Phosphorus-doped nickel cobalt sulfide nanotube catalyst, preparation method and application thereof
By preparing phosphorus-doped nickel-cobalt sulfide nanotube catalysts, the problems of scarce precious metal catalyst reserves and slow OER rate were solved, achieving low-energy consumption and high-efficiency bifunctional catalytic performance, which is suitable for electrocatalytic water splitting and sulfur ion oxidation coupled hydrogen production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-19
AI Technical Summary
In existing electrocatalytic water splitting technologies, precious metal catalysts are scarce and expensive, and the oxygen evolution reaction (OER) rate is slow, resulting in high energy consumption costs. Moreover, most existing catalysts only have a single reaction function, making it difficult to achieve efficient bifunctional catalysis.
A hollow catalyst was prepared by using phosphorus-doped nickel-cobalt sulfide nanotube catalysts through hydrothermal reaction and phosphating treatment. The electronic structure was optimized and the active sites were increased. The catalysts were applied to electrocatalytic hydrogen evolution, sulfur ion oxidation and two-electrode sulfur ion oxidation coupled hydrogen production reaction.
It significantly improves catalytic activity, enables efficient preparation of hydrogen and sulfur ion oxidation under low voltage, reduces energy consumption costs, and has dual-function catalytic performance, making it suitable for industrial applications.
Smart Images
Figure CN122235764A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the interdisciplinary field of nanomaterial preparation and catalytic application technology, and provides a phosphorus-doped nickel-cobalt sulfide nanotube catalyst, its preparation method and application. Background Technology
[0002] The continued consumption of fossil fuels and the ongoing deterioration of the ecological environment have led to a sustained increase in global demand for sustainable clean energy. Hydrogen, as a clean energy source with significant development potential, plays an indispensable and crucial role in the future energy structure transformation. Traditional hydrogen production technologies generally suffer from complex production equipment processes and high upfront and ongoing operating costs, making it difficult to meet the demands of large-scale applications. In contrast, electrocatalytic water splitting technology driven by renewable energy sources has become a promising technology for producing high-purity hydrogen due to its mild operating conditions and simple reaction process. However, this technology is limited by the slow rate of the oxygen evolution reaction (OER) at the anolyte, requiring a high voltage during the reaction process, significantly increasing energy consumption costs. Currently, noble metal-based materials such as Pt / C and RuO2, due to their excellent catalytic activity, have become the optimal choice for achieving low-energy electrocatalytic water splitting; however, the scarcity and high price of these materials severely restrict their promotion and application. Therefore, developing high-performance, low-cost novel catalysts has become a critical issue that urgently needs to be addressed in this field.
[0003] To optimize catalytic systems and reduce energy consumption, researchers have attempted to replace the anode oxidation reaction (OER) with thermodynamically more readily occurring molecular oxidation reactions, using molecules such as methanol, glycerol, urea, 5-hydroxymethylfurfural, and hydrazine hydrate. Among these alternative reactions, the sulfide oxidation reaction (SOR) has attracted widespread attention due to its significant advantage of low thermodynamic potential. However, in the SOR process, the formation and transformation of polysulfide intermediates involve the transfer of sixteen electrons, resulting in slow catalytic kinetics. Simultaneously, sulfur species readily poison metal catalysts, reducing their activity and stability. To address these challenges, researchers have explored various strategies to effectively improve catalytic performance by modulating the electronic structure of the catalyst and lowering the reaction energy barrier. However, most currently developed catalysts only possess the catalytic function of a single reaction, while research on catalysts with dual functions of hydrogen evolution reaction (HER) and SOR remains relatively limited. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of current technologies by proposing a transition metal sulfide catalyst, its preparation method, and its application. The prepared NiCo2S4-P catalyst exhibits high catalytic performance and achieves energy-saving hydrogen production and upgraded sulfur ion recovery in a two-electrode sulfur ion oxidation coupled hydrogen production system.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] In a first aspect, the present invention provides a method for preparing a phosphorus-doped nickel-cobalt sulfide nanotube catalyst, comprising the following steps:
[0007] S1. A homogeneous solution was prepared by dissolving nickel salt, cobalt salt, and urea in deionized water. A conductive substrate was added, and a first hydrothermal reaction was carried out to obtain a nickel-cobalt hydroxide nanorod precursor.
[0008] S2. The nickel-cobalt hydroxide nanorod precursor is added to a sodium sulfide solution to carry out a second hydrothermal reaction to prepare a nickel-cobalt sulfide nanotube catalyst;
[0009] S3. The nickel-cobalt sulfide nanotube catalyst and sodium hypophosphite were placed in a tube furnace and subjected to a phosphating reaction in a nitrogen atmosphere to obtain a phosphorus-doped nickel-cobalt sulfide nanotube catalyst with a hollow structure.
[0010] Furthermore, in step S1, the nickel salt is nickel nitrate or nickel chloride; the cobalt salt is cobalt nitrate or cobalt chloride.
[0011] Furthermore, in step S1, the molar ratio of nickel salt, cobalt salt, and urea is 10:(5-30):(30-100).
[0012] Furthermore, in step S1, the temperature of the first hydrothermal reaction is 100-160℃, and the reaction time is 4-12 hours.
[0013] Furthermore, in step S1, the conductive substrate is one or more of the following: cobalt foam, nickel foam, copper foam, titanium foam, titanium mesh, and carbon cloth.
[0014] Furthermore, in step S2, the temperature of the second hydrothermal reaction is 100-160℃, and the reaction time is 6-12 hours.
[0015] Furthermore, in step S2, the concentration of the sodium sulfide solution is 0.1-1 mol / L.
[0016] Furthermore, in S3, the mass ratio of nickel-cobalt sulfide nanotube catalyst to sodium hypophosphite is 1:2-1:15, the phosphating reaction temperature is 300-400 ℃, and the reaction time is 0.5-2 hours.
[0017] In a second aspect, the present invention provides a phosphorus-doped nickel-cobalt sulfide nanotube catalyst prepared according to the above-described preparation method, wherein the phosphorus-doped nickel-cobalt sulfide nanotube catalyst uses a conductive substrate as a support, and a phosphorus-doped nickel-cobalt sulfide nanotube material with a hollow structure is grown on the surface of the support.
[0018] A third aspect of the present invention provides the application of the phosphorus-doped nickel-cobalt sulfide nanotube catalyst described above in electrocatalytic hydrogen evolution reaction, sulfur ion oxidation reaction, and two-electrode sulfur ion oxidation coupled hydrogen production.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] 1. The transition metal sulfide catalyst prepared by this invention optimizes the electronic structure of the catalyst through phosphorus doping and uniform nanotube structure design, and significantly increases the exposed area of catalytic active sites, thereby accelerating the charge transfer rate and significantly improving the catalytic performance.
[0021] 2. The transition metal sulfide catalyst prepared by this invention exhibits excellent activity in electrocatalytic hydrogen evolution, sulfide ion oxidation, and sulfide ion oxidation coupled hydrogen production reactions, thereby significantly improving the problem of limited reaction kinetics in the process of hydrogen production by water electrolysis.
[0022] 3. When the transition metal NiCo2S4-P catalyst prepared in this invention is applied to a two-electrode sulfur ion oxidation coupled hydrogen production system, it requires relatively small electrolysis voltages of 0.373 and 0.696 V and output current densities of 10 and 200 mA cm⁻¹, respectively. -2 This achieves the goal of energy-saving hydrogen production and sulfur ion oxidation to elemental sulfur.
[0023] 4. The preparation process adopted in this invention has the advantages of low cost, simple operation and high controllability, and can effectively replace traditional precious metal catalysts, providing a feasible technical path for the industrialization and large-scale promotion of hydrogen production by water electrolysis. Attached Figure Description
[0024] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.
[0025] Figure 1 The X-ray diffraction (XRD) spectra of NiCo2S4 and (sample 1) NiCo2S4-P (sample 2) prepared in Example 1 of this invention are shown.
[0026] Figure 2 These are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of (sample 2) obtained in Example 1 of the present invention; where a is the SEM image of (sample 2) and b is the TEM image of (sample 2).
[0027] Figure 3The graphs show the HER performance of (Sample 1) and (Sample 2) prepared in Example 1 of this invention in alkaline medium; where a is the polarization curve of HER and b is the corresponding Tafel slope graph.
[0028] Figure 4 The above are the SOR performance diagrams of (Sample 1) and (Sample 2) prepared in Example 1 of the present invention; where a is the polarization curve of SOR and b is the corresponding Tafel slope diagram.
[0029] Figure 5 The images show the performance of (Sample 1) and (Sample 2) prepared in Example 1 of this invention in a conventional water electrolysis and sulfur ion oxidation coupled hydrogen production electrolyzer, and the anode product obtained after adding sulfuric acid to the electrolyzer; wherein a is the polarization curve of (Sample 2) in a conventional water electrolysis and sulfur ion oxidation coupled hydrogen production electrolyzer, and b is the XRD pattern and optical photograph of the anode product obtained after adding sulfuric acid to the stabilized electrolyte.
[0030] Figure 6 The X-ray photoelectron spectroscopy (X-ray Photoelectron Spectroscopy) spectra of (Sample 1) and (Sample 2) prepared in Example 1 of the present invention are shown in the following: a shows the high-resolution Ni 2p spectrum of (Sample 1) and (Sample 2), b shows the Co 2p spectrum of (Sample 1), c shows the S 2p spectrum of (Sample 1) and (Sample 2), and d shows the P 2p spectrum of (Sample 1) and (Sample 2). Detailed Implementation
[0031] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that those skilled in the art can fully understand the technical solutions, advantages, and features of the present invention, thereby clarifying the scope of protection of the present invention. It should be noted that the embodiments described are only some examples of the present invention, and not all of them. Based on the content disclosed in this invention, all other variations and improvements obtained by those skilled in the art through conventional technical means without creative improvements should also be considered to fall within the scope of protection of this invention.
[0032] In a first aspect, the present invention provides a method for preparing a transition metal sulfide catalyst, comprising the following steps:
[0033] S100: Prepare a homogeneous solution by dissolving 10 parts of nickel salt, 5-30 parts of cobalt salt, and 30-100 parts of urea in deionized water according to the molar ratio.
[0034] S200: The above solution is transferred to a polytetrafluoroethylene-lined reactor, a conductive substrate is added, the reactor is sealed and placed in an oven, and reactive materials are grown on the conductive substrate using the first hydrothermal reaction to prepare nickel cobalt hydroxide nanorod precursors.
[0035] S300: The above nickel cobalt hydroxide nanorod precursor is added to a sodium sulfide solution, and the nickel cobalt hydroxide nanorod precursor is sulfided by a second hydrothermal reaction to prepare a nickel cobalt sulfide nanotube catalyst.
[0036] S400: Nickel-cobalt sulfide nanotube catalyst and sodium hypophosphite are placed in a ceramic boat, and phosphorus doping of the nickel-cobalt sulfide nanotube catalyst is carried out by low-temperature phosphating reaction to prepare a phosphorus-doped nickel-cobalt sulfide nanotube catalyst with a hollow structure.
[0037] For example, in step S100, the nickel salt is nickel nitrate or nickel chloride, and the cobalt salt is cobalt nitrate or cobalt chloride.
[0038] For example, in step S200, the temperature and reaction time of the first hydrothermal reaction are 100-160℃ and 4-12 hours, respectively.
[0039] For example, in step S200, the conductive substrate is one or more of cobalt foam, nickel foam, copper foam, titanium foam, titanium mesh, and carbon cloth.
[0040] For example, in step S300, the temperature and time of the second hydrothermal reaction are 100-160 °C and 6-12 hours, respectively, and the concentration of sodium sulfide solution is 0.1-1 mol / L.
[0041] For example, in step S400, the mass ratio of nickel cobalt sulfide nanotube catalyst to sodium hypophosphite is 1:2-1:15, and the temperature and time of the phosphating reaction are 300-400 °C and 0.5-2 hours, respectively.
[0042] To further illustrate the embodiments of this application, the following description, in conjunction with specific examples and accompanying drawings, will be provided. Figure 1-5 The transition metal sulfide catalysts and their preparation methods according to the embodiments of this application will be described in detail.
[0043] Example 1
[0044] A method for preparing a transition metal sulfide catalyst specifically includes the following steps:
[0045] 1) Dissolve 1 mmol nickel nitrate, 2 mmol cobalt nitrate and 6 mmol urea in 35 mL deionized water to obtain a homogeneous reaction solution;
[0046] 2) Transfer the above solution to a 50 mL polytetrafluoroethylene liner, add nickel foam, seal and place in a forced-air drying oven, heat to 120 °C and keep warm for 6 hours to prepare NiCo(OH)2 precursor;
[0047] 3) Add deionized water and one piece of the above-mentioned NiCo(OH)2 precursor to the sodium sulfide solution and prepare NiCo2S4 catalyst (sample 1) by hydrothermal reaction. The reaction temperature and time are 120 °C and 8 hours, respectively.
[0048] 4) NiCo2S4 catalyst and 0.1 g sodium hypophosphite were placed in a tube furnace and phosphating reaction was carried out in a nitrogen atmosphere. The reaction temperature and time were 300 °C and 0.5 h, respectively, to prepare NiCo2S4-P (sample 2).
[0049] Example 2
[0050] Same as in Example 1, except that no phosphating reaction was performed, resulting in Sample 1.
[0051] Example 3
[0052] Same as Example 1, except that the amount of sodium hypophosphite added during the phosphating reaction is changed to 0.05 g, and the output current density of the HER and SOR processes is 10 mA cm⁻¹. -2 The required potentials are -156 V and 0.273 V, respectively.
[0053] Example 4
[0054] Same as Example 1, except that the amount of sodium hypophosphite added during the phosphating reaction is changed to 0.2 g, and the output current density of the HER and SOR processes is 10 mA cm⁻¹. -2 The required potentials are -181 V and 0.287 V, respectively.
[0055] The performance of the NiCo2S4-P catalyst prepared above was tested in alkaline solution for HER, SOR, full water electrolysis and sulfur ion oxidation coupled hydrogen production processes. The working electrode in the electrolytic cell was the product of this invention. The electrocatalytic reaction performance was tested using an electrochemical workstation. In the test results, all electrode potentials were converted to reversible hydrogen electrode potentials (RHE).
[0056] The phase composition, microstructure, and electrocatalytic performance of the catalyst sample 2 prepared above were studied. Figure 1 The XRD pattern of sample 2 shows that the catalyst of sample 2 was synthesized.
[0057] like Figure 2 As shown, a and b are SEM and TEM images of sample 2, respectively. Figure 2 This indicates that the synthesized sample 2 has a hollow nanotube morphology.
[0058] like Figure 3 As shown, a is the HER polarization curve of sample 1 and sample 2, and b is the Tafel slope plot of HER for sample 1 and sample 2. Figure 3This indicates that the synthesized sample 2 has good HER activity, with an output of 10 mA cm⁻¹. -2 The required overpotential for the current density is -132 mV, and the Tafel slope is 91 mV dec. -1 .
[0059] like Figure 4 As shown, a is the SOR polarization curve of sample 1 and sample 2, and b is the Tafel slope diagram of the SOR of sample 1 and sample 2. Figure 4 This indicates that the synthesized sample 2 has good SOR activity, with an output current density of 10 mA cm⁻¹. -2 The required potential is 0.264 V, and the Tafel slope is 101 mV dec. -1 .
[0060] like Figure 5 As shown, a is the polarization curve of sample 2 in a conventional water electrolysis and sulfur ion oxidation coupled hydrogen production electrolysis cell, and b is the anode product obtained by adding sulfuric acid to the stabilized electrolyte. Figure 5 This indicates that the synthesized sample 2 exhibits good catalytic activity in a sulfur ion oxidation coupled hydrogen production electrolyzer, with an output current density of 10 mA cm⁻¹. -2 The required voltage is 0.373 V, and the anode product is elemental sulfur.
[0061] like Figure 6 As shown, the XPS spectrum of sample 2 confirms the presence of Ni, Co, S and P elements in the sample, indicating that P has been successfully incorporated and effectively modulates the electronic structure of the nickel-cobalt sulfide nanotube catalyst.
[0062] In summary, the NiCo2S4-P catalyst prepared in this invention exhibits good catalytic activity for HER and SOR. In the integrated sulfur ion oxidation coupled hydrogen production two-electrode electrolyzer, a relatively low voltage of 0.373 V and an output current density of 10 mAcm⁻¹ are required. -2 This invention achieves the goal of energy-saving hydrogen production and upgrading sulfide ion oxidation to high-value-added elemental sulfur products. The preparation method of this invention is simple to operate, environmentally friendly, and suitable for large-scale production, and can be widely applied to the efficient catalysis of water electrolysis for hydrogen production and sulfide ion oxidation reactions.
[0063] The content and embodiments described in this invention can be easily understood and implemented by those skilled in the art, and can be reasonably improved or modified without departing from the core principles of this invention. Therefore, all equivalent variations or improvements made based on the principles of this invention should be included within the scope of protection of this invention.
Claims
1. A method for preparing a phosphorus-doped nickel-cobalt sulfide nanotube catalyst, characterized in that, Includes the following steps: S1. A homogeneous solution was prepared by dissolving nickel salt, cobalt salt, and urea in deionized water. A conductive substrate was added, and a first hydrothermal reaction was carried out to obtain a nickel-cobalt hydroxide nanorod precursor. S2. The nickel-cobalt hydroxide nanorod precursor is added to a sodium sulfide solution to carry out a second hydrothermal reaction to prepare a nickel-cobalt sulfide nanotube catalyst; S3. The nickel-cobalt sulfide nanotube catalyst and sodium hypophosphite were placed in a tube furnace and subjected to a phosphating reaction in a nitrogen atmosphere to obtain a phosphorus-doped nickel-cobalt sulfide nanotube catalyst with a hollow structure.
2. The preparation method according to claim 1, characterized in that, In step S1, the nickel salt is nickel nitrate or nickel chloride; the cobalt salt is cobalt nitrate or cobalt chloride.
3. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of nickel salt, cobalt salt, and urea is 10:(5-30):(30-100).
4. The preparation method according to claim 1, characterized in that, In step S1, the temperature of the first hydrothermal reaction is 100-160℃, and the reaction time is 4-12 hours.
5. The preparation method according to claim 1, characterized in that, In step S1, the conductive substrate is one or more of the following: cobalt foam, nickel foam, copper foam, titanium foam, titanium mesh, and carbon cloth.
6. The preparation method according to claim 1, characterized in that, In step S2, the temperature of the second hydrothermal reaction is 100-160℃, and the reaction time is 6-12 hours.
7. The preparation method according to claim 1, characterized in that, In step S2, the concentration of sodium sulfide solution is 0.1-1 mol / L.
8. The preparation method according to claim 1, characterized in that, In S3, the mass ratio of nickel-cobalt sulfide nanotube catalyst to sodium hypophosphite is 1:2-1:15, the phosphating reaction temperature is 300-400 ℃, and the reaction time is 0.5-2 hours.
9. A phosphorus-doped nickel-cobalt sulfide nanotube catalyst prepared by the preparation method according to any one of claims 1-8, wherein the phosphorus-doped nickel-cobalt sulfide nanotube catalyst uses a conductive substrate as a support, and phosphorus-doped nickel-cobalt sulfide nanotube material with a hollow structure is grown on the surface of the support.
10. The application of the phosphorus-doped nickel-cobalt sulfide nanotube catalyst as described in claim 9 in electrocatalytic hydrogen evolution reaction, sulfur ion oxidation reaction and two-electrode sulfur ion oxidation coupled hydrogen production.