Ruthenium disulfide / iron-nickel sulfide / carbon composite material with abundant heterogeneous interfaces, preparation method thereof and application of ruthenium disulfide / iron-nickel sulfide / carbon composite material in hydrogen production through catalytic electrolysis of water

Abstract

The invention belongs to the technical field of catalytic electrolysis of water, relates to a catalyst for electrolysis of water, and relates to a ruthenium disulfide / iron-nickel sulfide / carbon composite material with abundant heterogeneous interfaces, a preparation method of the ruthenium disulfide / iron-nickel sulfide / carbon composite material and application of the ruthenium disulfide / iron-nickel sulfide / carbon composite material in catalytic electrolysis of water for hydrogen production. The composite material is a nanoparticle and comprises a metal sulfide and a carbon matrix loaded with the metal sulfide, according to the metal sulfide, a heterostructure is formed by RuS2 and (FeNi) S1.03, the heterostructure is of a crystal structure, the grain size is 5-50 nm, and the interface of the two grains is a heterointerface. According to the preparation method disclosed by the invention, positive ions are dispersed to obtain a uniform precursor precipitate through a liquid-phase chelating coprecipitation method, and then abundant heterostructures are better constructed through synchronous high-temperature calcination. The composite material provided by the invention can efficiently catalyze hydrogen evolution and oxygen evolution reactions at the same time, and shows a good industrial application prospect in the application of laboratory electrolytic cells and commercial AEM electrolytic cells.

Description

Technical Field

[0001] The present invention belongs to the technical field of catalytic electrolytic water, relates to a catalyst for electrolytic water, and relates to a ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterointerfaces, a preparation method thereof, and an application thereof in catalytic electrolytic water for hydrogen production. Background Art

[0002] Disclosing the information of this background art section is only intended to enhance the overall understanding of the present invention and is not necessarily to be regarded as an admission or an implication in any form that this information constitutes the prior art already known to those of ordinary skill in the art.

[0003] The hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in electrolytic water usually require the use of noble metals such as platinum (Pt) and iridium (Ir)-based electrocatalysts, but the scarcity of resources and high cost of Pt and Ir seriously hinder their practical applications.

[0004] Ruthenium-based chalcogenides are considered to be an ideal electrocatalytic material due to their relatively low price and Pt-like catalytic activity. Most of the reported preparation methods of ruthenium disulfide are derived from RuO 2 derived sulfidation, with high cost and complex process. Although ruthenium-based chalcogenides currently show excellent HER activity, they are not suitable for the OER reaction and have poor OER activity. Most of the reported ruthenium disulfide-based catalysts are about HER, and there is no report on ruthenium disulfide acting as a bifunctional catalyst for both HER and OER at the same time, which limits its application in overall water splitting. Therefore, how to obtain a bifunctional catalytic activity for HER and OER through a simple preparation method, control the cost, and apply it to overall water splitting is the research focus and difficulty of ruthenium disulfide as an electrocatalyst. Summary of the Invention

[0005] In order to solve the deficiencies of the prior art, the purpose of the present invention is to provide a ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterointerfaces, a preparation method thereof, and an application thereof in catalytic electrolytic water. The composite material provided by the present invention can simultaneously catalyze the hydrogen evolution and oxygen evolution reactions efficiently, and shows good industrial application prospects in the applications of laboratory electrolytic cells and commercial AEM electrolyzers.

[0006] In order to achieve the above purpose, the technical solution of the present invention is as follows: In the first aspect, a ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterointerfaces, the composite material is nanoparticles, including metal sulfides and a carbon matrix supporting the metal sulfides; the metal sulfides are composed of RuS 2 and (FeNi)S 1.03A heterogeneous structure is formed. The heterogeneous structure is a crystal structure with a grain size of 5 - 50 nm, and the interface between the two grains is a heterogeneous interface.

[0007] The present invention provides (FeNi)S 1.03 nanomaterials with good OER performance, and introduces (FeNi)S 2 into the nano - RuS 1.03 material. At the same time, through the heterogeneous interface between RuS 2 and (FeNi)S 1.03 grains, a heterogeneous structure interface is constructed, which can adjust the charge redistribution of active sites, thereby creating a local electronic structure with optimized adsorption strength of key reaction intermediates. Through the synergistic effect of multiple active sites, the electrocatalytic activity of the composite material is improved.

[0008] In a second aspect, a method for preparing a ruthenium disulfide / iron - nickel sulfide / carbon composite material with rich heterogeneous interfaces as described above is provided. Sodium dimethyldithiocarbamate (C 3 H 6 NNaS 2 ) is used to simultaneously carry out a chelation precipitation reaction on ruthenium salt, ferric salt and nickelous salt in a solution to obtain a precursor precipitate; then, under an inert atmosphere condition, the precursor precipitate is heated to 500 - 600 °C for synchronous annealing treatment to obtain the product.

[0009] The preparation method provided by the present invention can construct a composite material with the above - mentioned rich heterogeneous interfaces, and the preparation method is simple and has a low cost.

[0010] In a third aspect, an application of a ruthenium disulfide / iron - nickel sulfide / carbon composite material with rich heterogeneous interfaces as described above in catalytic electrolysis water to produce hydrogen is provided.

[0011] The beneficial effects of the present invention are as follows: 1. The ruthenium disulfide / iron - nickel sulfide / carbon (named RuS 2 / (FeNi)S 1.03 / C) composite material with rich heterogeneous interfaces provided by the present invention has a rich heterogeneous structure and multiple active sites, and exhibits high - efficiency HER and OER bifunctional catalysts as an electrocatalyst, with excellent electrolysis water performance: (1) For HER catalytic activity, the hydrogen evolution reaction polarization curve has a lower over - potential under the same current density condition. At the same time, after continuous catalysis for 5000 cycles, the over - potential only decays less, which is better than the over - potential decay (18 mV) of commercial Pt / C; (2) For OER catalytic activity, the oxygen evolution reaction polarization curve has a lower over - potential under the same current density condition, especially lower than that of commercial RuO 2 , and after continuous catalysis for 5000 cycles, the over - potential decay is less, which is better than RuO 2Overpotential decay (64 mV); (3) For overall water splitting performance, it can effectively drive the electrolyzer as both the anode and cathode materials. Whether it is the potential (~1.68 V) under a small current density (e.g., 10 mA cm -2 ), or the potential (~1.78 V) under a large current density (e.g., 40 mA cm -2 ), it is better than that of commercial Pt / C ‖ RuO 2 at 1.92 V; (4) For industrial AEM water electrolysis applications, it is applied as the cathode catalyst (RuS 2 / (FeNi)S 1.03 / C-3‖ NiFe LDH) in an actual AEM electrolyzer. It can stably operate for more than 255 hours at a large current density of 1000 mA·cm -2 . Its performance is comparable to that of a commercial electrolyzer (Pt / C ‖ NiFe LDH), showing good industrial application prospects.

[0012] 2. The RuS 2 / (FeNi)S 1.03 / C composite material provided by the present invention can obtain a RuS 2 -based HER and OER bifunctional overall water splitting catalytic material with rich heterointerfaces and low cost only through simple liquid-phase homogeneous chelation coprecipitation and synchronous high-temperature calcination. The steps are simple and the cost is low, which is conducive to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The specification drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0014] Figure 1 is the scanning electron microscope (SEM) image of RuS 2 / (FeNi)S 1.03 / C-3 prepared in Example 3 of the present invention. (a) is at low magnification, and (b) is at high magnification; Figure 2 is the high-resolution transmission electron microscope (HRTEM) image of RuS 2 / (FeNi)S 1.03 / C-3 prepared in Example 3 of the present invention. (a) is the crystal structure, (b) is the high-resolution transmission image and its corresponding fast Fourier transform image, (c) is the high-resolution transmission image and its corresponding fast Fourier transform image, (d) is the selected area electron diffraction, and (e) is the high-angle annular dark field element mapping; Figure 3XRD patterns of the composite materials prepared in Examples 1, 3, 5 and Comparative Examples 1, 2 of the present invention, (a) is from 5 to 80 degrees, and (b) is from 20 to 60 degrees; Figure 4 HER performance test result graphs of the composite materials prepared in Examples 1 - 5 and Comparative Examples 1, 2 of the present invention, (a) is the linear sweep voltammetry (LSV) polarization curve, and (b) is the comparison graph at 10 mA·cm -2 and 20 mA·cm -2 potential; Figure 5 HER cycling stability result graphs of RuS 2 / (FeNi)S 1.03 / C - 3 prepared in Example 3 of the present invention and commercial Pt / C; Figure 6 OER performance test result graphs of the composite materials prepared in Examples 1 - 5 and Comparative Examples 1, 2 of the present invention, (a) is the linear sweep voltammetry (LSV) polarization curve, and (b) is the comparison graph at 20 mA·cm -2 and 50 mA·cm -2 potential; Figure 7 OER cycling stability result graphs of RuS 2 / (FeNi)S 1.03 / C - 3 prepared in Example 3 of the present invention and commercial RuO 2 ; Figure 8 Overall water splitting performance comparison graphs of RuS 2 / (FeNi)S 1.03 / C - 3 prepared in Example 3 of the present invention and commercial Pt / C ‖ RuO 2 ; Figure 9 Stability test result graphs of the RuS 2 / (FeNi)S 1.03 / C - 3 ‖ NiFe LDH electrolyzer at 1000 mA·cm -2 at 25°C; Detailed Description of the Invention

[0015] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs.

[0016] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular forms are also intended to include the plural forms. In addition, it should also be understood that when the terms "comprising" and / or "including" are used in this specification, they specify the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0017] In view of the poor OER activity of existing ruthenium disulfide, it is difficult to act on HER and OER simultaneously, which limits its application in overall water splitting. Therefore, the present invention proposes a ruthenium disulfide / iron-nickel sulfide / carbon composite material with rich heterointerfaces, a preparation method thereof, and its application in catalytic electrolytic water.

[0018] In a typical embodiment of the present invention, a ruthenium disulfide / iron-nickel sulfide / carbon composite material with rich heterointerfaces is provided. The composite material is nanoparticles, including metal sulfides and a carbon matrix supporting the metal sulfides; the metal sulfides are composed of RuS 2 and (FeNi)S 1.03 to form a heterostructure. The heterostructure is a crystal structure and the grain size is 5-50 nm. The interface between the two grains is a heterointerface.

[0019] In some embodiments, the particle size of the nanoparticles is 10-500 nm.

[0020] In another embodiment of the present invention, a preparation method of the above-mentioned ruthenium disulfide / iron-nickel sulfide / carbon composite material with rich heterointerfaces is provided. Sodium dimethyldithiocarbamate (C 3 H 6 NNaS 2 ) is used to carry out a chelating precipitation reaction on ruthenium salt, ferric salt and nickelous salt simultaneously in a solution to obtain a precursor precipitate; then, under an inert atmosphere condition, the precursor precipitate is heated to 500-600 °C for synchronous annealing treatment to obtain the product.

[0021] The ruthenium salt is a compound with ruthenium ion as the cation, such as ruthenium trichloride, ruthenium nitrate, ruthenium sulfate, etc.

[0022] The ferric salt is a compound with ferric ion as the cation, such as ferric chloride, ferric nitrate, ferric sulfate, etc.

[0023] The nickelous salt is a compound with nickelous ion as the cation, such as nickelous chloride, nickelous nitrate, nickelous sulfate, etc.

[0024] In some embodiments, a ruthenium salt, a ferric salt, and a nickelous salt are dissolved in water to obtain a mixed salt solution, which is then mixed and reacted with an aqueous solution of sodium dimethyldithiocarbamate to obtain a precursor precipitate. Using water to disperse the ruthenium salt, the ferric salt, and the nickelous salt evenly and then performing a precipitation reaction can obtain a precursor precipitate with a more uniform element distribution, so that subsequent annealing (or calcination) can better construct a heterostructure.

[0025] Specifically, the concentration of nickelous in the mixed salt solution is 0.11 - 0.13 mol / L.

[0026] Specifically, the concentration of the aqueous solution of sodium dimethyldithiocarbamate is 0.09 - 0.11 mol / L.

[0027] Specifically, under stirring conditions, the mixed salt solution is (slowly) added to the aqueous solution of sodium dimethyldithiocarbamate.

[0028] Specifically, after the chelation precipitation reaction, solid-liquid separation is carried out, and then the precursor precipitate is washed and dried. The drying temperature is 50 - 70 °C, and the drying time is one whole night.

[0029] In some embodiments, the molar ratio of ruthenium element, iron element, and nickel element is 0.15:0.5:1 - 0.18:0.5:1. Research shows that the yield of the target material is higher under this condition. When the ruthenium element is too high, too many impurity phases will be produced.

[0030] In some embodiments, the molar ratio of sodium dimethyldithiocarbamate to nickel element is 1.8 - 2.2:1.

[0031] In some embodiments, during the annealing treatment, it is heated to 500 - 600 °C and kept warm for 1.5 - 2.5 hours.

[0032] In some embodiments, during the annealing treatment, the heating rate is 4 - 6 °C·min -1 。

[0033] The third implementation mode of the present invention provides an application of the above ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterointerfaces in catalytic electrolytic water for hydrogen production.

[0034] In some embodiments, the ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterointerfaces serves as an anode catalyst and a cathode catalyst for catalytic electrolytic water for hydrogen production.

[0035] In order to enable those skilled in the art to more clearly understand the technical solution of the present invention, the following will specifically describe the technical solution of the present invention in detail with examples and comparative examples.

[0036] Example 1 RuS 2 / (FeNi)S 1.03 / C-1 preparation method, including the following steps: First, dissolve 1.2 mmol FeCl 3 ∙6H 2 O, 2.4 mmol NiCl 2 ∙6H 2 O and 0.19 mmol RuCl 3 in 20 mL deionized water and disperse evenly to obtain a mixed salt solution; meanwhile, disperse 5 mmol C 3 H 6 NNaS 2 ·2H 2 O evenly in 50 mL deionized water to form a clear and transparent solution, namely the ligand solution. Then, under continuous magnetic stirring, slowly add the mixed salt solution to the ligand solution and react for 30 minutes to obtain a black precipitate. After the reaction, wash the precipitate thoroughly with deionized water and dry it overnight at 60 °C. Subsequently, transfer the obtained black powder to a tube furnace, heat it to 550 °C at a heating rate of 5 °C min -1 in a nitrogen atmosphere and hold for 1.5 hours to complete the thermal annealing treatment, obtaining a black sample RuS 2 / (FeNi)S 1.03 / C-1.

[0037] Example 2 RuS 2 / (FeNi)S 1.03 / C-2 preparation method, including the following steps: First, dissolve 1.2 mmol FeCl 3 ∙6H 2 O, 2.4 mmol NiCl 2 ∙6H 2 O and 0.238 mmol RuCl 3 in 20 mL deionized water and disperse evenly to obtain a mixed salt solution; meanwhile, disperse 5 mmol C 3 H 6 NNaS 2 ·2H 2 O evenly in 50 mL deionized water to form a clear and transparent solution, namely the ligand solution. Then, under continuous magnetic stirring, slowly add the mixed salt solution to the ligand solution and react for 30 minutes to obtain a black precipitate. After the reaction, wash the precipitate thoroughly with deionized water and dry it overnight at 60 °C. Subsequently, transfer the obtained black powder to a tube furnace, in a nitrogen atmosphere at 5 °Cmin -1Heat it to 550 °C at a heating rate of and hold for 1.5 hours to complete the thermal annealing treatment, obtaining the black sample RuS 2 / (FeNi)S 1.03 / C-2.

[0038] Example 3 RuS 2 / (FeNi)S 1.03 The preparation method of / C-3 comprises the following steps: First, dissolve 1.2 mmol FeCl 3 ∙6H 2 O, 2.4 mmol NiCl 2 ∙6H 2 O and 0.285 mmol RuCl 3 in 20 mL of deionized water and disperse evenly to obtain a mixed salt solution; meanwhile, disperse 5 mmol C 3 H 6 NNaS 2 ·2H 2 O evenly in 50 mL of deionized water to form a clear and transparent solution, i.e., the ligand solution. Then, under continuous magnetic stirring, slowly add the mixed salt solution to the ligand solution and react for 30 minutes to obtain a black precipitate. After the reaction, wash the precipitate thoroughly with deionized water and dry it at 60 °C overnight. Subsequently, transfer the obtained black powder to a tubular furnace, and heat it to 550 °C at a heating rate of 5 °C / min in a nitrogen atmosphere and hold for 1.5 hours to complete the thermal annealing treatment, obtaining the black sample RuS -1 / (FeNi)S 2 / (FeNi)S 1.03 / C-3.

[0039] Example 4 RuS 2 / (FeNi)S 1.03 The preparation method of / C-4 comprises the following steps: First, dissolve 1.2 mmol FeCl 3 ∙6H 2 O, 2.4 mmol NiCl 2 ∙6H 2 O and 0.333 mmol RuCl 3 in 20 mL of deionized water and disperse evenly to obtain a mixed salt solution; meanwhile, disperse 5 mmol C 3 H 6 NNaS 2 ·2H 2O was uniformly dispersed in 50 mL of deionized water to form a clear and transparent solution, i.e., the ligand solution. Then, under continuous magnetic stirring, the mixed salt solution was slowly added to the ligand solution and reacted for 30 minutes to obtain a black precipitate. After the reaction, the precipitate was thoroughly washed with deionized water and dried overnight at 60 °C. Subsequently, the obtained black powder was transferred to a tubular furnace and heated to 550 °C at a heating rate of 5 °C min -1 and held at this temperature for 1.5 hours to complete the thermal annealing treatment, obtaining a black sample RuS 2 / (FeNi)S 1.03 / C-4.

[0040] Example 5 RuS 2 / (FeNi)S 1.03 / C-5 was prepared by the following steps: First, 1.2 mmol of FeCl 3 ∙6H 2 O, 2.4 mmol of NiCl 2 ∙6H 2 O and 0.38 mmol of RuCl 3 were dissolved in 20 mL of deionized water and dispersed evenly to obtain a mixed salt solution; meanwhile, 5 mmol of C 3 H 6 NNaS 2 ·2H 2 O was uniformly dispersed in 50 mL of deionized water to form a clear and transparent solution, i.e., the ligand solution. Then, under continuous magnetic stirring, the mixed salt solution was slowly added to the ligand solution and reacted for 30 minutes to obtain a black precipitate. After the reaction, the precipitate was thoroughly washed with deionized water and dried overnight at 60 °C. Subsequently, the obtained black powder was transferred to a tubular furnace and heated to 550 °C at a heating rate of 5 °C min -1 and held at this temperature for 1.5 hours to complete the thermal annealing treatment, obtaining a black sample RuS 2 / (FeNi)S 1.03 / C-5.

[0041] Comparative Example 1 First, 0.19 mmol of RuCl 3 was dissolved in 20 mL of deionized water and dispersed evenly to obtain a ruthenium salt solution; meanwhile, 5 mmol of C 3 H 6 NNaS 2 ·2H 2O was uniformly dispersed in 50 mL of deionized water to form a clear and transparent solution, i.e., the ligand solution. Then, under continuous magnetic stirring, the ruthenium salt solution was slowly added to the ligand solution and reacted for 30 minutes to obtain a precipitate. After the reaction, the precipitate was washed thoroughly with deionized water and dried overnight at 60 °C. Subsequently, the obtained powder was transferred to a tube furnace and heated to 550 °C at a heating rate of 5 °C min -1 and held at this temperature for 1.5 hours to complete the thermal annealing treatment, and the sample without heterostructure obtained was RuS 2 / C.

[0042] Comparative Example 2 First, 1.2 mmol of FeCl 3 ∙6H 2 O and 2.4 mmol of NiCl 2 ∙6H 2 O were dissolved in 20 mL of deionized water and dispersed evenly to obtain a mixed salt solution; meanwhile, 5 mmol of C 3 H 6 NNaS 2 ·2H 2 O was uniformly dispersed in 50 mL of deionized water to form a clear and transparent solution, i.e., the ligand solution. Then, under continuous magnetic stirring, the mixed salt solution was slowly added to the ligand solution and reacted for 30 minutes to obtain a precipitate. After the reaction, the precipitate was washed thoroughly with deionized water and dried overnight at 60 °C. Subsequently, the obtained powder was transferred to a tube furnace and heated to 550 °C at a heating rate of 5 °C min -1 and held at this temperature for 1.5 hours to complete the thermal annealing treatment, and the sample without heterostructure obtained was (FeNi)S 1.03 / C.

[0043] The SEM image of RuS 2 / (FeNi)S 1.03 / C-3 prepared in Example 3 is as shown in Figure 1 . After high-temperature carbonization, an irregular nanoparticle structure is formed, and the particle size diameter is 10 - 500 nm.

[0044] Figure 2 In (a) of 2 / (FeNi)S 1.03 / C-3 sample clearly shows the crystal structure, and the grain size is 5 - 50 nm. Different crystal structures constitute rich heterostructures and interfaces. The crystal structures of RuS 2 and NiS 1.03 correspond to the (100) plane of the NiS 1.03 phase and RuS 2plane of the phase (210). From Figure 2 in the high-resolution transmission (TEM) of (a) in Figure 2 and the fast Fourier transform (FFT) diffraction patterns of (b) and (c) in Figure 2 it can be seen that the lattice fringe spacings are 0.298 nm and 0.250 nm respectively. As 2 shown in (d) in 1.03 the existence of crystal planes of various RuS Figure 2 and NiS 2 / (FeNi)S 1.03 / C-3 contains evenly distributed elements of Fe, Ni, Ru, S, and C, and it can be seen that the distribution trends of Fe and Ni are exactly the same, only the issue of signal strength, and not exactly the same as Ru, attributed to the inevitable coverage and overlap of various fine grains in the bulk.

[0045] Figure 3 In (a) of 2 / (FeNi)S 1.03 / C-1, RuS 2 / (FeNi)S 1.03 / C-3, RuS 2 / (FeNi)S 1.03 / C-5, RuS 2 / C and (FeNi)S 1.03 / C XRD patterns. The XRD spectra of Examples 1, 3, and 5 all show several sharp peaks, corresponding to RuS 2 (PDF#19-1107) and NiS 1.03 (PDF#02-1273) standard PDF cards, proving the coexistence of RuS 2 and NiS 1.03 in the material. And Figure 3 the enlarged XRD pattern in (b) of 2 shows that the angles of several main peaks (gray area) of RuS 2 / C relative to the standard PDF card have no obvious deviation, indicating that no heteroatoms enter RuS 1.03 / C. However, (FeNi)S 2 / (FeNi)S 1.03 / C-1, RuS 2 / (FeNi)S 1.03 / C-3, RuS 2 / (FeNi)S 1.03The angles of several main diffraction peaks of / C-5 (pink area) all show obvious offsets, attributed to the entry of a small amount of larger Fe atoms into NiS, replacing the sites of smaller Ni, which will cause lattice expansion and thus increase the interplanar spacing. In addition, the different degrees of offset angles are mainly due to the formation of heterojunctions and different Ru contents. In short, the XRD results are completely consistent with the SEM results. Except for RuS 1.03 and NiS 2 When the content of Ru is excessive, there are also several sharp miscellaneous peaks in Example 5, and these miscellaneous peaks correspond to the standard peaks of (FeNi) 1.03 S 9 , indicating that after the increase of Ru, it will interfere with the crystal structure of Fe-doped NiS 8 , deriving other miscellaneous peaks, which also indirectly confirms that Fe is doped into the crystal structure of NiS 1.03 . In addition, the peaks of Comparative Example 1 without adding Fe and Ni correspond well to NiS 1.03 , and the sharp peaks of Comparative Example 2 just correspond to the standard PDF card of RuS 1.03 , indicating that the two comparative examples form their respective pure phases without the existence of heterointerfaces. 2

[0046] Under 1 M KOH electrolyte, the HER performance of the composite materials prepared in each example was evaluated. The preparation processes of the slurry and the electrode head are as follows: 2 mg of the catalyst is mixed with 2 mg of acetylene black and ultrasonically dispersed in a mixture of 20 μL of Nafion, 380 μL of ethanol and 100 μL of deionized water for 30 minutes to obtain an ink with a loading of 0.32 mg·cm -2 . Then it is dropped on the glassy carbon working electrode, while the graphite rod and Hg / HgO are used as the counter electrode and the reference electrode respectively. The overpotential of the RuS 2 / (FeNi)S 1.03 / C-3 heterostructure is only 188 mV at 10 mA cm -2 , while the two pure-phase comparative examples RuS 2 / C and (FeNi)S 1.03 / C require 190 and 365 mV respectively to reach the same current density, as shown in Figure 4 (a). Compared with the pure-phase materials without heterointerfaces, the RuS 2 / (FeNi)S 1.03 heterostructure can effectively enhance the HER catalytic activity, and the existence of the heterojunction accelerates the electron transfer and improves the electrochemical performance. Figure 4 (b) lists RuS 2 / (FeNi)S 1.03 / C-1, RuS​2 / (FeNi)S 1.03 / C-2, RuS 2 / (FeNi)S 1.03 / C-3, RuS 2 / (FeNi)S 1.03 / C-4, RuS 2 / (FeNi)S 1.03 / C-5, (FeNi)S 1.03 / C, RuS 2 / C and Pt / C at 10 mA·cm -2 and 20 mA·cm -2 showed the same variation pattern of overpotential as well.

[0047] As Figure 5 shown, after 5000 consecutive cycles, the polarization curve of RuS 2 / (FeNi)S 1.03 / C-3 for HER only decayed by 7 mV, while the commercial Pt / C material decayed by 18 mV under the same voltage conditions, demonstrating the advantage of RuS 2 / (FeNi)S 1.03 / C-3 material in terms of HER stability. This advantage is attributed to the optimization of electron transfer at the heterointerfaces, promoting the electrocatalytic reaction. This enables RuS 2 / (FeNi)S 1.03 / C-3 catalyst to maintain high catalytic performance during long-term operation, showing excellent electrochemical stability.

[0048] To investigate the effect of Ru on the OER performance in alkaline media in the RuS 2 / (FeNi)S 1.03 / C heterostructure (the preparation processes of the slurry and the electrode tip are the same as those for HER), the OER performance of RuS 2 / (FeNi)S 1.03 / C-1, RuS 2 / (FeNi)S 1.03 / C-2, RuS 2 / (FeNi)S 1.03 / C-3, RuS 2 / (FeNi)S 1.03 / C-4, RuS 2 / (FeNi)S 1.03 / C-5, (FeNi)S 1.03 / C, RuS 2 / C and RuO 2 was evaluated. AsFigure 6 As shown. From Figure 6 in (a), it can be seen that RuS 2 / (FeNi)S 1.03 / C-3 heterostructure has an overpotential of 277 mV at a current density of 20 mA·cm -2 (277 mV@η 20 ), which is significantly lower than that of pure-phase RuS 2 / C (423 mV@ η 20 ), indicating that the addition of Fe and Ni forms RuS 2 / (FeNi)S 1.03 heterointerface and then optimizes the local coordination environment of RuS 2 , thus improving the electrocatalytic performance. RuS 2 / (FeNi)S 1.03 / C-3 exhibits the lowest overpotential, indicating that excessive Ru may cause aggregation and lead to a decrease in activity, while it is difficult to play a role when the content of Ru is low. Figure 6 In (b), RuS 2 / (FeNi)S 1.03 / C-1, RuS 2 / (FeNi)S 1.03 / C-2, RuS 2 / (FeNi)S 1.03 / C-3, RuS 2 / (FeNi)S 1.03 / C-4, RuS 2 / (FeNi)S 1.03 / C-5, (FeNi)S 1.03 / C, RuS 2 / C and RuO 2 at overpotentials of 20 mA·cm -2 and 50 mA·cm -2 also show the same variation law.

[0049] As Figure 7 shown, after 5000 consecutive cycles, the OER polarization curve of RuS 2 / (FeNi)S 1.03 / C-3 only decays by 19 mV, while the commercial RuO 2 material decays by 64 mV under the same voltage conditions, proving the advantage of RuS 2 / (FeNi)S 1.03 / C-3 material in terms of OER stability.

[0050] As Figure 8As shown, the two glassy carbon working electrodes with the catalyst added are used as the imprint and the anode respectively (the preparation process is the same as that of HER and OER), and RuS 2 / (FeNi)S 1.03 / C-3 is used as both the cathode and anode catalysts to form an electrolyzed water device. At a current density of 10 mA cm -2 the voltage reaches 1.68 V, slightly higher than that of commercial Pt / C ‖ RuO 2 (1.64 V). However, as the current density increases, at a current density of 40 mA cm -2 it is 1.78 V, significantly better than 1.92 V of commercial Pt / C ‖ RuO 2 , initially proving the practical applicability of this RuS 2 / (FeNi)S 1.03 / C composite material with rich hetero-interfaces.

[0051] To further evaluate the feasibility of the catalyst in actual commercial applications, 0.25 g of RuS 2 / (FeNi)S 1.03 / C-3 (cathode catalyst) or 0.4 g of NiFe LDH (anode catalyst) and 0.8 mL of FAA-3-SOLUTE-10 anionic polymerization solution are ultrasonically treated (ice-water bath, 40 kHz) for 60 min in a 1:1 (v / v) ethanol-isopropanol solvent mixture to prepare the ink. First, the catalyst slurry is sprayed onto a Teflon plate, and then the cathode and anode catalysts are respectively pressed onto both sides of the anion exchange membrane by hot pressing transfer printing to assemble an anion exchange membrane (AEM) electrolytic cell. As Figure 9 shown, under the condition of 1 M KOH, at a current density of 1000 mA·cm -2 its long-term durability was evaluated. The electrolytic cell with an assembled application area of 45 cm 2 showed excellent stability and operated for more than 255 hours at 25°C and 1000 mA·cm -2 , comparable to the performance of the electrolytic cell assembled with commercial catalysts Pt / C‖NiFe LDH, proving the good industrial application prospects of this catalyst.

[0052] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterogeneous interface, characterized in that: The composite material is a nanoparticle, comprising a metal sulfide and a carbon matrix loaded with the metal sulfide; the metal sulfide is composed of RuS2 and (FeNi)S 1.03 A heterogeneous structure is formed, wherein the heterogeneous structure is a crystalline structure with a grain size of 5 to 50 nm, and an interface between two grains is a heterogeneous interface.

2. The heterogeneous interface-rich ruthenium disulfide / iron nickel sulfide / carbon composite material according to claim 1, characterized in that: The particle size of the nanoparticles is 10-500 nm.

3. A method for preparing the ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterogeneous interface as claimed in claim 1, characterized in that: Sodium dimethyldithiocarbamate is used to simultaneously carry out chelate precipitation reaction on ruthenium salt, trivalent iron salt and divalent nickel salt in a solution to obtain a precursor precipitate; then, under inert atmosphere conditions, the precursor precipitate is heated to 500-600° C. for synchronous annealing treatment to obtain the product.

4. The preparation method according to claim 3, characterized in that: The ruthenium salt, the trivalent iron salt and the divalent nickel salt are dissolved in water to obtain a mixed salt solution, which is then mixed with an aqueous solution of sodium dimethyldithiocarbamate to react and obtain a precursor precipitate.

5. The preparation method according to claim 4, characterized in that: The mixed salt solution was added to the aqueous solution of sodium dimethyldithiocarbamate under stirring.

6. The preparation method according to claim 3, characterized in that: The molar ratio of ruthenium element, iron element and nickel element is 0.15:0.5:1~0.18:0.5:

1.

7. The preparation method according to claim 3, characterized in that: The molar ratio of sodium dimethyldithiocarbamate to nickel element is 1.8-2.2:

1.

8. The preparation method according to claim 3, characterized in that: During the annealing process, the temperature is heated to 500-600 °C and kept at this temperature for 1.5-2.5 hours; Or, during the annealing process, the heating rate is 4~6 °C·min -1 .

9. Use of the ruthenium disulfide / iron nickel sulfide / carbon composite material with rich heterogeneous interface as claimed in claim 1 or 2 in catalytic water electrolysis to produce hydrogen.

10. The use according to claim 9, characterized in that: The heterogeneous interface-rich ruthenium disulfide / iron nickel sulfide / carbon composite material is used as an anode catalyst and a cathode catalyst for catalyzing the electrolysis of water to produce hydrogen.

Images