A photoelectrochemical hydrogen production catalyst and preparation method thereof

Abstract

The present invention relates to the technical field of hydrogen production catalysts, and specifically relates to a photo-electrochemical hydrogen production catalyst and a preparation method thereof. The photo-electrochemical hydrogen production catalyst includes modified carbon nanotubes, WTiO5 and GeNiSnO4. WTiO5 can effectively capture sunlight and improve the photo-electric conversion efficiency. GeNiSnO4 can accelerate the separation and transfer of photo-generated charges, thereby improving the efficiency of photo-electrochemical water splitting for hydrogen production. The built-in electric field effect between the two can accelerate the separation and migration of photo-generated electron-hole pairs and improve the hydrogen production activity of the catalyst. In the present invention, phytic acid-aminoboric acid is prepared to modify the carbon nanotubes, which can improve the electrical conductivity of the carbon nanotubes, fill the gaps between the carbon nanotubes, increase the electron transport channels, and the prepared modified carbon nanotubes can provide a large number of attachment sites and more photocatalytic active sites for WTiO5 and GeNiSnO4, improving the catalytic efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen production catalysts, and specifically to a photoelectrochemical hydrogen production catalyst and a preparation method thereof. Background Art

[0002] Photoelectrochemical hydrogen production is a process that uses light energy to promote the electrolysis of water molecules to produce hydrogen. This technology usually involves the use of photocatalysts, which can absorb light energy and promote the decomposition of water molecules to produce hydrogen. Photoelectrochemical hydrogen production is considered a method of clean energy production because it uses renewable solar energy and the hydrogen produced can be used as a clean fuel to replace traditional fossil fuels. In the process of photoelectrochemical hydrogen production, light energy is absorbed and excites electrons on the catalyst. These electrons participate in the electrolysis of water molecules and decompose water into hydrogen and oxygen. Although photoelectrochemical hydrogen production catalysts have great potential in clean energy production, they also have some disadvantages and challenges, including: high catalyst cost, which limits large-scale application; poor photostability, long-term illumination will lead to a decrease in catalytic activity, affecting the efficiency of hydrogen production; low conversion efficiency, need to further improve the photoelectric conversion efficiency and catalytic efficiency to increase the amount of hydrogen produced; may be corroded or deactivated during long-term operation, resulting in a decrease in catalytic activity. Based on this, how to develop a photoelectrochemical hydrogen production catalyst with high efficiency, low cost and strong stability is a technical problem that needs to be solved urgently. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a photoelectrochemical hydrogen production catalyst and a preparation method thereof. The photoelectrochemical hydrogen production catalyst prepared by the present invention comprises WTiO 5 GeNiSnO 4 , WTiO 5 It has good light corrosion resistance and suitable band gap width, which can effectively capture sunlight and improve the photoelectric conversion efficiency. 4 It can accelerate the separation and transfer of photogenerated charges, thereby improving the efficiency of photoelectrochemical water decomposition to produce hydrogen. 5 GeNiSnO 4 The built-in electric field effect between them can accelerate the separation and migration of photogenerated electron-hole pairs, enhance the photoelectric effect, effectively promote the separation and migration of photogenerated charges, and reduce their recombination efficiency, thereby improving the activity of photoelectric hydrogen production catalysts in decomposing water to produce hydrogen. The modified carbon nanotubes prepared by the present invention have good adsorption properties and can be used for loading WTiO 5 GeNiSnO 4It provides a large number of attachment sites and more photocatalytic active sites, preventing metal oxides from agglomerating, making it easier for reactant molecules to contact active sites, improving catalytic efficiency, and having high conductivity. It can effectively improve light absorption efficiency, quickly transfer electrons, accelerate photogenerated charge separation and transfer, enhance the interaction between metal oxides, and enhance catalytic activity during the photoelectrocatalytic process. The photoelectrochemical hydrogen production catalyst prepared by the present invention has excellent activity, good stability, excellent anti-photocorrosion performance, significantly improved photoelectric conversion efficiency, and has a high efficiency photocatalytic water decomposition hydrogen production effect.

[0004] The present invention is achieved through the following technical solutions:

[0005] A photoelectrochemical hydrogen production catalyst comprising modified carbon nanotubes, WTiO 5 and GeNiSnO 4 .

[0006] The present invention provides a method for preparing the photoelectrochemical hydrogen production catalyst, comprising the following steps:

[0007] S1: (NH 4 ) 6 W 7 O 24 6H 2 O was dissolved in deionized water and stirred magnetically for 10-20 min, then Ti(C 4 H 9 O) 4 and NaOH, stirred magnetically for 1-2 h, then transferred to a stainless steel autoclave lined with polytetrafluoroethylene, heated at 180-200 °C for 24-36 h, cooled naturally to room temperature after the reaction, centrifuged at 8000 r / min for 5 min, the precipitate was washed 3 times with 20-30 vol% acetic acid aqueous solution, then washed 3 times with deionized water and anhydrous ethanol, placed in a vacuum drying oven, and dried at 60 °C for 12 h to obtain WTiO 5 ;

[0008] S2: WTiO prepared in step S1 5 and methanol in a ratio of 100 mg:20 mL, and ultrasonicated at 20 kHz for 10 min to obtain reaction solution A; weigh Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O and SnCl 2 ·2H 2O was dissolved in methanol and ultrasonicated at 20 kHz for 10 min to obtain reaction solution B; the modified carbon nanotubes were weighed and dissolved in methanol and ultrasonicated for 10 min to obtain reaction solution C;

[0009] S3: The reaction solution B obtained in step S2 is quickly added to the reaction solution A to form a mixed solution, and then the reaction solution C is added to the above mixed solution, stirred at 500 r / min for 24 h, centrifuged at 8000 r / min for 5 min, the precipitate is washed three times with methanol, placed in a vacuum drying oven, dried at 60°C for 12 h, put into a crucible, placed in a muffle furnace, heated to 350°C in air at a rate of 2°C / min, calcined for 4 h, and then naturally cooled to room temperature to obtain a photoelectrochemical hydrogen production catalyst.

[0010] Further, in step S1 (NH 4 ) 6 W 7 O 24 6H 2 O, deionized water, Ti(C 4 H 9 O) 4 The dosage ratio of , NaOH is 27 g:800 mL:34 g:7 g.

[0011] Furthermore, in the reaction solution B in step S2, Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O、SnCl 2 ·2H 2 The dosage ratio of O and methanol is 12 g:15 g:11 g:1200 mL.

[0012] Furthermore, in the reaction solution C in step S2, the ratio of modified carbon nanotubes to methanol is 30 mg:1 mL.

[0013] Furthermore, in step S3, the volume ratio of reaction solution A, reaction solution B and reaction solution C is 1:2:1.

[0014] Furthermore, the method for preparing the modified carbon nanotubes comprises the following steps:

[0015] (1) dissolving carbon nanotubes in DMSO, and ultrasonically treating the mixture for 1 h in a cell crusher to obtain a first solution; dissolving phytic acid-aminoboric acid in DMSO, and mixing the mixture to obtain a second solution;

[0016] (2) slowly adding the second solution obtained in step (1) to the first solution through a constant pressure funnel, the volume ratio of the second solution to the first solution is 1:1, the dropping speed is 0.8-1 mL / min, and then reacting at 60° C. with magnetic stirring for 10 h, and then vacuum filtering to collect the residue;

[0017] (3) The filter residue obtained in step (2) is placed in a 60-80 vol% ethanol solution, the mass volume ratio of the filter residue to the ethanol solution is 1 g:20 mL, and ultrasonic treatment is performed at 80 kHz for 3 h at room temperature, and centrifuged at 16000 rpm for 5 min. The precipitate is washed 3-5 times with a 20 wt% ethanol solution, placed in an oven, and dried at 70°C to constant weight to obtain modified carbon nanotubes.

[0018] Furthermore, in the first solution of step (1), the ratio of carbon nanotubes to DMSO is 2 mg:1 mL; and in the second solution, the ratio of phytic acid-aminoboric acid to DMSO is 2.5 mg:1 mL.

[0019] Furthermore, the preparation method of phytic acid-aminoboric acid comprises the following steps:

[0020] (a) adding phytic acid to deionized water, stirring and dissolving, preparing a phytic acid solution with a concentration of 0.1 g / mL, adding triethylenetetramine, the mass ratio of triethylenetetramine to phytic acid being 4:3, stirring at 180 rpm for 1 h, and obtaining a mixed solution A; adding 4-aminophenylboric acid to anhydrous ethanol, stirring and dissolving, and obtaining a 4-aminophenylboric acid solution with a concentration of 0.2 g / mL;

[0021] (b) The 4-aminophenylboronic acid solution obtained in step (a) is added to the mixed solution A at a rate of 10-20 mL / min, the volume ratio of the 4-aminophenylboronic acid solution to the mixed solution A is 1:1.5, the mixture is transferred to a reactor, reacted at 120° C. for 8 h, cooled to room temperature, and diluted ammonia water is added dropwise in an ice-salt bath environment until the solution pH is 8, vacuum filtered, and the solid on the filter paper is washed 3 times with anhydrous ethanol, rotary evaporated at 95° C. for 1 h, washed 3 times with deionized water, and vacuum dried at 80° C. for 1 h to obtain phytic acid-aminoboric acid.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The photoelectrochemical hydrogen production catalyst prepared by the present invention comprises WTiO 5 GeNiSnO 4 The built-in electric field effect between the two can accelerate the separation and migration of photogenerated electron-hole pairs, enhance the photoelectric effect, effectively promote the separation and migration of photogenerated charges, and reduce their recombination efficiency. Under the action of the built-in electric field, the photogenerated electrons are transported from GeNiSnO to the4 The conduction band flows to WTiO 5 conduction band, reducing H to obtain H 2 , photogenerated holes from WTiO 5 The valence band flows to GeNiSnO 4 The valence band of WTiO increases the activity of photoelectric hydrogen production catalysts in decomposing water to produce hydrogen. 5 It has good resistance to light corrosion and suitable band gap width, can effectively capture sunlight, has strong visible light response ability, has good photoelectric response and strong light absorption ability under ultraviolet visible light irradiation, and can enhance photoelectric conversion performance and improve photoelectric conversion efficiency. GeNiSnO 4 It can accelerate the separation and transfer of photogenerated charges, and can accelerate the kinetics of water decomposition reaction, thereby improving the efficiency of photoelectrochemical water decomposition to produce hydrogen. The present invention prepares phytic acid-aminoboric acid, and uses phytic acid-aminoboric acid to modify carbon nanotubes, which can form a composite structure with carbon nanotubes, fill the gaps between carbon nanotubes, improve the electron transmission between carbon nanotubes, increase the conductive channel, and thus improve the conductivity of carbon nanotubes. The modified carbon nanotubes prepared by the present invention have good adsorption properties and can be used for subsequent loading of WTiO 5 GeNiSnO 4 Providing a large number of attachment sites is not only beneficial for WTiO 5 、GeNiSnO 4 The loading capacity and large specific surface area can provide more photocatalytic active sites. 5 and GeNiSnO 4 Loading on the surface of modified carbon nanotubes is conducive to preventing metal oxides from agglomerating, and is also conducive to reducing the leaching of metal oxides, making it easier for reactant molecules to contact active sites, improving catalytic efficiency, and effectively protecting the catalyst from being corroded during the photoelectrocatalytic reaction, playing the role of a protective layer, and having high conductivity at the same time, ensuring the high-quality transmission of carriers at the interface, and can effectively improve the light absorption efficiency in the photoelectrocatalytic process, reduce the recombination probability of photogenerated electron-hole pairs, and be conducive to the transfer of charge carriers, improve its photoelectrochemical activity and photoelectric conversion efficiency. The modified carbon nanotubes have good conductivity, which can quickly transfer electrons, effectively accelerate the separation and transfer of photogenerated charges, and can effectively enhance the interaction between metal oxides and enhance catalytic activity. The photoelectrochemical hydrogen production catalyst prepared by the present invention has the advantages of excellent catalytic activity, good stability, excellent anti-photocorrosion performance, etc., and the photoelectric conversion efficiency is significantly improved and has an efficient photocatalytic water decomposition hydrogen production effect. At the same time, the preparation method is simple, the performance is excellent, the cost of raw materials is low, and it has potential industrial value. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the present invention or 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 in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The chemical structural formula of phytic acid-aminoboric acid described in Example 1 of the present invention is shown;

[0026] Figure 2 is the nuclear magnetic resonance spectrum of phytic acid-aminoboric acid described in Example 1 of the present invention, wherein a is 1 H figure, b is 13 Figure C;

[0027] Figure 3 The microscopic morphology of the photoelectrochemical hydrogen production catalyst described in Example 1 of the present invention, wherein a is a transmission electron microscope image, and b is a high-resolution transmission electron microscope image;

[0028] Figure 4 This is a test diagram of hydrogen production efficiency of the products obtained from Example 1 of the present invention and Comparative Examples 1-6;

[0029] Figure 5 It is the LSV test graph of the products obtained from Example 2 and Comparative Examples 1-6 of the present invention; the positions on the y-axis from top to bottom are Comparative Example 6, Comparative Example 4, Comparative Example 5, Comparative Example 1, Comparative Example 3, Comparative Example 2, and Example 2;

[0030] Figure 6 It is the UV-visible diffuse reflectance spectrum of the products obtained from Example 3 and Comparative Examples 1-6 of the present invention; the positions on the y-axis from top to bottom are Example 3, Comparative Example 1, Comparative Example 5, Comparative Example 2, Comparative Example 3, Comparative Example 4, and Comparative Example 6. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

[0032] It should be noted that, unless otherwise specified, the chemical reagents involved in the present invention were purchased through commercial channels.

[0033] Example 1: This example provides a photoelectrochemical hydrogen production catalyst, including modified carbon nanotubes, WTiO 5 and GeNiSnO 4 .

[0034] The method for preparing the modified carbon nanotubes described in this embodiment comprises the following steps:

[0035] (1) adding phytic acid to deionized water, stirring to dissolve, preparing a phytic acid solution with a concentration of 0.1 g / mL, adding triethylenetetramine, the mass ratio of triethylenetetramine to phytic acid being 4:3, stirring at 180 rpm for 1 h, and obtaining a mixed solution A; adding 4-aminophenylboric acid to anhydrous ethanol, stirring to dissolve, and obtaining a 4-aminophenylboric acid solution with a concentration of 0.2 g / mL;

[0036] (2) The 4-aminophenylboronic acid solution obtained in step (1) was added to the mixed solution A at a rate of 20 mL / min, the volume ratio of the 4-aminophenylboronic acid solution to the mixed solution A was 1:1.5, the mixture was transferred to a reactor, reacted at 120°C for 8 h, cooled to room temperature, and diluted ammonia water was added dropwise in an ice-salt bath environment until the solution pH was 8, vacuum filtered, and the solid on the filter paper was washed 3 times with anhydrous ethanol, rotary evaporated at 95°C for 1 h, washed 3 times with deionized water, and vacuum dried at 80°C for 1 h to obtain phytic acid-aminoboric acid; the chemical structure is shown in the figure Figure 1 The NMR spectrum is shown in Figure 2 As shown;

[0037] (3) dissolving carbon nanotubes in DMSO, and ultrasonically treating the mixture for 1 h in a cell crusher to obtain a first solution; dissolving phytic acid-aminoboric acid in DMSO, and mixing the mixture to obtain a second solution; in the first solution, the ratio of carbon nanotubes to DMSO was 2 mg:1 mL; in the second solution, the ratio of phytic acid-aminoboric acid to DMSO was 2.5 mg:1 mL;

[0038] (4) slowly adding the second solution obtained in step (3) to the first solution through a constant pressure funnel, the volume ratio of the second solution to the first solution is 1:1, the dropping speed is 1 mL / min, and then reacting with magnetic stirring at 60°C for 10 h, and then vacuum filtering to collect the residue;

[0039] (5) The filter residue obtained in step (4) is placed in an 80 vol% ethanol solution, the mass volume ratio of the filter residue to the ethanol solution is 1 g:20 mL, and ultrasonically treated at 80 kHz for 3 h at room temperature, centrifuged at 16000 rpm for 5 min, and the precipitate is washed 5 times with a 20 wt% ethanol solution, placed in an oven, and dried at 70°C to constant weight to obtain modified carbon nanotubes.

[0040] This embodiment also provides a method for preparing the photoelectrochemical hydrogen production catalyst, comprising the following steps:

[0041] S1: (NH 4 ) 6 W 7 O 24 6H 2O was dissolved in deionized water and stirred magnetically for 20 min, then Ti(C 4 H 9 O) 4 and NaOH, (NH 4 ) 6 W 7 O 24 6H 2 O, deionized water, Ti(C 4 H 9 O) 4 The amount ratio of NaOH was 27 g:800 mL:34 g:7 g. After magnetic stirring for 2 h, the mixture was transferred to a stainless steel autoclave lined with polytetrafluoroethylene and heated at 200 °C for 36 h. After the reaction, the mixture was naturally cooled to room temperature and centrifuged at 8000 r / min for 5 min. The precipitate was washed three times with a 30 vol% acetic acid aqueous solution, then washed three times with deionized water and anhydrous ethanol, and placed in a vacuum drying oven at 60 °C for 12 h to obtain WTiO 5 ;

[0042] S2: WTiO prepared in step S1 5 and methanol in a ratio of 100 mg:20 mL, and ultrasonicated at 20 kHz for 10 min to obtain reaction solution A; weigh Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O and SnCl 2 ·2H 2 O was dissolved in methanol and ultrasonicated at 20 kHz for 10 min to obtain reaction solution B; the modified carbon nanotubes were weighed and dissolved in methanol and ultrasonicated for 10 min, which was recorded as reaction solution C; in reaction solution B, Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O、SnCl 2 ·2H 2 The dosage ratio of O and methanol was 12 g:15 g:11 g:1200 mL; in reaction solution C, the dosage ratio of modified carbon nanotubes and methanol was 30 mg:1 mL;

[0043] S3: The reaction liquid B obtained in step S2 is quickly added to the reaction liquid A to form a mixed solution, and then the reaction liquid C is added to the above mixed solution, the volume ratio of reaction liquid A, reaction liquid B and reaction liquid C is 1:2:1, stirred at 500 r / min for 24 h, centrifuged at 8000 r / min for 5 min, the precipitate is washed three times with methanol, placed in a vacuum drying oven, dried at 60°C for 12 h, put into a crucible, placed in a muffle furnace, heated to 350°C in air at a rate of 2°C / min, calcined for 4 h, and then naturally cooled to room temperature to obtain a photoelectrochemical hydrogen production catalyst.

[0044] Example 2: This example provides a photoelectrochemical hydrogen production catalyst, including modified carbon nanotubes, WTiO 5 and GeNiSnO 4 .

[0045] The method for preparing the modified carbon nanotubes described in this embodiment comprises the following steps:

[0046] (1) adding phytic acid to deionized water, stirring to dissolve, preparing a phytic acid solution with a concentration of 0.1 g / mL, adding triethylenetetramine, the mass ratio of triethylenetetramine to phytic acid being 4:3, stirring at 180 rpm for 1 h, and obtaining a mixed solution A; adding 4-aminophenylboric acid to anhydrous ethanol, stirring to dissolve, and obtaining a 4-aminophenylboric acid solution with a concentration of 0.2 g / mL;

[0047] (2) adding the 4-aminophenylboronic acid solution obtained in step (1) to the mixed solution A at a rate of 10 mL / min, the volume ratio of the 4-aminophenylboronic acid solution to the mixed solution A being 1:1.5, transferring the mixture to a reactor, reacting at 120°C for 8 h, cooling to room temperature, adding dilute ammonia water dropwise in an ice-salt bath environment until the solution pH is 8, vacuum filtering, washing the solid on the filter paper with anhydrous ethanol three times, rotary evaporating at 95°C for 1 h, washing with deionized water three times, and vacuum drying at 80°C for 1 h to obtain phytic acid-aminoboric acid;

[0048] (3) dissolving carbon nanotubes in DMSO, and ultrasonically treating the mixture for 1 h in a cell crusher to obtain a first solution; dissolving phytic acid-aminoboric acid in DMSO, and mixing the mixture to obtain a second solution; in the first solution, the ratio of carbon nanotubes to DMSO was 2 mg:1 mL; in the second solution, the ratio of phytic acid-aminoboric acid to DMSO was 2.5 mg:1 mL;

[0049] (4) slowly adding the second solution obtained in step (3) to the first solution through a constant pressure funnel, the volume ratio of the second solution to the first solution is 1:1, the dropping speed is 0.8 mL / min, and then reacting under magnetic stirring at 60° C. for 10 h, and then vacuum filtering to collect the residue;

[0050] (5) The filter residue obtained in step (4) is placed in a 60 vol% ethanol solution, the mass volume ratio of the filter residue to the ethanol solution is 1 g:20 mL, and ultrasonic treatment is performed at 80 kHz for 3 h at room temperature, and centrifuged at 16000 rpm for 5 min. The precipitate is washed three times with a 20 wt% ethanol solution, placed in an oven, and dried at 70°C to constant weight to obtain modified carbon nanotubes.

[0051] This embodiment also provides a method for preparing the photoelectrochemical hydrogen production catalyst, comprising the following steps:

[0052] S1: (NH 4 ) 6 W 7 O 24 6H 2 O was dissolved in deionized water and stirred magnetically for 10 min, then Ti(C 4 H 9 O) 4 and NaOH, (NH 4 ) 6 W 7 O 24 6H 2 O, deionized water, Ti(C 4 H 9 O) 4 The amount ratio of NaOH was 27 g:800 mL:34 g:7 g. After magnetic stirring for 1 h, the mixture was transferred to a stainless steel autoclave lined with polytetrafluoroethylene and heated at 180 °C for 24 h. After the reaction, the mixture was naturally cooled to room temperature and centrifuged at 8000 r / min for 5 min. The precipitate was washed 3 times with a 20 vol% acetic acid aqueous solution, then washed 3 times with deionized water and anhydrous ethanol, and placed in a vacuum drying oven at 60 °C for 12 h to obtain WTiO 5 ;

[0053] S2: WTiO prepared in step S1 5 and methanol in a ratio of 100 mg:20 mL, and ultrasonicated at 20 kHz for 10 min to obtain reaction solution A; weigh Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O and SnCl 2 ·2H 2 O was dissolved in methanol and ultrasonicated at 20 kHz for 10 min to obtain reaction solution B; the modified carbon nanotubes were weighed and dissolved in methanol and ultrasonicated for 10 min, which was recorded as reaction solution C; in reaction solution B, Ge(C 2 O4 ) 2 ,Ni(NO 3 ) 2 6H 2 O、SnCl 2 ·2H 2 The dosage ratio of O and methanol was 12 g:15 g:11 g:1200 mL; in reaction solution C, the dosage ratio of modified carbon nanotubes and methanol was 30 mg:1 mL;

[0054] S3: The reaction liquid B obtained in step S2 is quickly added to the reaction liquid A to form a mixed solution, and then the reaction liquid C is added to the above mixed solution, the volume ratio of reaction liquid A, reaction liquid B and reaction liquid C is 1:2:1, stirred at 500 r / min for 24 h, centrifuged at 8000 r / min for 5 min, the precipitate is washed three times with methanol, placed in a vacuum drying oven, dried at 60°C for 12 h, put into a crucible, placed in a muffle furnace, heated to 350°C in air at a rate of 2°C / min, calcined for 4 h, and then naturally cooled to room temperature to obtain a photoelectrochemical hydrogen production catalyst.

[0055] Example 3: This example provides a photoelectrochemical hydrogen production catalyst, including modified carbon nanotubes, WTiO 5 and GeNiSnO 4 .

[0056] The method for preparing the modified carbon nanotubes described in this embodiment comprises the following steps:

[0057] (1) adding phytic acid to deionized water, stirring to dissolve, preparing a phytic acid solution with a concentration of 0.1 g / mL, adding triethylenetetramine, the mass ratio of triethylenetetramine to phytic acid being 4:3, stirring at 180 rpm for 1 h, and obtaining a mixed solution A; adding 4-aminophenylboric acid to anhydrous ethanol, stirring to dissolve, and obtaining a 4-aminophenylboric acid solution with a concentration of 0.2 g / mL;

[0058] (2) adding the 4-aminophenylboronic acid solution obtained in step (1) to the mixed solution A at a rate of 15 mL / min, the volume ratio of the 4-aminophenylboronic acid solution to the mixed solution A being 1:1.5, transferring the mixture to a reactor, reacting at 120°C for 8 h, cooling to room temperature, adding dilute ammonia water dropwise in an ice-salt bath environment until the solution pH is 8, vacuum filtering, washing the solid on the filter paper with anhydrous ethanol three times, rotary evaporating at 95°C for 1 h, washing with deionized water three times, and vacuum drying at 80°C for 1 h to obtain phytic acid-aminoboric acid;

[0059] (3) dissolving carbon nanotubes in DMSO, and ultrasonically treating the mixture for 1 h in a cell crusher to obtain a first solution; dissolving phytic acid-aminoboric acid in DMSO, and mixing the mixture to obtain a second solution; in the first solution, the ratio of carbon nanotubes to DMSO was 2 mg:1 mL; in the second solution, the ratio of phytic acid-aminoboric acid to DMSO was 2.5 mg:1 mL;

[0060] (4) slowly adding the second solution obtained in step (3) to the first solution through a constant pressure funnel, the volume ratio of the second solution to the first solution is 1:1, the dropping speed is 0.9 mL / min, and then reacting at 60° C. with magnetic stirring for 10 h, and then vacuum filtering to collect the residue;

[0061] (5) The filter residue obtained in step (4) is placed in a 70 vol% ethanol solution, the mass volume ratio of the filter residue to the ethanol solution is 1 g:20 mL, and ultrasonic treatment is performed at 80 kHz for 3 h at room temperature, and centrifuged at 16000 rpm for 5 min. The precipitate is washed four times with a 20 wt% ethanol solution, placed in an oven, and dried at 70°C to constant weight to obtain modified carbon nanotubes.

[0062] This embodiment also provides a method for preparing the photoelectrochemical hydrogen production catalyst, comprising the following steps:

[0063] S1: (NH 4 ) 6 W 7 O 24 6H 2 O was dissolved in deionized water and stirred magnetically for 15 min, then Ti(C 4 H 9 O) 4 and NaOH, (NH 4 ) 6 W 7 O 24 6H 2 O, deionized water, Ti(C 4 H 9 O) 4 The amount ratio of NaOH was 27 g:800 mL:34 g:7 g. After magnetic stirring for 1.5 h, the mixture was transferred to a stainless steel autoclave lined with polytetrafluoroethylene and heated at 190 °C for 30 h. After the reaction, the mixture was naturally cooled to room temperature and centrifuged at 8000 r / min for 5 min. The precipitate was washed three times with a 25 vol% acetic acid aqueous solution, then washed three times with deionized water and anhydrous ethanol, and placed in a vacuum drying oven at 60 °C for 12 h to obtain WTiO 5 ;

[0064] S2: WTiO prepared in step S1 5 and methanol in a ratio of 100 mg:20 mL, and ultrasonicated at 20 kHz for 10 min to obtain reaction solution A; weigh Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O and SnCl 2 ·2H 2 O was dissolved in methanol and ultrasonicated at 20 kHz for 10 min to obtain reaction solution B; the modified carbon nanotubes were weighed and dissolved in methanol and ultrasonicated for 10 min, which was recorded as reaction solution C; in reaction solution B, Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O、SnCl 2 ·2H 2 The dosage ratio of O and methanol was 12 g:15 g:11 g:1200 mL; in reaction solution C, the dosage ratio of modified carbon nanotubes and methanol was 30 mg:1 mL;

[0065] S3: The reaction liquid B obtained in step S2 is quickly added to the reaction liquid A to form a mixed solution, and then the reaction liquid C is added to the above mixed solution, the volume ratio of reaction liquid A, reaction liquid B and reaction liquid C is 1:2:1, stirred at 500 r / min for 24 h, centrifuged at 8000 r / min for 5 min, the precipitate is washed three times with methanol, placed in a vacuum drying oven, dried at 60°C for 12 h, put into a crucible, placed in a muffle furnace, heated to 350°C in air at a rate of 2°C / min, calcined for 4 h, and then naturally cooled to room temperature to obtain a photoelectrochemical hydrogen production catalyst.

[0066] The only difference between Comparative Example 1 and Example 1 is that phytic acid-aminoboric acid is not added.

[0067] The difference between Comparative Example 2 and Example 1 is that the method for preparing the photoelectrochemical hydrogen production catalyst comprises the following steps: 4 ) 6 W 7 O 24 6H 2 O、Ti(C 4 H 9 O) 4 , NaOH and methanol were mixed in a ratio of 27 mg:34 mg:7 mg:13.6 mL to obtain reaction solution A; Ge(C 2 O 4) 2 ,Ni(NO 3 ) 2 6H 2 O and SnCl 2 ·2H 2 O was dissolved in methanol to obtain reaction solution B; the modified carbon nanotubes were weighed and dissolved in methanol, which was recorded as reaction solution C; in reaction solution B, Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O、SnCl 2 ·2H 2 The amount ratio of O and methanol is 12 g:15 g:11 g:1200 mL; in the reaction liquid C, the amount ratio of modified carbon nanotubes to methanol is 30 mg:1 mL; the reaction liquid B obtained in step S2 is quickly added to the reaction liquid A to form a mixed solution, and then the reaction liquid C is added to the above mixed solution, the volume ratio of reaction liquid A, reaction liquid B and reaction liquid C is 1:2:1, 20 kHz ultrasound for 10 min, 500 r / min stirring for 24 h, 8000 r / min centrifugation for 5 min, the precipitate is washed three times with methanol, placed in a vacuum drying oven, dried at 60°C for 12 h, put into a crucible, placed in a muffle furnace, heated to 350°C in air at a rate of 2°C / min, calcined for 4 h, and then naturally cooled to room temperature to obtain a photoelectrochemical hydrogen production catalyst.

[0068] The difference between Comparative Example 3 and Example 1 is that the method for preparing the photoelectrochemical hydrogen production catalyst comprises the following steps: 4 ) 6 W 7 O 24 6H 2 O was dissolved in deionized water and stirred magnetically for 20 min, then Ti(C 4 H 9 O) 4 and NaOH, (NH 4 ) 6 W 7 O 24 6H 2 O, deionized water, Ti(C 4 H 9 O) 4The amount ratio of NaOH was 27 g:800 mL:34 g:7 g. After magnetic stirring for 2 h, the mixture was transferred to a stainless steel autoclave lined with polytetrafluoroethylene and heated at 200 °C for 36 h. After the reaction, the mixture was naturally cooled to room temperature and centrifuged at 8000 r / min for 5 min. The precipitate was washed three times with a 30 vol% acetic acid aqueous solution, then washed three times with deionized water and anhydrous ethanol, and placed in a vacuum drying oven at 60 °C for 12 h to obtain WTiO 5 ; Weigh Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O and SnCl 2 ·2H 2 O was dissolved in methanol and ultrasonicated at 20 kHz for 10 min to obtain reaction solution B. In reaction solution B, Ge(C 2 O 4 ) 2 ,Ni(NO 3 ) 2 6H 2 O、SnCl 2 ·2H 2 The amount ratio of O and methanol was 12 g:15 g:11 g:1200 mL; magnetic stirring at 300 rpm for 24 h, centrifugation at 8000 rpm for 5 min, the precipitate was washed with methanol three times, placed in a vacuum drying oven, dried at 60 °C for 12 h, placed in a crucible, placed in a muffle furnace, heated to 350 °C in air at a rate of 2 °C / min, calcined for 4 h, and then naturally cooled to room temperature to obtain GeNiSnO 4 ;WTiO 5 、GeNiSnO 4 The modified carbon nanotubes are uniformly mixed in a weight ratio of 1:12:6 to obtain a photoelectrochemical hydrogen production catalyst.

[0069] The difference between Comparative Example 4 and Example 1 is that only WTiO 5 Alternative photoelectrochemical hydrogen production catalysts.

[0070] The only difference between Comparative Example 5 and Example 1 is that no modified carbon nanotubes are added.

[0071] Comparative Example 6 GeNiSnO was prepared by the method of Comparative Example 3. 4 , replacing photoelectrochemical hydrogen production catalysts.

[0072] Experimental Example 1: The photoelectrochemical catalyst prepared in Example 1 was observed using a transmission electron microscope and a high-resolution transmission electron microscope. Figure 3As shown, the metal oxide particles WTiO 5 and GeNiSnO 4 Good dispersion on carbon nanotubes can reduce particle agglomeration, and the modified carbon nanotubes can be WTiO 5 and GeNiSnO 4 Provide a large number of loading sites and photocatalytic active sites to improve catalytic efficiency.

[0073] Experimental Example 2: The photocatalytic hydrogen production experiment was conducted using an online photocatalytic hydrogen production system (CEL-PAEM-D8), with the temperature controlled at about 6°C; a 300WXe lamp (covered with a cutoff filter: JB300) was used as a light source to simulate sunlight (300-1100nm); 30 mg of the product obtained in Example 1 and Comparative Examples 1-3 was dispersed in a mixed solution containing 6 mL of methanol and 24 mL of deionized water; before turning on the xenon lamp, a vacuum pump was used to evacuate for 30 min to ensure that the reaction environment was in a vacuum state; hydrogen was extracted once an hour, analyzed using an online gas chromatograph, and the amount of hydrogen produced and the hydrogen production rate were recorded. The results are shown in FIG. Figure 4 And as shown in Table 1.

[0074] Table 1 Stability of photoelectrochemical hydrogen production catalysts

[0075]

[0076] Figure 4 The results in Table 1 show that the hydrogen production rate of Example 1 is significantly higher than that of Comparative Examples 1-6, and the hydrogen production rate of Comparative Example 6 is almost 0, indicating that the hydrogen production rate of GeNiSnO 4 and WTiO 5 The interaction between the composite structure can significantly improve the efficiency of photocatalytic hydrogen production, and the modified carbon nanotubes can further enhance the electron transmission capacity. After 24 hours, the hydrogen production rate of the catalyst in Example 1 did not decrease significantly. This shows that the photoelectrochemical hydrogen production catalyst prepared by the present invention can produce hydrogen under light, has high hydrogen production efficiency, strong stability, and excellent anti-photocorrosion performance.

[0077] Experimental Example 3: Under 300 W xenon lamp irradiation (filter: AM1.5G, light intensity: 100 mW / cm 2 ), the products obtained in Example 2 and Comparative Examples 1-6 were subjected to linear sweep voltammetry (LSV) test, and the results are as follows Figure 5 shown. Figure 5The results show that the photocurrent intensity of Example 2 is significantly stronger than that of Comparative Examples 1-6, indicating that the separation and transfer rate of photogenerated electron-hole pairs on the surface is greatly improved, which is beneficial to improving the photocatalytic hydrogen production rate. At the same time, the starting point of hydrogen production in Example 2 is lower than that of Comparative Examples 1-6, indicating that the photoelectrochemical hydrogen production catalyst of the present invention has a large current density, can significantly promote the transmission of photogenerated electrons, and has a high hydrogen production efficiency.

[0078] Experimental Example 4: Draw the UV-visible diffuse reflectance spectra of the products obtained in Example 3 and Comparative Examples 1-6. The results are as follows: Figure 6 As shown, Figure 6 The results show that, except for Comparative Example 6, all samples have strong absorption in the visible light region, indicating that the photoelectrochemical hydrogen production catalyst of the present invention is an excellent visible light-photoresponsive catalyst, and the expansion of the light absorption range is conducive to improving the photocatalytic hydrogen production rate.

[0079] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention (including the claims) is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0080] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A photoelectrochemical hydrogen production catalyst, characterized in that: The photoelectrochemical hydrogen production catalyst comprises modified carbon nanotubes, WTiO5 and GeNiSnO4; the WTiO5 and GeNiSnO4 are loaded on the surface of the modified carbon nanotubes; The method for preparing the modified carbon nanotubes comprises the following steps: (1) dissolving carbon nanotubes in DMSO, and ultrasonically treating the mixture for 1 h in a cell crusher to obtain a first solution; dissolving phytic acid-aminoboric acid in DMSO, and mixing the mixture to obtain a second solution; (2) slowly adding the second solution obtained in step (1) to the first solution through a constant pressure funnel, the volume ratio of the second solution to the first solution is 1:1, the dropping speed is 0.8-1 mL / min, and then reacting at 60° C. with magnetic stirring for 10 h, and then vacuum filtering to collect the residue; (3) placing the filter residue obtained in step (2) in a 60-80 vol% ethanol solution, with a mass volume ratio of the filter residue to the ethanol solution of 1 g:20 mL, ultrasonically treating at 80 kHz for 3 h at room temperature, centrifuging at 16000 rpm for 5 min, washing the precipitate with a 20 wt% ethanol solution for 3-5 times, placing it in an oven, and drying it at 70°C to constant weight to obtain modified carbon nanotubes; The preparation method of phytic acid-aminoboric acid comprises the following steps: (a) adding phytic acid to deionized water, stirring and dissolving, preparing a phytic acid solution with a concentration of 0.1 g / mL, adding triethylenetetramine, the mass ratio of triethylenetetramine to phytic acid being 4:3, stirring at 180 rpm for 1 h, and obtaining a mixed solution A; adding 4-aminophenylboric acid to anhydrous ethanol, stirring and dissolving, and obtaining a 4-aminophenylboric acid solution with a concentration of 0.2 g / mL; (b) The 4-aminophenylboronic acid solution obtained in step (a) is added to the mixed solution A at a rate of 10-20 mL / min, the volume ratio of the 4-aminophenylboronic acid solution to the mixed solution A is 1:1.5, the mixture is transferred to a reactor, reacted at 120° C. for 8 h, cooled to room temperature, and diluted ammonia water is added dropwise in an ice-salt bath environment until the solution pH is 8, vacuum filtered, and the solid on the filter paper is washed 3 times with anhydrous ethanol, rotary evaporated at 95° C. for 1 h, washed 3 times with deionized water, and vacuum dried at 80° C. for 1 h to obtain phytic acid-aminoboric acid.

2. The photoelectrochemical hydrogen production catalyst according to claim 1, characterized in that Step (1) In the first solution, the ratio of carbon nanotubes to DMSO is 2 mg:1 mL; in the second solution, the ratio of phytic acid-aminoboric acid to DMSO is 2.5 mg:1 mL.

3. A method for preparing a photoelectrochemical hydrogen production catalyst according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1: (NH4)6W7O 24 6H2O was dissolved in deionized water and stirred magnetically for 10-20 min, then Ti(C4H9O)4 and NaOH were added thereto, and after stirring magnetically for 1-2 h, the mixture was transferred to a stainless steel autoclave lined with polytetrafluoroethylene, and heated at 180-200°C for 24-36 h. After the reaction, the mixture was naturally cooled to room temperature, centrifuged at 8000 r / min for 5 min, and the precipitate was washed 3 times with a 20-30 vol% acetic acid aqueous solution, and then washed 3 times with deionized water and anhydrous ethanol respectively, and placed in a vacuum drying oven and dried at 60°C for 12 h to obtain WTiO5; S2: The WTiO5 prepared in step S1 and methanol were mixed in a ratio of 100 mg:20 mL, and ultrasonicated at 20 kHz for 10 min to obtain reaction solution A; Ge(C2O4)2, Ni(NO3)2·6H2O and SnCl2·2H2O were weighed and dissolved in methanol, and ultrasonicated at 20 kHz for 10 min to obtain reaction solution B; modified carbon nanotubes were weighed and dissolved in methanol, and ultrasonicated for 10 min, which was recorded as reaction solution C; S3: The reaction solution B obtained in step S2 is quickly added to the reaction solution A to form a mixed solution, and then the reaction solution C is added to the above mixed solution, stirred at 500 r / min for 24 h, centrifuged at 8000 r / min for 5 min, the precipitate is washed three times with methanol, placed in a vacuum drying oven, dried at 60°C for 12 h, put into a crucible, placed in a muffle furnace, heated to 350°C in air at a rate of 2°C / min, calcined for 4 h, and then naturally cooled to room temperature to obtain a photoelectrochemical hydrogen production catalyst.

4. The method for preparing the photoelectrochemical hydrogen production catalyst according to claim 3, characterized in that: (NH4)6W7O in step S1 24 The usage ratio of 6H2O, deionized water, Ti(C4H9O)4, and NaOH is 27 g:800 mL:34 g:7 g.

5. The method for preparing the photoelectrochemical hydrogen production catalyst according to claim 4, characterized in that: In the reaction solution B described in step S2, the dosage ratio of Ge(C2O4)2, Ni(NO3)2·6H2O, SnCl2·2H2O and methanol is 12 g:15 g:11 g:1200 mL.

6. The method for preparing the photoelectrochemical hydrogen production catalyst according to claim 5, characterized in that: In the reaction solution C in step S2, the ratio of modified carbon nanotubes to methanol is 30 mg:1 mL.

7. The method for preparing the photoelectrochemical hydrogen production catalyst according to claim 6, characterized in that: In step S3, the volume ratio of reaction solution A, reaction solution B and reaction solution C is 1:2:1.

Images