A Pd / P-MoS2 / NF electrode and its preparation method and application

Abstract

The present invention provides a Pd / P-MoS2 / NF electrode, a preparation method, and an application thereof. The preparation method of the Pd / P-MoS2 / NF electrode comprises the following steps: preparing a nanoflower-shaped MoS2 / NF electrode by a hydrothermal method; doping a phosphorus source with the nanoflower-shaped MoS2 / NF electrode by a calcination method to obtain a defect-rich P-MoS2 / NF electrode; and loading palladium onto the defect-rich P-MoS2 / NF electrode by an electrodeposition method to obtain a defect-rich P-MoS2 / NF palladium-loaded electrode. The present invention utilizes the synergistic effect of heteroatom doping and defect engineering to introduce P-MoS2 with a nanoflower-like structure rich in active sites as a Pd NPs attachment site, thereby obtaining a better electrode cathode material, achieving both cost reduction and improved performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic hydrogenation dechlorination, and in particular relates to a Pd / P-MoS2 / NF electrode and a preparation method and application thereof. Background Art

[0002] Electrocatalytic hydrodechlorination technology is favored by many researchers because of its green and non-secondary pollution characteristics, making it widely used in the removal of chlorinated organic compounds. It is worth noting that electrocatalytic hydrodechlorination technology is often limited by its cathode material. How to effectively solve the problems of expensive precious metals, low atomic H* production rate and catalyst poisoning is currently the focus of researchers' exploration. Patent publication number CN105879891A discloses a method for preparing a nickel-phosphorus / molybdenum disulfide hydrogen evolution composite material, which mainly involves first preparing layered molybdenum disulfide particles and performing a stripping treatment on them, then sensitizing and activating the molybdenum disulfide after the stripping treatment, and then using chemical plating technology to deposit a nickel-phosphorus coating on its surface, and finally heat-treating it under a nitrogen atmosphere to obtain a nickel-phosphorus / molybdenum disulfide composite material. However, its removal effect on chlorinated organic compounds is poor. Patent publication number CN102849798A discloses two methods for preparing molybdenum disulfide nanosheet thin films. One involves placing a conductive substrate in a sulfur-containing solution of molybdate for a hydrothermal reaction, which results in the growth of a dense, uniform, and ordered MoS2 nanosheet film on the substrate. The other method involves directly placing molybdenum flakes in a solution containing a sulfur source, where a sulfurization reaction occurs under hydrothermal conditions, forming a dense, uniform, and ordered MoS2 nanosheet film on the molybdenum substrate. However, the materials produced using this technique exhibit low electrocatalytic activity.

[0003] Therefore, the key to solving the problem is to prepare an electrode material with high activity and low precious metal content. Summary of the Invention

[0004] In light of this, the present invention aims to overcome the shortcomings of the prior art and proposes a Pd / P-MoS2 / NF electrode, its preparation method, and its application. By leveraging the synergistic effects of heteroatom doping and defect engineering, the present invention introduces P-MoS2, a nanoflower-like structure with abundant active sites, as a Pd NP attachment site, resulting in a superior electrode cathode material, reducing costs while improving performance.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] In a first aspect, the present invention provides a method for preparing a Pd / P-MoS2 / NF electrode, comprising the following steps:

[0007] Step S1: preparing nanoflower-like MoS2 / NF electrodes by hydrothermal method;

[0008] Step S2: doping the phosphorus source with the nanoflower-shaped MoS2 / NF electrode by a calcination method to obtain a defect-rich P-MoS2 / NF electrode;

[0009] Step S3: palladium element is loaded into the defect-rich P-MoS2 / NF electrode by electrodeposition to obtain a defect-rich P-MoS2 / NF palladium-loaded electrode, represented by Pd / P-MoS2 / NF.

[0010] In some embodiments of the present invention, the molar ratio of the phosphorus source to the nanoflower-shaped MoS2 / NF electrode is (1-2.3):3.3.

[0011] In some embodiments of the present invention, step S2 includes the following steps:

[0012] The phosphorus source and nanoflower-like MoS2 / NF electrode were loaded into a ceramic ark and placed in a tube furnace, and annealed under a nitrogen atmosphere to obtain a defect-rich P-MoS2 / NF electrode.

[0013] In some embodiments of the present invention, the phosphorus source is sodium hypophosphite and / or sodium phosphate.

[0014] In some embodiments of the present invention, the annealing process is as follows:

[0015] The calcination temperature is 200℃-450℃, and the heating rate is 3℃·min -1 -8℃·min -1 , the calcination time is 1-3h.

[0016] In some embodiments of the present invention, step S1 includes the following steps:

[0017] Step S11: (NH4)6Mo7O 24 •4H2O and CH4N2S were dissolved in deionized water and mixed well to obtain a precursor solution;

[0018] Step S12: pouring the precursor solution into a reactor, and immersing the Ni-foam substrate in the precursor solution to perform a hydrothermal reaction to obtain a nanoflower-shaped MoS2 / NF electrode;

[0019] Step S13: Clean the nanoflower-shaped MoS2 / NF electrode until the solution is clear, and dry it for later use.

[0020] In some embodiments of the present invention, the temperature of the hydrothermal reaction in step S12 is 150-200° C., and the reaction time is 8-16 hours.

[0021] In some embodiments of the present invention, step S3 includes the following steps:

[0022] The defect-rich P-MoS2 / NF electrode was placed in a deposition solution containing Pd element for electrodeposition and then dried to obtain a defect-rich P-MoS2 / NF palladium-loaded electrode.

[0023] In some embodiments of the present invention, the deposition liquid is a PdCl2 solution, a chloropalladic acid solution, or a mixed solution of the two.

[0024] In some embodiments of the present invention, the concentration of the deposition solution is 0.2-0.5 mmol·L -1 .

[0025] In some embodiments of the present invention, the electrodeposition parameters are: electrodeposition for 1.5-2.5 h at a constant current of 6-10 mA.

[0026] In a second aspect, the present invention provides a Pd / P-MoS2 / NF electrode prepared by the above preparation method.

[0027] In a third aspect, the present invention provides the use of the above-mentioned Pd / P-MoS2 / NF electrode as a catalytic electrode in the electrocatalytic hydrodechlorination reaction of chlorinated organic compounds.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] (1) The MoS2 prepared by the hydrothermal method in the present invention has a nanoflower structure of stacked flake structures, and the stable structure is maintained by doping with the P element under high temperature conditions. This provides more attachment sites for the deposition of Pd NPs, which is beneficial for electron transport between the structures. At the same time, the Pd NPs reduced by the electrodeposition method have a smaller nanometer size, which provides an advantage for increasing the active sites of the catalyst.

[0030] (2) The present invention confirmed the presence of catalyst defects by performing XRD analysis on defect-rich palladium-supported electrodes and MoS2-related powder catalysts. Calculation of the ratio of the two characteristic peaks in the Raman spectrum, the in-plane vibration peak E12g and the out-of-plane vibration peak A1g, confirmed the activation of the active sites on the edge of the inert MoS2. Electron paramagnetic resonance spectroscopy confirmed that P element doping can induce the generation of S vacancies, which strongly illustrates that the defect-rich electrode is affected by the synergistic effect of heteroatom doping and defect engineering. Electrochemical impedance spectroscopy showed that Pd / P-MoS2 / NF can provide more catalyst active sites, accelerate electron transfer between the electrode and pollutants, and thus achieve more efficient pollutant removal.

[0031] (3) The present invention found that the defect-rich P-MoS2 / NF palladium-supported electrode achieved the best effect and the best removal rate for lamotrigine, and the pollutant was completely removed within 120 minutes. At the same time, the defect-rich P-MoS2 / NF palladium-supported electrode also showed excellent catalytic activity for a variety of chlorinated PPCPs. The Pd / P-MoS2 / NF electrode basically achieved complete removal of the three pollutants bezafibrate, florfenicol, and chlorpheniramine maleate within 150 minutes. The removal efficiency of lornoxicam and losartan potassium both reached more than 90%. This shows that the Pd / P-MoS2 / NF electrode has good universal applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 SEM images of Pd / P-MoS2 / NF at different magnifications: (a) 1000×; (b) 5000×; (c) 10000×; (d) 20000×; (e) 30000×; (f) 50000×;

[0033] Figure 2 HRTEM images of defect-rich P-MoS2 / NF electrode (ac) and Pd / P-MoS2 / NF (df): (a) scale bar is 100 nm; (b) scale bar is 10 nm; (c) scale bar is 1 nm; (d) scale bar is 100 nm; (e) scale bar is 5 nm; (f) scale bar is 10 nm; (g) Pd / P-MoS2 / NF particle size distribution diagram;

[0034] Figure 3 X-ray diffraction patterns of defect-rich P-MoS2 palladium-supported electrode and Pd / MoS2 / NF electrode;

[0035] Figure 4 Raman spectra of MoS2 and P-MoS2;

[0036] Figure 5 Electron paramagnetic resonance spectra of MoS2, MoS2(def) and P-MoS2;

[0037] Figure 6 Electrochemical impedance spectroscopy (EIS) of the Pd / P-MoS2 / NF electrode (counter electrode: carbon black; reference electrode: Ag / AgCl).

[0038] Figure 7 Figure 3 shows the removal efficiency of lamotrigine for four electrodes: Pd / P-MoS2 / NF, Pd / MoS2(def) / NF, Pd / MoS2 / NF, and P-MoS2 / NF: (a) removal effect; (b) reaction kinetics; (c) removal rate of lamotrigine at different times;

[0039] Figure 8Figure 2 is the removal efficiency diagram of Pd / P-MoS2 / NF electrode for various chlorinated PPCPs;

[0040] Figure 9 This is the long-term stability result of defect-rich P-MoS2 supported palladium electrode. DETAILED DESCRIPTION

[0041] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0042] Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0043] Where values ​​are described herein as ranges, it should be understood that such disclosure includes disclosure of all possible sub-ranges within that range, as well as specific values ​​falling within that range, regardless of whether a specific value or sub-range is explicitly stated.

[0044] In this document, "a plurality of" and the like, unless otherwise specified, refer to a number greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0045] In this document, the terms “preferably” and “more preferably” are only used to describe implementation methods or examples with better effects. It should be understood that they do not limit the scope of protection of the present invention.

[0046] In this document, the word "further" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present invention.

[0047] In this article, the term "and / or" is used to describe the association relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0048] As used herein, the term "about" means + / - 10%, preferably + / - 5%, more preferably + / - 1% of the specified value.

[0049] In this document, the terms “include,” “including,” “have,” “contain,” etc. are open-ended terms, meaning including but not limited to.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention.

[0051] The present invention will be described in detail below with reference to the embodiments.

[0052] Example 1

[0053] (1) Preparation of MoS2 nanoflower electrodes

[0054] First, 0.22 mmol of (NH4)6Mo7O 24 4H2O and 6.6 mmol of CH4N2S were dissolved in 50 mL of deionized water and magnetically stirred for 30 minutes to form a homogeneous precursor mixture. Next, the homogeneously mixed precursor solution was poured into a 100 mL polytetrafluoroethylene-lined autoclave. A pretreated Ni-foam substrate was immersed in the precursor solution to allow MoS2 nanoflowers to grow on the Ni-foam substrate. The hydrothermal reaction was carried out at 180°C for 12 hours, followed by natural cooling to room temperature. Finally, the prepared nanoflower-shaped MoS2 / NF electrode was rinsed thoroughly with deionized water until the solution was clear and then dried at 60°C for later use.

[0055] (2) Preparation of defect-rich P-MoS2 / NF electrode

[0056] 1.5 mmol of anhydrous sodium hypophosphite (NaH2PO2) and the prepared MoS2 / NF electrode were placed in two porcelain arks. The ark containing NaH2PO2 was placed at the air inlet end, and the ark containing the MoS2 electrode was placed at the air outlet end, with a distance of 2 cm between the two. Under N2 atmosphere, the temperature was kept at 5 ℃·min -1 The temperature was raised to 300 °C at a rate of 100 °C and maintained for 2 h.

[0057] (3) Preparation of defect-rich P-MoS2 palladium-supported electrode

[0058] The defect-rich P-MoS2 / NF loaded Pd electrode was prepared by a simple electrodeposition method. The prepared defect-rich P-MoS2 / NF electrode was placed in a 0.4 mmol·L -1 The PdCl₂ solution was then electroplated at a constant current of 7 mA for 2 h. At this point, the PdCl₂ solution was clear and transparent, and the defect-rich P-MoS₂ / NF palladium-supported electrode was prepared. It was then dried in an oven at 60°C until ready for use, designated as Pd / P-MoS₂ / NF.

[0059] Example 2

[0060] (1) Preparation of MoS2 nanoflower electrodes

[0061] First, 0.22 mmol of (NH4)6Mo7O 244H2O and 6.6 mmol of CH4N2S were dissolved in 50 mL of deionized water and magnetically stirred for 30 minutes to form a homogeneous precursor mixture. Next, the homogeneously mixed precursor solution was poured into a 100 mL polytetrafluoroethylene-lined autoclave. A pretreated Ni-foam substrate was immersed in the precursor solution to allow MoS2 nanoflowers to grow on the Ni-foam substrate. The hydrothermal reaction was carried out at 150°C for 16 hours, followed by natural cooling to room temperature. Finally, the prepared nanoflower-shaped MoS2 / NF electrode was rinsed thoroughly with deionized water until the solution was clear and then dried at 60°C for later use.

[0062] (2) Preparation of defect-rich P-MoS2 / NF electrode

[0063] 2.3 mmol of anhydrous sodium hypophosphite (NaH2PO2) and the prepared MoS2 / NF electrode were placed in two porcelain arks respectively. The ark containing NaH2PO2 was placed at the air inlet end, and the ark containing the MoS2 electrode was placed at the air outlet end, with a distance of 2 cm between the two. Under N2 atmosphere, the temperature was kept at 3 ℃·min -1 The temperature was raised to 200 °C at a rate of 100 °C and maintained for 3 h.

[0064] (3) Preparation of defect-rich P-MoS2 palladium-supported electrode

[0065] The defect-rich P-MoS2 / NF loaded Pd electrode was prepared by a simple electrodeposition method. The prepared defect-rich P-MoS2 / NF electrode was placed in a 0.2 mmol·L -1 The electrodeposition was carried out for 1.5 hours at a constant current of 6 mA in a PdCl2 deposition solution. At this point, the PdCl2 solution was clear and transparent, and the defect-rich P-MoS2 / NF palladium-supported electrode was prepared. It was then dried in an oven at 60°C until ready for use, denoted as Pd / P-MoS2 / NF.

[0066] Example 3

[0067] (1) Preparation of MoS2 nanoflower electrodes

[0068] First, 0.22 mmol of (NH4)6Mo7O 244H2O and 6.6 mmol of CH4N2S were dissolved in 50 mL of deionized water and magnetically stirred for 30 minutes to form a homogeneous precursor mixture. Next, the homogeneously mixed precursor solution was poured into a 100 mL polytetrafluoroethylene-lined autoclave and pretreated Ni-foam was immersed in the precursor solution to allow MoS2 nanoflowers to grow on the Ni-foam substrate. The hydrothermal reaction was carried out at 200°C for 8 hours, followed by natural cooling to room temperature. Finally, the prepared nanoflower-shaped MoS2 / NF electrode was thoroughly rinsed with deionized water until the solution was clear and then dried at 60°C for later use.

[0069] (2) Preparation of defect-rich P-MoS2 / NF electrode

[0070] 1 mmol of anhydrous sodium hypophosphite (NaH2PO2) and the prepared MoS2 / NF electrode were placed in two porcelain arks. The ark containing NaH2PO2 was placed at the air inlet end, and the ark containing the MoS2 electrode was placed at the air outlet end, with a distance of 2 cm between the two. Under N2 atmosphere, the temperature was kept at 8 ℃·min -1 The temperature was raised to 450 °C at a rate of 0.1 ℃ and maintained for 1 h.

[0071] (3) Preparation of defect-rich P-MoS2 palladium-supported electrode

[0072] The defect-rich P-MoS2 / NF loaded Pd electrode was prepared by a simple electrodeposition method. The prepared defect-rich P-MoS2 / NF electrode was placed in a 0.5 mmol·L -1 The PdCl₂ solution was then electroplated at a constant current of 10 mA for 2.5 h. At this point, the PdCl₂ solution became clear and transparent, and the defect-rich P-MoS₂ / NF palladium-supported electrode was prepared. It was then dried in an oven at 60°C until ready for use, designated as Pd / P-MoS₂ / NF.

[0073] Example 4

[0074] 1.5 mmol of anhydrous sodium hypophosphite (NaH2PO2) and the prepared MoS2 electrode were placed in two porcelain arks. The ark containing NaH2PO2 was placed at the air inlet end, and the ark containing the MoS2 electrode was placed at the air outlet end, with a distance of 2 cm between the two. Under N2 atmosphere, the temperature was kept at 8 ℃·min -1 The temperature was raised to 300℃ at a rate of 0.5℃ and maintained for 2 h. Defect-rich MoS2 electrodes were prepared using the same heating program.

[0075] Example 5

[0076] When the phosphorus source is sodium phosphate and the amount of sodium phosphate added is 1.5 mmol, the other steps and conditions for electrode preparation are the same as those in Example 1.

[0077] Comparative Example 1

[0078] When the addition amount of anhydrous sodium hypophosphite is 2.5 mmol, the other steps and conditions for electrode preparation are the same as those in Example 1.

[0079] Comparative Example 2

[0080] When the addition amount of anhydrous sodium hypophosphite is 0.5 mmol, the other steps and conditions for electrode preparation are the same as those in Example 1.

[0081] Comparative Example 3

[0082] When the addition amount of anhydrous sodium hypophosphite is 3.0 mmol, the other steps and conditions for electrode preparation are the same as those in Example 1.

[0083] Comparative Example 4

[0084] 1.5mmol black phosphorus and 3.3mmol MoS2 were mixed and subjected to a spheroidal graphite procedure with the preparation conditions of 1200 r / min, temperature 25℃, and time 2h to obtain phosphorus-doped molybdenum sulfide powder. The phosphorus-doped molybdenum sulfide powder was added to a nafion solution and drop-coated on a nickel foam electrode substrate to prepare a phosphorus-doped molybdenum sulfide / nickel foam electrode.

[0085] Comparative Example 5

[0086] The difference between this comparative example and Example 1 is that the prepared nanoflower-shaped MoS2 / NF electrode is directly placed in a solution containing 0.4 mmol·L -1 Electrodeposition was performed for 2 h in a PdCl₂ deposition solution at a constant current of 7 mA. At this point, the PdCl₂ solution was clear and transparent, and the MoS₂ / NF palladium-supported electrode was prepared. It was then dried in an oven at 60°C until ready for use, denoted as Pd / MoS₂ / NF.

[0087] Comparative Example 6

[0088] The difference between this comparative example and Example 1 is that the MoS2 palladium electrode (Pd / MoS2(def) / NF) contains only S vacancy defects. The specific preparation method is:

[0089] The prepared nanoflower-like MoS2 / NF electrode was placed in a ark and placed in a tube furnace under N2 atmosphere at 5℃·min -1 The temperature was raised to 300℃ at a rate of 0.5℃ and maintained for 2 h to obtain MoS2(def) / NF. The MoS2(def) / NF electrode was placed in a 0.4 mmol·L -1Electrodeposition was performed for 2 h in a PdCl₂ deposition solution at a constant current of 7 mA. At this point, the PdCl₂ solution was clear and transparent, and the MoS₂(def) / NF palladium-supported electrode was prepared. It was then dried in an oven at 60°C until ready for use, designated as Pd / MoS₂(def) / NF.

[0090] Electrochemical hydrogenation dechlorination experiments were conducted on the electrodes prepared in Examples 1 to 5 and Comparative Examples 1 to 6. The specific steps are as follows:

[0091] The electrochemical hydrogenation dechlorination experiment was carried out in an H-type electrolytic cell made of polytetrafluoroethylene. In order to prevent the detached chlorine atoms from being freed to the anode and leaking harmful chlorine gas, a cation exchange membrane was used between the two cells. The dechlorination experiment was carried out under the conditions of a constant current of 7 mA and a water bath temperature of 40°C, with a platinum sheet as the counter electrode (anode) and the electrodes (cathode) prepared in Examples 1 to 5 and Comparative Examples 1 to 7 as the working electrodes. The working electrode was immersed in a solution containing 15 mg·L -1 Lamotrigine (abbreviated as LTG, the same below) and 50 mmol·L -1 The electrode was immersed in a solution containing 50 mmol·L -1 Na2SO4 solution. The distance between the two electrodes is 2 cm. When the electrocatalytic hydrodechlorination time is 150 minutes, the removal rate is shown in the table below:

[0092] Table 1 Removal efficiency of lamotrigine

[0093]

[0094] The SEM images of Pd / P-MoS2 / NF prepared in Example 1 at different magnifications are as follows: Figure 1 As shown in the figure, it can be seen that obvious spherical particle clusters appear on the surface of the Ni-foam electrode, indicating that the catalyst is loaded. At the same time, as the magnification continues to increase, the defect-rich P-MoS2 supported palladium catalyst grows on the Ni-foam substrate, showing a flower-like structure.

[0095] The HRTEM images of the defect-rich P-MoS2 / NF electrode and the prepared Pd / P-MoS2 / NF electrode in Example 1 are as follows: Figure 2 As shown, it can be seen that the defect-rich P-MoS2 / NF electrode ( Figure 2 a) with Pd / P-MoS2 / NF electrode ( Figure 2d) is composed of a flake structure, which fully confirms that Pd nanoparticles are attached to the surface of the flake P-MoS2 / NF electrode, making the flake flower structure less obvious. The preparation of defect-rich MoS2 by P doping and vacancy engineering is conducive to the activation of more inert sites. It is obvious that the lattice of the P-MoS2 / NF electrode is not complete ( Figure 2 b) The presence of dislocations and deletions fully demonstrates the existence of catalyst defects and confirms the successful preparation of defect-rich materials. Figure 2 The illustration of site 1 in b shows that the lattice spacing in P-MoS2 / NF is 0.673nm, corresponding to the (002) crystal plane of 2H-MoS2. Figure 2 c) indicates the presence of vacancies in the lattice, confirming the existence of catalyst defect sites. Similarly, the lattice spacing of Pd was analyzed ( Figure 2 e). The lattice spacing of 0.219 nm corresponds perfectly to the (111) plane of Pd. The size of Pd particles has a significant impact on the catalytic performance of the catalyst. Therefore, the Pd particle size in the HRTEM images was analyzed. Figure 2 Figure g shows that the Pd particles are approximately 1.82 nm in size. The presence of smaller Pd nanoparticles facilitates the exposure of more catalytically active sites. This suggests that the unique flaky nanoflower structure of the defect-rich P-MoS2 / NF facilitates uniform Pd dispersion and reduces particle agglomeration.

[0096] The X-ray diffraction patterns of Pd / P-MoS2 / NF prepared in Example 1 and Pd / MoS2 / NF prepared in Comparative Example 4 are as follows: Figure 3 As shown in the figure, the Pd / P-MoS2 / NF electrode and the Pd / MoS2 / NF electrode exhibit the same crystal structure. The diffraction peaks at 2θ of 40.148°, 46.696°, and 68.147° correspond to the (111), (200), and (220) crystal planes of Pd, respectively (PDF#46-1043). The appearance of these three characteristic peaks confirms the presence of Pd in ​​a particle state on the catalyst surface.

[0097] The Raman spectra of the nanoflower-like MoS2 / NF electrode and the defect-rich P-MoS2 / NF electrode in Example 1 are as follows: Figure 4 As shown, Figure 4 Center 375.15 cm -1 and 403.60 cm -1 Corresponding to E 1 2g and A 1g There are two characteristic peaks, and the frequency difference (△f) between the two peaks is 28.45 cm -1 , much larger than 20 cm -1, indicating that 2H-MoS2 is a multilayer nanoflower structure. 1 2g and A 1g The size of the ratio indicates the degree of defects in the catalyst material. By integrating the peaks of the two curves, the peak areas of MoS2 and P-MoS2 are shown in Table 2.

[0098] Table 2 MoS2 and P-MoS2E 1 2g and A 1g Characteristic peak integrated area

[0099]

[0100] The table shows that the peak ratio of the defect-rich P-MoS2 / NF electrode is 0.32, which is smaller than the peak ratio of the nanoflower-shaped MoS2 / NF electrode (0.45). A smaller ratio of the two characteristic peaks indicates greater edge exposure and higher catalyst activity. This also indicates that P doping creates more defect sites on the 2H-MoS2, enhancing the ability of the Pd / P-MoS2 / NF to generate atomic H* and improving the catalyst's electrocatalytic hydrogenation and dechlorination efficiency.

[0101] Figure 5 The EPR curves of three molybdenum sulfide catalysts, the nanoflower-shaped MoS2 / NF electrode prepared in Example 1, the MoS2(def) prepared in Comparative Example 6, and the defect-rich P-MoS2 / NF electrode prepared in Example 1, are shown. The vacancy content of the catalyst is indicated by the magnitude of the Mo-S dangling bond signal (g=2.004). The figure shows that the MoS2 catalyst prepared by the hydrothermal method has no S vacancies, while the signal peak of the Mo-S dangling bond is significantly enhanced after high-temperature calcination. The doped P atoms occupy the available S vacancies, acting as bridges and balancing the charge distribution between the Mo and S atoms. This also explains why the S vacancies are reduced after P doping.

[0102] Figure 6 The electrochemical impedance spectroscopy diagrams of the nanoflower-like MoS2 / NF electrode, Pd / P-MoS2 / NF electrode prepared in Example 1, the Pd / MoS2 / NF electrode prepared in Comparative Example 5, and the Pd / MoS2(def) / NF electrode prepared in Comparative Example 6 show that the MoS2 / NF, Pd / MoS 2 / The electrochemical impedance spectroscopy (EIS) values ​​for the activated Pd / P-MoS2 / NF electrode were 5.637 Ω, 3.336 Ω, 4.316 Ω, and 0.644 Ω, respectively. The EIS value of the activated Pd / P-MoS2 / NF electrode was significantly lower than that of the other electrodes, with the maximum impedance reduction being 8.75 times. This phenomenon suggests that exposing the edge active sites of the inert 2H-MoS2 provides more catalytic active sites, accelerating electron transfer between the electrode and pollutants, and thus achieving more efficient pollutant removal.

[0103] Figure 7 The removal efficiency of the nanoflower-shaped MoS2 / NF electrode, Pd / P-MoS2 / NF electrode prepared in Example 1, the Pd / MoS2 / NF electrode prepared in Comparative Example 5, and the Pd / MoS2(def) / NF electrode prepared in Comparative Example 6 for lamotrigine. It can be seen that the Pd / P-MoS2 / NF electrode can achieve complete removal of lamotrigine within 120 minutes. Under the same electrocatalytic conditions, the removal effects of the three electrodes, Pd / MoS2(def) / NF, Pd / MoS2 / NF, and P-MoS2 / NF, only reached 98.65%, 65.22%, and 27.81% within 150 minutes. The Pd / P-MoS2 / NF electrode significantly improved the removal effect of LTG. The reason for this phenomenon can be attributed to the fact that P doping creates more edge active sites in MoS2, accelerates the rate of atomic H* production by the catalyst electrolysis of water, and thus improves the electrocatalytic hydrogenation dechlorination effect of the Pd / P-MoS2 / NF electrode.

[0104] Pseudo first-order kinetic analysis was performed on different electrode materials, and the results were as follows: Figure 7 As shown in b. By fitting the negative logarithm of the lamotrigine concentration at different times, it is found that the removal kinetics of lamotrigine by the defect-rich P-MoS2 palladium-supported electrode follows a pseudo-first-order rate law (R 2 =0.98), the removal of LTG by the catalyst maintains a good linear relationship with the removal time. R 2 The results also reached 0.99, 0.80 and 0.98, which also confirmed that the removal effect maintained a good linear relationship with time. The defect-rich P-doped MoS2 palladium-supported electrode of the present invention obtained the fastest reaction rate for lamotrigine, with a reaction rate constant of 0.06 min -1 , which are 1.95 times that of Pd / MoS2(def) / NF, Pd / MoS2 / NF and P-MoS2 / NF electrodes (0.03 min -1), 10.61 times (0.006 min -1 ) and 20.48 times (0.003 min -1 ), the reaction rate is greatly improved. The largest k obs The numerical results obtained fully confirm that the introduction of defect-rich materials can optimize the catalyst's performance for the electrocatalytic hydrodechlorination of chlorinated PPCPs. The P-doped defect material exhibits superior S vacancy defect removal compared to the purely calcined material, demonstrating that P-doping plays a crucial role in stabilizing material defects and maintaining catalyst activity.

[0105] To evaluate the performance of a catalyst, in addition to looking at the final removal effect of the catalyst on pollutants, the removal rate is also an important indicator to describe the performance of the catalyst. Figure 7 c shows the removal rate of LTG by electrocatalytic hydrodechlorination of the four electrode materials at different time periods. Within 0–60 min, the removal rates of the four electrodes were significantly different, with the Pd / P-MoS2 / NF electrode having the fastest removal rate of 0.24 mg·L -1 min -1 , which is significantly better than Pd / MoS2(def) / NF, Pd / MoS2 / NF and P-MoS2 / NF electrodes. After 60 min, the removal rate decreased significantly, which was mainly attributed to the low LTG concentration in the system that could not achieve the reaction with H on the catalyst surface. ads The effective combination of the two electrodes results in a large amount of H* escaping as H2. Throughout the entire reaction process, there was no significant difference in the overall removal rate between the Pd / P-MoS2 / NF electrode and the Pd / MoS2(def) / NF electrode, achieving only a 1.02-fold increase. However, the removal rate of the Pd / P-MoS2 / NF electrode increased significantly within the first 60 minutes. The removal rate of the Pd / P-MoS2 / NF electrode was 1.26 times that of the Pd / MoS2(def) / NF electrode, and the removal rate reached 99.77% at 90 minutes of dechlorination.

[0106] Figure 8 The Pd / P-MoS2 / NF electrode prepared in Example 1 demonstrates the removal performance of five target chlorinated PPCPs: bezafibrate, lornoxicam, losartan potassium, florfenicol, and chlorphenamine maleate. The Pd / P-MoS2 / NF electrode achieved near-complete removal of bezafibrate, florfenicol, and chlorphenamine maleate within 150 minutes. The removal performance for lornoxicam and losartan potassium both exceeded 90%, demonstrating the universal applicability of the Pd / P-MoS2 / NF electrode.

[0107] Figure 9 In order to test the stability of the electrode under long-term use, the electrocatalytic hydrodechlorination experiment of LTG was carried out ten times at a constant current of 7 mA. Figure 9 As shown. The experimental conditions of each cycle are the same as those of the single-cycle exploration. It can be seen that at the end of each cycle, the removal effect of the Pd / P-MoS2 / NF electrode prepared in Example 1 on LTG is reduced. In the first six cycles, the Pd / P-MoS2 / NF electrode showed good stability. At the end of the sixth cycle, the LTG removal effect was maintained at 91.60%. The results demonstrate the strong stability of the Pd / P-MoS2 / NF electrode of the present invention.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a Pd / P-MoS2 / NF electrode, characterized in that: The steps include: Step S1: preparing nanoflower-like MoS2 / NF electrodes by hydrothermal method; Step S2: doping the phosphorus source with the nanoflower-shaped MoS2 / NF electrode by a calcination method to obtain a defect-rich P-MoS2 / NF electrode; Step S3: using an electrodeposition method to load palladium element into the defect-rich P-MoS2 / NF electrode to obtain a defect-rich P-MoS2 / NF palladium-loaded electrode; The molar ratio of the phosphorus source to the nanoflower-shaped MoS2 / NF electrode is (1-2.3):3.

3.

2. The method for preparing the Pd / P-MoS2 / NF electrode according to claim 1, wherein: The step S2 comprises the following steps: The phosphorus source and the nanoflower-shaped MoS2 / NF electrode are loaded into a ceramic ark and placed in a tube furnace, and annealed under a nitrogen atmosphere to obtain a defect-rich P-MoS2 / NF electrode; and / or The phosphorus source is sodium hypophosphite and / or sodium phosphate.

3. The method for preparing the Pd / P-MoS2 / NF electrode according to claim 2, wherein: The process of the annealing treatment is as follows: The calcination temperature is 200℃-450℃, and the heating rate is 3℃·min -1 -8℃·min -1 , the calcination time is 1-3h.

4. The method for preparing the Pd / P-MoS2 / NF electrode according to claim 1, wherein: The step S1 comprises the following steps: Step S11: (NH4)6Mo7O 24 •4H2O and CH4N2S were dissolved in deionized water and mixed well to obtain a precursor solution; Step S12: pouring the precursor solution into a reactor, and immersing the Ni-foam substrate in the precursor solution to perform a hydrothermal reaction to obtain a nanoflower-shaped MoS2 / NF electrode; Step S13: Clean the nanoflower-shaped MoS2 / NF electrode until the solution is clear, and dry it for later use.

5. The method for preparing the Pd / P-MoS2 / NF electrode according to claim 4, wherein: The temperature of the hydrothermal reaction in step S12 is 150-200° C., and the reaction time is 8-16 h.

6. The method for preparing the Pd / P-MoS2 / NF electrode according to claim 1, wherein: The step S3 comprises the following steps: The defect-rich P-MoS2 / NF electrode was placed in a deposition solution containing Pd element for electrodeposition and then dried to obtain a defect-rich P-MoS2 / NF palladium-loaded electrode.

7. The method for preparing the Pd / P-MoS2 / NF electrode according to claim 6, wherein: The deposition liquid is a PdCl2 solution, a chloropalladic acid solution, or a mixed solution of the two; and / or The concentration of the sedimentation solution is 0.2-0.5 mmol·L -1 .

8. The method for preparing the Pd / P-MoS2 / NF electrode according to claim 1, wherein: The parameters of the electrodeposition are: electrodeposition for 1.5-2.5 h at a constant current of 6-10 mA.

9. The Pd / P-MoS2 / NF electrode prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the Pd / P-MoS2 / NF electrode according to claim 9 as a catalytic electrode in the electrocatalytic hydrodechlorination reaction of chlorinated organic compounds, wherein the chlorinated organic compounds are selected from one or more of bezafibrate, lornoxicam, losartan potassium, florfenicol, and chlorpheniramine maleate.

Images