阅读说明：本技术 水溶性卟啉稳定的金属纳米颗粒催化剂的制备方法及应用 (Preparation method and application of water-soluble porphyrin-stabilized metal nanoparticle catalyst ) 是由 晏佳莹 周宇航 刘湘 张诺诺 刘根江 于 2021-07-21 设计创作，主要内容包括：本发明提供了一种新型水溶性卟啉稳定的金属纳米颗粒催化剂的制备方法及其在催化氨硼烷水解产氢中的应用,以金属盐为原料,水溶性卟啉(TPP-PEG-(350))为稳定剂,在去离子水中充分搅拌混合二者,随后在还原剂硼氢化钠的作用下,金属离子被还原成原子。金属原子与水溶性卟啉(TPP-PEG-(350))上的PEG链上的氧和大环上的氮原子结合,使金属纳米颗粒得以稳定在卟啉分子上,催化氨硼烷水解产氢。通过比较不同金属催化剂、不同物质的量催化剂、不同稳定剂的含量、不同氨硼烷浓度等条件下氨硼烷的产氢效率,发现该催化剂具有良好的催化氨硼烷产氢性能,还进行了循环实验表明该催化剂具有良好的稳定性和循环性。(The invention provides a preparation method of a novel water-soluble porphyrin-stabilized metal nanoparticle catalyst and application of the novel water-soluble porphyrin-stabilized metal nanoparticle catalyst in catalyzing ammonia borane hydrolysis to produce hydrogen, wherein metal salt is used as a raw material, and water-soluble porphyrin (TPP-PEG) 350 ) As a stabilizer, the two are mixed in deionized water with sufficient stirring, and then metal ions are reduced to atoms under the action of a reducing agent, sodium borohydride. Metal atom and water-soluble porphyrin (TPP-PEG) 350 ) The oxygen on the PEG chain is combined with the nitrogen atom on the large ring, so that the metal nano-particles are stabilized on porphyrin molecules to catalyzeThe ammonia borane is hydrolyzed to produce hydrogen. By comparing the hydrogen production efficiency of ammonia borane under the conditions of different metal catalysts, different amount of catalysts, different stabilizer contents, different ammonia borane concentrations and the like, the catalyst is found to have good hydrogen production performance for catalyzing ammonia borane, and a circulation experiment is carried out to show that the catalyst has good stability and circulation performance.)

1. The water-soluble porphyrin is characterized in that the water-soluble porphyrin is PEG-350 modified porphyrin, and the structural formula is as follows:

wherein n represents the number in the unit and has a value of 7-9.

2. The method of preparing a water-soluble porphyrin according to claim 1, characterized in that it comprises the following steps:

(1) dissolving polyethylene glycol monomethyl ether 350 and p-toluenesulfonamide in dichloroethane, adding triethylamine, and reacting overnight to obtain a PEG compound;

(2) dissolving the compound in the step (1) and p-hydroxybenzaldehyde in acetonitrile, and adding potassium carbonate to react for 2h to obtain a PEG modified aldehyde compound;

(3) dissolving the PEG-modified aldehyde compound obtained in the step (2) and pyrrole in redistilled dichloromethane, adding boron trifluoride diethyl ether, triethyl orthoacetate and tetrachlorobenzoquinone to react for 20-25h in a dark place under the nitrogen atmosphere, and then carrying out spin-drying separation on the mixed solution to obtain water-soluble porphyrin TPP-PTG₃₅₀The reaction formula is as follows:

n represents the number in the unit and has a value of 7-9.

3. The method for preparing water-soluble porphyrin according to claim 2, wherein the molar ratio of polyethylene glycol monomethyl ether 350 to p-toluene sulfonamide in step (1) is 1: 1.

4. The method for preparing water-soluble porphyrin according to claim 2, wherein the molar ratio of the PEG compound to the p-hydroxybenzaldehyde in the step (2) is 1.1: 1.

5. The method for preparing water-soluble porphyrin according to claim 2, wherein the molar ratio of the PEG-modified aldehyde compound, the pyrrole, the boron trifluoride diethyl etherate, the triethyl orthoacetate and the tetrachlorobenzoquinone in step (3) is 10:10:1:1: 7.5.

6. The application of the water-soluble porphyrin prepared by the method of claim 1 in preparing a metal nanoparticle catalyst with stable water-soluble porphyrin is characterized in that the preparation method comprises the following steps:

(1) dissolving water-soluble porphyrin in deionized water, stirring the solution under an ice bath condition until the solution is uniform, adding a metal solution into the aqueous solution of the porphyrin, and stirring the solution and the aqueous solution of the porphyrin under the ice bath condition until the solution and the porphyrin are uniformly mixed;

(2) and (3) slowly adding the sodium borohydride solution into the mixed solution obtained in the step (2), reacting under an ice bath condition, and obtaining the metal nanoparticle solution with stable water-soluble porphyrin after the reaction is finished.

7. Use according to claim 6, characterized in that the ratio of the quantities of the substances water-soluble porphyrin, metal solution and sodium borohydride is between 1 and 2: 1-4: 10-40.

8. The use according to claim 6, wherein the metal salt solution comprises a halide salt solution or a nitrate salt solution of rhodium, ruthenium or palladium.

9. The use of claim 6, wherein after the dropwise addition of the metal solution, stirring is carried out for 10-30min, and then the sodium borohydride solution is added dropwise, wherein the dropwise addition speed of the sodium borohydride solution is 2-10 min/mL.

10. The application of the water-soluble porphyrin-stabilized metal nanoparticle catalyst prepared according to any one of claims 6-9 in catalyzing ammonia borane hydrolysis to produce hydrogen.

Technical Field

The invention belongs to the field of functional materials, and relates to a preparation method and application of a novel water-soluble porphyrin-stabilized nanoparticle catalyst.

Background

Hydrogen is considered to be an environmentally friendly fuel due to its harmless by-product and regenerability, and is expected to be a clean energy source to solve the shortage of fossil materials, and ammonia borane and formic acid have been widely used for research. Ammonia borane is considered one of the most promising chemical hydride candidates due to its very high capacity and excellent stability under ambient conditions.

To date, there have been many reports on the preparation and optimization of metal nanoparticle catalysts. It has been found that the catalytic activity of metal nanoparticle catalysts depends to a large extent on the metal nanoparticles and the support and the interaction between them. The high surface energy of the ultra-small nanoparticles may agglomerate due to thermodynamic instability, thereby degrading their catalytic performance. Therefore, it is very important to use an appropriate support to stabilize the metal nanoparticle catalyst. Such as activated carbon, graphene, MOF and MOF derived nanomaterials. Water has been actively studied as an environmental condition for homogeneous catalysis because it provides a green catalytic condition. For example, water-soluble polymers have been synthesized as stabilizers to anchor metal nanoparticles for applications in the field of catalysis. Tetrahydroxyphenyl porphyrins (THPP) have been used to anchor metal nanoparticles, suggesting that O and N atoms can be bound to the metal nanoparticles. The PEG-350 modified porphyrin has good water solubility, and due to the existence of O atoms and macrocycles in the porphyrin, the porphyrin has good stabilizing effect on metal nanoparticles, so that the catalytic performance is improved.

Disclosure of Invention

Based on the background, the invention aims to provide a preparation method and application of novel water-soluble porphyrin-stabilized metal nanoparticles.

The water-soluble porphyrin (hereinafter referred to as TPP-PEG) of the invention₃₅₀) Stabilized metal nanoparticle catalyst based on water-soluble porphyrin (TPP-PEG)₃₅₀) Uniformly mixing porphyrin aqueous solution dissolved in deionized water and metal salt solution dissolved in deionized water as raw materials, dropwise adding sodium borohydride solution into the mixed solution, reducing metal particles in the mixed solution into atoms by utilizing the reducibility of sodium borohydride, and mixing the metal atoms and water-soluble porphyrin (TPP-PEG)₃₅₀) The oxygen on the PEG chain binds to the nitrogen atom on the macrocycle, thereby stabilizing the metal nanoparticles on the porphyrin molecule. Due to water-soluble porphyrin (TPP-PEG)₃₅₀) Is uniformly dispersed in the solution, thereby obtaining uniformly dispersed metal nanoparticles. Tests show that the metal nanoparticle catalyst has good performance of catalyzing ammonia borane hydrolysis to produce hydrogen.

The water-soluble porphyrin PEG-350 modified porphyrin has the following structural formula:

wherein n represents the number in the unit and has a value of 7-9.

The preparation method of the water-soluble porphyrin comprises the following steps:

(1) dissolving polyethylene glycol monomethyl ether 350 and p-toluenesulfonamide in dichloroethane, adding triethylamine, and reacting overnight to obtain a PEG compound;

(2) dissolving the compound in the step (1) and p-hydroxybenzaldehyde in acetonitrile, and adding potassium carbonate to react for 2h to obtain a PEG modified aldehyde compound;

(3) dissolving the PEG-modified aldehyde compound obtained in the step (2) and pyrrole in redistilled dichloromethane, adding boron trifluoride diethyl ether, triethyl orthoacetate and tetrachlorobenzoquinone to react for 20-25h in a dark place under the nitrogen atmosphere, and then carrying out spin-drying separation on the mixed solution to obtain water-soluble porphyrin TPP-PTG₃₅₀The reaction formula is as follows:

n represents the number in the unit and has a value of 7-9.

In the step (1), the molar ratio of the polyethylene glycol monomethyl ether 350 to the p-toluenesulfonamide is 1: 1.

The molar ratio of the PEG compound to the p-hydroxybenzaldehyde in the step (2) is 1.1: 1.

The molar ratio of the PEG-modified aldehyde compound, the pyrrole solvent, the boron trifluoride diethyl etherate, the triethyl orthoacetate and the tetrachlorobenzoquinone in the step (3) is 10:10:1:1: 7.5.

The preparation method of the novel water-soluble porphyrin-stabilized metal nanoparticle catalyst comprises the following preparation steps:

(1) mixing water soluble porphyrin (TPP-PEG)₃₅₀) Dissolving in deionized water, stirring under ice bath condition to uniformity, slowly adding metal solution into the porphyrin aqueous solution, and stirring under ice bath condition to uniformity;

(2) slowly adding the sodium borohydride solution into the mixed solution obtained in the step (1), reacting for 2 hours under the ice-bath condition, and obtaining the water-soluble porphyrin (TPP-PEG) after the reaction is finished₃₅₀) A stable metal nanoparticle solution.

The mass ratio of the water-soluble porphyrin, the metal solution and the sodium borohydride is 1:1-4: 10-40.

Further preferred is a ratio of the amounts of the water-soluble porphyrin, the metal solution and the sodium borohydride in the range of 1:1: 10.

The metal salt solution comprises halide salt solution or nitrate salt solution of rhodium, ruthenium or palladium.

The metal salt solution comprises one of rhodium nitrate, ruthenium trichloride or potassium tetrachloropalladate aqueous solution.

And after the dripping of the metal solution is finished, stirring for 10-30min, and then dripping a sodium borohydride solution, wherein the dripping speed of the sodium borohydride solution is 2-10 min/mL.

The water-soluble porphyrin (TPP-PEG)₃₅₀) The application of the stable metal nanoparticle catalyst in catalyzing ammonia borane hydrolysis to produce hydrogen.

The water-soluble porphyrin synthesized by the invention is PEG-350 modified novel porphyrin, the PEG-350 modified novel porphyrin not only has good water solubility, but also has good stability to NPs due to the existence of O atoms and macrocycles in the porphyrin, thereby improving the hydrogen production efficiency of ammonia borane catalysis.

Drawings

FIG. 1 is TPP-PEG synthesized in example 1₃₅₀Hydrogen spectrum of (2).

FIG. 2 is TPP-PEG synthesized in example 1₃₅₀Mass spectrum of (2).

Fig. 3 is a transmission electron micrograph of the rhodium nanoparticle catalyst prepared in example 2.

Fig. 4 is a statistical plot of the particle size distribution of the rhodium nanoparticle catalyst prepared in example 2.

Fig. 5 is an X-ray photon energy spectrum of the rhodium nanoparticle catalyst prepared in example 2.

FIG. 6 is a graph of the reaction time of different metal nanoparticle catalysts prepared in example 2 to catalyze the hydrolysis of ammonia borane to produce hydrogen versus the volume of hydrogen produced.

FIG. 7 is a graph of the hydrogen production efficiency of rhodium nanoparticle catalysts catalyzed ammonia borane hydrolysis prepared in example 4 at different porphyrin/rhodium molar ratios.

Fig. 8 is a graph of ammonia borane hydrolysis hydrogen production efficiency at different amounts of species for the rhodium nanoparticle catalyst prepared in example 2.

Fig. 9 is a graph of ammonia borane hydrolysis hydrogen production efficiency at different ammonia borane concentrations for rhodium nanoparticle catalysts prepared in example 2.

Detailed Description

The reagents and purchase places used in the invention are as follows:

example 1

Firstly, polyethylene glycol monomethyl ether 350(17.5g, 50mmol, n in polyethylene glycol monomethyl ether represents the number in the unit, and the number is 8-9) and p-benzenesulfonamide chloride (10g, 50)mmol) was dissolved in 150mL of dichloromethane and 10mL of triethylamine was added to react overnight to give compound 1, and then the above compound 1(16.7g, 33mmol) and p-hydroxybenzaldehyde (3.66g, 30mmol) were reacted for two hours to give compound 2. Finally, compound 2(2.976g, 6mmol) and pyrrole (414uL, 6mmol) were dissolved in 600mL of dichloromethane and stirred for 15min, to which boron trifluoride diethyl ether (75 uL, 0.6mmol), triethyl orthoacetate (1.09mL, 0.6mmol), tetrachlorobenzoquinone (1.11g, 4.5mmol) were added and reacted under nitrogen atmosphere protected from light for 20 h. The product is subjected to rotary evaporation, separation and purification to obtain the final product TPP-PEG₃₅₀The specific structural formula is as follows:

n represents the number in the unit and has a value of 8-9.

FIGS. 1 and 2 are TPP-PEG synthesized by the present invention₃₅₀The obtained TPP-PEG can be determined from the hydrogen spectrum and the mass spectrum of the TPP-PEG₃₅₀The structure of the product is consistent with that of the target product.

Example 2

The preparation scheme adopted by the invention comprises the following steps

The method comprises the following steps: will be 5X 10^-3mmolTPP-PEG₃₅₀Prepared in example 1 was dissolved in deionized water (8mL) and placed in a round bottom flask and stirred.

Step two: will be 5X 10^-3And (3) dissolving the mmol rhodium nitrate solution in deionized water (1mL), dropwise adding the solution into the aqueous solution obtained in the step one, and stirring the solution in an ice bath environment until the solution is uniform.

Step three: will be 5X 10^-2And (3) mmol sodium borohydride is dissolved in 1mL deionized water, and the solution is dripped into the ice bath mixed solution obtained in the second step at the dripping speed of 3min/mL, and the reaction is carried out for 2 hours. Obtaining the rhodium nanoparticle (RhNP/TPP-PEG) with stable water-soluble porphyrin₃₅₀) A catalyst.

Respectively replacing rhodium nitrate solution with ruthenium trichloride and potassium tetrachloropalladate, and repeating the above operations to obtain water-soluble porphyrin-stabilized platinum nanoparticles (RuNP/TPP-PEG)₃₅₀) And palladium nanoparticles (PdNP/TPP-PEG)₃₅₀) A catalyst.

Example 3

Rhodium metal nanoparticles (RhNP/TPP-PEG) prepared according to example 2₃₅₀) Catalyst in catalyzing ammonia (NH)₃BH₃) The method comprises the following specific steps of hydrolyzing borane to produce hydrogen:

NH₃BH₃+4H₂O→NH₄B(OH)₄+3H₂(g)

the method comprises the following steps: dissolving a proper amount of ammonia borane in deionized water to prepare 0.5mmol/L solution;

step two: will be 4X 10^-3mmol RhNP/TPP-PEG₃₅₀Dissolving in deionized water (4mL), then placing the solution in a reactor, sealing the reactor, and stirring;

step three: taking 1mL of ammonia borane solution in the step one by using an injector, quickly injecting the ammonia borane solution into the reactor in the step two, and starting timing;

step four: the volume of hydrogen at the corresponding time was recorded.

The RhNP/TPP-PEG in the second step is reacted₃₅₀Respectively changed into RuNP/TPP-PEG₃₅₀And PdNP/TPP-PEG₃₅₀And obtaining a relational graph of the reaction time of the ruthenium nanoparticle catalyst and the palladium nanoparticle catalyst for catalyzing ammonia borane hydrolysis hydrogen production and the volume of the generated hydrogen.

FIG. 3 is a projection electron microscope image of the novel catalyst prepared by the invention, and it can be seen from FIG. 1 that rhodium nanoparticles are uniformly dispersed and have a particle size much smaller than 50nm, which indicates that the prepared nanoparticles have a smaller particle size.

FIG. 4 is a statistical graph of the particle size distribution of the novel catalyst prepared by the present invention, and it can be seen from FIG. 2 that the rhodium nanoparticles have a particle size distribution mainly between 5 and 7nm and an average particle size of 6.27 nm.

FIG. 5 is the X-ray photon energy spectrum of the novel catalyst prepared by the present invention, and from FIG. 5, the water-soluble porphyrin-stabilized rhodium nanoparticles (RhNP/TPP-PEG) can be seen₃₅₀) Chemical state of surface Rh, characteristic peaks at 306.69eV and 311.52eV correspond to zero-valent rhodium atoms, indicating RhNP/TPP-PEG₃₅₀Rh of (a) is efficiently reduced.

FIG. 6 shows different metals prepared according to the present inventionThe reaction time of the nano-particle catalyst for catalyzing ammonia borane hydrolysis to produce hydrogen and the volume of the generated hydrogen are plotted. Wherein complete hydrolysis of a 0.5mmol/L ammonia borane solution may yield 1.5mmol of H₂As can be seen from the figure, RhNP/TPP-PEG₃₅₀And RuNP/TPP-PEG₃₅₀The catalytic reaction can be finished within 5min, and the PdNP/TPP-PEG₃₅₀Does not end within 30min, wherein RhNP/TPP-PEG₃₅₀The hydrogen production effect is best.

Example 4

The preparation scheme adopted by the invention comprises the following steps

The method comprises the following steps: will be 5X 10^-2mmolTPP-PEG₃₅₀Dissolved in deionized water (8mL) and placed in a round bottom flask to stir.

Step two: will be 5X 10^-3And (3) dissolving the mmol rhodium nitrate solution in deionized water (1mL), dropwise adding the solution into the aqueous solution obtained in the step one, and stirring the solution in an ice bath environment until the solution is uniform.

Step three: will be 5X 10^-2mmol sodium borohydride is dissolved in 1mL deionized water, and the solution is dripped into the ice bath mixed solution obtained in the second step at the dripping speed of 3min/mL, and the reaction is carried out for 2 hours, thus obtaining the rhodium nanoparticle (RhNP/TPP-PEG) with stable water-soluble porphyrin₃₅₀) A catalyst.

Wherein TPP-PEG in the step one₃₅₀The molar amounts of (A) and (B) are respectively changed to 1X 10^-2mmol、2.5×10^-3mmol、1.25×10^-3mmol, repeating the above operations to obtain rhodium nanoparticle catalysts with porphyrin/rhodium ion molar ratios of 2:1, 1:2 and 1:4, labeled as RhNPs-1, RhNPs-2, RhNPs-3 and RhNPs-4.

Example 5

Rhodium nanoparticles (RhNP/TPP-PEG) prepared according to example 4₃₅₀) Catalyst in catalyzing ammonia (NH)₃BH₃) The method comprises the following specific steps of hydrolyzing borane to produce hydrogen:

NH₃BH₃+4H₂O→NH₄B(OH)₄+3H₂(g)

the method comprises the following steps: dissolving a proper amount of ammonia borane in deionized water to prepare 0.5mmol/L solution;

step two: 2 x 10 to^-3mmol RhNP/TPP-PEG₃₅₀Dissolving in deionized water (4mL), then placing the solution in a reactor, sealing the reactor, and stirring;

step three: taking 1mL of ammonia borane solution in the step one by using an injector, quickly injecting the ammonia borane solution into the reactor in the step two, and starting timing;

step four: the volume of hydrogen at the corresponding time was recorded.

FIG. 7 is a graph of the hydrogen production efficiency of rhodium nanoparticle catalysts prepared by the invention with different porphyrin/rhodium molar ratios in catalyzing ammonia borane hydrolysis, and it can be seen from the graph that the nano catalyst with the porphyrin/rhodium ion molar ratio of 1:1 shows the best hydrogen production performance.

Example 6

Different Metal nanoparticles (RhNP/TPP-PEG) prepared according to example 2₃₅₀) Catalyst in catalyzing ammonia (NH)₃BH₃) The method comprises the following specific steps of hydrolyzing borane to produce hydrogen:

NH₃BH₃+4H₂O→NH₄B(OH)₄+3H₂(g)

the method comprises the following steps: dissolving a proper amount of ammonia borane in deionized water to prepare 0.5mmol/L solution;

step two: will be 4X 10^-3mmol RhNP/TPP-PEG₃₅₀Dissolving in deionized water (4mL), then placing the solution in a reactor, sealing the reactor, and stirring;

step three: taking 1mL of ammonia borane solution in the step one by using an injector, quickly injecting the ammonia borane solution into the reactor in the step two, and starting timing;

step four: the volume of hydrogen at the corresponding time was recorded.

Wherein, the RhNP/TPP-PEG in the second step₃₅₀The amounts of substances are respectively changed to 1X 10^-3mmol、2×10^{- 3}mmol、3×10^-3mmol, the ammonia borane hydrolysis hydrogen production effect of the rhodium nanoparticle catalyst under different substance amounts can be obtained

FIG. 8 is ammonia borane at different amounts of species for the rhodium nanoparticle catalyst prepared in example 2And (5) a hydrogen hydrolysis efficiency diagram. From the figure, it can be seen that 4 × 10^-3mmol RhNP/TPP-PEG₃₅₀The hydrogen production efficiency is best.

Example 7

Different Metal nanoparticles (RhNP/TPP-PEG) prepared according to example 2₃₅₀) Catalyst in catalyzing ammonia (NH)₃BH₃) The method comprises the following specific steps of hydrolyzing borane to produce hydrogen:

NH₃BH₃+4H₂O→NH₄B(OH)₄+3H₂(g)

the method comprises the following steps: dissolving a proper amount of ammonia borane in deionized water to prepare 0.5mmol/L solution;

step two: will be 4X 10^-3mmol RhNP/TPP-PEG₃₅₀Dissolving in deionized water (4mL), then placing the solution in a reactor, sealing the reactor, and stirring;

step three: taking 1mL of ammonia borane solution in the step one by using an injector, quickly injecting the ammonia borane solution into the reactor in the step two, and starting timing;

step four: the volume of hydrogen at the corresponding time was recorded.

Wherein, the concentration of ammonia borane solution in the step one is respectively changed into 0.25mmol/L, 0.75mmol/L and 1mmol/L, and the operations are repeated to obtain the prepared rhodium nanoparticles (RhNP/TPP-PEG)₃₅₀) The catalyst has the effect of producing hydrogen by hydrolyzing ammonia borane under different ammonia borane concentrations.

Fig. 9 is a graph of ammonia borane hydrolysis hydrogen production efficiency at different ammonia borane concentrations for rhodium nanoparticle catalysts prepared in example 2. It can be seen from the graph that the rate of hydrogen generation increases with increasing ammonia borane concentration.