Nickel-based chalcogenide catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of functional materials, and discloses a nickel-based chalcogenide catalyst and a preparation method and application thereof.The preparation method comprises the steps that Ni-MOF precursor powder is prepared through coordination; carrying out chemical vapor deposition reaction on the Ni-MOF precursor powder and chalcogenide elementary substance powder, pyrolyzing and grinding to obtain the nickel-based chalcogenide catalyst. The electron deficiency degree of the nickel site can be regulated and controlled through the chalcogenide element, and in a membrane electrode assembly test, the prepared nickel-based chalcogenide catalyst shows excellent CO selectivity and stability and is suitable for preparing carbon monoxide through carbon dioxide electroreduction.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, and specifically relates to a nickel-based chalcogenide catalyst, namely a nickel-based chalcogenide catalyst, its preparation method and application. Background Technology

[0002] The consumption of fossil fuels has led to a significant increase in atmospheric carbon dioxide (CO2) concentration, exacerbating the greenhouse effect and triggering a global climate crisis. Electrocatalytic carbon dioxide reduction (CO2RR) offers a promising solution to the carbon cycle. This technology utilizes electricity generated from renewable energy sources to efficiently convert CO2 into high-value-added chemicals such as carbon monoxide (CO), formic acid (HCOOH), ethylene (C2H4), and ethanol (C2H5OH). CO formation requires only the coupling of two electrons and two protons, resulting in a relatively low reaction kinetic energy barrier. Furthermore, CO serves as a key raw material for the synthesis of basic chemicals and the Fischer-Tropsch synthesis process, possessing significant economic value.

[0003] Currently, the electroreduction of CO2 to CO relies heavily on precious metal catalysts such as gold and silver. However, the high cost and scarcity of these catalysts severely restrict the large-scale industrial application of this technology. Therefore, developing highly active and low-cost non-precious metal catalysts is crucial for advancing the industrialization of CO2 electroreduction to CO.

[0004] Nickel-based catalysts have attracted widespread attention due to their superior CO selectivity in CO2RR compared to other non-precious metal catalysts. However, the excessive binding of metallic nickel catalysts to CO intermediates during CO2RR hinders CO intermediate desorption and easily leads to catalyst poisoning. Existing nickel-based catalysts still exhibit unsatisfactory CO selectivity at industrial current densities, making it difficult to meet the application requirements of CO2RR at industrial current densities.

[0005] Therefore, there is an urgent need for a nickel-based catalyst that can exhibit both high selectivity and stability at industrial current densities. Summary of the Invention

[0006] To address the problems of existing nickel catalysts having excessively strong binding with CO intermediates during the reaction process, hindering CO intermediate desorption, and easily leading to catalyst poisoning, as well as unsatisfactory CO selectivity at industrial current densities, which makes it difficult to meet the requirements of industrial applications, this invention provides a nickel-based chalcogenide catalyst, its preparation method, and its application.

[0007] This invention is achieved using the following techniques: This invention provides a method for preparing a nickel-based chalcogenide catalyst, comprising the following steps: S1, coordination preparation of Ni-MOF precursor powder; Ni-MOFs were prepared using a direct liquid-phase synthesis method, which specifically includes the following steps: S11, nickel nitrate and 2-methylimidazole were dissolved in anhydrous methanol to prepare nickel nitrate solution and 2-methylimidazole solution, respectively. S12, 2-methylimidazole solution was rapidly added to nickel nitrate solution, stirred at room temperature for 8 hours to obtain a precipitate, and the precipitate was collected by centrifugation; S13, the precipitate is washed with methanol and deionized water alternately to remove impurities. That is, the precipitate is first washed with methanol and then washed with deionized water. The alternating washing is repeated 3 times to remove impurities. After drying, Ni-MOF precursor powder is obtained.

[0008] S2, Ni-MOF precursor powder and chalcogenide powder are subjected to chemical vapor deposition reaction in a tube furnace. The mass ratio of Ni-MOF precursor powder to chalcogenide powder is (0.8~1):(1~1.4). Preferably, the mass ratio of Ni-MOF precursor powder to chalcogenide powder is 0.8:1. The reaction is carried out under a protective atmosphere at a reaction temperature of 700~800℃. After pyrolysis, the mixture is ground to obtain a nickel-based chalcogenide catalyst.

[0009] Specifically, the chalcogenide powders are tellurium powder, selenium powder, or sulfur powder.

[0010] Specifically, the protective atmosphere is high-purity nitrogen, and the gas flow rate is 50 mL / min. -1 .

[0011] This invention also provides a nickel-based chalcogenide catalyst prepared by the above-described method. In the nickel-based chalcogenide catalyst, the nickel sites are in an electron-deficient state; specifically, the valence state of Ni is Ni. δ+ , where 0 < δ < 2.

[0012] The present invention also provides the application of the above-mentioned nickel-based chalcogenide catalyst in the electrocatalytic carbon dioxide reduction reaction.

[0013] Specifically, it is used in the electroreduction of carbon dioxide to produce carbon monoxide.

[0014] Specifically, it is applied to current densities of 300~500 mA·cm. -2 Electrocatalytic reactions under [condition].

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a nickel-based chalcogenide catalyst, its preparation method, and its application. Nickel-based chalcogenides are prepared by chemical vapor deposition pyrolysis of Ni-MOF. The method is simple, rapid, and easy to scale up.

[0016] The prepared nickel-based chalcogenides have a nanosheet structure and abundant active sites, and the nickel sites exhibit varying degrees of electron deficiency. By changing the chalcogen elements deposited by chemical vapor deposition, nickel catalysts with varying degrees of electron deficiency can be obtained.

[0017] This catalyst is applied to the efficient electroreduction of CO2 to CO. In CO2RR, it weakens the binding strength with CO intermediates, reduces catalyst surface poisoning, and greatly improves CO selectivity. Electrocatalytic results show that the catalyst exhibits excellent catalytic activity and stability at industrial current densities. In membrane electrode assembly (MEA) testing, under acidic electrolyte conditions at 300 mA·cm⁻¹, it showed good performance. -2 The current density achieved a CO Faradaic efficiency of 91.8% under neutral electrolyte conditions at 500 mA·cm⁻¹ -2 The current density achieved a CO Faraday efficiency of 97.6%; the prepared nickel-based chalcogenides exhibited excellent catalytic activity, making them highly promising for CO2RR and providing a valuable reference for studying the effect of electron deficiency at nickel sites on CO2RR. Attached Figure Description

[0018] Figure 1 The XRD patterns are of the catalysts prepared in Examples 1-3.

[0019] Figure 2 The XRD pattern of the catalyst prepared in Comparative Example 1 is shown.

[0020] Figure 3 The XAFS spectra of the catalysts prepared in Examples 1-3 are shown.

[0021] Figure 4 The XAFS spectrum of the catalyst prepared in Comparative Example 1 is shown.

[0022] Figure 5 The images show SEM images of the catalysts prepared in Examples 1-3, where a and b are the catalysts prepared in Example 1, c and d are the catalysts prepared in Example 2, and e and f are the catalysts prepared in Example 3.

[0023] Figure 6 The image shows the SEM image of the catalyst prepared in Comparative Example 1.

[0024] Figure 7 The images are TEM images of the catalysts prepared in Examples 1-3, where a and b are the catalysts prepared in Example 1, c and d are the catalysts prepared in Example 2, and e and f are the catalysts prepared in Example 3.

[0025] Figure 8 TEM image of the catalyst prepared in Comparative Example 1.

[0026] Figure 9The graph shows the CO Faradaic efficiency performance of the catalysts prepared in Examples 1-3 in acidic electrolyte.

[0027] Figure 10 The graph shows the CO Faradaic efficiency performance of the catalysts prepared in Examples 1-3 in a neutral electrolyte.

[0028] Figure 11 The graph shows the single-pass carbon efficiency performance of the catalyst prepared in Example 1 in an acidic electrolyte.

[0029] Figure 12 The graph shows the performance of the catalyst prepared in acidic electrolyte for Comparative Example 1.

[0030] Figure 13 The image shows the stability test results of the catalyst prepared in Example 1 in acidic MEA.

[0031] Figure 14 The graph shows the stability test results of the catalyst prepared in Example 1 in a neutral MEA. Detailed Implementation

[0032] The specific embodiments of the present invention will be described in detail below. Example 1

[0033] A method for preparing a nickel-based chalcogenide catalyst includes the following steps: S1, coordination preparation of Ni-MOF precursor powder; S11, dissolve 1.3g of nickel nitrate in 30mL of anhydrous methanol and stir for 30 minutes to obtain a nickel nitrate solution, denoted as solution A; Dissolve 3.2 g of 2-methylimidazole in 30 mL of anhydrous methanol and stir for 30 minutes to obtain a 2-methylimidazole solution, denoted as solution B. S12, 2-methylimidazole solution is rapidly added to nickel nitrate solution, that is, solution B is rapidly added to solution A, and stirred at room temperature for 8 hours to obtain a precipitate, which is then separated by centrifugation to obtain the precipitate; S13, the precipitate was washed with methanol and deionized water to remove impurities, and then dried in an oven at 60°C for 12 hours to obtain Ni-MOF precursor powder.

[0034] S2, 0.8 g of Ni-MOF precursor powder was placed downstream of the ceramic boat, and 1.0 g of tellurium powder was placed upstream of the ceramic boat. The ceramic boat was then placed in a tube furnace, and a vacuum was drawn. Chemical vapor deposition was carried out in the tube furnace, with the powder being added to the furnace at a rate of 50 mL / min. -1 High-purity nitrogen gas is introduced at a flow rate of 5℃·min. -1 The temperature was increased to 800°C at a rate of [missing information] and maintained at pyrolysis for 3 hours; After calcination, the sample was removed, ground, and the resulting catalyst sample was denoted as NiTe@C. Example 2

[0035] A method for preparing a nickel-based chalcogenide catalyst includes the following steps: In step S2, 1.0g of selenium powder was used as raw material, and the rest was completely consistent with Example 1 to prepare a catalyst sample, denoted as NiSe@C. Example 3

[0036] A method for preparing a nickel-based chalcogenide catalyst includes the following steps: In step S2, 1.0g of sulfur powder was used as raw material, the chemical vapor deposition reaction temperature was 700℃, and the rest was completely consistent with Example 1 to obtain a catalyst sample, denoted as NiS@C. Comparative Example 1

[0037] A method for preparing a nickel-based catalyst includes the following steps: In step S2, 0.8g of Ni-MOF precursor powder was placed in a ceramic boat without adding any chalcogenide powder. The rest was completely consistent with Example 1 to obtain a catalyst sample, denoted as Ni@C.

[0038] The catalyst samples prepared in Examples 1-3 and Comparative Example 1 were tested.

[0039] Structural characterization X-ray diffraction (XRD) analysis was performed on the nickel-based chalcogenide catalysts obtained in Examples 1-3, as follows: Figure 1 As shown, the diffraction peaks of Example 1 (NiTe@C), Example 2 (NiSe@C), and Example 3 (NiS@C) are consistent with their respective standard PDF cards, indicating that NiTe@C, NiSe@C, and NiS@C catalysts were successfully synthesized.

[0040] like Figure 2 As shown, the XRD pattern of Comparative Example 1 shows that the diffraction peaks of Ni@C are consistent with its standard PDF card, indicating that the Ni@C catalyst was successfully synthesized.

[0041] The X-ray absorption fine structure (XAFS) analysis results of Examples 1-3 are as follows: Figure 3 As shown, in Examples 1 (NiTe@C), 2 (NiSe@C), and 3 (NiS@C), the absorption edge of Ni lies between the Ni foil and NiO, indicating that the valence state of Ni is typical of Ni. δ+(0 < δ < 2), and all are in an electron-deficient state. Furthermore, compared to NiSe@C and NiS@C, the absorption edge of Ni in NiTe@C is located at a lower energy, indicating the lowest degree of electron deficiency. In contrast, the absorption edge of Ni in NiS@C is located at a higher energy, indicating the highest degree of electron deficiency. The absorption edge of Ni in NiSe@C is located at an intermediate energy, indicating a moderate degree of electron deficiency. By introducing different chalcogen elements, the degree of electron deficiency at Ni sites can be directionally controlled, providing a feasible strategy for finely controlling the electronic structure of catalysts.

[0042] The XAFS analysis results for Comparative Example 1 are as follows: Figure 4 As shown, the absorption edge of Ni in Ni@C coincides with the Ni foil, indicating that Ni in Ni@C is an intrinsically zero-valence metallic state and is in an electron-rich state.

[0043] The scanning electron microscopy (SEM) characterization results of Examples 1-3 are as follows: Figure 5 As shown in the figure, a is a low-magnification SEM image of Example 1 (NiTe@C) (scale bar: 5 μm), showing that NiTe@C exhibits a nanosheet structure overall; b is a high-magnification SEM image of Example 1 (NiTe@C) (scale bar: 500 nm), further showing that the nanosheets have a smooth surface and uniform thickness. Meanwhile, SEM images c (scale bar: 5 μm) and d (scale bar: 500 nm) of Example 2 (NiSe@C) and SEM images e (scale bar: 5 μm) and f (scale bar: 500 nm) of Example 3 (NiS@C) show a nanosheet structure similar to that of Example 1 (NiTe@C).

[0044] Comparative example 1 SEM image as follows Figure 6 As shown, a is a SEM image of Comparative Example 1 (Ni@C) at low magnification (scale bar is 5 μm), and b is a SEM image of Comparative Example 1 (Ni@C) at high magnification (scale bar is 500 nm). Comparative Example 1 (Ni@C) exhibits a nanosheet structure.

[0045] The transmission electron microscopy (TEM) characterization results of Examples 1-3 are as follows: Figure 7As shown, a is a low-resolution TEM image of Example 1 (NiTe@C) (scale bar 500 nm), showing that NiTe@C has a nanosheet structure with NiTe nanoparticles coated with C nanosheets; b is a high-resolution TEM image of Example 1 (NiTe@C) (scale bar 5 nm), with a lattice spacing of 0.29 nm and lattice fringes corresponding to the (101) crystal plane of NiTe. c is a low-resolution TEM image of Example 2 (NiSe@C) (scale bar 500 nm), showing that NiSe@C has a nanosheet structure with NiSe nanoparticles coated with C nanosheets; d is a high-resolution TEM image of Example 2 (NiSe@C) (scale bar 5 nm), with a lattice spacing of 0.27 nm and lattice fringes corresponding to the (101) crystal plane of NiSe. e is a low-resolution TEM image of Example 3 (NiS@C) (scale bar: 500 nm), showing that NiS@C has a nanosheet structure with NiS nanoparticles coated with C nanosheets; f is a high-resolution TEM image of Example 3 (NiS@C) (scale bar: 5 nm), with a lattice spacing of 0.26 nm, and the lattice fringes corresponding to the (101) crystal plane of NiS. Notably, the (101) crystal plane spacing of NiS, NiSe, and NiTe gradually increases, which is consistent with the gradual increase in atomic radius of S, Se, and Te. TEM analysis results indicate the successful synthesis of NiTe@C, NiSe@C, and NiS@C catalysts. This further confirms the successful loading of the active components on carbon nanosheets and verifies the successful construction of different phases from a crystallographic perspective.

[0046] Comparative Example 1 TEM image as follows Figure 8 As shown, a is a low-resolution TEM image of Comparative Example 1 (Ni@C) (scale bar 500 nm), showing that Ni@C has a nanosheet structure with Ni nanoparticles coated with C nanosheets; b is a high-resolution TEM image of Comparative Example 1 (Ni@C) (scale bar 5 nm), with a lattice spacing of 0.20 nm. The lattice fringes correspond to the (111) crystal plane of Ni. The TEM results indicate that the Ni@C catalyst was successfully synthesized.

[0047] Performance testing CO2RR tests were performed on NiTe@C, NiSe@C, NiS@C, and Ni@C in membrane electrode assemblies under ambient temperature and pressure.

[0048] The catalysts prepared in Examples 1-3 and Comparative Example 1 were uniformly sprayed onto carbon paper as cathodes, and titanium mesh loaded with iridium oxide was used as anodes to assemble a membrane electrode assembly (MEA) electrolytic cell. A mixed solution of 0.05 M H₂SO₄ and 0.4 M K₂SO₄ was used as the acidic electrolyte, and 1 M KHCO₃ was used as the neutral electrolyte. During the test, humidified CO₂ was continuously introduced into the cathode chamber at a flow rate of 50 mL / min.-1 The anolyte is continuously circulated via a peristaltic pump.

[0049] like Figure 9 As shown, under acidic electrolyte conditions at 300 mA·cm -2 At a current density of 300 mA·cm⁻¹, Example 1 (NiTe@C) achieved a CO Faradaic efficiency of 91.8%. Examples 2 (NiSe@C) and 3 (NiS@C) achieved similar efficiency at 300 mA·cm⁻¹. -2 The CO Faraday efficiencies at the given current densities were 79.3% and 16.9%, respectively.

[0050] like Figure 10 As shown, under neutral electrolyte conditions at 500 mA·cm -2 At a current density of 500 mA·cm⁻¹, Example 1 (NiTe@C) achieved a CO Faradaic efficiency of 97.6%. Example 2 (NiSe@C) achieved a CO Faradaic efficiency of 97.6% at a current density of 500 mA·cm⁻¹. -2 The CO Faraday efficiency at the specified current density is 57.1%. Example 3 (NiS@C) at 400 mA·cm⁻¹ -2 The CO Faraday efficiency at the specified current density is only 15.9%. In CO2RR, the moderate electron-deficient states of Ni sites in the NiTe@C catalyst significantly improve CO selectivity. However, as the degree of electron deficiency increases, the CO selectivity of NiSe@C and NiS@C gradually decreases.

[0051] In addition, such as Figure 11 As shown, the current density in the acidic electrolyte is 200 mA·cm. -2 CO2 flow rate is 1 mL·min -1 At that time, the single-pass carbon conversion efficiency of Example 1 (NiTe@C) was 78.1%, indicating that under actual working conditions, the utilization rate of CO2 was greatly improved, which has great application potential and is of great significance for reducing the cost of CO2RR.

[0052] like Figure 12 As shown, Comparative Example 1 (Ni@C) under acidic electrolyte conditions at 300 mA·cm -2 The CO selectivity at the current density is only 9.7%, and the CO selectivity of electron-rich Ni@C in CO2RR decreases sharply due to CO intermediate poisoning.

[0053] like Figure 13 As shown, after 15 hours of stable operation in an acidic electrolyte, Example 1 (NiTe@C) maintained a Faraday efficiency of over 90%.

[0054] like Figure 14As shown, after 60 hours of stable operation in neutral electrolyte, the Faraday efficiency of Example 1 (NiTe@C) did not decrease significantly, indicating that it has excellent stability. Long-term operational stability is crucial in practical applications.

[0055] In summary, this invention prepares a nickel-based chalcogenide catalyst by pyrolysis of Ni-MOF via chemical vapor deposition. The prepared NiTe@C exhibits excellent CO selectivity and stability in CO2RR. Investigating the effect of the electron-deficient degree of nickel sites in nickel-based chalcogenides on CO2RR activity is of great significance.

[0056] The scope of protection claimed by this invention is not limited to the specific embodiments described above. Moreover, for those skilled in the art, this invention can have various modifications and alterations. Any modifications, improvements, and equivalent substitutions made within the concept and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing a nickel-based chalcogenide catalyst, characterized in that, Includes the following steps: S1, coordination preparation of Ni-MOF precursor powder; S2, Ni-MOF precursor powder and chalcogenide powder are subjected to chemical vapor deposition reaction in a tube furnace. The mass ratio of Ni-MOF precursor powder to chalcogenide powder is (0.8~1):(1~1.4). The reaction is carried out under a protective atmosphere at a reaction temperature of 700~800℃. After pyrolysis, the mixture is ground to obtain a nickel-based chalcogenide catalyst.

2. The method for preparing a nickel-based chalcogenide catalyst according to claim 1, characterized in that, In step S2, the chalcogenide powder is tellurium powder, selenium powder, or sulfur powder.

3. The method for preparing a nickel-based chalcogenide catalyst according to claim 1, characterized in that, The protective atmosphere is high-purity nitrogen, and the gas flow rate is 50 mL / min. -1 .

4. The method for preparing a nickel-based chalcogenide catalyst according to claim 1, characterized in that, Step S1 includes the following steps: S11, nickel nitrate and 2-methylimidazole were dissolved in anhydrous methanol to prepare nickel nitrate solution and 2-methylimidazole solution, respectively. S12, 2-methylimidazole solution is rapidly added to nickel nitrate solution, stirred at room temperature to obtain a precipitate, and the precipitate is collected by centrifugation; S13, the precipitate was washed with methanol and deionized water alternately to remove impurities, and then dried to obtain Ni-MOF precursor powder.

5. The nickel-based chalcogenide catalyst prepared by any one of claims 1 to 4.

6. The nickel-based chalcogenide catalyst according to claim 5, characterized in that, In nickel-based chalcogenide catalysts, the nickel sites are in an electron-deficient state.

7. The nickel-based chalcogenide catalyst according to claim 6, characterized in that, The valence state of Ni is Ni δ+ , where 0 < δ < 2.

8. The application of the nickel-based chalcogenide catalyst of claim 5 in the electrocatalytic reduction of carbon dioxide.

9. The application according to claim 8, characterized in that, It is used in the electroreduction of carbon dioxide to prepare carbon monoxide.

10. The application according to claim 9, characterized in that, Applicable to current densities of 300~500mA·cm -2 Electrocatalytic reactions under [condition].

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