High-performance oxygen evolution reaction composite electrocatalyst and preparation method thereof

Abstract

The application discloses a high-performance oxygen evolution reaction composite electrocatalyst and a preparation method thereof, and belongs to the field of electrocatalytic material preparation. The application solves the problem that it is difficult to realize uniform loading and precise size control of RuO2 nanoparticles on a three-dimensional porous complex substrate (foamed nickel), thereby affecting the performance and repeatability of the prepared electrocatalyst. The method comprises the following steps: sulfidizing the foamed nickel with thiourea first, and then uniformly depositing RuO2 nanoparticles on the surface of the foamed nickel-based Ni3S2 by using an ALD technology. The application precisely controls the size of the RuO2 nanoparticles on the surface of the foamed nickel-based Ni3S2 to be 1.5-3.5 nm, and the surface density to be 0.8-1.2´10 12 / cm 2 , so that the conductivity and electrochemical activity of the catalyst can be improved, the charge transfer rate can be improved, and the OER performance of the electrocatalyst is improved.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic material preparation, specifically relating to a high-performance oxygen evolution reaction composite electrocatalyst and its preparation method. Background Technology

[0002] With the increasing prominence of environmental problems caused by the overuse of fossil fuels, the development of clean, efficient, and sustainable energy is imperative. Hydrogen energy is considered one of the most promising clean energy sources of the 21st century, and water electrolysis is considered one of the most promising methods for large-scale production of high-purity hydrogen and oxygen. The oxygen evolution reaction (OER) at the anode in water electrolysis is a four-electron transfer process. Compared to the two-electron transfer hydrogen evolution reaction, it requires a higher overpotential to overcome the kinetic barrier, which is a key factor limiting the overall efficiency of the water electrolysis reaction; therefore, exploring highly active OER catalysts has become a research hotspot.

[0003] Highly efficient water splitting transition metal catalysts, such as oxides, phosphides, carbides, chalcogenides, and selenides, are gradually replacing expensive iridium-based OER catalysts due to their excellent activity. Among them, nickel sulfide foam (Ni3S2) based on nickel sulfide has attracted increasing attention due to its good conductivity and ease of preparation. However, the excessive binding strength between Ni3S2 and oxygen-containing intermediates leads to poor OER activity. To improve the performance of Ni3S2, it can be modified by loading suitable catalyst particles onto its surface to increase the specific surface area and active sites, thereby improving electrochemical activity. Studies have shown that RuO2 is not only a material with good conductivity but also has excellent OER activity. Currently, methods for preparing RuO2 nanoparticles have been studied, mainly including hydrothermal methods, thermal decomposition methods, electrochemical deposition methods, and sol-gel methods. However, these traditional methods are still insufficient in terms of precisely controlling particle size and distribution, especially in achieving uniform particle deposition on three-dimensional porous complex substrates, where significant difficulties exist. Summary of the Invention

[0004] This invention provides a high-performance oxygen evolution reaction (OER) composite electrocatalyst and its preparation method. Addressing the current challenge of achieving uniform loading and precise size control of RuO2 nanoparticles on three-dimensional porous complex substrates (nickel foam), which affects the performance and reproducibility of the prepared electrocatalysts, this invention utilizes a precise and controllable ALD method to uniformly deposit RuO2 nanoparticles on the surface of nickel foam-based Ni3S2, thereby obtaining a stable and high-performance OER composite electrocatalyst.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A high-performance composite electrocatalyst for the oxygen evolution reaction (OER) is a uniformly loaded RuO2 nanoparticle on the surface of a nickel foam-based Ni3S2 substrate. The RuO2 nanoparticles have a precisely controlled size of 1.5-3.5 nm and an areal density of 0.8-1.2 × 10⁻⁶. 12 / cm 2 .

[0007] A method for preparing a high-performance oxygen evolution reaction composite electrocatalyst includes the following steps:

[0008] Step 1: Cut the foamed nickel mesh, ultrasonically clean it with ethanol and deionized water, and use it as a template;

[0009] Step 2: Place the cleaned foamed nickel mesh into an HCl solution and sonicate it. Then clean the surface with ethanol and deionized water, followed by drying to obtain a clean nickel mesh.

[0010] Step 3: Add thiourea and high-purity water to a stainless steel hydrothermal reactor, place the treated nickel foam mesh inside, and carry out a sulfidation reaction under heating conditions. The reaction temperature is 150℃ and the time is 5h. After the reaction is completed, take out the sample, wash it thoroughly with water and anhydrous ethanol, and dry it to obtain nickel foam-based Ni3S2.

[0011] Step 4: RuO2 nanoparticles were grown on nickel foam-based Ni3S2 using ALD. The precursor used was ethyl ruthenium thiocene, the source temperature was 65℃, and the reactant was oxygen, to obtain nickel foam-based Ni3S2 / RuO2.

[0012] The growth temperature for RuO2 in ALD is 200℃-350℃, the oxygen flow rate is 100-200 sccm, and the number of cycles is 150-250.

[0013] Beneficial Effects: This invention provides a high-performance composite electrocatalyst for the oxygen evolution reaction (OER) and its preparation method. Ni3S2 is synthesized using nickel foam sulfidation, followed by uniform deposition of RuO2 nanoparticles onto the nickel foam-based Ni3S2 using an ALD (Alternating Current Deposition) method, resulting in a nickel foam-based Ni3S2 / RuO2 composite electrocatalyst. The method precisely controls the size and density of the RuO2 nanoparticle catalyst by changing the ALD cycle number, achieving a particle size of 1.5-3.5 nm and an areal density of 0.8-1.2 × 10⁻⁶. 12 / cm 2This invention enables precise control over the uniform loading and size of RuO2 nanoparticles, optimizing the interface between nickel-based Ni3S2 and RuO2 nanoparticles. This Ni3S2 / RuO2 interface optimization not only maximizes the exposure of active sites but also increases the number of active sites due to the higher RuO2 areal density. The smaller RuO2 particle size helps shorten the diffusion distance, promoting charge transport within the RuO2 particles and improving the catalyst's conductivity and electrochemical activity, thereby enhancing the electrocatalytic performance of OER (Optical Emission Reduction). The process is simple and controllable, and the prepared composite electrocatalyst exhibits excellent OER performance and good stability, making it suitable for application in energy catalysis. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the synthesis of the composite electrocatalyst in an embodiment of the present invention;

[0015] Figure 2 SEM image (a) of the synthesized nickel-based Ni3S2 foam and TEM image (b) of 200-cycle RuO2 nanoparticles in the embodiments of the present invention.

[0016] Figure 3 Linear scanning voltammetry curves of the composite electrocatalyst prepared in the embodiments of the present invention and its reference sample;

[0017] Figure 4 This is a Tafel slope curve of the composite electrocatalyst prepared in the embodiments of the present invention and its reference sample;

[0018] Figure 5 The following are cyclic voltammetry curves of the composite electrocatalyst prepared in the embodiments of the present invention and its reference sample, where (a) is the Ni3S2 / RuO2-200 cycle, (b) is Ni3S2, (c) is RuO2-200 cycle, and (d) is the current density difference of the three at different scan rates.

[0019] Figure 6 The figures show the stability curves of (a) the composite electrocatalyst and (b) Ni3S2 prepared in the embodiments of the present invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0021] Example 1

[0022] like Figure 1 As shown, a method for preparing a high-performance oxygen evolution reaction composite electrocatalyst includes the following steps:

[0023] 1) First, cut the nickel foam into 1 cm × 3 cm pieces and clean them in anhydrous ethanol and deionized water;

[0024] 2) Sonicate the cleaned nickel foam mesh in anhydrous ethanol and 3M HCl for 30 min each. After sonication, rinse it multiple times with deionized water and ethanol to ensure thorough cleaning. After cleaning, place it in an oven at 80℃ to dry.

[0025] 3) Add 13 mL of water and 0.11 g of thiourea to a hydrothermal reactor and stir for 30 min to ensure that the thiourea is completely dissolved. Then, put the pretreated nickel foam mesh into the hydrothermal reactor containing the thiourea aqueous solution. After the treatment is completed, place the hydrothermal reactor at 150 °C and heat for 5 h. After the heating is completed, take out the sulfided nickel foam mesh, wash it with deionized water and anhydrous ethanol and dry it to obtain nickel foam-based Ni3S2.

[0026] 4) RuO2 nanoparticles were grown on nickel foam-based Ni3S2 using the ALD method. The specific growth conditions were as follows: the growth temperature was 250℃; the precursor was ethyl ruthenium thiocene, the source temperature was 65℃, and the reactant was oxygen; the deposition pulse cycles were 1 s ethyl ruthenium thiocene pulse, 4 s cleaning pulse, 8 s O2 pulse, and 4 s cleaning pulse; the cleaning gas and carrier gas were both high-purity nitrogen (N2, 99.999%); the oxygen flow rate was 150 sccm; and the number of growth cycles was 200 cycles, resulting in nickel foam-based Ni3S2 / RuO2.

[0027] Example 2

[0028] like Figure 1 As shown, a method for preparing a high-performance oxygen evolution reaction composite electrocatalyst includes the following steps:

[0029] 1) First, cut the nickel foam into 1 cm × 3 cm pieces and clean them in anhydrous ethanol and deionized water;

[0030] 2) The cleaned foamed nickel mesh was ultrasonicated in anhydrous ethanol and 3M HCl for 30 min each. After ultrasonication, it was rinsed multiple times with deionized water and ethanol to ensure thorough cleaning. After cleaning, it was placed in an oven at 80℃ to dry.

[0031] 3) Add 13 mL of water and 0.11 g of thiourea to a hydrothermal reactor and stir for 30 min to ensure complete dissolution of the thiourea. Then, place the pretreated nickel foam mesh into the hydrothermal reactor containing the thiourea aqueous solution. After treatment, place the hydrothermal reactor at 150 °C for 5 h. After heating, remove the sulfidated nickel foam mesh, wash it with deionized water and anhydrous ethanol, and dry it to obtain nickel foam-based Ni3S2.

[0032] 4) RuO2 nanoparticles were grown on nickel foam-based Ni3S2 using the ALD method. The specific growth conditions were as follows: the growth temperature was 200℃; the precursor was ethyl ruthenium thiocene, the source temperature was 65℃, and the reactant was oxygen; the deposition pulse cycles were 1 s ethyl ruthenium thiocene pulse, 4 s cleaning pulse, 8 s O2 pulse, and 4 s cleaning pulse; the cleaning gas and carrier gas were both high-purity nitrogen (N2, 99.999%); the oxygen flow rate was 100 sccm; and the number of growth cycles was 250 cycles; thus, nickel foam-based Ni3S2 / RuO2 was obtained.

[0033] Example 3

[0034] like Figure 1 As shown, a method for preparing a high-performance oxygen evolution reaction composite electrocatalyst includes the following steps:

[0035] 1) First, cut the nickel foam into 1 cm × 3 cm pieces and clean them in anhydrous ethanol and deionized water;

[0036] 2) The cleaned foamed nickel mesh was ultrasonicated in anhydrous ethanol and 3M HCl for 30 min each. After ultrasonication, it was rinsed multiple times with deionized water and ethanol to ensure thorough cleaning. After cleaning, it was placed in an oven at 80℃ to dry.

[0037] 3) Add 13 mL of water and 0.11 g of thiourea to a hydrothermal reactor and stir for 30 min to ensure complete dissolution of the thiourea. Then, place the pretreated nickel foam mesh into the hydrothermal reactor containing the thiourea aqueous solution. After treatment, place the hydrothermal reactor at 150 °C for 5 h. After heating, remove the sulfidated nickel foam mesh, wash it with deionized water and anhydrous ethanol, and dry it to obtain nickel foam-based Ni3S2.

[0038] 4) RuO2 nanoparticles were grown on nickel foam-based Ni3S2 using the ALD method. The specific growth conditions were as follows: growth temperature was 300℃; the precursor was ethyl ruthenium thiocene, the source temperature was 65℃, and the reactant was oxygen; the deposition pulse cycles were 1 s ethyl ruthenium thiocene pulse, 4 s cleaning pulse, 8 s O2 pulse, and 4 s cleaning pulse; both the cleaning gas and the carrier gas were high-purity nitrogen (N2, 99.999%); the oxygen flow rate was 200 sccm; and the number of growth cycles was 150 cycles; resulting in nickel foam-based Ni3S2 / RuO2.

[0039] like Figure 2 As shown, the Ni3S2 obtained in the above embodiments is in the form of nanosheets, and the resulting composite catalyst is Ni3S2 with 200 recycled RuO2 nanoparticles uniformly loaded on its surface, with an average particle size of only 2.6 nm and an areal density of 1.2 × 10⁻⁶. 12 / cm 2 .

[0040] The composite electrocatalyst prepared in Example 1 was used as the working electrode, with a graphite electrode and Hg / HgO as the counter electrode and reference electrode, respectively, forming a three-electrode system. Using an electrochemical workstation at room temperature, with an oxygen-saturated KOH solution of 1 mol / L as the electrolyte, the electrochemical performance of the foamed nickel-based Ni3S2 / RuO2-200 cyclic sample and the reference samples (foamed nickel-based Ni3S2 and RuO2-200 cyclic catalysts) was tested. The test results are as follows: Figure 3 As shown, at 10mA / cm 2 At the specified current densities, the overpotentials for cycling with nickel foam-based Ni3S2 / RuO2-200, and cycling with nickel foam-based Ni3S2 and RuO2-200 were 1.37 mV, 1.62 mV, and 1.59 mV, respectively. Figure 4 It can be seen that the Tafel slopes of the three samples are 59 mV / dec, 200 mV / dec, and 134 mV / dec, respectively. The nickel foam-based Ni3S2 / RuO2-200 cycled sample exhibits the best Tafel slope, proving that the prepared electrocatalyst has high OER catalytic activity. Figure 5 In the cyclic voltammetry curves, the cyclic sample of nickel foam-based Ni3S2 / RuO2-200 showed a value of 51.36 mF / cm. 2 The double-layer capacitance further demonstrates that the composite electrocatalyst prepared by the above method can provide more charge storage sites and promote charge transfer. Figure 6 Cyclic stability test curves of the nickel foam-based Ni3S2 / RuO2-200 cyclic sample show that the nickel foam-based Ni3S2 / RuO2-200 cyclic sample has better stability than Ni3S2, indicating that the present invention utilizes ALD technology to grow uniformly loaded RuO2 nanoparticles on nickel foam-based Ni3S2, thereby improving the corrosion resistance of the electrocatalyst.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high-performance oxygen evolution reaction composite electrocatalyst, characterized in that, The method comprises the following steps: Preparation of three-dimensional porous complex substrate foam nickel-based Ni3S2; Uniformly depositing nanoparticles of RuO2 on the three-dimensional porous complex substrate by ALD technology, using ethylruthenocene as the precursor and oxygen as the reactant in the ALD to obtain the composite electrocatalyst.

2. The preparation method of the high-performance oxygen evolution reaction composite electrocatalyst according to claim 1, characterized in that, The source temperature in the ALD is 65℃.

3. The preparation method of the high-performance oxygen evolution reaction composite electrocatalyst according to claim 1, characterized in that, The growth temperature of RuO2 deposited by the ALD technology is 200-350℃.

4. The method of claim 1, wherein the high performance oxygen evolution reaction composite electrocatalyst is prepared by the steps of: The flow rate of oxygen is 100-200sccm.

5. The method of claim 1, wherein the high performance oxygen evolution reaction composite electrocatalyst is prepared by the steps of: The cycle number is 150-250 cycles.

6. The method for preparing the high-performance oxygen evolution reaction composite electrocatalyst according to claim 1 or 5, characterized in that, The ALD deposition pulse cycle is respectively 1s ethylruthenocene pulse, 4s cleaning pulse, 8s O2 pulse and 4s cleaning pulse.

7. The method for preparing the high-performance oxygen evolution reaction composite electrocatalyst according to claim 1, characterized in that, The preparation method of the foam nickel-based Ni3S2 comprises the following steps: Step one: cutting the foam nickel mesh, then cleaning it with ethanol and deionized water under ultrasonic, and taking the cleaned foam nickel mesh as the template; Step two: placing the cleaned foam nickel mesh into an HCl solution under ultrasonic, then cleaning the surface with ethanol and deionized water, and drying to obtain a clean nickel mesh; Step three: adding thiourea and high-purity water into a stainless steel hydrothermal reactor, placing the treated foam nickel mesh into the reactor, and performing a sulfidation reaction under heating, wherein the reaction temperature is 150℃ and the reaction time is 5h, after the reaction, taking out the sample, cleaning it with water and anhydrous ethanol, and drying to obtain the foam nickel-based Ni3S2.

8. The high performance oxygen evolution reaction composite electrocatalyst prepared by the method of any one of claims 1-7, characterized in that, The composite electrocatalyst is three-dimensional porous complex substrate surface uniformly loaded RuO2 nanoparticles, the size of the RuO2 nanoparticles is controlled in 1.5-3.5 nm, the surface density is in 0.8-1.2×10 12 / cm 2 .

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