1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst as well as preparation method and application thereof

Abstract

The invention provides a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst and a preparation method and application thereof, the preparation method comprises the following steps: dissolving sodium molybdate dehydrate and nickel nitrate hexahydrate in ultrapure water, stirring to form a uniform suspension, putting carbon cloth into the suspension, and transferring to an autoclave; putting the high-pressure kettle into a drying oven, carrying out hydrothermal treatment to obtain NiMoO-Pre / CC, taking out the NiMoO-Pre / CC after the reaction is finished, washing and drying; finally, the NiMoO-Pre / CC is placed in a tubular furnace for vulcanization treatment; the 1TMoS2-NiS2 / CC heterojunction with abundant interfaces and abundant defects is prepared, high-activity 1T-MoS2 can be kept in the hydrogen evolution process, the preparation operation is simple and convenient, the controllability is high, the excellent electrochemical performance is shown in alkaline electrolysis seawater, and specifically, the current density can reach 10 mA cm <-2 > when the current density is 52 mV.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalyst materials, and relates to a simple strategy for constructing a high-efficiency alkaline electrolysis seawater hydrogen evolution catalyst and a preparation method thereof, specifically a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst and a preparation method and application thereof. Background Art

[0002] Electrocatalytic seawater splitting to produce hydrogen (H2) from renewable resources is a promising strategy to address the growing demand for easily transportable and storable forms of energy in locations where ultrapure water availability is hindered by cost, space, or system complexity considerations. However, seawater contains over 90 ions, particularly chloride ions, which can poison catalysts and degrade the long-term durability of seawater electrolysis. Therefore, developing efficient and stable electrocatalysts with high salt tolerance and corrosion resistance is crucial for seawater electrolysis. Nanostructured MoS2 has attracted significant attention for hydrogen production due to its low cost, large surface area, and tunable electronic structure. Furthermore, MoS2 is considered the most promising alternative to Pt-based hydrogen evolution catalysts. MoS2 typically exists in two phases: the semiconducting 2H phase and the metallic 1T phase. 1T-MoS2 has a conductivity 107 times higher than 2H-MoS2, resulting in faster interfacial electron transport, making 1TMoS2 an ideal hydrogen evolution catalyst.

[0003] In recent years, people have conducted extensive research on improving the HER catalytic activity of MoS2-based materials, most of which are devoted to the development and preparation of 1T-MoS2. Methods include electron beam irradiation, chemical alkali metal intercalation, and plasma electron transfer. However, most of these synthesis methods have complicated steps, and the single 1T-MoS2 crystal is metastable and more easily converted into stable 2H-MoS2. The high-quality structure can induce spontaneous electron transfer at the interface, thereby regulating the electronic state between the contact components, optimizing the catalytic activity, and improving the catalytic performance; therefore, the inventors proposed a method for synthesizing 1TMoS2-NiS2 / CC heterojunction on flexible carbon cloth through a sulfide phase precipitation strategy. Through the electronic interaction at the heterojunction interface, the phase transformation of 1T-MoS2 to 2H-MoS2 was successfully suppressed, and a large amount of active 1T-MoS2 was obtained, which maintained high activity for a long time in the electrolysis of seawater for hydrogen evolution. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst and its preparation method and application. The technical solutions adopted by the present invention are as follows: The present invention first provides a method for preparing a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst, comprising the following steps: Step 1: Sodium molybdate dihydrate and nickel nitrate hexahydrate are dissolved in ultrapure water and stirred vigorously at room temperature for a period of time to form a uniform green suspension. Subsequently, the green suspension is transferred to a Teflon-lined stainless steel autoclave and a treated carbon cloth is immersed in the solution. Step 2: Place the stainless steel autoclave in an oven and heat it to 150°C for 6 hours to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction is completed, remove the NiMoO-Pre / CC, wash it several times with deionized water, and dry it in an oven for later use. Step 3: Place the NiMoO-Pre / CC in a temperature-controlled tube furnace and perform a sulfurization treatment at a temperature of approximately 350°C-450°C using sublimed sulfur as the sulfur source. During the sulfurization process, maintain a constant heating rate and time, and maintain a constant nitrogen flow rate.

[0005] Specifically, in the implementation of step 1, the mass of sodium molybdate dihydrate is 100 mg-1000 mg, the mass of nickel nitrate hexahydrate is 100 mg-1000 mg, and the volume of the solution is 30 mL-100 mL.

[0006] In step 3, the heating rate of the tube furnace is 5°C / min, the sulfur source is sublimed sulfur, and the amount of sulfur powder is 50 mg. -1 / g;; the sulfurization temperature is 400℃, the time is 2h, and the argon flow rate is 68 sccm to obtain the final product, which is marked as 1TMoS2-NiS2 / CC.

[0007] The seawater electrolysis catalyst prepared using the above-mentioned 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst preparation method still falls within the scope of protection of the present invention.

[0008] The electrolysis seawater catalyst prepared by the above preparation method is used for electrolysis of seawater under alkaline conditions, which also falls within the protection scope of the present invention.

[0009] The beneficial effects of the present invention are as follows: 1. This invention prepares a homogeneous solution of sodium nitrate dihydrate and nickel nitrate hexahydrate of varying masses. The resulting NiMoO nanoarray precursor material is hydrothermally grown at 150°C for 6 hours on carbon cloth. The precursor is then precipitated through a tube furnace sulfurization phase, ultimately resulting in a nanosheet-modified nanoneedle array structure. This nanosheet-modified nanoarray increases the active surface area, thereby improving electron transfer rates and enhancing the adsorption capacity for hydrogen evolution reaction intermediates. The carbon cloth provides a three-dimensional structure, which helps enhance the material's electrical conductivity. 2. The heterojunction 1TMoS2-NiS2 / CC prepared by this invention can significantly control the electronic structure of 1T-MoS2, fully utilizing the catalytic performance of each active site, further facilitating the dissociation of water molecules and the desorption of hydrogen, and also improving the stability of 1TMoS2. 3. The preparation process of the present invention is simple, the synthesis route is controllable, the reaction time is short, the materials are easily available, the efficiency of hydrogen production by alkaline electrolysis of seawater is high, and it can be used for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying any creative work, other drawings obtained based on these drawings still fall within the scope of the present invention.

[0011] Figure 1 Scanning electron micrographs of NiMoO-pre / CC (a) and 1T-MoS2 / NiS2 / CC (b) in Example 1 show that NiMoO-pre is a nanoneedle-shaped nanoarray. After sulfurization, the surface of the nanoneedles becomes rough, and nanosheets precipitate on the nanoneedles, further increasing the contact area between the electrolyte and the catalyst. Figure 2 The XRD pattern (a) and Raman pattern (b) of 1T-MoS2 / NiS2 / CC in Example 1. From the shift of the XRD pattern and the shift of the Ni-S bond in the Raman pattern, it can be seen that the 1TMoS2 / NiS2 / CC heterojunction was successfully prepared. Figure 3 The linear cycle curve and double-layer capacitance diagram of Example 1, (a) is the comparison of HER performance of different electrodes, and (b) is the relationship between capacitance current and different scan rates. It can be seen from the figure that the 1TMoS2-NiS2 / CC catalyst performs better in hydrogen evolution in seawater electrolysis; Figure 4 The linear cycle curves of Examples 1, 2, 3, 4, and 5 are shown in Figures 1 and 5. (a) shows the HER performance at different vulcanization temperatures, and (b) shows the HER performance at different sulfur powder dosages. It can be seen from the figure that the optimal vulcanization temperature is 400°C and the sulfur powder dosage is 500 mg. Figure 5 These are the Raman images of 1TMoS2-NiS2 / CC before and after the hydrogen evolution reaction in alkaline electrolysis of seawater. It can be seen from the figure that after the hydrogen evolution reaction in alkaline electrolysis of seawater, 1TMoS2-NiS2 / CC can still maintain the highly active 1T phase. DETAILED DESCRIPTION

[0012] To make the objectives, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to Examples 1-7 and the accompanying drawings.

[0013] Example 1: Sample preparation: Sodium molybdate dihydrate (363 mg) and nickel nitrate hexahydrate (436 mg) were dissolved in 25 mL of ultrapure water and stirred vigorously at room temperature for 1 hour to form a homogeneous green suspension. The suspension was then transferred to a 50 mL stainless steel autoclave lined with Teflon, and a piece of treated carbon cloth (2 x 3 cm) was immersed in the solution. The autoclave was placed in an oven and maintained at 150°C for 6 hours to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction, the NiMoO-Pre / CC was removed, washed several times with deionized water, and dried in an oven at 60°C for later use. Subsequently, the NiMoO-Pre / CC was placed in a temperature-controlled tube furnace and sulfurized at 400°C using sublimed sulfur (500 mg) as a sulfur source. During the sulfurization process, a certain heating rate (5°C / min) and time (2h) were maintained, and the nitrogen flow rate (68 sccm) was maintained. The obtained material was marked as 1T-MoS2 / NiS2 / CC.

[0014] Electrocatalytic application: The linear sweep voltammetry curve of the catalyst was measured using the prepared nanomaterial 1T-MoS2 / NiS2 / CC as the working electrode in a three-electrode system (platinum wire electrode as the counter electrode and saturated Ag / AgCl electrode as the reference electrode) with 1 M KOH + 0.5 M NaCl solution as the electrolyte solution.

[0015] The current density of the sample during hydrogen production was 10 mA cm -2 When the overpotential is 52 mV, the performance of this sample is the best.

[0016] Example 2: Sample preparation: Sodium molybdate dihydrate (363 mg) and nickel nitrate hexahydrate (436 mg) were dissolved in 25 mL of ultrapure water and stirred vigorously at room temperature for 1 h to form a homogeneous green suspension. The suspension was then transferred to a 50 mL stainless steel autoclave lined with Teflon, and a piece of treated carbon cloth (2 x 3 cm) was immersed in the solution. The autoclave was placed in an oven and heated at 150°C for 6 h to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction, the NiMoO-Pre / CC was removed, washed several times with deionized water, and dried in an oven at 60°C for later use. Subsequently, the NiMoO-Pre / CC was placed in a temperature-controlled tube furnace and sulfurized at 400°C using sublimed sulfur (1 g) as the sulfur source. During the sulfurization process, a constant heating rate (5°C / min) and time (2 h) were maintained, along with a nitrogen flow rate (68 sccm). The obtained material was labeled as 1TMoS2-NiS2 / CC.

[0017] Electrocatalytic application: The preparation and testing of electrodes were the same as in Example 1. The current density of this sample was 10 mA cm -2 The oxygen evolution overpotential is 118 mV.

[0018] Example 3: Sodium molybdate dihydrate (363 mg) and nickel nitrate hexahydrate (436 mg) were dissolved in 25 mL of ultrapure water and stirred vigorously at room temperature for 1 hour to form a homogeneous green suspension. The suspension was then transferred to a 50 mL stainless steel autoclave lined with Teflon, and a piece of treated carbon cloth (2 x 3 cm) was immersed in the solution. The autoclave was placed in an oven and heated at 150°C for 6 hours to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction, the NiMoO-Pre / CC was removed, washed several times with deionized water, and dried in an oven at 60°C for later use. Subsequently, the NiMoO-Pre / CC was placed in a temperature-controlled tube furnace and sulfurized at 400°C using sublimed sulfur (300 mg) as the sulfur source. During the sulfurization process, a constant heating rate (5°C / min) and time (2 hours) were maintained, along with a nitrogen flow rate (68 sccm). The obtained material was labeled as 1TMoS2-NiS2 / CC.

[0019] Electrocatalytic application: The preparation and testing of electrodes were the same as in Example 1. The current density of this sample was 10 mA cm -2 The oxygen evolution overpotential is 125 mV.

[0020] Example 4: Sample preparation: Sodium molybdate dihydrate (363 mg) and nickel nitrate hexahydrate (436 mg) were dissolved in 25 mL of ultrapure water and stirred vigorously at room temperature for 1 hour to form a homogeneous green suspension. The suspension was then transferred to a 50 mL stainless steel autoclave lined with Teflon, and a piece of treated carbon cloth (2 x 3 cm) was immersed in the solution. The autoclave was placed in an oven and heated at 150°C for 6 hours to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction, the NiMoO-Pre / CC was removed, washed several times with deionized water, and dried in an oven at 60°C for later use. Subsequently, the NiMoO-Pre / CC was placed in a temperature-controlled tube furnace and sulfurized at 350°C using sublimed sulfur (500 mg) as the sulfur source. During the sulfurization process, a constant heating rate (5°C / min) and time (2 hours) were maintained, along with a nitrogen flow rate (68 sccm). The obtained material was labeled as 1TMoS2-NiS2 / CC.

[0021] Electrocatalytic application: The preparation and testing of electrodes were the same as in Example 1. The current density of this sample was 10 mA cm -2 When the oxygen evolution overpotential is 180 mV Example 5: Sample preparation: Sodium molybdate dihydrate (363 mg) and nickel nitrate hexahydrate (436 mg) were dissolved in 25 mL of ultrapure water and stirred vigorously at room temperature for 1 hour to form a homogeneous green suspension. The suspension was then transferred to a 50 mL stainless steel autoclave lined with Teflon, and a piece of treated carbon cloth (2 x 3 cm) was immersed in the solution. The autoclave was placed in an oven and heated at 150°C for 6 hours to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction, the NiMoO-Pre / CC was removed, washed several times with deionized water, and dried in an oven at 60°C for later use. Subsequently, the NiMoO-Pre / CC was placed in a temperature-controlled tube furnace and sulfurized at 450°C using sublimed sulfur (500 mg) as the sulfur source. During the sulfurization process, a constant heating rate (5°C / min) and time (2 hours) were maintained, along with a nitrogen flow rate (68 sccm). The obtained material was labeled as 1TMoS2-NiS2 / CC.

[0022] Electrocatalytic application: The preparation and testing of electrodes were the same as in Example 1. The current density of this sample was 10 mA cm -2 When the oxygen evolution overpotential is 83 mV Example 6: Sample Preparation: Sodium molybdate dihydrate (363 mg) and nickel nitrate hexahydrate (436 mg) were dissolved in 25 mL of ultrapure water and stirred vigorously at room temperature for 1 hour to form a homogeneous green suspension. The suspension was then transferred to a 50 mL stainless steel autoclave lined with Teflon, and a piece of treated carbon cloth (2 x 3 cm) was immersed in the solution. The autoclave was placed in an oven and heated at 150°C for 6 hours to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction, the NiMoO-Pre / CC was removed, washed several times with deionized water, and dried in an oven at 60°C for later use. Subsequently, the NiMoO-Pre / CC was placed in a temperature-controlled tube furnace and sulfurized at 400°C using sublimed sulfur (500 mg) as the sulfur source. During the sulfurization process, a constant heating rate (5°C / min) and time (1 hour) were maintained, along with a nitrogen flow rate (68 sccm). The obtained material was labeled as 1TMoS2-NiS2 / CC.

[0023] Electrocatalytic application: The preparation and testing of electrodes were the same as in Example 1. The current density of this sample was 10 mA cm -2 The oxygen evolution overpotential is 92 mV.

[0024] Example 7: Sample Preparation: Sodium molybdate dihydrate (363 mg) and nickel nitrate hexahydrate (436 mg) were dissolved in 25 mL of ultrapure water and stirred vigorously at room temperature for 1 hour to form a homogeneous green suspension. The suspension was then transferred to a 50 mL stainless steel autoclave lined with Teflon, and a piece of treated carbon cloth (2 x 3 cm) was immersed in the solution. The autoclave was placed in an oven and heated at 150°C for 6 hours to obtain the NiMoO precursor (labeled as NiMoO-Pre / CC). After the reaction, the NiMoO-Pre / CC was removed, washed several times with deionized water, and dried in an oven at 60°C for later use. Subsequently, the NiMoO-Pre / CC was placed in a temperature-controlled tube furnace and sulfurized at 400°C using sublimed sulfur (500 mg) as the sulfur source. During the sulfurization process, a constant heating rate (5°C / min) and time (3 hours) were maintained, along with a nitrogen flow rate (68 sccm). The obtained material was labeled as 1T-MoS2 / NiS2 / CC.

[0025] Electrocatalytic application: The preparation and testing of electrodes were the same as in Example 1. The current density of this sample was 10 mA cm -2 The oxygen evolution overpotential is 87 mV.

[0026] The above disclosure is merely a preferred embodiment of the present invention and certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A method for preparing a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst, characterized by: The following steps are involved: Step 1: Sodium molybdate dihydrate and nickel nitrate hexahydrate are dissolved in ultrapure water and stirred at room temperature to form a uniform green suspension. Subsequently, the green suspension is transferred to an autoclave and the carbon cloth is immersed in the green suspension; Step 2: Place the autoclave in an oven and keep it at 150°C for 6 hours to obtain the NiMoO precursor, labeled as NiMoO-Pre / CC; remove the NiMoO-Pre / CC, wash it several times with deionized water, and dry it in an oven for later use; Step 3: Place NiMoO-Pre / CC in a temperature-controlled tube furnace and perform sulfurization treatment at a temperature of 350°C-450°C to obtain 1TMoS2-NiS2 / CC.

2. The method for preparing a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst according to claim 1, characterized in that: In step 1, the mass of sodium molybdate dihydrate is 100 mg-1000 mg, the mass of nickel nitrate hexahydrate is 100 mg-1000 mg, and the stirring time at room temperature is 1 h.

3. The method for preparing a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst according to claim 1, characterized in that: In step 3, the heating rate of the tube furnace is 5°C / min, the sulfur source is sublimed sulfur, and the amount of sulfur powder is 50 mg. -1 / g; the sulfurization temperature is 350℃-450℃, the time is 2h, and the argon flow rate is 68 sccm.

4. A seawater electrolysis catalyst prepared by the method for preparing a 1TMoS2-NiS2 / CC heterojunction seawater electrolysis catalyst according to any one of claims 1 to 3.

5. The seawater electrolysis catalyst as claimed in claim 4 is used for electrolysis of seawater under alkaline conditions.

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