Iron atom loaded molybdenum disulfide catalyst as well as preparation method and application thereof

Abstract

The invention discloses an iron atom loaded molybdenum disulfide catalyst and a preparation method and application thereof, and the preparation method of the catalyst comprises the following steps: preparing molybdenum disulfide nano flower balls, dispersing the molybdenum disulfide nano flower balls in water, adding a ferric salt and a reducing agent, and carrying out a hydrothermal reaction to obtain the iron atom loaded molybdenum disulfide catalyst. In the preparation method, under the combined action of the 1T-phase molybdenum disulfide, the ferric iron and the reducing agent, the iron atom loaded molybdenum disulfide catalyst with many reaction active sites, good stability and high catalytic activity can be prepared, and when the iron atom loaded molybdenum disulfide catalyst is used for activating persulfate, efficient activation of persulfate can be achieved; furthermore, a large amount of. SO4 <-> and singlet oxygen can be rapidly generated by utilizing the persulfate to realize efficient degradation of organic pollutants. Meanwhile, the preparation method disclosed by the invention also has the advantages of simple process, high preparation efficiency, easily controlled preparation conditions, safe preparation process and the like, is suitable for large-scale preparation and is convenient for industrial application.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of environmental functional materials and water pollution control, and relates to an iron atom-loaded molybdenum disulfide catalyst and a preparation method and application thereof. Background Art

[0002] In the daily industrial production process, a large amount of organic pollutants (such as antibiotics, phenolic pollutants etc.) will be produced. These organic pollutants enter into the water body and have caused great impact on the water environment. Taking phenol as an example, phenol is an organic compound with a special smell and a colorless needle-shaped crystal structure, and is an important organic chemical raw material. Phenol and its derivatives are widely used in industrial fields such as petroleum industry, weaving, papermaking, medicine and dyes. However, along with the large-scale use of phenol, the discharge volume of phenol-containing wastewater is increased day by day. Simultaneously, because phenol is a kind of persistent organic pollutant, it has characteristics such as high water solubility, high chemical stability, poor biodegradability and high toxicity, can enter organisms through skin, respiratory tract and digestive tract, has certain carcinogenicity, mutagenicity and endocrine disrupting effect, even at low concentrations, also can have a serious impact on aquatic ecosystems and human health. Therefore, it is imperative to effectively remove the organic pollutants in the water body.

[0003] Currently, traditional organic pollutant wastewater treatment technologies mainly include adsorption, extraction, coagulation, microbial degradation, etc., but they still have problems such as low treatment efficiency and easy secondary pollution. Peroxymonosulfate (PMS) based on advanced oxidation technology is an active oxidant with strong oxidizing ability, which can induce the generation of various active free radicals ( · OH, · O2 - 、 · SO4 - etc.) can efficiently degrade organic pollutants and even mineralize them into carbon dioxide and water, which has become one of the most promising ways to rapidly degrade organic pollutants. · OH) compared to PMS · SO4 - It has higher redox potential, longer life and wider pH adaptability, and has better application prospects.

[0004] Currently, transition metal catalysts (such as Fe, Co, Mn, and Ni-based materials) have been widely used for PMS activation, but they still face challenges such as transition metal leaching leading to secondary contamination. Single-atom catalysts (SACs) offer atomically dispersed metal activity and high selectivity, maximizing metal atom utilization and combining the advantages of both homogeneous and heterogeneous catalysts. These catalysts hold great promise for future applications, but they also suffer from the drawbacks of agglomeration, limited active sites, and a tendency to agglomerate. Furthermore, anchoring single atoms on suitable supports improves stability while allowing for the regulation of their reactivity through metal-support interactions. In recent years, molybdenum disulfide (MoS2) has been considered an ideal catalyst for single-atom support due to its unique layered structure and tunable electronic structure. In theory, rationally designing the metal-support interface between transition metals and MoS2 is an effective approach to increasing the number of active sites. Furthermore, the crystal phase is a key factor in determining performance. Three common crystal phases, defined by the atomic stacking order within the layers, are 1T, 2H, and 3R. Due to its unique crystal structure, the metallic 1T phase MoS2 is significantly superior to the 2H phase MoS2 in terms of catalytic performance for PMS. Nevertheless, the following problems still exist in the preparation of atomic-level catalyst-supported MoS2: (1) The current preparation method usually involves complex processes such as chemical exfoliation or intercalation, which is dangerous and expensive, limiting large-scale production; (2) The current preparation method focuses on the loading of single atoms on the MoS2 matrix, which has the problem of metal agglomeration leading to uneven distribution of active sites; (3) The existing atomic-level catalyst-supported MoS2 materials have low 1T phase content or poor structural stability, and the 1T phase is prone to spontaneous transformation into the more thermodynamically stable 2H phase under reaction conditions. The existence of the above problems limits the widespread application of atomic-level catalyst-supported MoS2. Therefore, how to overcome the deficiencies in the above-mentioned prior art and obtain a single-atom-supported MoS2 catalyst that is simple to prepare, has high catalytic activity and a stable chemical structure and is dominated by the 1T phase is of great significance for the efficient use of persulfate to degrade organic pollutants in water. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide an iron atom-loaded molybdenum disulfide catalyst with simple process, high preparation efficiency, safe preparation process, multiple reaction active sites, good stability and high catalytic activity, as well as its preparation method and application.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for preparing an iron atom-supported molybdenum disulfide catalyst comprises the following steps:

[0008] S1, preparing molybdenum disulfide nano flower balls;

[0009] S2. Dispersing the molybdenum disulfide nanospheres obtained in step S1 in water, adding a trivalent iron salt and a reducing agent to carry out a hydrothermal reaction to obtain an iron atom-supported molybdenum disulfide catalyst.

[0010] The above preparation method is further improved. In step S2, the ratio of the molybdenum disulfide nanospheres to the trivalent iron salt is 200 mg: 0.025 mmol to 0.15 mmol; and the ratio of the trivalent iron salt to the reducing agent is 0.025 mmol to 0.15 mmol: 2 mL.

[0011] The above preparation method is further improved. In step S2, the ratio of the molybdenum disulfide nanoflower ball to the trivalent iron salt is 200 mg: 0.07 mmol~0.12 mmol; the ratio of the trivalent iron salt to the reducing agent is 0.07 mmol~0.12 mmol: 2 mL; the trivalent iron salt is at least one of ferric nitrate nonahydrate, ferric chloride hexahydrate, and ferric acetate; and the reducing agent is at least one of hydrazine hydrate, sodium borohydride, and oxalic acid.

[0012] The above preparation method is further improved in that in step S2, the hydrothermal reaction is carried out at a temperature of 180°C to 220°C; and the time of the hydrothermal reaction is 18h to 24h.

[0013] The above preparation method is further improved, in step S1, the preparation method of the molybdenum disulfide nano flower ball comprises the following steps:

[0014] (1) dissolving a molybdenum source to prepare a molybdenum source solution;

[0015] (2) mixing the molybdenum source solution obtained in step (1) with a sulfur source to carry out a hydrothermal reaction to obtain molybdenum disulfide nanospheres.

[0016] The above preparation method is further improved. In step (1), the molybdenum source solution is prepared by dissolving a molybdenum source in water; the ratio of the molybdenum source to water is 2.14 g:60 mL; and the molybdenum source is at least one of sodium molybdate, ammonium molybdate, molybdenum nitrate, and ammonium heptamolybdate tetrahydrate.

[0017] The above preparation method is further improved, in step (2), the molar ratio of the molybdenum source to the sulfur source in the molybdenum source solution is 1:11.88; the sulfur source is at least one of thioacetamide, thiourea, L-cysteine, and sodium sulfide; the hydrothermal reaction is carried out at a temperature of 180°C to 220°C; and the hydrothermal reaction time is 18h to 24h.

[0018] As a general technical concept, the present invention also provides an iron atom-supported molybdenum disulfide catalyst, which is prepared by the above-mentioned preparation method.

[0019] The above-mentioned iron atom-loaded molybdenum disulfide catalyst is further improved, wherein the iron atom-loaded molybdenum disulfide catalyst includes molybdenum disulfide nanoflower balls, on which iron atoms are loaded; the molybdenum disulfide nanoflower balls are composed of molybdenum dioxide nanosheets; the size of the molybdenum disulfide nanoflower balls is 500nm to 600nm; and the content of 1T phase molybdenum disulfide in the iron atom-loaded molybdenum disulfide catalyst is 69.22%.

[0020] As a general technical concept, the present invention also provides an application of the above-mentioned iron atom-supported molybdenum disulfide catalyst in treating organic pollutant wastewater.

[0021] The above application is further improved, comprising the following steps: mixing an iron atom-loaded molybdenum disulfide catalyst and organic pollutant wastewater, stirring, and adding persulfate to carry out a catalytic degradation reaction to complete the degradation of organic pollutants in the water.

[0022] The above application is further improved in that the mass volume ratio of the iron atom-supported molybdenum disulfide catalyst to the organic pollutant wastewater is 0.5 mg to 2 mg: 10 mL.

[0023] The above application is further improved, wherein the persulfate is added to the organic pollutant wastewater in the form of a persulfate solution; the concentration of the persulfate solution is 10 mmol / L to 150 mmol / L; the volume ratio of the persulfate solution to the organic pollutant wastewater is 0.1:10; and the persulfate in the persulfate solution is potassium monopersulfate.

[0024] The above application is further improved, wherein the concentration of organic pollutants in the organic pollutant wastewater is 5ppm to 30ppm; the organic pollutants include at least one of antibiotics and phenolic pollutants; the antibiotics are at least one of tetracycline, sulfadiazine, and carbamazepine; and the phenolic pollutants include at least one of phenol, parachlorophenol, and acetaminophen.

[0025] The above application is further improved in that the stirring time is 1 min to 30 min; and the catalytic degradation reaction time is 1 min to 20 min.

[0026] Compared with the prior art, the advantages of the present invention are:

[0027] (1) In view of the shortcomings of the existing atomic-level catalyst-loaded molybdenum disulfide catalyst, such as the complex preparation process, uneven and small distribution of active sites, low 1T phase content, and poor structural stability, the present invention provides a preparation method of an iron atom-loaded molybdenum disulfide catalyst, which first prepares molybdenum disulfide nano-flower balls, which is a type of molybdenum disulfide with a high 1T phase content, and then disperses the molybdenum disulfide nano-flower balls in water, and dropwise adds trivalent iron salt and a reducing agent, so that iron ions can be uniformly adsorbed on the surface of the molybdenum disulfide nano-flower balls under the action of van der Waals force, and finally, through a hydrothermal reaction and under the action of a reducing agent, the iron atoms can form an Fe-S coordination structure with the sulfur atoms in the molybdenum disulfide, thereby The iron atoms can be uniformly and firmly loaded on the sulfur dioxide nanoflower balls to form an iron-loaded molybdenum disulfide catalyst. More importantly, under the protection of the Fe-S coordination structure, the molybdenum disulfide crystal phase can be effectively prevented from undergoing phase transformation during the hydrothermal reaction or actual use. In particular, it can effectively prevent the 1T phase from transforming into the 2H phase, thereby ensuring that the 1T phase in the iron-loaded molybdenum disulfide catalyst always maintains a dominant position. In this way, an iron-loaded molybdenum disulfide catalyst with many reaction active sites, good stability and high catalytic activity is prepared. When it is used to activate persulfate, it can achieve efficient activation of the persulfate, and then a large amount of persulfate can be quickly produced. · SO4 - The preparation method of the present invention has the advantages of simple process, high preparation efficiency, easy control of preparation conditions, and safe preparation process, and is suitable for large-scale preparation and convenient for industrial application.

[0028] (2) In the preparation method of the present invention, the ratio of molybdenum disulfide nanospheres to trivalent iron salt is optimized to 200 mg: 0.025 mmol to 0.15 mmol, and in particular, the ratio of the two is 200 mg: 0.07 mmol to 0.12 mmol. By optimizing the amount of trivalent iron salt, it is beneficial to improve the dispersion of iron atoms on the surface of molybdenum disulfide nanosheets. At the same time, while effectively preventing the agglomeration of iron atoms, it is also possible to increase the loading amount of iron atoms on the surface of molybdenum disulfide nanosheets, thereby preparing an iron atom-loaded molybdenum disulfide catalyst with a larger specific surface area, more active sites, and stronger catalytic activity.

[0029] (3) The present invention also provides an iron atom-supported molybdenum disulfide catalyst, comprising molybdenum disulfide nanospheres, on which iron atoms are supported, and the molybdenum disulfide nanospheres are composed of molybdenum dioxide nanosheets, the size of the molybdenum disulfide nanospheres (i.e., the particle diameter measured in SEM) being 500 nm to 600 nm, and the content of 1T phase molybdenum disulfide in the iron atom-supported molybdenum disulfide catalyst (i.e., the peak area ratio obtained by XPS deconvolution operation fitting) being 69.22%. Compared with conventional atomic-level catalyst-supported molybdenum disulfide catalysts, the iron atom-supported molybdenum disulfide catalyst, which is supported by molybdenum disulfide nanospheres, has more reaction sites, higher metal atom utilization, faster reaction rate, more stable structure, and better catalytic performance, thereby being able to more efficiently activate persulfate.

[0030] (4) The present invention also provides an application of an iron atom-loaded molybdenum disulfide catalyst in treating organic pollutant wastewater. Specifically, the iron atom-loaded molybdenum disulfide catalyst and organic pollutant wastewater are mixed and stirred, and persulfate is added to carry out a catalytic degradation reaction, thereby achieving efficient degradation of organic pollutants in water. The process has the advantages of simple process, convenient operation, fast degradation rate, good degradation effect, etc., and can achieve repeated degradation of organic pollutant wastewater with lower treatment cost, which is of great significance for achieving efficient purification of organic pollutant wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0032] Figure 1 These are the XRD patterns of the molybdenum disulfide nanospheres (MoS2) and iron atom-loaded molybdenum disulfide catalysts (0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, 0.15Fe / MoS2) prepared in Examples 1-4 of the present invention.

[0033] Figure 2 These are the XRD patterns of the iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the iron oxide-loaded molybdenum disulfide catalysts (0.1Fe / MoS2 (200°C), 0.1Fe / MoS2 (300°C), 0.1Fe / MoS2 (400°C), 0.1Fe / MoS2 (500°C)) prepared in Comparative Examples 1-4.

[0034] Figure 3These are SEM images of the molybdenum disulfide nanospheres (MoS2) and iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention, and the molybdenum disulfide (MoS2 (500°C)) and iron oxide-loaded molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4.

[0035] Figure 4 TEM images of the iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the iron oxide-loaded molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4.

[0036] Figure 5 This is an STEM image of the iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention.

[0037] Figure 6 These are the Raman graphs of the iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the iron oxide-loaded molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4.

[0038] Figure 7 These are the XPS graphs of the molybdenum disulfide nanospheres (MoS2) and iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention, and the molybdenum disulfide (MoS2 (500°C)) and iron oxide-loaded molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4.

[0039] Figure 8 This is a time-degradation efficiency graph corresponding to the degradation of phenol solution by activating persulfate with molybdenum disulfide nanospheres (MoS2), iron atom-loaded molybdenum disulfide catalysts (0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, 0.15Fe / MoS2), and iron oxide-loaded molybdenum disulfide catalysts (0.1Fe / MoS2 (200°C), 0.1Fe / MoS2 (300°C), 0.1Fe / MoS2 (400°C), 0.1Fe / MoS2 (500°C)) in Example 5 of the present invention.

[0040] Figure 9 This is a time-degradation efficiency diagram corresponding to the activation of persulfate and degradation of different organic pollutant solutions by the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) in Example 5 of the present invention.

[0041] Figure 10This is a graph showing the number of cycles-degradation efficiency corresponding to the activation of persulfate and degradation of different organic pollutant solutions by the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) in Example 6 of the present invention. DETAILED DESCRIPTION

[0042] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0043] Example 1

[0044] A method for preparing an iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) comprises the following steps:

[0045] S1. Weigh 2.14 g of ammonium heptamolybdate tetrahydrate and dissolve it in 60 mL of deionized water with vigorous stirring to obtain a molybdenum source solution. Subsequently, 1.54 g of thioacetamide was added, and the mixture was stirred at room temperature for 30 min. The mixture was transferred to a 100 mL polytetrafluoroethylene-lined autoclave and reacted at 200 ° C for 24 hours. The mixture was cooled to room temperature, washed with deionized water and ethanol several times, and dried in vacuo at 40 ° C overnight to obtain a black powder sample, which is a molybdenum disulfide nanosphere, named MoS2.

[0046] S2. Weigh 200 mg of molybdenum disulfide nano-flower balls and disperse them in 60 mL of deionized water. Add 1 mL of 0.1 mol / L ferric nitrate solution (prepared by dissolving 40.4 mg of ferric nitrate nonahydrate (0.1 mmol) in 1 mL of ultrapure water) and 2 mL of hydrazine hydrate dropwise. Stir at room temperature for 30 min. Transfer to a 100 mL polytetrafluoroethylene-lined autoclave and react for 24 hours at 200 ° C. After cooling to room temperature, wash with deionized water and ethanol several times. Dry in vacuo at 40 ° C overnight to obtain a black powder sample, which is an iron atom-loaded molybdenum disulfide catalyst, named 0.1Fe / MoS2.

[0047] Example 2

[0048] A method for preparing an iron atom-loaded molybdenum disulfide catalyst (0.025Fe / MoS2) is basically the same as the method for preparing an iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) in Example 1, with the only difference being that in step S2 of Example 2, 0.025 mmol of ferric nitrate nonahydrate is added.

[0049] The iron atom-supported molybdenum disulfide catalyst prepared in Example 2 is named 0.025Fe / MoS2.

[0050] Example 3

[0051] A method for preparing an iron atom-loaded molybdenum disulfide catalyst (0.05Fe / MoS2) is basically the same as the method for preparing an iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) in Example 1, with the only difference being that in step S2 of Example 3, 0.05 mmol of ferric nitrate nonahydrate is added.

[0052] The iron atom-supported molybdenum disulfide catalyst prepared in Example 3 is named 0.05Fe / MoS2.

[0053] Example 4

[0054] A method for preparing an iron atom-loaded molybdenum disulfide catalyst (0.15Fe / MoS2) is basically the same as the method for preparing the iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) in Example 1, with the only difference being that in step S2 of Example 4, 0.15 mmol of ferric nitrate nonahydrate is added.

[0055] The iron atom-supported molybdenum disulfide catalyst prepared in Example 4 is named 0.15Fe / MoS2.

[0056] Comparative Example 1

[0057] A method for preparing an iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (200°C)) is substantially the same as that in Example 1, except that the method for preparing molybdenum dioxide (MoS2 (200°C)) used in Comparative Example 1 is different, wherein the method for preparing molybdenum dioxide (MoS2 (200°C)) comprises the following steps:

[0058] The molybdenum disulfide nanospheres prepared in step S1 of Example 1 were placed in a porcelain boat, placed in a tube furnace, heated to 200°C at a heating rate of 5°C / min in a nitrogen atmosphere, and calcined for 2 hours. The mixture was then cooled to room temperature at the same rate to obtain a black powder sample, namely molybdenum dioxide, named MoS2 (200°C).

[0059] The iron oxide-supported molybdenum disulfide catalyst prepared in Comparative Example 1 was named 0.1Fe / MoS2 (200°C).

[0060] Comparative Example 2

[0061] A method for preparing an iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (300°C)) is substantially the same as that of Example 1 except that the method for preparing molybdenum dioxide (MoS2 (300°C)) is different, wherein the method for preparing molybdenum dioxide (MoS2 (300°C)) comprises the following steps:

[0062] The molybdenum disulfide nanospheres prepared in step S1 of Example 1 were placed in a porcelain boat, placed in a tube furnace, heated to 300°C at a heating rate of 5°C / min in a nitrogen atmosphere, and calcined for 2 hours. The mixture was then cooled to room temperature at the same rate to obtain a black powder sample, namely molybdenum dioxide, named MoS2 (300°C).

[0063] The iron oxide-supported molybdenum disulfide catalyst prepared in Comparative Example 2 was named 0.1Fe / MoS2 (300°C).

[0064] Comparative Example 3

[0065] A method for preparing an iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (400°C)) is substantially the same as that of Example 1 except that the method for preparing molybdenum dioxide (MoS2 (400°C)) is different, wherein the method for preparing molybdenum dioxide (MoS2 (400°C)) comprises the following steps:

[0066] The molybdenum disulfide nanospheres prepared in step S1 of Example 1 were placed in a porcelain boat, placed in a tube furnace, heated to 400°C at a heating rate of 5°C / min in a nitrogen atmosphere, and calcined for 2 hours. The mixture was then cooled to room temperature at the same rate to obtain a black powder sample, namely molybdenum dioxide, named MoS2 (400°C).

[0067] The iron oxide-supported molybdenum disulfide catalyst prepared in Comparative Example 3 was named 0.1Fe / MoS2 (400°C).

[0068] Comparative Example 4

[0069] A method for preparing an iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) is substantially the same as that of Example 1 except that the method for preparing molybdenum dioxide (MoS2 (500°C)) is different, wherein the method for preparing molybdenum dioxide (MoS2 (500°C)) comprises the following steps:

[0070] The molybdenum disulfide nanospheres prepared in step S1 of Example 1 were placed in a porcelain boat, placed in a tube furnace, heated to 500°C at a heating rate of 5°C / min in a nitrogen atmosphere, and calcined for 2 hours. The mixture was then cooled to room temperature at the same rate to obtain a black powder sample, namely molybdenum dioxide, named MoS2 (500°C).

[0071] The iron oxide-supported molybdenum disulfide catalyst prepared in Comparative Example 4 was named 0.1Fe / MoS2 (500°C).

[0072] (1) The X-ray diffraction analysis patterns (XRD patterns) of the molybdenum disulfide nanospheres (MoS2) and iron atom-supported molybdenum disulfide catalysts (0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, 0.15Fe / MoS2) prepared in Examples 1-4 were examined. The results are as follows: Figure 1 shown.

[0073] The iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 and the iron oxide-supported molybdenum disulfide catalysts (0.1Fe / MoS2 (200°C), 0.1Fe / MoS2 (300°C), 0.1Fe / MoS2 (400°C), 0.1Fe / MoS2 (500°C)) prepared in Comparative Examples 1-4 were subjected to X-ray diffraction analysis. The results are as follows: Figure 2 shown.

[0074] Figure 1 The XRD patterns of the molybdenum disulfide nanospheres (MoS2) and iron atom-supported molybdenum disulfide catalysts (0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, 0.15Fe / MoS2) prepared in Examples 1-4 of the present invention are shown in FIG. Figure 1 It can be seen that the broad diffraction peak of the molybdenum disulfide nanospheres (MoS2) prepared by the present invention at 9.7° corresponds to the (001) crystal plane of 1T phase MoS2, confirming that the prepared product is 1T phase molybdenum disulfide (MoS2). Figure 1 No Fe-related diffraction peaks were observed, indicating the uniform distribution of iron atoms on MoS2, and the slight changes in the diffraction peak intensity are related to the loading level of metal atoms.

[0075] Figure 2 The XRD patterns of the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the iron oxide-supported molybdenum disulfide catalysts (0.1Fe / MoS2 (200°C), 0.1Fe / MoS2 (300°C), 0.1Fe / MoS2 (400°C), 0.1Fe / MoS2 (500°C)) prepared in Comparative Examples 1-4 are shown. Figure 2 It can be seen that with the increase of the precursor calcination temperature, the (002) crystal plane shifts significantly, indicating the transformation of the molybdenum disulfide crystal phase from 1T phase to 2H phase, and the Fe diffraction peak related to Fe3O4 is observed in the XRD spectrum of 0.1Fe / MoS2 (500℃).

[0076] (2) Scanning electron micrographs (SEM images) of the molybdenum disulfide nanospheres (MoS2) and the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the molybdenum disulfide (MoS2 (500°C)) and the iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4 were examined. The results are as follows: Figure 3 shown.

[0077] Figure 3 These are SEM images of the molybdenum disulfide nanospheres (MoS2) and iron atom-loaded molybdenum disulfide catalyst (0.1 Fe / MoS2) prepared in Example 1 of the present invention, and the molybdenum disulfide (MoS2 (500°C)) and iron oxide-loaded molybdenum disulfide catalyst (0.1 Fe / MoS2 (500°C)) prepared in Comparative Example 4. Figure 3 Among them, (a) is MoS2, (b) is 0.1 Fe / MoS2, (c) is MoS2 (500℃), and (d) is 0.1 Fe / MoS2 (500℃); Figure 3 Figures ac show that the MoS2 nanospheres are composed of MoS2 nanosheets. The 0.1 Fe / MoS2 and MoS2 (500℃) catalysts loaded with metal atoms or calcined have no obvious morphological changes. Figure 3 d Obvious iron nanoparticles or clusters were observed, indicating that the change of MoS2 crystal phase affects the metal-interface loading form of iron and MoS2.

[0078] (3) The transmission electron microscopy (TEM) images of the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 and the iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4 were examined. The structures are shown in FIG. Figure 4 shown.

[0079] Figure 4 TEM images of the iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the iron oxide-loaded molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4. Figure 4 In the figure, a and b are TEM images of 0.1Fe / MoS2 in the range of 100nm and 5nm, respectively, and c and d are TEM images of 0.1Fe / MoS2 (500℃) in the range of 200nm and 5nm, respectively. Figure 4 Typical MoS2 lattice fringes can be observed in the ab, and no iron nanoparticles or clusters are observed, indicating that the iron atoms are uniformly anchored on the MoS2 matrix. Figure 4The cd can be observed, and the lattice fringes of ferroferric oxide particles are clearly observed in 0.1Fe / MoS2 (500℃). The results show that the change of the MoS2 crystal phase will affect the metal-interface loading form of iron and MoS2.

[0080] (4) The scanning transmission electron microscopy (STEM) of the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 was examined. Figure 5 shown.

[0081] Figure 5 This is a STEM image of the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention. Figure 5 As shown in the left figure, it can be observed that 0.1Fe / MoS2 has a typical 1T phase and 2H phase S-Mo-S atomic arrangement structure, confirming the simultaneous existence of 1T phase and 2H phase in the catalyst. Figure 5 In the right figure, many isolated bright spots (circled) can be seen that are different from the carrier, which indicates that the iron atoms in the carrier are dispersed on the MoS2 carrier in an atomic-level form.

[0082] (5) The Raman spectra of the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 and the iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4 were examined. The results are as follows: Figure 6 shown.

[0083] Figure 6 The Raman graphs of the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4 are shown. Figure 6 As shown, 0.1Fe / MoS2 has J1, J2, E related to 1T phase MoS2 1g and J3 vibration modes, while 0.1Fe / MoS2 (500℃) has a strong in-plane Mo-S phonon mode related to 2H phase MoS2 (E 1 2g ) and out-of-plane Mo-S mode (A 1g ), indicating that its crystal phase transitions from 1T phase to 2H phase.

[0084] (6) The XPS patterns of the molybdenum disulfide nanospheres (MoS2), the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 and the molybdenum disulfide (MoS2 (500°C)), the iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4 were examined. Figure 7 shown.

[0085] Figure 7 The XPS graphs of the molybdenum disulfide nanospheres (MoS2) and the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 of the present invention and the molybdenum disulfide (MoS2 (500°C)) and the iron oxide-supported molybdenum disulfide catalyst (0.1Fe / MoS2 (500°C)) prepared in Comparative Example 4 are shown. Figure 7 As shown, compared with MoS2 (500℃), the Mo3d 5 / 2 and 3D 3 / 2 The binding energy increased by about 1.2eV, indicating a transition from a distorted 1T phase to a 2H phase. Based on the deconvolution calculation of the XPS fitting results, the proportion of different phases in MoS2 was quantified. The proportion of 1T phase in 0.1Fe / MoS2 was 69.22%, while 0.1Fe / MoS2 (500℃) was almost entirely composed of 2H phase. The parallel movement of these peaks confirmed the phase transition from 1T phase to 2H phase. At the same time, Figure 7 The successful loading of iron was confirmed by medium- and high-resolution Fe2p-XPS spectroscopy, and the presence of Fe-S bonds in 0.1Fe / MoS2 compared with MoS2 (500℃) confirmed that the change in the MoS2 crystal phase affects the coordination structure of the iron atomic sites.

[0086] Table 1 Comparison of 1T phase content in different catalysts

[0087] Catalyst type 1T phase content <![CDATA[MoS2]]> 67.49％ <![CDATA[0.1Fe / MoS2]]> 69.22％ <![CDATA[0.1Fe / MoS2(200℃)]]> 41.59％ <![CDATA[0.1Fe / MoS2(300℃)]]> 14.61％ <![CDATA[0.1Fe / MoS2(400℃)]]> 8.04％ <![CDATA[0.1Fe / MoS2(500℃)]]> 6.52％

[0088] As can be seen from Table 1, the 1T phase content is the highest in the iron atom-supported molybdenum disulfide catalyst prepared in the present invention, which is beneficial to improving the catalytic activity of the catalyst.

[0089] Example 5

[0090] An application of an iron atom-supported molybdenum disulfide catalyst in treating organic pollutant wastewater, specifically using the molybdenum disulfide nanoflower balls (MoS2) prepared in Examples 1-4, iron atom-supported molybdenum disulfide catalysts (0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, 0.15Fe / MoS2) and iron oxide-supported molybdenum disulfide catalysts prepared in Comparative Examples 1-4 (0.1Fe / MoS2 (200°C), 0.1Fe / MoS2 (300°C), 0.1Fe / MoS2 (400°C), 0.1Fe / MoS2 (500°C)) to treat phenol wastewater, comprising the following steps:

[0091] Weigh 5 mg each of the molybdenum disulfide nanoflower balls (MoS2) prepared in Examples 1-4, iron atom-loaded molybdenum disulfide catalysts (0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, 0.15Fe / MoS2), and iron oxide-loaded molybdenum disulfide catalysts prepared in Comparative Examples 1-4 (0.1Fe / MoS2 (200°C), 0.1Fe / MoS2 (300°C), 0.1Fe / MoS2 (400°C), 0.1Fe / MoS2 (500°C)), and place them in 50 mL of a phenol solution with a concentration of 10 ppm. Stir for 10 minutes to reach adsorption equilibrium, and then add 1 mL of a PMS (potassium permonosulfate) solution with a concentration of 25 mmol / L to the solution for catalytic degradation reaction for 20 min. The degradation of phenol in the water is completed by utilizing the catalyst to activate the persulfate.

[0092] At the same time, this example also examines the degradation effect of iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) on other organic pollutants (tetracycline, sulfadiazine, carbamazepine, parachlorophenol, and acetaminophen), with other conditions being the same.

[0093] During the persulfate activation reaction, 1 ml of organic pollutant solution was taken at 1 min, 2 min, 3 min, 5 min, 10 min, 15 min, and 20 min time points, and the characteristic peaks of organic pollutants in the solution were measured by liquid chromatography. The degradation efficiency of different catalysts for different organic pollutant solutions under different time conditions was calculated. The results are as follows: Figure 8 and 9 shown.

[0094] Figure 8 This is a time-degradation efficiency graph corresponding to the degradation of phenol solution by activating persulfate with molybdenum disulfide nanospheres (MoS2), iron atom-loaded molybdenum disulfide catalysts (0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, 0.15Fe / MoS2), and iron oxide-loaded molybdenum disulfide catalysts (0.1Fe / MoS2 (200°C), 0.1Fe / MoS2 (300°C), 0.1Fe / MoS2 (400°C), 0.1Fe / MoS2 (500°C)) in Example 5 of the present invention.

[0095] like Figure 8As shown in the figure, after 20 minutes of reaction, the degradation efficiency of phenol over the activated persulfate of MoS2 catalyst was 8.6%, while the degradation efficiency of phenol over 0.025Fe / MoS2, 0.05Fe / MoS2, 0.1Fe / MoS2, and 0.15Fe / MoS2 all reached 100%, indicating that the introduction of iron can significantly enhance the degradation efficiency of phenol. However, with the increase of the calcination temperature of molybdenum disulfide, the degradation efficiency of phenol decreased significantly, with the degradation efficiency of 0.1Fe / MoS2 (200℃), 0.1Fe / MoS2 (300℃), 0.1Fe / MoS2 (400℃), and 0.1Fe / MoS2 (500℃) reaching 100%, 27.3%, 20.4%, and 17.7%, respectively. This is related to the support-interface loading form of iron atoms and molybdenum disulfide. 0.1Fe / MoS2 is loaded on MoS2 in the form of single atoms, increasing the exposed active sites of iron.

[0096] Figure 9 The graph is a time-degradation efficiency diagram corresponding to the activation of persulfate and degradation of different organic pollutant solutions by the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) in Example 5 of the present invention. Figure 9 As shown in the figure, after 10 min of reaction, the degradation efficiency of 0.1Fe / MoS2 for phenol, tetracycline, sulfadiazine, carbamazepine and p-chlorophenol reached 100%, and the degradation efficiency of acetaminophen reached 98.3%, indicating that the catalyst has wide applicability.

[0097] From the above opinions, it can be seen that the iron atom-loaded molybdenum disulfide catalyst prepared by the present invention can efficiently activate persulfate, and the degradation efficiency of organic pollutants is significantly improved, and it can efficiently and thoroughly remove organic pollutants in water bodies. This also shows that the iron atom-loaded molybdenum disulfide catalyst of the present invention has good persulfate activation ability, stability and practicality.

[0098] Example 6

[0099] The stability of the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 was investigated. Specifically, the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) was recycled multiple times to activate persulfate to degrade phenol in water. The specific steps are as follows:

[0100] Step 1: Take 10 mg of the iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) prepared in Example 1 and place it in 50 mL of a phenol solution with a concentration of 10 ppm. Stir for 5 minutes to reach adsorption equilibrium, add 1 mL of a PMS solution with a concentration of 25 mmol / L to the solution for a catalytic degradation reaction for 20 minutes. The degradation of organic pollutants in the water body is completed by activating persulfate, completing one cycle.

[0101] Step 2: After completing one cycle, the reaction system in step 1 was filtered to obtain a catalyst, which was filtered and washed five times with deionized water, and dried at 40° C. for 12 h to obtain a regenerated catalyst.

[0102] Step 3: Repeat steps 1 and 2 for a total of six times, using iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) to cyclically treat the phenol solution to complete the degradation cycle experiment.

[0103] During the persulfate activation reaction, 1 mL of phenol solution was taken at time points of 1 min, 2 min, 3 min, 5 min, 10 min, 15 min, and 20 min. The characteristic peak of phenol in the solution was measured by liquid chromatography. The degradation efficiency of the catalyst on the phenol solution under different time conditions in each cycle was calculated. The results are as follows: Figure 9 shown.

[0104] Figure 10 The graph of the number of cycles and degradation efficiency corresponding to the activation of persulfate and degradation of different organic pollutant solutions by the iron atom-supported molybdenum disulfide catalyst (0.1Fe / MoS2) in Example 6 of the present invention is shown. Figure 9 As shown, after six cycles of reaction, the efficiency of iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) in activating persulfate to degrade phenol still remained at 95.5% within 20 minutes. The results show that iron atom-loaded molybdenum disulfide catalyst (0.1Fe / MoS2) has excellent stability and is a catalyst with broad development prospects for activating persulfate to degrade phenol.

[0105] Based on the above opinions, it can be seen that compared with the conventional preparation method, in the preparation method of the present invention, under the joint action of 1T phase molybdenum disulfide, trivalent iron and reducing agent, an iron atom-supported molybdenum disulfide catalyst with multiple reaction active sites, good stability and high catalytic activity can be prepared. As a catalyst with excellent performance, it can be used to activate persulfate and can achieve efficient activation of persulfate, thereby rapidly generating a large amount of persulfate. · SO4 - The efficient degradation of organic pollutants by the use of singlet oxygen is of great significance for the efficient purification of wastewater containing organic pollutants. Furthermore, the preparation method of the present invention has the advantages of simple process, high preparation efficiency, easily controllable preparation conditions, and safe preparation process, making it suitable for large-scale preparation and easy for industrial application.

[0106] The above embodiments are merely preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of protection of the present invention are within the scope of protection of the present invention. It should be noted that improvements and modifications that can be made by a person skilled in the art without departing from the principles of the present invention are also considered to be within the scope of protection of the present invention.

Claims

1. A method for preparing an iron atom-supported molybdenum disulfide catalyst, characterized in that: The following steps are involved: S1, preparing molybdenum disulfide nano flower balls; S2. Dispersing the molybdenum disulfide nanospheres obtained in step S1 in water, adding a trivalent iron salt and a reducing agent to carry out a hydrothermal reaction to obtain an iron atom-supported molybdenum disulfide catalyst.

2. The preparation method according to claim 1, characterized in that In step S2, the ratio of the molybdenum disulfide nanospheres to the ferric salt is 200 mg: 0.025 mmol to 0.15 mmol; and the ratio of the ferric salt to the reducing agent is 0.025 mmol to 0.15 mmol: 2 mL.

3. The preparation method according to claim 2, characterized in that In step S2, the ratio of the molybdenum disulfide nanoflower ball to the trivalent iron salt is 200 mg: 0.07 mmol to 0.12 mmol; the ratio of the trivalent iron salt to the reducing agent is 0.07 mmol to 0.12 mmol: 2 mL; the trivalent iron salt is at least one of ferric nitrate nonahydrate, ferric chloride hexahydrate, and ferric acetate; and the reducing agent is at least one of hydrazine hydrate, sodium borohydride, and oxalic acid.

4. The preparation method according to claim 1, characterized in that In step S2, the hydrothermal reaction is carried out at a temperature of 180° C. to 220° C.; and the hydrothermal reaction time is 18 h to 24 h.

5. The preparation method according to any one of claims 1 to 4, characterized in that In step S1, the method for preparing the molybdenum disulfide nanoflower ball comprises the following steps: (1) dissolving a molybdenum source to prepare a molybdenum source solution; (2) mixing the molybdenum source solution obtained in step (1) with a sulfur source to carry out a hydrothermal reaction to obtain molybdenum disulfide nanospheres.

6. The preparation method according to claim 5, characterized in that In step (1), the molybdenum source solution is prepared by dissolving a molybdenum source in water; the ratio of the molybdenum source to water is 2.14 g: 60 mL; the molybdenum source is at least one of sodium molybdate, ammonium molybdate, molybdenum nitrate, and ammonium heptamolybdate tetrahydrate; In step (2), the molar ratio of the molybdenum source to the sulfur source in the molybdenum source solution is 1:11.88; the sulfur source is at least one of thioacetamide, thiourea, L-cysteine, and sodium sulfide; the hydrothermal reaction is carried out at a temperature of 180°C to 220°C; and the hydrothermal reaction time is 18h to 24h.

7. An iron atom-supported molybdenum disulfide catalyst, characterized in that: The iron atom-supported molybdenum disulfide catalyst is prepared by the preparation method according to any one of claims 1 to 6.

8. The iron atom-supported molybdenum disulfide catalyst according to claim 7, characterized in that The iron atom-loaded molybdenum disulfide catalyst includes molybdenum disulfide nano-flower balls, on which iron atoms are loaded; the molybdenum disulfide nano-flower balls are composed of molybdenum dioxide nanosheets; the size of the molybdenum disulfide nano-flower balls is 500nm to 600nm; and the content of 1T phase molybdenum disulfide in the iron atom-loaded molybdenum disulfide catalyst is 69.22%.

9. Use of the iron atom-supported molybdenum disulfide catalyst according to claim 7 or 8 in treating organic pollutant wastewater, characterized in that: The method comprises the following steps: mixing an iron atom-loaded molybdenum disulfide catalyst and organic pollutant wastewater, stirring, adding persulfate to carry out a catalytic degradation reaction, and completing the degradation of organic pollutants in the water body.

10. The use according to claim 9, characterized in that The mass volume ratio of the iron atom-supported molybdenum disulfide catalyst to the organic pollutant wastewater is 0.5 mg to 2 mg:10 mL; the persulfate is added to the organic pollutant wastewater in the form of a persulfate solution; the concentration of the persulfate solution is 10 mmol / L to 150 mmol / L; the volume ratio of the persulfate solution to the organic pollutant wastewater is 0.1:10; the persulfate in the persulfate solution is potassium peroxymonosulfate; the concentration of organic pollutants in the organic pollutant wastewater is 5 ppm to 30 ppm; the organic pollutants include at least one of antibiotics and phenolic pollutants; the antibiotics are at least one of tetracycline, sulfadiazine, and carbamazepine; the phenolic pollutants include at least one of phenol, parachlorophenol, and acetaminophen; the stirring time is 1 min to 30 min; and the catalytic degradation reaction time is 1 min to 20 min.

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