Preparation method and application of surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst

Abstract

The present application relates to the technical field of catalyst, in particular to a preparation method and application of a surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst, comprising the following steps: firstly, taking Ketjen black and performing acidification treatment in a mixed acid environment to optimize the surface properties; then, performing hydroxyl functional modification on the surface; finally, uniformly dispersing the modified sample in ethylene glycol solvent, and growing platinum and nickel metals in the form of binary alloy in the carbon matrix through high-temperature reduction method, so as to obtain the surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst. Electrochemical test shows that the catalyst prepared by the present application exhibits excellent catalytic performance in the field of seawater hydrogen production, and the current density thereof in seawater can reach 4200 mA cm ‑2 , which is nearly 3 times (1500 mA cm ‑2 ) the performance of a commercial PtC under the same overpotential. Meanwhile, the catalyst prepared by the present application also has excellent hydrogen evolution reaction stability, low cost, economic and environmental protection, and wide application prospect in the field of electrolytic seawater hydrogen production.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of catalysts, in particular to a preparation method and application of a surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst. BACKGROUND

[0002] Hydrogen energy can be divided into green hydrogen, gray hydrogen, blue hydrogen and the like according to different production methods, wherein green hydrogen is the optimal choice for green hydrogen production due to the use of renewable energy for power generation. Seawater hydrogen production is an important way to produce green hydrogen, and has a broad development prospect due to the advantages that the raw material is almost not limited by region and is rich in reserves. Seawater hydrogen production is to decompose water in seawater into hydrogen and oxygen through electrolysis. However, due to the large amount of salts and impurities in seawater, it puts forward strict requirements for electrolysis equipment and catalysts; at the same time, in the water electrolysis system, the selection of the catalyst also greatly affects the efficiency of the cathode hydrogen evolution reaction and the anode oxygen evolution reaction, therefore, it is the key to promote the development of seawater hydrogen production to research a high-efficiency catalyst system with large current density, salt corrosion resistance, high activity, high stability and easy to scale in seawater.

[0003] Common catalysts on the market can be roughly divided into noble metal type and non-noble metal type. Pt and Ru in the noble metal type are common noble metal catalysts, which have unfilled d orbitals, so as to facilitate the adsorption of reactants and have high reaction rate. In addition, the noble metal catalyst has excellent selectivity and stability in various environments such as high temperature and high pressure, and is the only choice for seawater hydrogen evolution catalyst. However, its high price hinders a large number of industrial applications. Therefore, it is an important link to realize the industrialized production of green hydrogen to develop a seawater hydrogen production catalyst which can reduce the content of Pt, improve the atomic utilization rate, reduce the production cost, and at the same time improve the hydrogen evolution performance. SUMMARY

[0004] The purpose of the present application is to solve the problems existing in the prior art, and a preparation method and application of a surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst are provided. The catalyst prepared by the method has excellent hydrogen evolution reaction stability, low cost, is economic and environmentally friendly, and has a broad application prospect in the field of electrolytic seawater hydrogen production.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A preparation method of a surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst, the specific steps are as follows:

[0007] Step 1, synthesis of acid-treated Ketjen black: a certain amount of Ketjen black was uniformly dispersed in an acid solution prepared by mixing hydrochloric acid, nitric acid and deionized water, and then, under the combined action of oil bath heating and magnetic stirring, the reaction was carried out for 15-24 h, and then, the product was filtered and washed by centrifugation for several times until the washing liquid was neutral, and then, the product was vacuum dried to obtain acid-treated Ketjen black;

[0008] Step 2, hydroxyl functionalization of Ketjen black surface: the acid-treated Ketjen black was uniformly dispersed in a Tris-HCl buffer solution with a pH of 8.5, and then, dopamine hydrochloride was added to the system and stirred magnetically for 3 h, and then, the product was dispersed in a Tris-HCl buffer solution with a pH of 7.0 again, and then, dextran (T-40) was added as a hydroxylating agent, and then, the product was reacted in an oil bath for 17 h, and then, the product was washed by centrifugation and vacuum dried to obtain the sample;

[0009] Step 3, preparation of a surface-hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst: the sample prepared in Step 2 was uniformly dispersed in ethylene glycol, and then, a platinum and nickel metal salt precursor solution was added to the system and ultrasonicated, and then, ascorbic acid was added as a reducing agent, and then, the product was reacted in an oil bath at a high temperature under magnetic stirring for 12 h, and then, the product was washed by centrifugation and vacuum dried to obtain a surface-hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst.

[0010] Preferably, in Step 1, the amount of Ketjen black is 0.5 g, the amount of hydrochloric acid is 35 mL, the amount of nitric acid is 35 mL, and the amount of deionized water is 70 mL.

[0011] Preferably, in Step 1, the oil bath temperature is 90-100℃, and the washing condition is deionized water washing, which is repeated for 4-5 times.

[0012] Preferably, in Step 2, the amount of acid-treated Ketjen black is 50 mg, the amount of Tris-HCl buffer solution with a pH of 8.5 is 10 mL, the amount of dopamine hydrochloride is 5 mg, the amount of dextran is 50-350 mg, and the amount of Tris-HCl buffer solution with a pH of 7.0 is 10 mL.

[0013] Preferably, in Step 2, the oil bath temperature is 30-40℃, the magnetic stirring speed is 400-410 r / min, and the vacuum drying time is 20-24 h. -1

[0014] Preferably, in Step 3, the amount of sample is 8 mg, the amount of ethylene glycol is 10-12 mL, the platinum metal salt precursor is potassium tetrachloroplatinate, and the amount thereof is 14 mg, the nickel metal salt precursor is nickel nitrate, and the amount thereof is 42 mg, and the amount of ascorbic acid is 120 mg.

[0015] ​Preferably, in step 3, the ultrasonic temperature is 0-20℃, the oil bath temperature is 90-100℃, and the magnetic stirring speed is 400-410r / min -1 .

[0016] The application also provides application of the surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst prepared by the preparation method in a hydrogen evolution reaction (HER).

[0017] By adopting the technical scheme, the catalyst has the following advantages: first, the catalyst uses platinum-nickel binary alloy as an active component, which can reduce the platinum loading, reduce the hydrogen production cost, improve the electrocatalytic activity, and realize large current density output at a low overpotential, and the current density of the catalyst in seawater can reach 4200mAcm -2 , which is nearly 3 times (1500mAcm -2 ) of the performance of a commercial PtC at the same overpotential (609mV). Second, the surface functionalization treatment improves the catalyst performance and further improves the stability of the catalyst.

[0018] In seawater, the hydrogen evolution reaction (HER) test results show that the current density of the PtNiNC-OH 0.25 can reach 4200mAcm -2 , which is nearly 3 times (1500mAcm -2 ) of the performance of a commercial PtC at the same overpotential (609mV), which shows that the surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst has good application and commercial prospects. Meanwhile, at a current density of 100mAcm -2 , the overpotential of the PtNiNC-OH 0.25 is 31.88mV, and the overpotential of the commercial PtC is 79.31mV, and at the same current density, the smaller the overpotential is, the better, which further proves that the catalytic activity of the hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst in the hydrogen evolution reaction is better than that of the commercial PtC. Therefore, the surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst has great potential in the field of electrolytic seawater.

[0019] Compared with the prior art, the application has the following beneficial effects:

[0020] 1. The surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst prepared by the application has excellent activity and stability, and can achieve large current density (the current density of the PtNiNC-OH0.25 can reach 4200mAcm -2 , which is nearly 3 times (1500mAcm -2 ) of the performance of a commercial PtC at the same overpotential (609mV), and has great potential in the field of electrolytic seawater and broad application prospects.

[0021] 2、The surface hydroxylated platinum nickel bimetallic seawater hydrogen production catalyst prepared by the method has good catalytic activity, the reaction condition of the preparation method is relatively mild, compared with the commercial PtC on the market, the cost is low, economic and environmental protection, and the catalytic performance is better. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 PtNiNC-OH prepared for the present application examples 1, 2, 3 and comparative example 1 0.15 , PtNiNC-OH 0.25 , PtNiNC-OH 0.35 , PtNiNC sample infrared spectrum image;

[0023] Figure 2 PtNiNC-OH prepared for the present application examples 1, 2, 3 and comparative example 1 0.15 , PtNiNC-OH 0.25 , PtNiNC-OH 0.35 , PtNiNC sample XRD image;

[0024] Figure 3 PtNiNC-OH prepared for the present application examples 2 and comparative example 1 0.25 , PtNiNC sample TEM image and its corresponding EDS element spectrum distribution chart;

[0025] Figure 4 PtNiNC-OH prepared for the present application examples 1, 2, 3 and comparative examples 1, 2 0.15 , PtNiNC-OH 0.25 , PtNiNC-OH 0.35 , PtNiNC and commercial PtC in seawater HER performance comparison chart. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings, so that those skilled in the art can better understand the advantages and features of the present application, and the protection scope of the present application can be more clearly defined. The described embodiments of the present application are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0027] Example 1

[0028] Surface hydroxylated platinum nickel bimetallic seawater hydrogen production catalyst PtNiNC-OH 0.15 Preparation method:

[0029] (1) Acid treatment of Ketjen black:

[0030] a) 35 mL of hydrochloric acid, nitric acid and 70 mL of deionized water were added to a flask containing 0.5 g of Ketjen black, under the condition of condensation reflux, 100 °C was maintained, and magnetic stirring was carried out with oil bath heating for 15-24 h.

[0031] b) After the reaction was completed, water was added and left overnight, and then filtered and centrifuged 4-5 times until the washing liquid was neutral, and vacuum drying was performed to obtain acid-treated Ketjen black.

[0032] (2) Hydroxyl functionalization of the surface of Ketjen black:

[0033] a) 50 mg of acid-treated Ketjen black was weighed and uniformly dispersed in 10 mL of Tris-HCl (pH 8.5).

[0034] b) Then 5 mg of dopamine hydrochloride was added, and after magnetic stirring for 3 h, it was washed with deionized water, anhydrous ethanol and Tris-HCl (pH 7.0), respectively.

[0035] c) 0.15 g of dextran (T-40) was weighed and dissolved in 3 mL of deionized water to obtain a dextran solution.

[0036] d) The washed Ketjen black was redispersed in 10 mL of Tris-HCl (pH 7.0), and the dextran solution was added and reacted in an oil bath at 35 °C for 17 h.

[0037] e) After the reaction was completed, it was washed with deionized water and anhydrous ethanol alternately for 3 times each, and vacuum dried for 24 h to collect the sample.

[0038] (3) Preparation of a surface-hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst:

[0039] a) 8 mg of the sample prepared in (2) above was weighed and dispersed in 12 mL of ethylene glycol, and ultrasonicated at low temperature for more than 30

[0040] min.

[0041] b) 14 mg of potassium tetrachloroplatinate and 42 mg of nickel nitrate were added, and ultrasonication was continued at low temperature for more than 30 min.

[0042] c) 120 mg of ascorbic acid was added and reacted at 100 °C with magnetic stirring for 12 h. After the reaction was completed, it was washed with deionized water for 2-3 times, and vacuum dried for 24 h to obtain a surface-hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst PtNiNC-OH 0.15 .

[0043] Example 2

[0044] Surface hydroxylated platinum nickel bimetallic seawater hydrogen production catalyst PtNiNC-OH 0.25 Preparation method:

[0045] (1) Synthesis of acid treated Ketjen black:

[0046] a) 35 mL of hydrochloric acid, nitric acid and 70 mL of deionized water were added to a flask containing 0.5 g of Ketjen black, under the condition of condensation reflux, 100 ℃ was maintained, and magnetic stirring was carried out, and the oil bath was heated for 15-24 h.

[0047] b) After the reaction was completed, water was added and left overnight, then filtered and centrifuged 4-5 times until the washing liquid was neutral, and vacuum drying was carried out to obtain acid treated Ketjen black.

[0048] (2) Hydroxyl functionalization of the surface of Ketjen black:

[0049] a) 50 mg of acid treated Ketjen black was weighed and uniformly dispersed in 10 mL of Tris-HCl (pH 8.5).

[0050] b) Then 5 mg of dopamine hydrochloride was added, and after magnetic stirring for 3 h, deionized water, anhydrous ethanol and Tris-HCl (pH 7.0) were used for washing, respectively.

[0051] c) 0.25 g of dextran (T-40) was weighed and dissolved in 5 mL of deionized water to obtain a dextran solution.

[0052] d) The washed Ketjen black was redispersed in 10 mL of Tris-HCl (pH 7.0), the dextran solution was added and reacted in an oil bath at 35 ℃ for 17 h.

[0053] e) After the reaction was completed, deionized water and anhydrous ethanol were used for centrifugal washing alternately for 3 times each, vacuum drying was carried out for 24 h, and the sample was collected.

[0054] (3) Preparation of surface hydroxylated platinum nickel bimetallic seawater hydrogen production catalyst:

[0055] a) 8 mg of the sample prepared in (2) above was weighed and dispersed in 12 mL of ethylene glycol, and ultrasonic treatment was carried out for more than 30

[0056] min at low temperature.

[0057] b) 14 mg of potassium tetrachloroplatinate and 42 mg of nickel nitrate were added, and ultrasonic treatment was continued for more than 30 min at low temperature.

[0058] c) 120 mg of ascorbic acid was added, and magnetic stirring was carried out at 100 ℃ for 12 h. After the reaction was completed, deionized water was used for centrifugal washing for 2-3 times, and vacuum drying was carried out for 24 h to obtain surface hydroxylated platinum nickel bimetallic seawater hydrogen production catalyst PtNiNC-OH 0.25.

[0059] Example 3

[0060] Surface hydroxylated platinum nickel bimetallic seawater hydrogen production catalyst PtNiNC-OH 0.35 Preparation method:

[0061] (1) Synthesis of acid treated Ketjen black:

[0062] a) 35 mL of hydrochloric acid, nitric acid and 70 mL of deionized water were added to a flask containing 0.5 g of Ketjen black, under the condition of condensation reflux, 100°C was maintained for magnetic stirring, and the oil bath was heated for 15-24 h.

[0063] b) After the reaction was completed, water was added and left overnight, then filtered and centrifuged 4-5 times until the washing liquid was neutral, and vacuum drying was performed to obtain acid treated Ketjen black.

[0064] (2) Hydroxyl functionalization of the surface of Ketjen black:

[0065] a) 50 mg of acid treated Ketjen black was weighed and uniformly dispersed in 10 mL of Tris-HCl (pH 8.5).

[0066] b) Then 5 mg of dopamine hydrochloride was added, and after magnetic stirring for 3 h, it was washed with deionized water, anhydrous ethanol and Tris-HCl (pH 7.0), respectively.

[0067] c) 0.35 g of dextran (T-40) was weighed and dissolved in 7 mL of deionized water to obtain a dextran solution.

[0068] d) The washed Ketjen black was redispersed in 10 mL of Tris-HCl (pH 7.0), and the dextran solution was added and reacted in an oil bath at 35°C for 17 h.

[0069] e) After the reaction was completed, it was washed with deionized water and anhydrous ethanol alternately for 3 times each, and vacuum dried for 24 h to collect the sample.

[0070] (3) Preparation of surface hydroxylated platinum nickel bimetallic seawater hydrogen production catalyst:

[0071] a) 8 mg of the sample prepared in (2) above was weighed and dispersed in 12 mL of ethylene glycol, and ultrasonicated for more than 30 min at low temperature.

[0072] min above.

[0073] b) 14 mg of potassium tetrachloroplatinate and 42 mg of nickel nitrate were added, and ultrasonication was continued for more than 30 min at low temperature.

[0074] c) adding 120 mg of ascorbic acid and stirring the reaction at 100°C for 12 h under magnetic stirring. After the reaction is completed, centrifugal washing with deionized water for 2-3 times, vacuum drying for 24 h to obtain the surface-hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst PtNiNC-OH 0.35 .

[0075] Comparative Example 1

[0076] Preparation method of unmodified platinum-nickel alloy catalyst PtNiNC:

[0077] (1) 8 mg of Ketjen black was weighed and dispersed in 12 mL of ethylene glycol under low temperature ultrasonic for more than 30 min.

[0078] (2) 14 mg of potassium tetrachloroplatinate and 42 mg of nickel nitrate were added, and the low temperature ultrasonic was continued for more than 30 min.

[0079] (3) 120 mg of ascorbic acid was added and stirred at 100°C for 12 h under magnetic stirring. After the reaction is completed, centrifugal washing with deionized water for 2-3 times, vacuum drying for 24 h to obtain the unmodified platinum-nickel alloy catalyst PtNiNC.

[0080] Comparative Example 2

[0081] The HER performance test was carried out by using commercial PtC catalyst to replace the catalyst in Example 1, Example 2, Example 3 and Comparative Example 1.

[0082] The specific implementation steps are as follows:

[0083] Step 1, 4 mg of catalyst in Example 1, Example 2, Example 3 and Comparative Example 1 and commercial PtC catalyst in Comparative Example 2 were added to a mixed solution of 720 μL of isopropyl alcohol and 80 μL of Nafion solution, and ultrasonic dispersion was carried out for 30-60 min to obtain a uniformly dispersed slurry.

[0084] Step 2, 800 μL of the slurry was drop-coated on a hydrophilic carbon paper with an area of 4.0 cm 2 , and a working electrode was obtained by baking and drying.

[0085] Electrochemical test

[0086] The electrochemical performance of PtNiNC-OH 0.15 , PtNiNC-OH 0.25 , PtNiNC-OH 0.35 , PtNiNC in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and commercial PtC catalyst was tested by an electrochemical workstation. The electrochemical workstation used was Donghua electrochemical workstation, model DH7002A. The specific method is as follows:

[0087] The treated seawater solution was used as an electrolyte, a three-electrode system was adopted, and the PtNiNC-OH prepared in Example 1 0.15 , the PtNiNC-OH prepared in Example 2 0.25 , and the PtNiNC-OH prepared in Example 3 0.35 , respectively, were used as working electrodes, a mercury oxide electrode was used as a reference electrode, and a graphite electrode was used as a counter electrode, and linear sweep voltammetry curves of the PtNiNC prepared in Comparative Example 1 and the PtC prepared in Comparative Example 2 were tested.

[0088] HER performance test:

[0089] The HER performance of the PtNiNC-OH 0.15 , the PtNiNC-OH 0.25 , the PtNiNC-OH 0.35 , and the PtNiNC was tested by linear sweep voltammetry, and HER polarization curve graphs (LSV graphs) obtained are shown in Figure 4 It can be known from the graphs that the current density of the PtNiNC-OH 0.25 can reach 4200 mAcm -2 , and the overpotential (609 mV) is nearly 3 times (1500 mAcm -2 ) of the performance of a commercial PtC. Meanwhile, under a current density of 100 mAcm -2 , the overpotential of the PtNiNC-OH 0.25 is 31.88 mV, and the overpotential of the commercial PtC is 79.31 mV.

[0090] In summary, the surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst prepared in the application has obvious advantages in water electrolysis performance over the noble metal catalyst PtC on the market, and the catalytic activity and stability of the catalyst under a large current density are very excellent, which is conducive to realizing industrial application in the electrolytic hydrogen production industry.

[0091] The description and practice disclosed in the application are easy to think and understand for ordinary skilled persons in the technical field, and some improvements and refinements can be made without departing from the principles of the application. Therefore, the modifications or improvements made without departing from the spirit of the application should also be regarded as the protection scope of the application.

Claims

1. A method for preparing a surface-hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst, characterized by, The specific steps are as follows: Step 1, synthesis of acid-treated Ketjen black: a certain amount of Ketjen black was uniformly dispersed in an acid solution prepared from hydrochloric acid, nitric acid and deionized water, then, under the combined action of oil bath heating and magnetic stirring, the reaction was carried out for 15-24 h, then, the product was filtered and washed by centrifugation for several times until the washing liquid was neutral, and then vacuum dried to obtain acid-treated Ketjen black; Step 2, surface hydroxyl functionalization of Ketjen black: the acid-treated Ketjen black was uniformly dispersed in a Tris-HCl buffer solution with a pH of 8.5, then, hydrochloric acid dopamine was added to the system and stirred for 3 h, then, the product was dispersed in a Tris-HCl buffer solution with a pH of 7.0 again and dextran was added as a hydroxylating agent, and then the product was reacted in an oil bath for 17 h, and then washed by centrifugation, vacuum dried and collected; Step 3, preparation of surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst: the sample prepared in step 2 was uniformly dispersed in ethylene glycol, then, a platinum and nickel metal salt precursor solution was added to the system and ultrasonic treatment was continued, then, ascorbic acid was added as a reducing agent, and the product was reacted in an oil bath at high temperature under the action of magnetic stirring for 12 h, and then, the product was washed by centrifugation and vacuum dried to obtain a surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst; In step 1, the amount of Ketjen black was 0.5 g, the amount of hydrochloric acid was 35 mL, the amount of nitric acid was 35 mL, and the amount of deionized water was 70 mL; In step 1, the oil bath temperature was 90-100℃, and the washing condition was deionized water washing, repeated for 4-5 times; In step 2, the amount of acid-treated Ketjen black was 50 mg, the amount of Tris-HCl buffer solution with a pH of 8.5 was 10 mL, the amount of hydrochloric acid dopamine was 5 mg, the amount of dextran was 50-350 mg, and the amount of Tris-HCl buffer solution with a pH of 7.0 was 10 mL; In step 2, the oil bath temperature is 30-40℃, the magnetic stirring speed is 400-410r / min -1 , and the vacuum drying time is 20-24h. In step 3, the amount of sample was 8 mg, the amount of ethylene glycol was 10-12 mL, the platinum metal salt precursor was potassium tetrachloroplatinate with an amount of 14 mg, the nickel metal salt precursor was nickel nitrate with an amount of 42 mg, and the amount of ascorbic acid was 120 mg; In step 3, the ultrasonic temperature is 0-20℃, the oil bath temperature is 90-100℃, and the magnetic stirring speed is 400-410 r / min -1 .

2. Application of a surface hydroxylated platinum-nickel bimetallic seawater hydrogen production catalyst obtained by the preparation method of claim 1 in a hydrogen evolution reaction.

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