Alkynyl modified metal oxide carrier reinforced metal nanoparticle loaded catalyst and preparation method and application thereof
By modifying alkynyl functional groups on the surface of the metal oxide support, the problem of easy agglomeration of metal nanoparticles in high temperature or chemical environments is solved, and the stability and activity of the catalyst are significantly improved.
Patent Information
- Application Number
- CN202411656556.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-02-25
AI Technical Summary
In the prior art, when preparing supported metal nanocatalysts, metal nanoparticles are prone to agglomeration, resulting in a degradation of catalyst performance and poor stability under high temperature or chemical environments.
By modifying alkynyl functional groups on the surface of the metal oxide support, the coordination correlation between alkynyl and metal ions is used to anchor the metal, and when the metal precursor is reduced to metal nanoion, alkynyl functional groups act as a stabilizer to control the growth of nanoparticles. .
The stability and activity of metal catalysts are significantly improved, the agglomeration of nanoparticles is inhibited, and the dispersion and reactivity of the catalyst are enhanced.
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Figure CN119500264A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of catalysts, and in particular to a catalyst with an alkynyl-modified metal oxide carrier to enhance metal nanoparticle loading, and a preparation method and application thereof. Background Art
[0002] With the rapid development of modern industrialization, the demand for metal nanoparticle (NPs) catalysts in the energy and chemical industry is growing. The structural characteristics of nanoparticles, such as morphology, particle size and size distribution, directly affect their catalytic performance. However, under high temperature or chemical environment, nanoparticles are prone to sintering, resulting in particle agglomeration, size increase, reduction in specific surface area and loss of active sites, which leads to a decrease in catalyst performance or even deactivation. For supported metal nanocatalysts, the introduction of carriers can alleviate the above problems to a certain extent. Therefore, effectively inhibiting the agglomeration of nanoparticles and improving the stability of supported catalysts have become one of the focuses of current research.
[0003] At present, the impregnation method is one of the main methods for preparing supported metal nanocatalysts. This method is easy to operate, but it often faces difficulties such as "poor dispersion of metal nanoparticles after reduction, easy agglomeration, large particle size and wide distribution" during the preparation process. Technical means to optimize the loading of metal nanoparticles by modifying the surface of the carrier have become a key research direction for improving catalyst performance and have important application prospects. Oxide carriers such as silica, titanium dioxide, and cerium oxide are widely used for loading metal nanoparticles. At present, they are mainly modified with functional groups such as carboxyl or amino groups on their surfaces to enhance the bonding between metal precursors and carriers and promote the uniform distribution and stable loading of nanoparticles. There are no reports on modifying alkynyl functional groups on metal oxide carriers to strengthen metal nanoparticles. Summary of the invention
[0004] The purpose of the present invention is to overcome the defects of the prior art and provide a catalyst with an alkynyl-modified metal oxide carrier to enhance the loading of metal nanoparticles and a preparation method and application thereof.
[0005] The present invention provides the following technical solutions:
[0006] The present invention provides a method for preparing a catalyst having an alkynyl-modified metal oxide carrier and enhanced metal nanoparticle loading, comprising the following steps:
[0007] S1. Preparation of alkynyl functionalized polyvinyl alcohol: dissolving polyvinyl alcohol in a solvent, adding N,N'-carbonyl diimidazole, stirring and reacting for 3 hours, and then adding but-3-yn-1-amine and stirring and reacting for 10 hours to obtain alkynyl functionalized polyvinyl alcohol;
[0008] S2. Amino-modification of the metal oxide carrier: dispersing the metal oxide carrier in a solvent, adding an aminosilane coupling agent, stirring the reaction for 12 to 24 hours, centrifuging, washing, and drying the solid product to obtain an amino-modified metal oxide carrier;
[0009] S3, dispersing the amino-modified metal oxide carrier into a solvent, adding alkynyl-functionalized polyvinyl alcohol, stirring the reaction for 12 to 24 hours, centrifuging, washing, and drying the solid product to obtain the alkynyl-modified metal oxide carrier;
[0010] S4, dispersing the alkynyl-modified metal oxide carrier in a solvent, adding a metal salt precursor and stirring for 6 to 12 hours, adding a reducing agent, continuing to stir for 2 to 6 hours, centrifuging, washing, and drying the solid product to obtain the catalyst.
[0011] The present invention modifies the surface of metal oxide with alkynyl functional groups, anchors the metal by utilizing the coordination-related effect between alkynyl groups and metal ions, and controls the growth of nanoparticles as a stabilizer when the metal precursor is reduced to metal nano-ions, thereby greatly improving the stability of the metal catalyst.
[0012] The present invention performs alkynyl functional modification on the surface of a metal oxide carrier. The alkynyl functional group can interact with the metal in the form of π electron and σ electron donors. The presence of the alkynyl group can stabilize the metal ions. In the subsequent reduction process, the terminal alkynyl group can also act as a stabilizer to control the growth of nanoparticles, enhance the interaction between the nanoparticles and the carrier, effectively inhibit the migration and agglomeration of the particles, and thus improve the stability and activity of the catalyst.
[0013] Furthermore, in step S1, the molar amount of polyvinyl alcohol is calculated based on monomer molecules, the molar ratio of polyvinyl alcohol to N,N'-carbonyldiimidazole is 1:1 to 1:0.5, and the molar ratio of N,N'-carbonyldiimidazole to but-3-yn-1-amine is 1:0.8 to 1:0.5.
[0014] Furthermore, in step S1, the solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.
[0015] Furthermore, in step S2, the metal oxide carrier is one of silicon dioxide, titanium dioxide, aluminum oxide, cerium oxide, zirconium oxide, and zinc oxide; the solvent is one of methanol, ethanol, dimethyl sulfoxide, dioxane, N,N-dimethylformamide, and N-methylpyrrolidone; and the aminosilane coupling agent is one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane.
[0016] Furthermore, in step S3, the molar mass ratio of the alkynyl functionalized polyvinyl alcohol to the amino-modified metal oxide is 5 mmol / g to 15 mmol / g, and the amount of the alkynyl functionalized polyvinyl alcohol is calculated based on the molar amount of the polyvinyl alcohol monomer in step S1.
[0017] Furthermore, in step S3, the solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone, and is consistent with the solvent used in step S1.
[0018] Furthermore, in step S4, the molar mass ratio of the metal salt precursor to the alkynyl-modified metal oxide is 0.2 mmol / g to 1.0 mmol / g.
[0019] Furthermore, in step S4, the solvent is one of water and N,N-dimethylformamide; the metal salt precursor is RuCl 3 、Na 2 PdCl 4 、PdNO 3 , PdCl 2 , H 2 PtCl 6 6H 2 O、Co(NO 3 ) 2 6H 2 O、CoCl 2 The reducing agent is NaBH 4 NH 3 BH 3 , one of the citric acids.
[0020] The present invention also provides a catalyst loaded with metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier prepared by the above preparation method.
[0021] The present invention also provides the use of the alkynyl-modified metal oxide carrier-enhanced metal nanoparticle-loaded catalyst in hydrogen production by hydrolysis of ammonia borane. The prepared catalyst has good reaction activity.
[0022] The present invention has the following beneficial effects:
[0023] 1. The present invention modifies the surface of metal oxide with alkynyl functional groups, anchors the metal by utilizing the coordination-related effect between alkynyl groups and metal ions, and controls the growth of nanoparticles as a stabilizer when the metal precursor is reduced to metal nano-ions, thereby greatly improving the stability of the metal catalyst;
[0024] 2. The present invention modifies the alkynyl functional group on the metal oxide carrier through the carbamate reaction, which is applicable to a variety of metal oxides and has wide universality;
[0025] 3. The catalyst prepared by the present invention can be applied to the hydrolysis of ammonia borane to produce hydrogen and has good reaction activity. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0027] Figure 1 RuNPs / APVA-SiO prepared in Example 1 2 TEM images of
[0028] Figure 2 PdNPs / APVA-SiO prepared in Example 2 2 TEM images of
[0029] Figure 3 PtNPs / APVA-SiO prepared in Example 3 2 TEM images of
[0030] Figure 4 A schematic diagram of the synthesis of the catalyst prepared in the embodiment of the present invention;
[0031] Figure 5 The evaluation results of the activity of the catalysts prepared in Examples 1 to 4 in catalyzing the hydrolysis of ammonia borane to produce hydrogen;
[0032] Figure 6 RuNPs / APVA-SiO prepared in Example 1 2 Evaluation results of the catalytic cycle stability of ammonia borane hydrolysis to produce hydrogen;
[0033] Figure 7 The evaluation results of the activity of the catalysts prepared in Examples 1, 5, 6 and 7 in catalyzing the hydrolysis of ammonia borane to produce hydrogen;
[0034] Figure 8 The results of comparative evaluation of the catalytic activity of the catalysts prepared in Examples 1, 5, 6, and 7 and the corresponding Ru-based catalysts obtained by directly modifying the oxide support without alkynyl functionalization in the reaction of hydrolysis of ammonia borane to produce hydrogen are shown. DETAILED DESCRIPTION
[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0036] The present invention provides a method for preparing a catalyst having an alkynyl-modified metal oxide carrier and enhanced metal nanoparticle loading, comprising the following steps:
[0037] S1. Preparation of alkynyl functionalized polyvinyl alcohol: dissolving polyvinyl alcohol in a solvent, adding N,N'-carbonyl diimidazole, stirring and reacting for 3 hours, and then adding but-3-yn-1-amine and stirring and reacting for 10 hours to obtain alkynyl functionalized polyvinyl alcohol;
[0038] S2. Amino-modification of the metal oxide carrier: dispersing the metal oxide carrier in a solvent, adding an aminosilane coupling agent, stirring the reaction for 12 to 24 hours, centrifuging, washing, and drying the solid product to obtain an amino-modified metal oxide carrier;
[0039] S3, dispersing the amino-modified metal oxide carrier into a solvent, adding alkynyl-functionalized polyvinyl alcohol, stirring the reaction for 12 to 24 hours, centrifuging, washing, and drying the solid product to obtain the alkynyl-modified metal oxide carrier;
[0040] S4, dispersing the alkynyl-modified metal oxide carrier in a solvent, adding a metal salt precursor and stirring for 6 to 12 hours, adding a reducing agent, continuing to stir for 2 to 6 hours, centrifuging, washing, and drying the solid product to obtain the catalyst.
[0041] Specifically, in step S1, the molar amount of polyvinyl alcohol is calculated based on monomer molecules, the molar ratio of polyvinyl alcohol to N,N'-carbonyl diimidazole is 1:1 to 1:0.5, and the molar ratio of N,N'-carbonyl diimidazole to but-3-yn-1-amine is 1:0.8 to 1:0.5.
[0042] Specifically, in step S1, the solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.
[0043] Specifically, in step S2, the metal oxide carrier is one of silicon dioxide, titanium dioxide, aluminum oxide, cerium oxide, zirconium oxide, and zinc oxide; the solvent is one of methanol, ethanol, dimethyl sulfoxide, dioxane, N,N-dimethylformamide, and N-methylpyrrolidone; the aminosilane coupling agent is one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane.
[0044] Specifically, in step S3, the molar mass ratio of the alkynyl functionalized polyvinyl alcohol to the amino-modified metal oxide is 5 mmol / g to 15 mmol / g, and the amount of the alkynyl functionalized polyvinyl alcohol is calculated based on the molar amount of the polyvinyl alcohol monomer in step S1.
[0045] Specifically, in step S3, the solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone, and is consistent with the solvent used in step S1.
[0046] Specifically, in step S4, the molar mass ratio of the metal salt precursor to the alkynyl-modified metal oxide is 0.2 mmol / g to 1.0 mmol / g.
[0047] Specifically, in step S4, the solvent is one of water and N,N-dimethylformamide; the metal salt precursor is RuCl 3 、Na 2 PdCl 4 、PdNO 3 , PdCl 2 , H 2 PtCl 6 6H 2 O、Co(NO 3 ) 2 6H 2 O、CoCl 2 The reducing agent is NaBH 4 NH 3 BH 3 , one of the citric acids.
[0048] The present invention will be further described below by the following specific embodiments:
[0049] Example 1
[0050] The catalysts supported on alkynyl-modified metal oxide supports and enhanced metal nanoparticles were prepared by the following steps:
[0051] S1. Dissolve 1.0 g of polyvinyl alcohol (PVA) in 20 mL of N,N-dimethylformamide, then add 2.45 g of N,N'-carbonyl diimidazole (CDI), stir and react for 3 h, then add 0.52 g of but-3-yn-1-amine and continue stirring and reacting for 10 h to obtain an alkynyl functionalized polyvinyl alcohol (APVA) solution.
[0052] S2, 1.25g SiO 2 The nanospheres were dispersed in 50 mL of ethanol, 1 mL of γ-aminopropyltrimethoxysilane was added, the reaction was stirred for 24 h, centrifuged and washed, and the solid was vacuum dried at 60 °C for 12 h to obtain amino-modified SiO2 carrier.
[0053] S3, 1.0g of amino-modified SiO synthesized in step S2 2 The carrier was dispersed in 20 mL of N,N-dimethylformamide, and 10 mL of the APVA solution in step S1 was added. The mixture was stirred for 12 h, centrifuged and washed, and the solid was vacuum dried at 80 °C for 24 h to obtain the carrier APVA-SiO 2 .
[0054] S4, 200 mg of APVA-SiO synthesized in step S3 2 Dispersed in 10 mL N,N-dimethylformyl, add 20.74 mg RuCl 3 The mixture was stirred at room temperature for 6 h and 1 mL of freshly prepared NaBH 4 (37.83 mg) N,N-dimethylformyl solution, continue stirring for 2 h, centrifuge and wash, collect the solid product and dry it in vacuum at 80 °C for 10 h. The obtained catalyst is recorded as RuNPs / APVA-SiO 2 .
[0055] Example 2
[0056] The catalysts supported on alkynyl-modified metal oxide supports and enhanced metal nanoparticles were prepared by the following steps:
[0057] S1. Dissolve 0.5 g PVA in 10 mL N,N-dimethylformamide, then add 1.30 g CDI, stir and react for 3 h, then add 0.26 g but-3-yn-1-amine and continue stirring and reacting for 10 h to obtain APVA solution.
[0058] S2, 1.25g SiO 2 The nanospheres were dispersed in 50 mL of ethanol, 1 mL of γ-aminopropyltrimethoxysilane was added, the reaction was stirred for 24 h, centrifuged and washed, and the solid was vacuum dried at 60 °C for 12 h to obtain amino-modified SiO 2 carrier.
[0059] S3, 1.0g of amino-modified SiO synthesized in step S2 2 The carrier was dispersed in 20 mL of N,N-dimethylformamide, and 10 mL of the APVA solution in step S1 was added. The mixture was stirred for 12 h, centrifuged and washed, and the solid was vacuum dried at 80 °C for 24 h to obtain the carrier APVA-SiO 2 .
[0060] S4, 200 mg of APVA-SiO synthesized in step S3 2 Dispersed in 10 mL N, N-dimethylformyl, add 29.4 mg Na 2PdCl 4 The mixture was stirred at room temperature for 6 h and 1 mL of freshly prepared NaBH 4 (37.83 mg) N,N-dimethylformyl solution, continue stirring for 2 h, centrifuge and wash, collect the solid product and dry it in vacuum at 80 °C for 10 h. The obtained catalyst is recorded as PdNPs / APVA-SiO 2 .
[0061] Example 3
[0062] The catalysts supported on alkynyl-modified metal oxide supports and enhanced metal nanoparticles were prepared by the following steps:
[0063] S1. Dissolve 0.5 g PVA in 10 mL N,N-dimethylformamide, then add 1.30 g CDI, stir and react for 3 h, then add 0.26 g but-3-yn-1-amine and continue stirring and reacting for 10 h to obtain APVA solution.
[0064] S2, 1.25g SiO 2 The nanospheres were dispersed in 50 mL of ethanol, 1 mL of γ-aminopropyltrimethoxysilane was added, the reaction was stirred for 24 h, centrifuged and washed, and the solid was vacuum dried at 60 °C for 12 h to obtain amino-modified SiO 2 carrier.
[0065] S3, 1.0g of amino-modified SiO synthesized in step S2 2 The carrier was dispersed in 20 mL of N,N-dimethylformamide, and 10 mL of the APVA solution in step S1 was added. The mixture was stirred for 12 h, centrifuged and washed, and the solid was vacuum dried at 80 °C for 24 h to obtain the carrier APVA-SiO 2 .
[0066] S4, 100 mg of APVA-SiO synthesized in step S3 2 Dispersed in 5 mL N,N-dimethylformyl, add 25.90 mg H 2 PtCl 6 6H 2 O was stirred at room temperature for 6 h, and 1 mL of freshly prepared NaBH 4 (18.92 mg) N,N-dimethylformyl solution, continue stirring for 2 h, centrifuge and wash, collect the solid product and dry it in vacuum at 80 °C for 10 h. The obtained catalyst is recorded as PtNPs / APVA-SiO 2 .
[0067] Example 4
[0068] The catalysts supported on alkynyl-modified metal oxide supports and enhanced metal nanoparticles were prepared by the following steps:
[0069] S1. Dissolve 0.5 g of PVA in 10 mL of N,N-dimethylformamide, then add 1.30 g of CDI, stir and react for 3 h, then add 0.26 g of but-3-yn-1-amine and continue stirring and reacting for 10 h to obtain an APVA solution.
[0070] S2. 1.25 g SiO 2 The nanospheres were dispersed in 50 mL of ethanol, 1 mL of γ-aminopropyltrimethoxysilane was added, the reaction was stirred for 24 h, centrifuged and washed, and the solid was vacuum dried at 60 °C for 12 h to obtain amino-modified SiO 2 carrier.
[0071] S3. 1.0 g of amino-modified SiO synthesized in step S2 2 The carrier was dispersed in 20 mL of N,N-dimethylformamide, and 10 mL of the APVA solution in step S1 was added. The mixture was stirred for 12 h, centrifuged and washed, and the solid was vacuum dried at 80 °C for 24 h to obtain the carrier APVA-SiO 2 .
[0072] S4. 200 mg of APVA-SiO synthesized in step S3 was added 2 Dispersed in 10 mL N,N-dimethylformyl, 29.10 mg Co(NO 3 ) 2 6H 2 O was stirred at room temperature for 6 h, and 1 mL of freshly prepared NaBH 4 (37.83 mg) N,N-dimethylformyl solution, continue stirring for 2 h, centrifuge and wash, collect the solid product and dry it in vacuum at 80 °C for 10 h. The obtained catalyst is recorded as CoNPs / APVA-SiO 2 .
[0073] Example 5
[0074] The catalysts supported on alkynyl-modified metal oxide supports and enhanced metal nanoparticles were prepared by the following steps:
[0075] S1. Dissolve 1.5 g PVA in 30 mL N,N-dimethylformamide, then add 3.90 g CDI, stir and react for 3 h, then add 0.78 g but-3-yn-1-amine and continue stirring and reacting for 10 h to obtain an APVA solution.
[0076] S2, 2.5g TiO 2 Dispersed in 100 mL of ethanol, 2 mL of γ-aminopropyltrimethoxysilane was added, stirred for 24 h, centrifuged and washed, and the solid was vacuum dried at 60 °C for 12 h to obtain amino-modified TiO 2 carrier.
[0077] S3, 0.5 g of the amino-modified TiO synthesized in step S2 2 The carrier was dispersed in 10 mL of N,N-dimethylformamide, and 5 mL of the APVA solution in step S1 was added. The mixture was stirred for 12 h, centrifuged and washed, and the solid was vacuum dried at 80 °C for 24 h to obtain the carrier APVA-TiO 2 .
[0078] S4, 200 mg of APVA-TiO synthesized in S3 2 Dispersed in N,N-dimethylformyl, add 20.74 mg RuCl 3 The mixture was stirred at room temperature for 6 h and 1 mL of freshly prepared NaBH 4 (37.83 mg) N,N-dimethylformyl solution, continue stirring for 2 h, centrifuge and wash, collect the solid product and dry it in vacuum at 80 °C for 10 h. The obtained catalyst is labeled as RuNPs / APVA-TiO 2 .
[0079] Example 6
[0080] The catalysts supported on alkynyl-modified metal oxide supports and enhanced metal nanoparticles were prepared by the following steps:
[0081] S1. Dissolve 1.0 g of PVA in 20 mL of N,N-dimethylformamide, then add 2.45 g of CDI, stir and react for 3 h, then add 0.52 g of but-3-yn-1-amine and continue stirring and reacting for 10 h to obtain an APVA solution.
[0082] S2, 1.25g CeO 2 Dispersed in 50 mL of ethanol, 1 mL of γ-aminopropyltrimethoxysilane was added, stirred for 24 h, centrifuged and washed, and the solid was vacuum dried at 60 °C for 12 h to obtain amino-modified CeO 2 carrier.
[0083] S3, 0.5g of amino-modified CeO synthesized in step S2 2 The carrier was dispersed in 10 mL of N,N-dimethylformamide, and 5 mL of the APVA solution in step S1 was added. The mixture was stirred for 12 h, centrifuged and washed, and the solid was vacuum dried at 80 °C for 24 h to obtain the carrier APVA-CeO 2 .
[0084] S4, 100 mg of APVA-CeO synthesized in S3 2 Dispersed in N,N-dimethylformyl, add 10.37 mg RuCl 3 The mixture was stirred at room temperature for 6 h and 1 mL of freshly prepared NaBH4 (18.92 mg) N,N-dimethylformyl solution, continue stirring for 2 h, centrifuge and wash, and collect the solid product and vacuum dry it at 80 °C for 10 h. The obtained catalyst is labeled as RuNPs / APVA-CeO 2 .
[0085] Example 7
[0086] The catalysts supported on alkynyl-modified metal oxide supports and enhanced metal nanoparticles were prepared by the following steps:
[0087] S1. Dissolve 1.0 g of PVA in 20 mL of N,N-dimethylformamide, then add 2.45 g of CDI, stir and react for 3 h, then add 0.52 g of but-3-yn-1-amine and continue stirring and reacting for 10 h to obtain an APVA solution.
[0088] S2, 1.25g ZrO 2 Dispersed in 50 mL of ethanol, 1 mL of γ-aminopropyltrimethoxysilane was added, stirred for 24 h, centrifuged and washed, and the solid was vacuum dried at 60 ° C for 12 h to obtain amino-modified ZrO 2 carrier.
[0089] S3, 1.0 g of amino-modified ZrO synthesized in step S2 2 The carrier was dispersed in 20 mL of N,N-dimethylformamide, and 10 mL of the APVA solution in step S1 was added. The mixture was stirred for 12 h, centrifuged and washed, and the solid was vacuum dried at 80 °C for 24 h to obtain the carrier APVA-ZrO 2 .
[0090] S4, 200 mg of APVA-ZrO synthesized from S3 2 Dispersed in 10 mL N,N-dimethylformyl, add 20.74 mg RuCl 3 The mixture was stirred at room temperature for 6 h and 1 mL of freshly prepared NaBH 4 (37.83 mg) N,N-dimethylformyl solution, continue stirring for 2 h, centrifuge and wash, collect the solid product and dry it in vacuum at 80 °C for 10 h. The obtained catalyst is marked as RuNPs / APVA-ZrO 2 .
[0091] The catalysts prepared in Examples 1-3 were subjected to TEM analysis. Figure 1-Figure 3 It can be seen that the metal nanoparticles are stably distributed on the surface of the carrier and have good dispersibility. It can be seen that the functionalization of the carrier with alkynyl groups can enhance the interaction between the metal nanoparticles and the carrier, effectively inhibit the migration and agglomeration of the particles, and effectively improve the stability and activity of the catalyst.
[0092] See also Figure 4 The invention discloses a synthesis route map of a catalyst. The invention modifies the surface of a metal oxide with alkynyl functional groups, anchors the metal by utilizing the coordination-related effect between the alkynyl groups and metal ions, and controls the growth of nanoparticles as a stabilizer when the metal precursor is reduced to metal nano-ions, thereby greatly improving the stability of the metal catalyst.
[0093] Application Examples
[0094] The catalyst prepared above was applied to the experiment of hydrogen production by hydrolysis of ammonia borane:
[0095] Weigh the obtained catalyst and add it to the Schlenk reaction bottle. Add 5 mL of water and stir magnetically to disperse the catalyst evenly. Then add 1 mmol of freshly prepared ammonia borane aqueous solution (1 mL). Start timing and periodically record H 2 The production volume and time were adjusted until the reaction was complete.
[0096] Figure 5 The results of the evaluation of the activity of the catalysts prepared in Examples 1 to 4 in catalyzing the hydrolysis of ammonia borane to produce hydrogen show that the catalysts prepared in the above examples have good reaction activity;
[0097] Figure 6 RuNPs / APVA-SiO prepared in Example 1 2 The evaluation results of the catalytic cycle stability of ammonia borane hydrolysis to produce hydrogen show that the prepared catalyst has good cycle stability.
[0098] Figure 7 The results are the activity results of ammonia borane hydrolysis to hydrogen production of catalysts supported on different metal carriers. The catalysts all have good reaction activities. It can be seen that the alkynyl functionalization modification is applicable to a variety of metal oxides and has wide universality.
[0099] At the same time, the Ru-based catalyst obtained by directly modifying the oxide support without alkynyl functionalization was prepared as a comparison, and the above-mentioned ammonia borane hydrolysis hydrogen production reaction experiment was carried out. The results obtained were compared with the catalysts prepared in Examples 1, 5, 6, and 7. The results are shown in FIG. Figure 8 It can be seen that after the metal oxide support is functionalized with alkynyl groups in the present invention, the activity of the catalyst is greatly improved.
[0100] In summary, the present invention modifies the alkynyl functional group on the surface of the metal oxide, uses the coordination-related effect between the alkynyl group and the metal ion to anchor the metal, and uses the alkynyl functional group as a stabilizer to control the growth of nanoparticles when the metal precursor is reduced to metal nano-ions, which can greatly improve the stability of the metal catalyst. The prepared catalyst has good reaction activity and stability in the hydrogen production reaction of ammonia borane hydrolysis.
[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier, characterized in that: The following steps are involved: S1. Preparation of alkynyl functionalized polyvinyl alcohol: dissolving polyvinyl alcohol in a solvent, adding N,N'-carbonyl diimidazole, stirring and reacting for 3 hours, and then adding but-3-yn-1-amine and stirring and reacting for 10 hours to obtain alkynyl functionalized polyvinyl alcohol; S2. Amino-modification of the metal oxide carrier: dispersing the metal oxide carrier in a solvent, adding an aminosilane coupling agent, stirring the reaction for 12 to 24 hours, centrifuging, washing, and drying the solid product to obtain an amino-modified metal oxide carrier; S3, dispersing the amino-modified metal oxide carrier into a solvent, adding alkynyl-functionalized polyvinyl alcohol, stirring the reaction for 12 to 24 hours, centrifuging, washing, and drying the solid product to obtain the alkynyl-modified metal oxide carrier; S4, dispersing the alkynyl-modified metal oxide carrier in a solvent, adding a metal salt precursor and stirring for 6 to 12 hours, adding a reducing agent, continuing to stir for 2 to 6 hours, centrifuging, washing, and drying the solid product to obtain the catalyst.
2. The method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier as claimed in claim 1, characterized in that: In step S1, the molar amount of polyvinyl alcohol is calculated based on monomer molecules, the molar ratio of polyvinyl alcohol to N,N'-carbonyl diimidazole is 1:1 to 1:0.5, and the molar ratio of N,N'-carbonyl diimidazole to but-3-yn-1-amine is 1:0.8 to 1:0.
5.
3. The method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier as claimed in claim 2, characterized in that: In step S1, the solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone.
4. The method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier as claimed in claim 1, characterized in that: In step S2, the metal oxide carrier is one of silicon dioxide, titanium dioxide, aluminum oxide, cerium oxide, zirconium oxide, and zinc oxide; the solvent is one of methanol, ethanol, dimethyl sulfoxide, dioxane, N,N-dimethylformamide, and N-methylpyrrolidone; the aminosilane coupling agent is one of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, and N-β(aminoethyl)-γ-aminopropyltrimethoxysilane.
5. The method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier as claimed in claim 1, characterized in that: In step S3, the molar mass ratio of the alkynyl functionalized polyvinyl alcohol to the amino-modified metal oxide is 5 mmol / g to 15 mmol / g, and the amount of the alkynyl functionalized polyvinyl alcohol is calculated based on the molar amount of the polyvinyl alcohol monomer in step S1.
6. The method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier as claimed in claim 3, characterized in that: In step S3, the solvent is one of dimethyl sulfoxide, N,N-dimethylformamide, and N-methylpyrrolidone, and is consistent with the solvent used in step S1.
7. The method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier as claimed in claim 1, characterized in that: In step S4, the molar mass ratio of the metal salt precursor to the alkynyl-modified metal oxide is 0.2 mmol / g to 1.0 mmol / g.
8. The method for preparing a catalyst supported by metal nanoparticles enhanced by an alkynyl-modified metal oxide carrier as claimed in claim 1, characterized in that: In step S4, the solvent is one of water and N,N-dimethylformamide; the metal salt precursor is one of RuCl3, Na2PdCl4, PdNO3, PdCl2, H2PtCl6·6H2O, Co(NO3)2·6H2O, CoCl2; and the reducing agent is one of NaBH4, NH3BH3, and citric acid.
9. A catalyst loaded with metal nanoparticles enhanced on an alkynyl-modified metal oxide support prepared by the preparation method according to any one of claims 1 to 8.
10. Application of an alkynyl-modified metal oxide carrier-enhanced metal nanoparticle-loaded catalyst in hydrogen production by ammonia borane hydrolysis.