CoS2 / PVIPS / PPyNT S Nanomaterials, methods of making and use in electrocatalytic nitrogen oxidation

Abstract

The application belongs to the field of new energy and electrochemical catalysis, and particularly relates to CoS2 / PVIPS / PPyNTs nanomaterial, a preparation method and application in electrocatalysis of nitrogen oxide. The CoS2 / PVIPS / PPyNTs is prepared by loading cobalt disulfide on poly(1-vinyl-3-propane sulfonic acid imidazole salt) / poly pyrrole nanotube. The CoS2 / PVIPS / PPyNTs modified electrode is prepared by loading CoS2 / PVIPS / PPyNTs on carbon cloth. In alkaline conditions, CoS2 is used as an active center, poly pyrrole nanotube is used as a carrier, and ionic liquid is used as a connecting agent and a structure inducer, so that the OER process can be inhibited, the NOR reaction activity can be enhanced, the nitrate yield can be improved, a higher Faraday efficiency is shown, and good stability is also shown, thereby providing a new idea and method for the research and design of NOR electrocatalysts under normal temperature and pressure.

Description

Technical Field

[0001] This invention belongs to the field of new energy and electrochemical catalysis, specifically involving CoS2 / PVIPS / PPyNTs nanomaterials, their preparation methods, and their application in electrocatalytic nitrogen oxidation. Background Technology

[0002] Nitrogen fixation, defined as the conversion of inert nitrogen (N2) into reactive nitrogen (nitrogen-containing compounds), is one of the most important chemical processes in nature. With the rapid growth of the global population, natural nitrogen fixation is far from meeting the needs of human activities. Therefore, artificial nitrogen fixation has emerged. An important nitrogen-containing compound is nitrate, primarily produced via a two-step process consisting of the Haber-Bosch (HB) process and the Ostwald oxidation process. Despite its significant contribution, this process inevitably generates substantial energy consumption and carbon emissions. Therefore, it is necessary to develop new methods for nitrate preparation, especially driven by renewable energy sources. In this regard, the electrochemical nitrogen oxidation reaction (NOR) for nitrate synthesis under mild conditions has been developed and is considered a potential alternative. Compared to the current centralized two-step method, electrochemical NOR enables small-scale, distributed production and is also compatible with intermittent renewable energy sources.

[0003] Unlike artificial nitrogen oxidation (NRR) inspired by natural nitrogenase, no living organism directly produces nitrate solutions from N2 and O2. Therefore, the advantages of electrocatalytic nitrogen oxidation (NOR) are obvious: it not only reduces energy consumption and carbon emissions but also enables small-scale, on-demand production. Thus, developing a highly efficient NOR catalyst is crucial for achieving energy conservation, atom economy, and carbon-free goals. Transition metal sulfides possess diverse crystal structures and tunable phase compositions, exhibiting high electrocatalytic activity, low oxygen evolution reaction activity, abundant reserves, and low cost, making them a promising NOR catalyst and attracting widespread attention. CoS2 has come to our attention due to its high catalytic activity, low cost, diverse crystal structures, and tunable phase compositions, making it a potentially promising NOR catalyst. However, due to the inherent poor stability and tendency to aggregate of metal-based catalysts, we selected PVIPS / PPyNT. S Nanotubes are used as a substrate for stabilization. Summary of the Invention

[0004] One objective of this invention is to provide a low-cost, high-catalytic-performance CoS2 / PVIPS / PPyNT catalytic solution. S Nanomaterials.

[0005] The second objective of this invention is to provide a method using CoS2 / PVIPS / PPyNT. S NOR electrocatalytic modified electrodes prepared from nanomaterials are used for electrocatalytic nitrogen oxidation.

[0006] To achieve the above objectives, the technical solution adopted by this invention is as follows: CoS2 / PVIPS / PPyNT S Nanomaterials, the preparation method includes the following steps:

[0007] 1) Add methyl orange to deionized water, disperse by ultrasonication, then add FeCl3 6H2O, continue to disperse by ultrasonication, add pyrrole (Py), transfer to an ice-water bath, stir for 6 hours, centrifuge, wash, and dry to obtain PPyNTs nanotubes.

[0008] 2) Add PPyNT to N,N-dimethylformamide S Nanotubes were ultrasonically dispersed, then allyl chloride and KOH were added and ultrasonically dispersed again. The mixture was then transferred to a 60°C oil bath and stirred for 24 hours. After centrifugation, washing, and vacuum drying, PPyNT was obtained. S -CH2-CH=CH2 nanotubes;

[0009] 3) Add PPyNT to anhydrous ethanol S -CH2-CH=CH2 nanotubes were ultrasonically dispersed, and then 1-vinyl-3-propanesulfonic acid imidazole salt (VIPS) and the initiator azobisisobutyronitrile (AIBN) were added. The mixture was then transferred to an oil bath at 80°C and refluxed for 5 hours under nitrogen protection. After the reaction was completed, the mixture was centrifuged, washed, and vacuum dried to obtain poly(1-vinyl-3-propanesulfonic acid imidazole salt / polypyrrole nanotubes) (PVIPS / PPyNT). S Nanotubes);

[0010] 4) PVIPS / PPyNT S Nanotubes were dispersed in water, and then CoCl2·6H2O and thioacetamide (TAA) were added sequentially. After stirring until homogeneous, the resulting reaction system underwent a hydrothermal reaction. The product was washed sequentially with distilled water and anhydrous ethanol, centrifuged, and vacuum dried to obtain CoS2 / PVIPS / PPyNT. S Nanomaterials.

[0011] Furthermore, the aforementioned CoS2 / PVIPS / PPyNT S In step 3) of the nanomaterials, the initiator is azobisisobutyronitrile (AIBN).

[0012] Furthermore, the aforementioned CoS2 / PVIPS / PPyNT S In step 4) of the nanomaterials, the mass ratio is CoCl2·6H2O:PVIPS / PPyNT. S Nanotubes = 1.5:1.

[0013] Furthermore, the aforementioned CoS2 / PVIPS / PPyNTS In step 4) of the nanomaterials process, the hydrothermal reaction is carried out by placing the obtained reaction system in a Teflon reactor with a polytetrafluoroethylene liner and hydrothermally reacting it at 200°C for 24 hours.

[0014] A CoS2 / PVIPS / PPyNT based S The NOR electrocatalytic modified electrode using nanomaterials is based on carbon cloth, with the aforementioned CoS2 / PVIPS / PPyNT composite material incorporated. S CoS2 / PVIPS / PPyNT made by attaching nanomaterials to carbon cloth S Modified electrodes.

[0015] A CoS2 / PVIPS / PPyNT based S A method for preparing a NOR electrocatalytically modified electrode made of nanomaterials, comprising the following steps:

[0016] 1) Combine CoS2 / PVIPS / PPyNT S Nanomaterials were ultrasonically dispersed in a mixed solution of anhydrous ethanol and Nafion to obtain a uniformly dispersed composite modifier.

[0017] 2) The uniformly dispersed composite modifier was drop-coated onto a clean carbon cloth surface and dried at room temperature to obtain CoS2 / PVIPS / PPyNT. S Modified electrodes.

[0018] Furthermore, in the above preparation method, the volume ratio of anhydrous ethanol to Nafion solution is 92:8.

[0019] The present invention provides a CoS2 / PVIPS / PPyNT based S Application of NOR electrocatalytically modified electrodes made of nanomaterials in the electrocatalytic synthesis of nitrate from nitrogen oxidation.

[0020] Furthermore, the method is as follows: [The text abruptly shifts to a seemingly unrelated topic about CoS2 / PVIPS / PPyNT, which appears to be a fragmented collection of characters and phrases. A more coherent translation would require the original context.] S A three-electrode system was formed, consisting of a NOR electrocatalytically modified electrode made of nanomaterials as the working electrode, an Hg / HgO electrode as the reference electrode, and a platinum sheet electrode as the auxiliary electrode, to achieve the electrocatalytic oxidation of nitrogen in a 0.1M potassium hydroxide solution.

[0021] Compared with the prior art, the present invention has the following significant advantages:

[0022] 1. The CoS2 / PVIPS / PPyNT based material prepared in this invention SThe NOR electrocatalytic modified electrode of nanomaterials, due to the presence of CoS2, enables N2 to be oxidized to nitrate ions with the participation of cobalt disulfide on the nanotube surface, realizing nitrogen oxidation at room temperature and pressure, reducing energy consumption and environmental pollution.

[0023] 2. The CoS2 / PVIPS / PPyNT based material prepared in this invention S The NOR electrocatalytic modified electrode made of nanomaterials exhibits advantages such as strong electrochemical performance, good stability, and good linearity.

[0024] 3. The CoS2 / PVIPS / PPyNT based material prepared in this invention S The NOR electrocatalytic modification of the electrode with nanomaterials enables the electrocatalytic oxidation of nitrogen to produce nitrate, providing a new approach and method for the practical application of electrocatalytic nitrogen fixation.

[0025] 4. In this invention, cobalt is relatively inexpensive and has large reserves. Simultaneously, poly(1-vinyl-3-propanesulfonic acid) imidazole salt / polypyrrole nanotubes (PVIPS / PPyNT) are used. S The cobalt sulfide-organic conductive complex synthesized as a substrate promotes the dispersion of cobalt sulfide on organic conductive polymers and the electron mobility in electrochemical catalysis, further improving the catalytic performance of metal sulfides.

[0026] 5. The modified electrode prepared by this invention is inexpensive, has good stability, is easy to operate, and has a fast reaction speed. Attached Figure Description

[0027] Figure 1 For CoS2 / PVIPS / PPyNT S Electron micrograph of nanotubes;

[0028] Among them, (a)CoS2 / PVIPS / PPyNT S Scanning electron microscope (SEM) image of nanotubes;

[0029] (b)CoS2 / PVIPS / PPyNT S Transmission electron microscopy (TEM) image of nanotubes.

[0030] Figure 2 For CoS2 / PVIPS / PPyNT S XRD pattern of nanomaterials.

[0031] Figure 3 For CoS2 / PVIPS / PPyNT S LSV plots of the modified electrode in saturated N2 and Ar, respectively.

[0032] Figure 4For CoS2 / PVIPS / PPyNT S The nitrate yield and Faraday efficiency of the modified electrode at different voltages.

[0033] Figure 5 For CoS2 / PVIPS / PPyNT S The nitrate yield and Faraday efficiency of the modified electrode were measured after six consecutive catalytic cycles of two hours at the same voltage.

[0034] Figure 6 For carbon fiber cloth (CC) and CoS2 / PVIPS / PPyNT S Nitrate yield and Faraday efficiency at 1.75V (vs. RHE) under different conditions. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to preferred embodiments and accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0036] Example 1: The preparation method of CoS2 / PVIPS / PPyNTs nanomaterials (I) is as follows:

[0037] 1) Preparation of polypyrrole (PPyNTs) nanotubes: 0.05 g of methyl orange was added to 30 mL of deionized water and ultrasonically dispersed. Then, 0.249 g of FeCl3·6H2O was added and ultrasonically dispersed again. Then, 0.115 mL of pyrrole (Py) was added. The mixture was stirred in an ice-water bath for 6 h, centrifuged, washed, and vacuum dried to obtain PPyNTs nanotubes.

[0038] 2)PPyNT S -CH2-CH=CH2 nanotubes: Add 0.03g PPyNT to 50mL of N,N-dimethylformamide (DMF). S Nanotubes were ultrasonically dispersed, and then 0.3 mL of allyl chloride (Cl-CH2-CH=CH2) and 0.1 g of KOH were added. After ultrasonic dispersion for 5 min, the mixture was transferred to an oil bath and stirred at 60 °C for 24 h. After centrifugation, washing, and vacuum drying at 50 °C, PPyNTs-CH2-CH=CH2 nanotubes were obtained.

[0039] 3) PVIPS / PPyNT S Nanotubes: Add 0.025g PPyNT to 40mL anhydrous ethanol. S-CH2-CH=CH2 nanotubes were ultrasonically dispersed, and then 0.2 g of 1-vinyl-3-propanesulfonic acid imidazole salt (VIPS) and 0.004 g of initiator azobisisobutyronitrile (AIBN) were added. The mixture was then transferred to an oil bath and refluxed at 80 °C for 5 h under nitrogen protection. After the reaction was completed, the mixture was centrifuged, washed, and vacuum dried at 50 °C for 12 h to obtain PVIPS / PPyNT. S Nanotubes.

[0040] 4) CoS2 / PVIPS / PPyNT S Preparation of nanomaterials: A 100 mL beaker was filled with 10 mg of PVIPS / PPyNTs and 60 mL of deionized water. The mixture was sonicated for 15 min to ensure complete dispersion. After sonication, 15.3 mg of cobalt chloride hexahydrate and 50.5 mg of thioacetamide were added, and the mixture was sonicated for 5 min to ensure complete dispersion. After sonication, the mixture was transferred to a 100 mL polytetrafluoroethylene (PTFE) stainless steel autoclave and hydrothermally reacted at 200 °C for 24 h. After the reaction, the product was washed successively with distilled water and ethanol, centrifuged, and vacuum dried to obtain CoS2 / PVIPS / PPyNTs. S Nanomaterials.

[0041] (II) Comparative Example:

[0042] Preparation of CoS / Co9O8 nanomaterials: Take a 100mL beaker and add 60mL of deionized water, 240mg of cobalt chloride hexahydrate and 270mg of thioacetamide in sequence. Sonicate for 5min to mix them completely. Then transfer the solution to a 100mL polytetrafluoroethylene stainless steel autoclave and hydrothermally react at 200℃ for 24h. After the reaction is completed, the product is washed with distilled water and ethanol in sequence, centrifuged and vacuum dried to obtain CoS / Co9O8 nanomaterials.

[0043] (III) Testing

[0044] 1. For example Figure 1 As shown, Figure 1 In the middle, 'a' represents CoS2 / PVIPS / PPyNT. S Scanning electron microscope (SEM) images of nanomaterials; Figure 1 b represents CoS2 / PVIPS / PPyNT S Transmission electron microscopy (TEM) images of nanomaterials. (By...) Figure 1 As can be seen, the CoS2 / PVIPS / PPyNT prepared by this invention S The surface of the nanomaterial exhibits a tubular texture.

[0045] 2. Figure 2The figure shows the XRD pattern of the CoS2 / PVIPS / PPyNTs nanomaterial. As can be seen from the figure, the present invention successfully synthesized tubular CoS2 / PVIPS / PPyNTs nanomaterial.

[0046] Example 2 is based on CoS2 / PVIPS / PPyNT S The preparation method of the NOR electrocatalytic modified electrode (I) using nanomaterials is as follows:

[0047] 1) Take 1.5 mg of the dried CoS2 / PVIPS / PPyNT prepared in Example 1 S The nanomaterial was added to 460 μL of anhydrous ethanol and 40 μL of Nafion solution and ultrasonically dispersed for 30 min to obtain a black suspension with a concentration of 3 mg / mL, which is the composite modifier, for later use.

[0048] 2) Electrode preparation: Cut the carbon cloth into 1cm×1.5cm pieces for later use.

[0049] 3) Preparation of modified electrode: The composite modifier prepared in step 1) was repeatedly transferred using a dropper and applied to the surface of a clean carbon cloth. It was then allowed to air dry at room temperature to obtain CoS2 / PVIPS / PPyNT. S Electrode modified with nanomaterials for electrocatalysis.

[0050] (II) Electrochemical Performance Testing

[0051] 1. CoS2 / PVIPS / PPyNT S Comparison of linear sweep voltammetry curves of NOR electrocatalytically modified electrodes made of nanomaterials in saturated Ar and N2.

[0052] Method: In an electrolytic cell containing 0.1M KOH solution, using CoS2 / PVIPS / PPyNT... S The nanomaterial electrocatalytic modified electrode was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum sheet electrode as the auxiliary electrode. The experiment was carried out on a CHI1040c electrochemical workstation, and its attached computer software was used for data acquisition and processing. Linear sweep voltammetry was performed in the potential range of 0.85V to 1.25V (vs. RHE), and stable linear sweep voltammetry diagrams were recorded.

[0053] like Figure 3 As shown, this is CoS2 / PVIPS / PPyNT. SLinear sweep voltammetry (LSV) curves of the NOR electrocatalytically modified electrode made of nanomaterials in saturated N2 and saturated Ar are shown. The upper curve represents the LSV curve under saturated N2 conditions, and the lower curve represents the LSV curve under saturated Ar conditions. Within the potential range of 1.25 V to 1.85 V (vs. RHE), the current density under saturated N2 conditions is significantly higher than that under saturated Ar conditions. This indicates that the prepared CoS2 / PVIPS / PPyNT electrode... S Electrode modified with nanomaterials exhibits NOR activity.

[0054] 2. CoS2 / PVIPS / PPyNT S Optimal catalytic voltage of nanomaterial electrocatalytic modified electrode

[0055] With CoS2 / PVIPS / PPyNT S The nanomaterial electrocatalytic modified electrode was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum sheet electrode as the auxiliary electrode. The experiment was conducted on a CHI1040c electrochemical workstation, including the acquisition and processing of experimental data. In 0.1M KOH solution, the voltage value was taken at 0.1V intervals within the potential range of 1.55V to 2.05V (vs. RHE) for two hours of chronoamperometry.

[0056] like Figure 4 As shown, this is CoS2 / PVIPS / PPyNT. S The nitrate yield and Faradaic efficiency of the nanomaterial electrocatalytically modified electrode under different voltages were investigated. The optimal voltage was determined to be 1.75 V (vs. RHE), at which the catalyst-modified electrode exhibited the highest nitrate yield and a relatively high Faradaic efficiency.

[0057] 3. Stability measurement of catalysts

[0058] With CoS2 / PVIPS / PPyNT S The NOR electrocatalytic modified electrode of nanomaterials was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum sheet electrode as the auxiliary electrode. The experiment was carried out on a CHI1040c electrochemical workstation, including the acquisition and processing of experimental data. Six consecutive two-hour chronoamperometry tests were conducted in 0.1M KOH solution at a potential of 1.75V (vs. RHE).

[0059] Figure 5 For CoS2 / PVIPS / PPyNT SThe nitrate yield and Faradaic efficiency of the nanomaterial-modified electrocatalytic electrode were measured after six consecutive catalytic cycles for two hours at the same voltage. It can be seen that even after the sixth catalytic cycle, the nitrate yield and Faradaic efficiency remained at 85%, demonstrating the effectiveness of the prepared CoS2 / PVIPS / PPyNT electrode. S Nanomaterials exhibit good stability.

[0060] 4. CoS2 / PVIPS / PPyNT S Source of nitrogen in electrocatalytic synthesis products of nanomaterials

[0061] The NOR electrocatalytic modified electrode of CoS2 / PVIPS / PPyNTs nanomaterials was used as the working electrode, the Hg / HgO electrode as the reference electrode, and the platinum sheet electrode as the auxiliary electrode. The experiment was carried out on a CHI1040c electrochemical workstation, including the acquisition and processing of experimental data. Figure 6 For carbon fiber cloth (CC) and CoS2 / PVIPS / PPyNT S Nitrate yield and Faradaic efficiency at 1.75V (vs. RHE) under different conditions were investigated to eliminate the influence of electrolyte, electrocatalyst, and feed gas on NO3 production during electrolysis. - No interference was observed in NO3 under N2 saturated electrolyte (O / C) with no external potential, Ar saturated electrolyte at 1.75V (vs. RHE), and CC bottom conditions. - Therefore, the detected NO3 was confirmed. - It is CoS2 / PVIPS / PPyNT S N2 is produced by the electrocatalytic oxidation of nanomaterials.

[0062] The above description is merely a preferred embodiment of the present invention and is illustrative rather than restrictive. Those skilled in the art will understand that many changes, modifications, and even equivalent alterations can be made within the spirit and scope defined by the claims of the present invention, but all such changes will fall within the protection scope of the present invention.

Claims

1. CoS2 / PVIPS / PPyNT S The application of NOR electrocatalytically modified electrodes made of nanomaterials in electrocatalytic nitrogen oxidation is characterized by, The CoS2 / PVIPS / PPyNT S The NOR electrocatalytic modified electrode of nanomaterials is based on carbon cloth and incorporates CoS2 / PVIPS / PPyNT. S CoS2 / PVIPS / PPyNT made by attaching nanomaterials to carbon cloth S Modified electrodes, The CoS2 / PVIPS / PPyNT S The preparation method of nanomaterials includes the following steps: 1) Methyl orange was added to deionized water and ultrasonically dispersed. Then FeCl3·6H2O was added and ultrasonically dispersed again. Pyrrole was then added, and the mixture was transferred to an ice-water bath and stirred for 6 hours. After centrifugation, washing, and drying, PPyNT was obtained. S Nanotubes; 2) Add PPyNT to N,N-dimethylformamide S Nanotubes were ultrasonically dispersed, then allyl chloride and KOH were added and ultrasonically dispersed again. The mixture was then transferred to a 60°C oil bath and stirred for 24 hours. After centrifugation, washing, and vacuum drying, PPyNT was obtained. S -CH2-CH=CH2 nanotubes; 3) Add PPyNT to anhydrous ethanol S -CH2-CH=CH2 nanotubes were ultrasonically dispersed, then 1-vinyl-3-propanesulfonic acid imidazole salt and an initiator were added for reflux reaction. After the reaction was completed, the nanotubes were centrifuged, washed, and vacuum dried to obtain PVIPS / PPyNT. S Nanotubes; 4) PVIPS / PPyNT S Nanotubes were dispersed in water, and then CoCl2·6H2O and thioacetamide were added sequentially. After stirring until homogeneous, the resulting reaction system underwent a hydrothermal reaction. The product was washed sequentially with distilled water and anhydrous ethanol, centrifuged, and vacuum dried to obtain CoS2 / PVIPS / PPyNT. S Nanomaterials.

2. The application according to claim 1, characterized in that, In step 3), the initiator is azobisisobutyronitrile (AIBN).

3. The application according to claim 1, characterized in that, In step 3), the reflux reaction is carried out in an oil bath at 80°C under nitrogen protection for 5 hours.

4. The application according to claim 1, characterized in that, In step 4), the mass ratio is CoCl2·6H2O: PVIPS / PPyNT. S Nanotubes = 1.5 :

1.

5. The application according to claim 1, characterized in that, In step 4), the hydrothermal reaction is as follows: the obtained reaction system is placed in a Teflon reactor with a polytetrafluoroethylene liner and hydrothermally reacted at 200°C for 24 h.

6. The application according to claim 1, characterized in that, Based on CoS2 / PVIPS / PPyNT S The preparation method of NOR electrocatalytic modified electrode made of nanomaterials includes the following steps: 1) Combine CoS2 / PVIPS / PPyNT S Nanomaterials were ultrasonically dispersed in a mixed solution of anhydrous ethanol and Nafion to obtain a uniformly dispersed composite modifier. 2) The uniformly dispersed composite modifier was drop-coated onto a clean carbon cloth surface and dried at room temperature to obtain CoS2 / PVIPS / PPyNT. S Modified electrodes.

7. The application according to claim 6, characterized in that, The volume ratio of anhydrous ethanol to Nafion solution is 92:

8.

8. The application according to claim 1, characterized in that, The method is as follows: The CoS2 / PVIPS / PPyNT... S A three-electrode system was formed, consisting of a NOR electrocatalytically modified electrode made of nanomaterials as the working electrode, an Hg / HgO electrode as the reference electrode, and a platinum sheet electrode as the auxiliary electrode, to achieve the electrocatalytic oxidation of nitrogen in a 0.1 M potassium hydroxide solution.

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