A metal / sulfur-doped porous carbon catalyst and its preparation method and application

Abstract

The present invention discloses a metal / sulfur-doped porous carbon catalyst, its preparation method, and application, and relates to the technical field of Fenton reaction catalyst preparation. The method comprises the following steps: dissolving starch in deionized water, adding a metal salt and a chloride pore-forming agent, stirring, then adding a reducing sulfur-containing amino acid substance as a sulfur source, continuing stirring until the solution is evaporated to dryness, and drying the resulting colloid to obtain a precursor; heating and carbonizing in a calcining atmosphere, followed by acid washing, water washing, and drying to obtain a metal / sulfur-doped porous carbon catalyst. The catalyst prepared by the present invention exhibits good organic wastewater oxidation and degradation activity and stability in Fenton-like reactions, solving the problems of low catalytic activity and poor stability of traditional Fenton-like catalysts.

Description

Technical Field

[0001] The present invention relates to the technical field of Fenton reaction catalyst preparation, and in particular to a metal / sulfur-doped porous carbon catalyst and a preparation method and application thereof. Background Art

[0002] At present, Fenton reaction is one of the effective methods for treating organic wastewater. Its principle is to use cheap and non-toxic hydrogen peroxide as an oxidant in the presence of metal ions (Fe 3+ 、Co 3+ 、Ni 2+ In the presence of ions (such as ions), hydrogen peroxide decomposes to produce HO·. HO·, with its strong oxidizing ability (standard electrode potential of 2.80 V), can deeply oxidize and degrade most organic pollutants. However, the traditional homogeneous Fenton reaction has certain drawbacks: (1) the generation of iron sludge causes secondary pollution; (2) the pH range of application is narrow; and (3) the catalyst is difficult to recover.

[0003] In the study of heterogeneous Fenton reaction catalysts, the choice of catalyst support is particularly important. Porous carbon materials (including activated carbon, mesoporous carbon, carbon nanotubes, graphene, carbon gel, carbon fiber, carbon black, etc.) have been used as catalysts or catalyst supports in advanced oxidation technologies due to their well-developed pore structures, acid and alkali resistance, easily regulated surface properties, and environmental friendliness. However, conventional metal / porous carbon catalysts suffer from problems such as easy loss during use, a narrow pH range, and low catalyst stability, which seriously restrict their practical application. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a metal / sulfur-doped porous carbon catalyst and its preparation method and application, so as to solve the problems of low catalytic activity and poor stability of existing Fenton catalysts.

[0005] The present invention solves the above technical problems with the following technical solution: a method for preparing a metal / sulfur-doped porous carbon catalyst is provided, comprising the following steps:

[0006] (1) Dissolve starch in deionized water, add metal salt and sodium chloride, stir for 0.8-1.2 hours, then add reducing sulfur-containing amino acid substances, continue stirring until the solution is evaporated to dryness, and dry the obtained colloid to obtain a precursor;

[0007] (2) The precursor prepared in step (1) is heated and carbonized for 2-5 hours, and then acid-washed, water-washed and dried to obtain a metal / sulfur-doped porous carbon catalyst.

[0008] The beneficial effects of the present invention are as follows: the present invention uses soluble starch as a precursor of porous carbon materials, and utilizes the strong reducing property of reducing sulfur-containing amino acids to reduce the metal to a valence state that is more easily complexed, and uniformly disperses it in the precursor. Through the method of "starch loading + metal ion reduction, complexation + high-temperature activation", a metal / sulfur-doped porous carbon heterogeneous Fenton catalyst is obtained, which can effectively improve the dispersion of active metals in metal / sulfur-doped porous carbon catalysts, while enhancing the interaction between active metals and porous carbon supports, thereby improving their catalytic activity and stability.

[0009] On the basis of the above technical solution, the present invention can also be improved as follows:

[0010] Furthermore, in step (1), the metal salt is ferric nitrate, ferric chloride, cobalt nitrate, cobalt chloride, nickel nitrate or nickel chloride.

[0011] Furthermore, in step (1), the metal salt is ferric chloride.

[0012] Furthermore, in step (1), the chloride salt pore-forming agent is sodium chloride, potassium chloride, calcium chloride or barium chloride.

[0013] Furthermore, in step (1), the chloride salt pore-forming agent is sodium chloride.

[0014] Furthermore, in step (1), the reducing sulfur-containing amino acid is L-cysteine, homocysteine ​​or methionine.

[0015] Furthermore, in step (1), the reducing sulfur-containing amino acid is L-cysteine.

[0016] Furthermore, in step (1), the mass volume ratio of starch, metal salt, chloride pore-forming agent and deionized water is 5-15g:8-12g:1g:90-110mL, and the molar ratio of metal salt and reducing sulfur-containing amino acid substance is 0.5-3:1.

[0017] Furthermore, in step (1), the mass volume ratio of starch, metal salt, chloride pore-forming agent and deionized water is 9g:10g:1g:100mL, and the molar ratio of metal salt and reducing sulfur-containing amino acid substance is 1.8:1.

[0018] Furthermore, in step (1), the mixture is dissolved at 50-80°C, stirred at 50-80°C and continued to be stirred.

[0019] Furthermore, in step (1), the mixture is dried at 60-120° C. for 6-24 hours.

[0020] Furthermore, in step (2), the calcination atmosphere is carbon dioxide, nitrogen or high-purity helium.

[0021] Furthermore, in step (2), heating and carbonization are performed at 350-850°C.

[0022] Furthermore, in step (2), heating and carbonization are performed at 550°C.

[0023] Furthermore, in step (2), the heating rate is 4-10°C / min.

[0024] Furthermore, in step (2), 0.8-1.2 mol / L nitric acid solution is used for pickling.

[0025] Furthermore, in step (2), the mixture is dried at 70-100°C.

[0026] The present invention also provides a metal / sulfur-doped porous carbon catalyst prepared by the method.

[0027] The present invention also provides application of the catalyst in a Fenton-like catalytic oxidation system.

[0028] The present invention has the following beneficial effects:

[0029] 1. The present invention uses soluble starch as a carrier to prepare a metal / sulfur-doped porous carbon catalyst, which exhibits good organic wastewater oxidation and degradation activity and stability in a Fenton-like reaction, effectively avoiding the problems of low catalytic activity and poor stability of traditional Fenton-like catalysts.

[0030] 2. The present invention selects the sulfur source as reducing sulfur-containing amino acid substances, which are green and safe. Its strong reducing property can convert metal ions (Fe 3+ 、Co 3+ 、Ni 2+ ) is reduced to a low-valent metal ion. The reduced metal ion is more likely to undergo coordination reaction with the -SH of the reducing sulfur-containing amino acid substance. The whole process can not only increase the metal loading capacity, but also the metal ion and -SH can form a strong coordination bond, which can avoid the migration and dissolution of active metals.

[0031] 3. The carbon source, sulfur source, metal salt, and pore-forming agent of the present invention are all soluble, resulting in a more even dispersion of the reactants in the homogeneous reaction. The active components formed during the subsequent calcination have smaller particle sizes and are more evenly distributed, effectively improving catalytic performance. Using a calcination atmosphere and chloride salt to activate and create pores in the material at high temperatures increases the catalyst specific area, exposing more active components and enhancing catalytic activity.

[0032] 4. S-doping modification can create numerous structural defects in porous carbon materials, such as dislocations, bends, and delocalizations. It also alters the local surface electronic structure, acting as active sites. These active sites can improve electron transfer or adsorption / desorption between the carbon material and reactants, or enhance the interaction between the carbon material and the active metal, thereby improving the dispersion and stability of the nanometal particles. The resulting metal / sulfur-doped porous carbon catalyst achieved a 95% removal rate for the degradation of dye pollutants using hydrogen peroxide. After three reuses, the removal rate only decreased by 5%, demonstrating excellent catalytic performance and stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The graphs are for the catalytic degradation of dye pollutants by the catalysts prepared in Examples 1 and 4-8;

[0034] Figure 2 The graphs are for the catalytic degradation of dye pollutants by the catalysts prepared in Examples 1 and 9-12;

[0035] Figure 3 The graphs are for the catalytic degradation of dye pollutants by the catalysts prepared in Examples 1 and 13-14;

[0036] Figure 4 The graphs are for the catalytic degradation of dye pollutants by the catalysts prepared in Examples 1, 15-18 and Comparative Examples 1-2;

[0037] Figure 5 The graphs are for the catalytic degradation of dye pollutants by the catalysts prepared in Examples 1 and 19-21;

[0038] Figure 6 The graphs are for the catalytic degradation of dye pollutants by the catalysts prepared in Examples 1 and 22-23;

[0039] Figure 7 The graphs are for the catalytic degradation of dye pollutants by the catalysts prepared in Examples 1 and 24-27;

[0040] Figure 8 This is a stability curve of the catalyst obtained in Example 1;

[0041] Figure 9 The temperature-programmed reduction spectra of the catalysts prepared in Examples 1, 16-17 and Comparative Examples 1-2 are shown;

[0042] Figure 10 Infrared-visible spectra of the catalysts prepared in Examples 1, 16-17 and Comparative Examples 1-2;

[0043] Figure 11 This is the X-ray photoelectron spectrum of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0044] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not intended to limit the scope of the invention. In the embodiments, if specific conditions are not specified, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0045] Example 1:

[0046] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0047] (1) 9 g of starch was dissolved in 100 mL of deionized water at 65°C, 10 g of metal salt ferric chloride and 1 g of sodium chloride were added, and the mixture was stirred at 1500 r / min for 1 h. Then, the reducing sulfur-containing amino acid L-cysteine ​​was added, and the mixture was stirred at 1500 r / min at 65°C until the solution was evaporated to dryness. The obtained white paste was dried at 105°C for 18 h to obtain a precursor; wherein the molar ratio of the metal salt to L-cysteine ​​was 1.8:1;

[0048] (2) The precursor prepared in step (1) was heated and carbonized at 550°C for 3 h in a carbon dioxide activation gas atmosphere at a heating rate of 5°C / min, and then pickled with a 1 mol / L nitric acid solution, washed with water, and dried at 80°C to obtain a metal / sulfur-doped porous carbon catalyst.

[0049] Example 2:

[0050] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0051] (1) 5 g of starch was dissolved in 90 mL of deionized water at 50 °C, 8 g of metal salt ferric chloride and 1 g of potassium chloride were added, and the mixture was stirred at 1000 r / min for 0.8 h. L-cysteine ​​was then added, and the mixture was continued to be stirred at 1000 r / min at 50 °C until the solution was evaporated to dryness. The obtained white paste was dried at 60 °C for 24 h to obtain a precursor; wherein the molar ratio of the metal salt to L-cysteine ​​was 0.5:1;

[0052] (2) The precursor prepared in step (1) was heated and carbonized at 350°C in a carbon dioxide activation gas atmosphere for 5 hours at a heating rate of 4°C / min, and then pickled with a 0.8 mol / L nitric acid solution, washed with water, and dried at 70°C to obtain a metal / sulfur-doped porous carbon catalyst.

[0053] Example 3:

[0054] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0055] (1) 15 g of starch was dissolved in 110 mL of deionized water at 80°C, 12 g of metal salt ferric chloride and 1 g of calcium chloride were added, and the mixture was stirred at 2000 r / min for 1.2 h. L-cysteine ​​was then added, and the mixture was continued to be stirred at 80°C at 2000 r / min until the solution was evaporated to dryness. The resulting white paste was dried at 120°C for 6 h to obtain a precursor; wherein the molar ratio of the metal salt to L-cysteine ​​was 3:1;

[0056] (2) The precursor prepared in step (1) was heated and carbonized at 850°C for 2 h in a carbon dioxide activation gas atmosphere at a heating rate of 8°C / min, and then pickled with a 1.2 mol / L nitric acid solution, washed with water, and dried at 100°C to obtain a metal / sulfur-doped porous carbon catalyst.

[0057] Example 4-8:

[0058] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0059] In step (1), the metal salts are ferric nitrate, cobalt chloride, cobalt nitrate, nickel chloride, and nickel nitrate, respectively. The rest is the same as in Example 1.

[0060] Examples 9-12:

[0061] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0062] In step (1), the weight of starch is 5g, 8g, 10g and 15g respectively. The rest is the same as in Example 1.

[0063] Examples 13-14:

[0064] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0065] In step (1), the reducing sulfur-containing amino acids are homocysteine ​​and methionine.

[0066] Examples 15-18:

[0067] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0068] In step (1), the molar ratios of the metal salt to L-cysteine ​​are 0.5:1, 1.5:1, 2:1, and 3:1, respectively. The rest are the same as in Example 1.

[0069] Examples 19-21:

[0070] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0071] In step (1), the chloride salt pore-forming agents are potassium chloride, calcium chloride, and barium chloride, respectively, and the rest are the same as in Example 1.

[0072] Examples 22-23:

[0073] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0074] In step (2), carbonization is carried out at 550° C., and the calcination atmospheres are nitrogen and high-purity helium respectively. The rest are the same as in Example 1.

[0075] Examples 24-27:

[0076] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0077] In step (2), heating and carbonization are performed at 350, 450, 650, and 850° C. The rest is the same as in Example 1.

[0078] Comparative Example 1-2:

[0079] A metal / sulfur-doped porous carbon catalyst, the preparation method of which comprises the following steps:

[0080] In step (1), the molar ratios of the metal salt and L-cysteine ​​are 0:1 and 1:0, respectively. The rest are the same as in Example 1.

[0081] Test example

[0082] 1. Catalytic performance

[0083] The catalytic performance testing method of the metal / sulfur-doped porous carbon catalyst is as follows: under the process conditions of 50°C, a catalyst dosage of 0.25wt%, and a hydrogen peroxide dosage of 1vt%, the metal / sulfur-doped porous carbon catalyst is used to catalyze the hydrogen peroxide oxidation degradation of dye pollutant wastewater, and the removal rate curve is recorded.

[0084] 1. The catalytic performance of the metal / sulfur-doped porous carbon catalysts prepared in Examples 1 and 4-8 (named FeCl3-S / AC, Fe(NO3)3-S / AC, CoCl3-S / AC, Co(NO3)3-S / AC, NiCl2-S / AC, and Ni(NO3)2-S / AC, respectively) was tested. The results are shown in Table 1. Figure 1 . ( Figure 1In the figure, at the horizontal axis of 30, from top to bottom are Co(NO3)3-S / AC, Ni(NO3)2-S / AC, Fe(NO3)3-S / AC, CoCl3-S / AC, NiCl2-S / AC, FeCl3-S / AC)

[0085] Depend on Figure 1 The FeCl3-S / AC catalyst achieved a 94.8% removal rate for the degradation of dye-polluted wastewater by hydrogen peroxide oxidation. The activity of the porous carbon catalyst co-doped with metallic iron and sulfur was superior to that of the other two metals. This is because the easy conversion of metallic iron between various valence states facilitates the Fenton reaction in catalyzing the decomposition of hydrogen peroxide. The activity of the porous carbon co-doped with ferric chloride and sulfur was superior to that of ferric nitrate (44.4%). This may be due to the oxidizing nature of nitrate ions, which consume some L-cysteine, thereby reducing the sulfur loading and leading to decreased activity. These results indicate that sulfur doping in metal / porous carbon can significantly enhance catalytic activity.

[0086] 2. The catalytic performance of the metal / sulfur-doped porous carbon catalysts (named Fe-S / 9AC, Fe-S / 5AC, Fe-S / 8AC, Fe-S / 10AC, and Fe-S / 15AC, respectively) prepared in Examples 1 and 9-12 was tested. The results are shown in Table 2. Figure 2 . ( Figure 2 In the figure, at the horizontal axis of 40, from top to bottom are Fe-S / 5AC, Fe-S / 15AC, Fe-S / 8AC, Fe-S / 10AC, and Fe-S / 9AC)

[0087] Depend on Figure 2 The results show that when the starch dosage was 9g, the dye removal rate was 65.2%. When the starch dosage was too low, the porous carbon produced had a smaller specific surface area, insufficient fluffiness, and fewer exposed active components. However, when the starch dosage was too high, the porous carbon could become compacted and the pore structure clogged. Furthermore, the increased starch content reduced the proportion of active components. Therefore, the catalytic performance was optimal when the starch dosage was 9g.

[0088] 3. The metal / sulfur doped porous carbon catalysts prepared in Examples 1 and 13-14 were tested for performance. The results are shown in Figure 3 .

[0089] Depend on Figure 3 It can be seen that the relationship between the removal rate of dye pollutants is: sulfur source is L-cysteine ​​(C3H7NO2S) > homocysteine ​​(C4H9NO2S) > methionine (C5H 11NO2S), which may be related to the structure of the sulfur source. The side chain of methionine is -CH3, which is less reducible than -SH, resulting in the lowest catalyst activity. Homocysteine ​​has a longer main chain than L-cysteine, resulting in -SH properties closer to -OH. However, -OH has weaker reducing properties than -SH. Therefore, the longer main chain leads to a decrease in reducibility and thus lower catalyst activity.

[0090] 4. The catalysts prepared in Examples 1, 15-18 and Comparative Examples 1-2 (named 1.8Fe-S / AC, 0.5Fe-S / AC, 1.5Fe-S / AC, 2Fe-S / AC, 3Fe-S / AC, S / AC, Fe / AC, respectively) were tested for performance. The results are shown in Table 4. Figure 4 . ( Figure 4 In the figure, at the horizontal axis of 40, from top to bottom are 0.5Fe-S / AC, 3Fe-S / AC, Fe / AC, S / AC, 1.5Fe-S / AC, 2Fe-S / AC, and 1.8Fe-S / AC)

[0091] Depend on Figure 4 It can be seen that the removal rate of dye pollutants is the highest (94.8%) when n(Fe):n(S)=1.8:1. The small amount of iron salt added leads to a decrease in the subsequent iron loading and the loading of active components, thereby affecting the catalytic activity. The excessive amount of iron salt added leads to the inability of L-cysteine ​​to completely reduce Fe 3+ , and Fe 3+ Compared with Fe 2+ The Fe / AC and S / AC samples with only iron and sulfur added, respectively, showed only 9% and 7% removal rates for dye contaminants, respectively. This result indicates that Fe-S co-doping can enhance the catalytic activity of porous carbon.

[0092] 5. The metal / sulfur doped porous carbon catalysts prepared in Examples 1 and 19-21 were tested for performance. The results are shown in Figure 5 . ( Figure 5 In the figure, at 60 on the horizontal axis, from top to bottom are calcium chloride, barium chloride, sodium chloride, and potassium chloride.

[0093] Depend on Figure 5 It can be seen that the effects of sodium chloride and potassium chloride pore-forming agents are better than the other two, and potassium chloride is slightly better than sodium chloride. However, potassium chloride corrodes the equipment more seriously during the pore-forming process, and sodium chloride is naturally abundant, cheap and easy to obtain. Therefore, sodium chloride is used as a pore-forming agent in subsequent processes.

[0094] 6. The metal / sulfur doped porous carbon catalysts prepared in Examples 1 and 22-23 were tested for performance. The results are shown in Figure 6 .

[0095] Depend on Figure 6 It can be seen that the activation effects of high-purity helium and carbon dioxide are better than those of nitrogen. Although high-purity helium is slightly better than carbon dioxide in activation, carbon dioxide is subsequently used as the calcination atmosphere due to price issues.

[0096] 7. The metal / sulfur-doped porous carbon catalysts prepared in Examples 1 and 24-27 (named Fe-S / AC550, Fe-S / AC350, Fe-S / AC450, Fe-S / AC650, and Fe-S / AC850, respectively) were subjected to performance testing. The results are shown in Table 1. Figure 7 . ( Figure 7 In the figure, at the horizontal axis of 60, from top to bottom are Fe-S / AC350, Fe-S / AC450, Fe-S / AC850, Fe-S / AC650, Fe-S / AC550)

[0097] Depend on Figure 7 It can be seen that the calcination temperature has the following effects on carbon materials: calcination temperature that is too low (350°C) will lead to an incomplete carbonization process, resulting in a porous carbon material with a small specific surface area, an incomplete pore structure, and little exposure to active components. Therefore, the removal rate of dye pollutants is only 42.7%. Calcination temperature that is too high (850°C, 73.3%) may destroy the pore structure of the porous carbon material. At high temperatures, the crystal form of iron will also change, forming a crystal form with better stability but lower activity. In addition, high-temperature calcination will also lead to a decrease in catalyst yield, which is not conducive to industrial application. The porous carbon catalyst is best calcined at 550°C.

[0098] 2. Stability

[0099] The metal / sulfur doped porous carbon catalyst prepared in Example 1 was subjected to a cyclic stability test, and the results are shown in FIG. Figure 8 .

[0100] Depend on Figure 8 It can be seen that the iron-sulfur co-doped porous carbon catalyst with FeCl3 as the iron source and L-cysteine ​​as the sulfur source showed good stability in the experimental process of catalyzing the oxidation and degradation of dye pollutants with hydrogen peroxide. The removal rate dropped from 95% to 90% after three cycles, and the catalyst removal rate increased by 3% after high-temperature regeneration.

[0101] 3. Structural Characterization

[0102] 1. The catalysts prepared in Examples 1, 16-17 and Comparative Examples 1-2 were tested for their reduction performance using programmed temperature reduction. The results are shown in Table 1. Figure 9 .

[0103] Depend on Figure 9The temperature-programmed reduction spectrum shows that the reducibility of the catalyst S / AC doped with sulfur alone is weak, and the Fe loading enhances the reducibility of the catalyst. The stronger the reducibility, the stronger the catalytic activity in the Fenton reaction system. The catalyst co-doped with Fe and S shows continuous peaks, which may be due to the presence of Fe. 3+ →Fe 2+ , Fe 2+ →Fe 0 The conversion process shows that the catalyst has stronger reducing ability.

[0104] 2. The surface functional group information of the catalysts prepared in Examples 1, 16-17 and Comparative Examples 1-2 was analyzed by FTIR. The results are shown in Figure 10 .

[0105] Depend on Figure 10 It can be seen that 3475cm -1 The broad absorption peak at 1123 cm is the characteristic peak of -OH functional group. -1 The absorption peak at 1625 cm is caused by the stretching vibration of CC. -1 The absorption peak at is the characteristic peak of CO. No obvious characteristic peak of CS functional group is observed in the spectrum. This may be due to the low content of S element, uniform distribution, and small particle size, indicating that S doping has efficient catalytic activity.

[0106] 3. The element content of the catalyst prepared in Example 1 was further analyzed by X-ray photoelectron spectroscopy. Figure 11 .

[0107] Depend on Figure 11 As can be seen, both Fe and S peaks are detected, indicating successful doping of Fe and S, which successfully verifies the FTIR results. The Fe and S peak areas are small, indicating low content, but they exhibit strong catalytic activity, demonstrating that the Fe-S co-doped catalyst Fe-S / AC has trace and efficient catalytic performance.

[0108] 4. The specific surface areas of the catalysts prepared in Examples 1, 16-17 and Comparative Examples 1-2 were tested. The results are shown in Table 1.

[0109] Table 1 shows the specific surface area and pore size of the catalyst

[0110]

[0111]

[0112] As shown in Table 1, compared with S / AC doped with S alone, the Fe-S co-doped catalyst has a larger specific surface area, which can expose more active components and increase the contact area, thereby improving the catalytic efficiency. However, the specific surface area is not the main factor affecting the catalytic ability. The specific surface area of ​​1.8Fe-S / AC is smaller than that of 2.0Fe-S / AC and Fe / AC, but its catalytic ability is the strongest. This may be because this ratio can generate more Fe-S structures, which may be the main active components of the catalytic reaction.

[0113] 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 metal / sulfur-doped porous carbon catalyst, characterized in that: The following steps are involved: (1) Dissolve starch in deionized water, add metal salt and chloride pore-forming agent, stir for 0.8-1.2 hours, then add reducing sulfur-containing amino acid substance, continue stirring until the solution is evaporated to dryness, and dry the obtained colloid to obtain the precursor; (2) heating and carbonizing the precursor prepared in step (1) in a calcining atmosphere for 2-5 hours, and then acid-washing, water-washing and drying to obtain a metal / sulfur-doped porous carbon catalyst; In step (1), the metal salt is cobalt nitrate, cobalt chloride, nickel nitrate or nickel chloride; In step (1), the reducing sulfur-containing amino acid substance is homocysteine ​​or methionine; In step (1), the chloride salt pore-forming agent is sodium chloride, potassium chloride, calcium chloride or barium chloride.

2. The method for preparing the metal / sulfur-doped porous carbon catalyst according to claim 1, characterized in that: In step (1), the mass volume ratio of starch, metal salt, chloride pore-forming agent and deionized water is 5-15 g:8-12 g:1 g:90-110 mL, and the molar ratio of metal salt to reducing sulfur-containing amino acid substance is 0.5-3:

1.

3. The method for preparing the metal / sulfur-doped porous carbon catalyst according to claim 1, characterized in that: In step (1), drying is performed at 60-120°C for 6-24 hours.

4. The method for preparing the metal / sulfur-doped porous carbon catalyst according to claim 1, characterized in that: In step (2), the calcination atmosphere is carbon dioxide, nitrogen or high-purity helium.

5. The method for preparing the metal / sulfur-doped porous carbon catalyst according to claim 1, characterized in that: In step (2), 0.8-1.2 mol / L nitric acid solution is used for pickling.

6. The metal / sulfur-doped porous carbon catalyst prepared by the method for preparing the metal / sulfur-doped porous carbon catalyst according to any one of claims 1 to 5.

7. Use of the metal / sulfur-doped porous carbon catalyst according to claim 6 in a Fenton-like catalytic oxidation system.

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