted that the term "in.
The embodiment of the invention provides a preparation method of a reusable nano core-shell structure mimic enzyme material, which comprises the following steps:
s1, adding an iron source and an ammonium source into a solvent, performing ultrasonic stirring to obtain a mixed solution A, reacting the mixed solution A under a first preset condition, performing magnetic separation, and washingWashing and drying to obtain the magnetic nano Fe3O4 NPs；
S2, mixing the magnetic nano-iron Fe3O4NPs, a manganese source and an ammonium source are ultrasonically stirred in deionized water to obtain a mixed solution B, the mixed solution B is reacted under a second preset condition, and the mixed solution B is washed and dried after magnetic separation to obtain the reusable nano core-shell structure mimic enzyme material Fe3O4@MnO2 MCM。
The invention realizes MnO under the conditions of high temperature and high pressure by a hydrothermal method2Controlled growth of crystalline structure, with simple MnO2MCs exhibit a needle-like structure, Fe3O4@MnO2The flower-like structure on the surface of the MCM is a three-dimensional structure, and the structure can expose more active sites and provide more contact areas for catalytic reaction, so that the catalytic performance of the material is improved; further, Fe3O4NPs have unique superparamagnetism and similar catalytic activity to natural enzymes, can still maintain higher catalytic activity under wider acid-base conditions and temperature intervals, and can regulate the catalytic activity by changing surface groups, particle structures and the like.
Specifically, in step S1, the iron source includes ferric nitrate or ferric trichloride, and the ammonium source includes ammonium persulfate (NH)4)2S2O8Ammonium oxalate (NH)4)2C2O4Tetrabutylammonium bromide C16H36BrN and methylethylenediamine C3H12N2Wherein the solvent comprises one of methanol, ethanol and ethylene glycol.
Wherein the mass ratio of the iron source to the ammonium source is 1: 0.2 to 1: 0.8, the first preset condition comprises that the reaction temperature is 200-400 ℃, and the reaction time is 10-20 h. That is, 2.0-4.0g of iron source and 0.8-1.6g of ammonium source are added into 40-80ml of solvent for ultrasonic stirring to obtain a mixed solution A, the mixed solution A is poured into a stainless steel autoclave and placed in a 200-400 ℃ muffle furnace for reaction for 10-20h, and after the reaction is finished, the mixed solution is cooled to room temperature to obtain Fe3O NPs。
Specifically, in step S2, the second stepThe two preset conditions comprise that the reaction temperature is in the range of 120 ℃ to 200 ℃ and the reaction time is in the range of 1h to 2 h. Magnetic nano-iron Fe3The mass ratio of the O NPs to the manganese source to the ammonium source is 1: 66: 92 to 1: 17: within 23. The manganese source comprises one of manganese sulfate, manganese nitrate and manganese chloride.
That is, 20-40mgFe3O4NPs, 0.68-1.36g of manganese source and 0.92-1.84g of ammonium source are added into 40-80mL of deionized water, the prepared mixed solution B is transferred into a polytetrafluoroethylene lining, the polytetrafluoroethylene lining is placed into a stainless steel autoclave, hydrothermal reaction is carried out for 1-2h at the temperature of 120-200 ℃, and the temperature is cooled to room temperature after the reaction is finished, so that the recyclable nano core-shell structure mimic enzyme material is obtained.
The preparation method is simple in preparation process, simple and easily available in raw materials, friendly to organisms and environment, and suitable for industrial large-scale production, and the prepared product has the characteristics of magnetic separation and recycling, still keeps extremely high enzyme activity in regeneration recycling, and has wide application prospect.
The other embodiment of the invention provides a reusable nano core-shell structure mimic enzyme material, which is prepared by adopting the preparation method of the reusable nano core-shell structure mimic enzyme material.
When MnO is present2MCs supported on (S) Fe3O4After the surface of the NPs, the magnetic saturation intensity of the composite particles is reduced, but the composite particles still have strong magnetic properties. Mixing Fe3O4@MnO2MCM is fully dispersed in deionized water, and the effect of quick separation can be realized. This unique property is Fe3O4@MnO2MCM can be rapidly separated, recycled and reused in a catalytic experiment, and the use cost is reduced.
On the basis of the above embodiments, the present invention provides the following specific examples of the preparation method of the reusable nano core-shell structure mimic enzyme material, and further illustrates the present invention. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. The following examples are examples of experimental procedures not specified under specific conditions, generally according to the conditions recommended by the manufacturer. Unless otherwise indicated, percentages and parts are by mass.
Example 1
The embodiment provides a preparation method of a reusable nano core-shell structure mimic enzyme material, which comprises the following steps:
1) 80mL of ethylene glycol was poured into a 250mL Erlenmeyer flask, and 4.0g of ammonium acetate and 1.6g of ferric chloride were added, and mechanical stirring was performed for 15min while sonicating to obtain a yellow emulsion. Then 2.0mL of tetramethylethylenediamine and 1.6g of tetrabutylammonium bromide were added to the flask, respectively, ultrasonically stirred for 15min, poured into a stainless steel autoclave, and placed in a 200 ℃ muffle furnace for reaction for 10 h. Cooling, performing magnetic separation on the collected product, repeating the processes of water washing and alcohol washing for 3 times, drying the obtained solid product by using a freeze dryer, and preparing the obtained Fe3O4 NPs。
2) Weighing 40mg of Fe prepared in step 1)3O4The NPs were placed in a 250mL conical flask, 80mL of deionized water was added, and 1.36g of MnSO was added thereto while mechanically stirring for 15min with sonication4And 1.84g of (NH)4)2S2O8And continuing ultrasonic stirring for 15min, transferring the obtained mixed solution into a polytetrafluoroethylene lining, putting the polytetrafluoroethylene lining into a stainless steel autoclave, and reacting for 2h at 120 ℃. After the autoclave is cooled to room temperature, carrying out magnetic separation, washing with water and ethanol for three times, and freeze-drying the washed black product in a freeze dryer to obtain Fe3O4@MnO2 MCM。
Fe as described in example 13O4 NPs、MnO2 MCM、Fe3O4@MnO2The MCM adopts a transmission electron microscope for structural characterization, and a result graph shown in figure 1 is obtained, wherein (S) Fe is shown in figures 1(a) and (b)3O4The transmission electron microscope image of NPs can find that the prepared solid-structure Fe3O4NPs have a highly uniform particle size, and the particle size is approximately 350 nm. Shown in FIGS. 1(c) and (d) are MnO2In transmission electron micrographs of MCs, it can be seen that the externally grown needles are approximately the same size, about 10 nm. FIG. 1(e) shows MnO2Grown on Fe3O4 NPsTEM image after surface, it can be seen that when MnO2MCs and Fe3O4After the NPs are bound, the size of the particles changes significantly, increasing to around 1.5 μm. In addition, as can be seen from FIG. 1(f), a large number of uniformly distributed, interlaced flower-like structures appear in Fe3O4@MnO2An MCM surface. With simple MnO2MCs exhibit a needle-like structure, Fe3O4@MnO2The flower-like structure of the MCM surface is a three-dimensional structure, and the structure can expose more active sites and provide more contact area for catalytic reaction, so that the catalytic performance of the material is improved, and Fe shown in the figure3O4The NPs spheres are all black, which indicates that the prepared particles are solid-structure nano microspheres.
Example 2
The embodiment provides a preparation method of a reusable nano core-shell structure mimic enzyme material, which comprises the following steps:
1) pouring 40mL of ethylene glycol into a 250mL conical flask, adding 2.0g of ammonium acetate and 0.8g of ferric chloride, and mechanically stirring for 20min while performing ultrasonic treatment to obtain a yellow emulsion; then respectively adding 1.0mL of tetramethylethylenediamine and 0.8g of tetrabutylammonium bromide into a bottle, ultrasonically stirring for 15min, pouring into a stainless steel high-pressure autoclave, and placing in a 200 ℃ muffle furnace for reaction for 10 h; cooling, performing magnetic separation, water washing and alcohol washing on the collected product, repeating for 3 times, drying the obtained solid product by using a freeze dryer, and preparing the obtained Fe3O4 NPs。
2) Weighing 20mg of Fe prepared in step 1)3O4The NPs were placed in a 250mL conical flask, 40mL of deionized water was added, and 0.68g of MnSO was added thereto while mechanically stirring for 15min with sonication4And 0.92g of (NH)4)2S2O8Continuing to ultrasonically stir for 15min, transferring the obtained mixed solution into a polytetrafluoroethylene lining, putting the polytetrafluoroethylene lining into a stainless steel autoclave, and reacting for 2h at the temperature of 240 ℃; cooling the autoclave to room temperature, performing magnetic separation, washing with water and ethanol for three times, and freeze-drying the washed black product in a freeze-dryerTo obtain Fe3O4@MnO2 MCM。
FIG. 2 shows Fe obtained in example 23O4XRD patterns of NPs, FIGS. 2(a) and (b) are (H) Fe, respectively3O4NPs and (S) Fe3O4XRD patterns of NPs revealed that Fe was present at 220 (30.1), 311 (35.4), 511 (57.0) and 440 (62.5) for both of them3O4The characteristic peaks of the NPs are kept highly consistent with those of the existing standard spectrogram (JCPDS No.01-1111), and meanwhile, no impurity peak is observed in the diagram, which indicates that the prepared Fe with two structures3O4NPs have a very high degree of crystallinity, also indicating that all are single spinel-structured Fe3O4 NPs。
FIG. 3 shows Fe obtained in example 23O4@MnO2XRD pattern of MCM, shown in FIG. 3, from (S) Fe3O4The XRD curves of the NPs show that the peaks appearing at 36.87 degrees, 42.34 degrees and 55.82 degrees correspond to Fe respectively3O4@MnO2Diffraction peaks (222), (400), and (511) in MCM. From MnO to MnO2The MCs can observe that diffraction peaks appear at 36.87 degrees, 55.01 degrees and 66.56 degrees, which correspond to Fe respectively3O4@MnO2Three diffraction peaks (100), (102) and (110) in the MCM. When the two are combined with each other, Fe3O4The diffraction peaks of NPs hardly changed significantly, and Fe3O4@MnO2The diffraction peak of MCM is Fe3O4NPs and MnO2Peak position superposition of MCs, which shows that in the second hydrothermal reaction step, Fe with spherical structure3O4NPs are not decomposed or converted into Fe with other structures3O4And (4) NPs. Characterization of the XRD further confirmed that the resulting material was made of Fe3O4NPs and MnO2MCs.
Example 4
The embodiment provides a preparation method of a reusable nano core-shell structure mimic enzyme material, which comprises the following steps:
1) pouring 40mL of ethanolInto a 250mL Erlenmeyer flask, 2.0g (NH) was added4)2S2O8And 0.8g of ferric nitrate, mechanically stirred for 20min while being ultrasonically agitated to obtain a yellow emulsion; then respectively adding 1.0mL of tetramethylethylenediamine and 0.8g of tetrabutylammonium bromide into a bottle, ultrasonically stirring for 20min, pouring into a stainless steel high-pressure autoclave, and placing in a muffle furnace at 200 ℃ for reacting for 10 h; cooling, performing magnetic separation, water washing and alcohol washing on the collected product, repeating for 3 times, drying the obtained solid product by using a freeze dryer, and preparing the obtained Fe3O4 NPs。
2) Weighing 20mg of Fe prepared in step 1)3O4The NPs were placed in a 250mL conical flask, 40mL deionized water was added, and 0.68g Mn (NO) was added thereto by mechanical stirring for 15min while sonicating3)2And 0.92g of (NH)4)2C2O4Continuing to ultrasonically stir for 15min, transferring the obtained mixed solution into a polytetrafluoroethylene lining, putting the polytetrafluoroethylene lining into a stainless steel autoclave, and reacting for 4h at the temperature of 240 ℃; after the autoclave is cooled to room temperature, carrying out magnetic separation, washing with water and ethanol for three times respectively, and freeze-drying the product in a freeze dryer to obtain Fe3O4@MnO2 MCM。
FIGS. 4-7 are Fe prepared in example 43O4@MnO2MCM for different pH values, temperatures and H2O2Characterization graph of catalytic response of content.
As can be seen from fig. 4, the catalyst activity was highest when the pH of the solution was stabilized around 4.5. Therefore, in the subsequent catalytic reaction, the pH of 4.5 was selected to perform the catalytic reaction.
In order to study the influence of the reaction temperature on the catalytic activity, the catalytic activity of the catalyst was studied in a reaction environment at a temperature of 10 ℃ to 50 ℃, and the results are shown in fig. 5, wherein it can be seen that the catalytic activity of all three products reaches the maximum at about 35 ℃, so we selected 35 ℃ as the optimal reaction temperature in the next catalytic experiment.
FIG. 6 shows Fe3O4@MnO2MCM is repeatedThe comparison of the activity in the using process shows that the catalyst still has high activity even after being repeatedly used for 7 times, and the repeatability enables the prepared material to be more beneficial to practical application.
In the catalytic reaction, when the amount of the catalyst is constant, the number of active sites on the surface is limited, and based on this, we examined H2O2The effect of the concentration in the range of 0.05 to 0.4. mu. mmol/L on the catalytic activity is shown in FIG. 7. From the figure we can see that when H2O2At a lower concentration of (3), Fe3O4@MnO2The active sites on the MCM surface are not completely covered by H2O2Occupancy, and only a small amount of hydroxyl radicals are generated in the solution, resulting in a low concentration of H2O2At this level, the catalytic activity is also lowest. When H is present2O2Sufficient amount of H when the concentration is gradually increased to 20mmol/L2O2With Fe3O4@MnO2Active sites on the surface of MCM react with each other to generate a large number of hydroxyl radicals to participate in the reaction, so that the activity of the catalyst reaches the highest, and based on the highest activity, 20mmol/L is selected as H in the subsequent catalytic reaction2O2The concentration of (c). When H is present2O2When the concentration of (A) is continuously increased, the absorbance of the reaction system is reduced, which is similar to the catalytic reaction phenomenon of the HRP.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.