Preparation method of titanium dioxide supported platinum copper diatomic catalyst and application thereof

Abstract

The application belongs to the technical field of electrocatalysis, and particularly relates to a preparation method of a titanium dioxide supported platinum copper diatomic catalyst and application thereof; the specific steps of the method are as follows: a certain proportion of hydrochloric acid and tetrabutyl titanate are stirred and mixed, then the mixture is kept at a certain temperature under high temperature in an autoclave, and then TiO2 nanosheets are obtained after cleaning and drying; then the TiO2 nanosheets are subjected to Ar plasma treatment, a mixed solution of a certain proportion of ethylenediamine copper and chloroplatinic acid is added into the TiO2 colloid, and a Pt x Cu1-TiO2 nanocatalyst; the Pt x Cu1-TiO2 nanosheet catalyst exhibits excellent hydrogen evolution catalytic performance under mild reaction conditions, and has a wide application prospect in the field of seawater hydrogen evolution.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrocatalysis, and particularly relates to a preparation method of a titanium dioxide supported platinum copper bimetallic catalyst and application thereof. BACKGROUND

[0002] Hydrogen is a clean and efficient new energy, and is an ideal green energy to replace fossil fuels. Among many hydrogen production methods, electrochemical water splitting is one of the most promising energy conversion technologies. Because it can not only produce high-purity hydrogen, but also does not emit any greenhouse gases. Under the background of water electrolysis, by optimizing the catalyst and electrolysis environment, the overall catalytic activity can be improved. However, the current commercial water electrolysis technology mainly relies on freshwater resources, which may lead to water shortage. In addition, the global seawater resources are abundant and have strong sustainability. Direct seawater splitting may be the most practical solution for water electrolysis. However, the biggest challenge of direct seawater splitting is the presence of high concentrations of chloride ions (corrosive ions) and cations (calcium deposits), as well as the low efficiency and slow reaction kinetics of the electrolysis system under near-neutral conditions (~pH 8.0), which leads to the performance of the cathode material being unsatisfactory, which seriously hinders its large-scale application in seawater electrolysis. In summary, the development of an efficient, green, and low-cost hydrogen evolution catalyst has extremely important economic value and broad application prospects for the entire hydrogen production industry.

[0003] Therefore, it is of great significance to develop a preparation method of a titanium dioxide supported platinum copper bimetallic catalyst. SUMMARY

[0004] In the existing method of electrocatalytic hydrogen evolution, platinum-based catalysts are widely used in hydrogen evolution reactions due to their excellent performance, although they are relatively expensive, but their high catalytic performance and stability make them still irreplaceable in many high-end applications. Therefore, the use of the above-mentioned electrocatalyst with low platinum dosage, high platinum atom utilization efficiency and low overpotential is crucial for the current and future hydrogen-driven economy.

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, and to provide a titanium dioxide supported platinum copper bimetallic catalyst (Pt x Cu1–TiO2) for direct seawater electrolysis for hydrogen production, a preparation method thereof and application thereof. Through the method of "doping-peeling", the atomic doping of platinum and copper atoms on the titanium dioxide nanosheet is regulated, and the utilization rate of platinum and copper atoms is maximized. The bimetallic platinum and copper doped titanium dioxide nanosheet catalyst prepared can drive efficient hydrogen evolution under the conditions of seawater.

[0006] In order to solve the above technical problems, a preparation method of a titanium dioxide supported platinum copper bimetallic catalyst is disclosed, and the specific steps are as follows:

[0007] S1. The mixed solution obtained by uniformly mixing the hydrochloric acid solution and the tetrabutyl titanate solution is added into an autoclave, and the temperature is raised and maintained;

[0008] S2. After the autoclave is cooled to room temperature, the product is collected, washed, peeled, centrifuged, and dried to obtain monolayer titanium dioxide nanosheets;

[0009] S3. The titanium dioxide nanosheets are dispersed into deionized water after Ar plasma treatment to obtain a titanium dioxide colloid;

[0010] S4. The ethylenediamine copper solution and the chloroplatinic acid solution are uniformly mixed and then added into the titanium dioxide colloid obtained in S5, and the titanium dioxide supported platinum-copper diatomic catalyst is obtained by centrifugation and drying.

[0011] The volume ratio of the hydrochloric acid solution to the tetrabutyl titanate solution is 1:(7-9), and the concentration of the hydrochloric acid solution is 2-4 wt%.

[0012] In S1, the temperature is controlled to be maintained at 180-200°C during the heat preservation process, and the maintenance time is 20-24 h.

[0013] In S3, the Ar plasma treatment process is performed for 30-40 s at a power of 100-120 W.

[0014] In S3, the solid-liquid ratio of the titanium dioxide nanosheets to the deionized water is 1 g:(250-300) mL.

[0015] The concentration of the chloroplatinic acid solution is 0.009-0.04 wt%, and the solid-liquid ratio of the titanium dioxide nanosheets treated by Ar plasma, the ethylenediamine copper solution, and the chloroplatinic acid is 1 g:100 mL:125 mL.

[0016] Preferably, the concentration of the chloroplatinic acid solution is 0.009-0.01 wt%.

[0017] Specifically, in the titanium dioxide supported platinum-copper diatomic catalyst prepared by the above preparation method, platinum and copper are doped in the form of diatomic atoms in the nanosheet layer of titanium dioxide, the doping ratio is 0.5-4 wt%, and the thickness of the titanium dioxide nanosheet is 1-1.4 nm.

[0018] Specifically, in some embodiments of the present application, the titanium dioxide supported platinum-copper diatomic catalyst prepared by the above preparation method is prepared into a catalyst slurry, which is added dropwise to carbon paper to prepare a working electrode, and then the working electrode is subjected to electrochemical hydrogen evolution test by a single electrolytic cell to verify the application prospect of the titanium dioxide supported platinum-copper diatomic catalyst prepared by the present application in the field of seawater direct electrolysis for hydrogen production.

[0019] The application method is preferably as follows: seawater is used as an electrolyte, titanium dioxide loaded with a platinum-copper bimetallic catalyst is added, and an electrocatalytic hydrogen evolution reaction is carried out at room temperature to produce hydrogen.

[0020] Advantages:

[0021] Compared with a pure titanium dioxide nanosheet catalyst, under the same catalytic conditions, the Pt x The Cu1-TiO2 nanosheet catalyst exhibits excellent hydrogen evolution performance. Among them, compared with the same type of catalysts reported, under the same catalytic conditions (seawater), the hydrogen evolution overpotential of Pt1Cu1-TiO2 is 160 mV, and the Tafel slope is 77.46 mV dec –1 At the same time, the electrode exhibits excellent stability during chronoamperometric measurement. Therefore, the Pt x The Cu1-TiO2 nanosheet catalyst has broad application prospects in the field of seawater hydrogen evolution. BRIEF DESCRIPTION OF DRAWINGS

[0022] The above and / or other aspects of the present application will become more apparent by describing in detail the preferred embodiments thereof with reference to the attached drawings.

[0023] Figure 1 It is an atomic force microscope (AFM) image of the Pt1Cu1-TiO2 nanosheet catalyst in Example 1 of the present application;

[0024] Figure 2 It is a transmission electron microscope (TEM) image and a high-resolution electron microscope image (HRTEM) of the Pt1Cu1-TiO2 nanosheet catalyst in Example 1 of the present application;

[0025] Figure 3 It is a high-angle annular dark field scanning electron microscope (HAADF-STEM) image of the Pt1Cu1-TiO2 nanosheet catalyst in Example 1 of the present application;

[0026] Figure 4 It is a linear sweep voltammetry (LSV) curve of the titanium dioxide loaded with a platinum-copper bimetallic nanosheet, titanium dioxide nanosheet and platinum carbon as catalysts for electrochemical hydrogen evolution prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0027] The experimental methods in the following examples are conventional methods unless otherwise specified; and the reagents and materials can be obtained from commercial channels unless otherwise specified.

[0028] Example 1:

[0029] The present application is a titanium dioxide supported platinum copper diatomic catalyst, which is Pt1Cu1-TiO2 in chemical formula, and is prepared by the following method, and the steps are as follows:

[0030] (1) 3 mL of hydrochloric acid (2-4 wt%) is added to 25 ml of tetrabutyl titanate solution (platinum strontium titanium; Aladdin / Aladdin; CAS No.: 5593-70-4), and continuously stirred for 10 min to obtain a mixed solution;

[0031] (2) The obtained mixed solution is stored in a 46 mL autoclave, and maintained at 180°C for 24 h;

[0032] (3) After the sample is cooled to room temperature in the autoclave, the prepared sample is collected and washed with deionized water and anhydrous ethanol respectively. After washing, the sample is placed in a shaker after adding thiobarbituric acid (TBA) and shaken for 10-15 days, and then the obtained sample is centrifuged and dried in an oven at 60°C for 6 h to obtain a TiO2 sample;

[0033] (4) The obtained TiO2 nanosheet is subjected to Ar plasma treatment to manufacture oxygen vacancies, and the plasma treatment time is 30-40 s and the power is 100-120 W;

[0034] (5) The obtained TiO2 sample rich in oxygen vacancies is redispersed into water at a solid-liquid ratio of 4 mg mL –1 ;

[0035] (6) 0.48 mg of chloroplatinic acid is dissolved in 5 mL of deionized water and mixed uniformly, and then mixed with 4 mL of ethylenediamine copper solution (platinum strontium titanium; Aladdin / Aladdin; CAS No.: 14552-35-3), and after stirring sufficiently, it is added dropwise into 10 mL of TiO2 colloid, wherein the dropwise adding speed is controlled at 10 μL every 10 seconds, and finally centrifuged and freeze-dried to obtain a Pt1Cu1-TiO2 nanosheet catalyst.

[0036] Example 2:

[0037] The present application is a titanium dioxide supported platinum copper diatomic catalyst, which is Pt2Cu1-TiO2 in chemical formula, and is prepared by the following method, and the steps are as follows:

[0038] (1) 3 mL of hydrochloric acid (2-4 wt%) is added to 25 ml of tetrabutyl titanate solution (platinum strontium titanium; Aladdin / Aladdin; CAS No.: 5593-70-4), and continuously stirred for 10 min to obtain a mixed solution;

[0039] (2) The obtained mixed solution is stored in a 46 mL autoclave, and maintained at 180°C for 24 h;

[0040] (3) After the sample is cooled to room temperature in the autoclave, the prepared sample is collected and washed with deionized water and anhydrous ethanol respectively. After washing, the sample is placed in a shaker after adding TBA for 10-15 days, and then the obtained sample is centrifuged and dried in an oven at 60°C for 6h to obtain a TiO2 sample;

[0041] (4) The obtained TiO2 nanosheet is subjected to Ar plasma treatment to manufacture oxygen vacancies, the plasma treatment time is 30-40s, and the power is 100-120W;

[0042] (5) The obtained TiO2 sample rich in oxygen vacancies is redispersed into water at a solid-liquid ratio of 4mg mL –1

[0043] (6) 0.96mg of chloroplatinic acid is dissolved in 5mL of deionized water and mixed uniformly, mixed with 4mL of ethylenediamine copper solution (platinum strontium titanium; Aladdin / Aladdin; CAS number: 14552-35-3), fully stirred, and then added dropwise into 10mL of TiO2 colloid, wherein the dropwise adding speed is controlled at 10μL every 10 seconds, and finally centrifuged and freeze-dried to obtain a Pt2Cu1-TiO2 nanosheet catalyst.

[0044] Example 3:

[0045] The titanium dioxide supported platinum copper bimetallic catalyst of the present application has a chemical formula of Pt3Cu1-TiO2, and is prepared by the following method, and the steps are as follows:

[0046] (1) 3mL of hydrochloric acid (2-4wt%) is added into 25ml of tetrabutyl titanate solution (platinum strontium titanium; Aladdin / Aladdin; CAS number: 5593-70-4), and continuously stirred for 10min to obtain a mixed solution;

[0047] (2) The obtained mixed solution is stored in a 46mL autoclave, and maintained at 180°C for 24h;

[0048] (3) After the sample is cooled to room temperature in the autoclave, the prepared sample is collected and washed with deionized water and anhydrous ethanol respectively. After washing, the sample is placed in a shaker after adding TBA for 10-15 days, and then the obtained sample is centrifuged and dried in an oven at 60°C for 6h to obtain a TiO2 sample;

[0049] (4) The obtained TiO2 nanosheet is subjected to Ar plasma treatment to manufacture oxygen vacancies, the plasma treatment time is 30-40s, and the power is 100-120W;

[0050] (5) The obtained TiO2 sample rich in oxygen vacancies is redispersed into water at a solid-liquid ratio of 4mg mL​–1 solid-liquid ratio of 4 mg mL

[0051] (6) 1.44 mg of chloroplatinic acid was dissolved in 5 mL of deionized water and mixed uniformly, mixed with 4 mL of copper ethylenediamine solution (platinum strontium titanium; Aladdin / Aladdin; CAS No.: 14552-35-3), and after stirring, it was added dropwise to 10 mL of TiO2 colloid, wherein the dropwise speed was controlled to be 10 μL every 10 seconds, and finally centrifuged and freeze-dried to obtain a Pt3Cu1-TiO2 nanosheet catalyst.

[0052] Example 4:

[0053] The titanium dioxide supported platinum copper bimetallic catalyst of the present application has a chemical formula of Pt4Cu1-TiO2, which is prepared by the following method, and the steps are as follows:

[0054] (1) 3 mL of hydrochloric acid (2-4 wt%) was added to 25 mL of tetrabutyl titanate solution (platinum strontium titanium; Aladdin / Aladdin; CAS No.: 5593-70-4), and continuously stirred for 10 min to obtain a mixed solution;

[0055] (2) The obtained mixed solution was stored in a 46 mL autoclave and maintained at 180°C for 24 h;

[0056] (3) After the sample was cooled to room temperature in the autoclave, the prepared sample was collected and washed with deionized water and anhydrous ethanol, respectively. After washing, the sample was placed in a shaker after adding TBA and shaken for 10-15 days, and then the obtained sample was centrifuged and dried in an oven at 60°C for 6 h to obtain a TiO2 sample;

[0057] (4) The obtained TiO2 nanosheet was subjected to Ar plasma treatment to manufacture oxygen vacancies, and the plasma treatment time was 30-40 s and the power was 100-120 W;

[0058] (5) The obtained TiO2 sample rich in oxygen vacancies was dispersed into water at a solid-liquid ratio of 4 mg mL –1 solid-liquid ratio of 4 mg mL

[0059] (6) 1.92 mg of chloroplatinic acid was dissolved in 5 mL of deionized water and mixed uniformly, mixed with 4 mL of copper ethylenediamine solution (platinum strontium titanium; Aladdin / Aladdin; CAS No.: 14552-35-3), and after stirring, it was added dropwise to 10 mL of TiO2 colloid, wherein the dropwise speed was controlled to be 10 μL every 10 seconds, and finally centrifuged and freeze-dried to obtain a Pt4Cu1-TiO2 nanosheet catalyst.

[0060] Comparative Example 1:

[0061] A method for preparing a single-layer titanium dioxide nanosheet without metal doping, comprising the following steps:

[0062] (1) 3 mL of hydrochloric acid (2-4 wt%) was added to 25 ml of tetrabutyl titanate solution (Pt Sr Ti; Aladdin; CAS No: 5593-70-4) and continuously stirred for 10 min to obtain a mixed solution;

[0063] (2) The obtained mixed solution was stored in a 46 mL autoclave and maintained at 180°C for 24 h;

[0064] (3) The above sample was cooled to room temperature in the autoclave, then the prepared sample was collected and washed with deionized water and anhydrous ethanol, respectively;

[0065] (4) Finally, the sample after washing was added to TBA and placed in a shaker for 10-15 days, then the obtained sample was centrifuged and dried in an oven at 60°C for 6 h to obtain a TiO2 sample.

[0066] Morphology test: The titanium dioxide supported platinum copper bimetallic catalyst obtained in Example 1 was tested for micro-morphology by atomic force microscopy and transmission electron microscopy, wherein, Figure 1 is an atomic force microscopy (AFM) image of the Pt1Cu1-TiO2 nanosheet catalyst; Figure 2 is a transmission electron microscopy (TEM) image and a high-resolution electron microscopy image (HRTEM) of the Pt1Cu1-TiO2 nanosheet catalyst; Figure 3 is a high-angle annular dark-field scanning electron microscopy (HAADF-STEM) image of the Pt1Cu1-TiO2 nanosheet catalyst;

[0067] It can be seen from Figure 1 that the atomic force microscopy (AFM) of Example 1 observed that the titanium dioxide supported platinum copper bimetallic catalyst was a single-layer nanosheet structure, and the thickness was 1.115 nm.

[0068] It can be seen from Figure 2 that in the transmission electron microscopy (TEM) image of Example 1, it was observed that the obtained Pt1Cu1-TiO2 nanosheet was almost transparent in morphology, and the lattice spacing was 1.96 angstroms, corresponding to the (200) face of titanium dioxide, which confirmed Figure 1 the findings in the atomic force microscopy (AFM).

[0069] It can be seen from Figure 3As can be seen from the HAADF-STEM image of Example 1, Pt atoms and Cu atoms in Pt1Cu1–TiO2 are loaded on TiO2 in the form of atomic pairs, indicating that the titanium dioxide-supported platinum-copper diatomic catalyst was successfully synthesized.

[0070] Electrochemical testing: 4.8 mg of the titanium dioxide nanomaterials prepared in Examples 1-4 and Comparative Example 1 were dispersed in 300 μL of ethanol, and 30 μL of Nafion (D520, 5 wt%) solution was added. After sonication for 20 min, 300 μL of deionized water was added, and the mixture was sonicated for another 20 min to form a uniformly dispersed catalyst slurry. 10 μL of the above catalyst slurry was dropped onto a surface with an area of ​​0.3 cm². –2 Dry on carbon paper, drop once on each side.

[0071] Electrochemical hydrogen evolution tests were conducted using a single electrolytic cell. The working electrode (cathode) was a carbon paper supported on the catalyst, the reference electrode was a silver chloride electrode, and the counter electrode was a carbon rod. A 0.5 M Na₂SO₄ solution (30 mL) was placed in the single electrolytic cell. The linear sweep voltaic-ampere (LSV) curve of the catalyst was tested at room temperature, with the voltage test range being –0.1 V to –0.75 V (reversible hydrogen electrode potential).

[0072] pass Figure 4 It can be seen that the Pt1Cu1–TiO2 prepared in Example 1 exhibits the best electrocatalytic hydrogen evolution performance in seawater, with an overpotential much lower than that of the Pt / C catalyst. The catalysts prepared in Examples 1-4 and Comparative Example 1 were applied to the electrocatalytic hydrogen evolution reaction in seawater, and their catalytic performance is shown in Table 1. Table 1 shows that Pt with different Pt contents exhibits... x The electrocatalytic hydrogen evolution performance of Cu1–TiO2 nanosheet catalysts showed significant differences. The overpotential of the Pt1Cu1–TiO2 nanosheet catalyst in Example 1 was as low as 160 mV, while the overpotential of the TiO2 nanosheet catalyst in Comparative Example 1 was as high as 830.4 mV.

[0073] Table 1 compares the electrocatalytic hydrogen evolution performance of titanium dioxide nanosheets in Examples 1-4 and Comparative Example 1.

[0074] Catalyst overpotential (η 10 )]]> Example 1 160 Example 2 174.8 Example 3 182.2 Example 4 189.9 Comparative Example 1 Comparative Example 2 830.4

[0075] This invention provides a method for preparing a titanium dioxide-supported platinum-copper diatomic catalyst and its application. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for preparing a titanium dioxide-supported platinum copper diatomic catalyst, characterized by, The specific steps are: S1. The mixed solution obtained by uniformly mixing hydrochloric acid solution and tetrabutyl titanate is added to an autoclave, which is heated and kept warm; S2. After the autoclave is cooled to room temperature, the product is collected and washed, and then the washed product is added to thiobarbituric acid and placed in a shaker for 10-15 days. After centrifugation and drying, monolayer titanium dioxide nanosheets are obtained; S3. The titanium dioxide nanosheets are dispersed in deionized water after Ar plasma treatment to obtain a titanium dioxide colloid; S4. Ethylenediamine copper and chloroplatinic acid solution are uniformly mixed and then added to the titanium dioxide colloid obtained in S3. After centrifugation and drying, a titanium dioxide supported platinum-copper diatomic catalyst is obtained.

2. The production method according to claim 1, characterized by, The volume ratio of the hydrochloric acid solution to tetrabutyl titanate is 1:(7-9); the concentration of the hydrochloric acid solution is 2-4 wt%.

3. The preparation method according to claim 1, characterized in that, In S1, the temperature is controlled to maintain at 180-200 ℃ during the warming process, and the maintenance time is 20-24 h.

4. The method of claim 1, wherein, In S3, the Ar plasma treatment process is performed for 30-40 s at a power of 100-120 W.

5. The preparation method according to claim 1, characterized in that, In S3, the solid-liquid ratio of the titanium dioxide nanosheets to deionized water is 1 g:(250-300) mL.

6. The method of claim 1, wherein, The concentration of the chloroplatinic acid solution is 0.009-0.04 wt%; the solid-liquid ratio of the titanium dioxide nanosheets treated by Ar plasma, ethylenediamine copper, and chloroplatinic acid is 1 g:100 mL:125 mL.

7. The application of the titanium dioxide supported platinum-copper diatomic catalyst prepared by the preparation method of any one of claims 1-6 in the field of seawater direct electrolysis for hydrogen production.

8. Use according to claim 7, characterized in that, The specific method is: using seawater as electrolyte, adding the titanium dioxide supported platinum-copper diatomic catalyst, and performing electrocatalytic hydrogen evolution reaction at room temperature to produce hydrogen.

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