Multi-active-site porphyrin copper atomic layer PML-Cu / Bi 12 O 17 Preparation method of Br2 catalyst and its application in photocatalytic CO2 reduction

Abstract

The present invention belongs to the field of catalytic material preparation and photocatalytic application, and discloses a multi-active site porphyrin copper atomic layer PML-Cu / Bi 12 O 17 Preparation method of Br2 catalyst and its application in photocatalytic CO2 reduction. 12 O 17 The Br2 surface is coated with a metal porphyrin atomic layer PML-Cu to achieve the construction of high-density active sites on its surface, thereby significantly improving the photocatalytic CO2 reduction performance of the material. The active site construction method used in the present invention is simple and efficient, and the prepared PML-Cu / Bi 12 O 17 The Br2 material has an enhanced ability to photocatalyze CO2 to generate CO, with a product selectivity of 100%. The invention broadens the preparation method of the novel functionalized photocatalyst and its application in the field of CO2 resource utilization, and has excellent prospects.

Description

Technical Field

[0001] The present invention belongs to the field of catalytic material preparation and photocatalytic application, and relates to a multi-active site porphyrin copper atomic layer PML-Cu / Bi 12 O 17 A method for preparing a Br2 catalyst and applying it to photocatalytic CO2 reduction. Background Art

[0002] Inspired by plant photosynthesis, photocatalytic CO2 reduction utilizes clean solar energy to achieve green CO2 conversion and utilization, helping to mitigate the greenhouse effect and address fossil energy issues. It is considered an effective strategy for green CO2 utilization. The realization of this technological pathway is expected to provide a non-fossil energy pathway for the synthesis of carbon-based chemicals.

[0003] Bi 12 O 17 Br2 is an emerging semiconductor material that has been used in photocatalytic CO2 reduction research due to its unique layered structure, diverse atomic coordination forms and easily modulated energy band characteristics. However, due to the lack of surface active sites, Bi 12 O 17 The photocatalytic CO2 reduction efficiency of Br2 monomer catalysts is low, making them difficult to meet practical application requirements. By introducing a metalloporphyrin atomic layer onto the surface of a bismuth oxyhalide catalyst, a high density of metal catalytic sites can be endowed on the surface, significantly improving the catalyst's ability to adsorb and activate CO2. Ultimately, this allows for high conversion and highly selective photocatalytic reduction of CO2 to CO. Currently, no related research has been reported, either domestically or internationally. Summary of the Invention

[0004] In order to solve the problem of insufficient active sites on the surface of existing bismuth halide photocatalysts, the present invention provides a multi-active site porphyrin copper atomic layer PML-Cu / Bi 12 O 17 Preparation method of Br2 catalyst and its application in photocatalytic CO2 reduction. The purpose of this invention is to significantly improve the efficiency of photocatalytic CO2 reduction by constructing high-density active sites on the surface, thereby promoting the resource utilization of CO2.

[0005] The technical solutions of the present invention are as follows:

[0006] Multi-active-site porphyrin copper atomic layer PML-Cu / Bi 12 O 17 The preparation method of Br2 catalyst is as follows:

[0007] Step (1)Bi 12 O 17 Preparation of Br2 material:

[0008] Bi(NO3)3·5H2O and polyvinylpyrrolidone were dissolved in mannitol solution, Br source solution was added and the pH of the reaction solution was adjusted. The reaction solution was transferred to a polytetrafluoroethylene-lined autoclave and heated at a constant temperature. The solution was collected by centrifugation, washed with water and anhydrous ethanol to remove impurities, and dried in vacuo to obtain Bi 12 O 17 Br2 material.

[0009] Step (2) Preparation of tetracarboxyphenylporphyrin copper Cu-TCPP based monoatomic layer material PML-Cu:

[0010] Prepare a dispersion by mixing N,N-dimethylformamide (DMF) and anhydrous ethanol (ETOH);

[0011] Cu(NO3)3·3H2O, formic acid and polyvinylpyrrolidone were added to the dispersion and mixed to form solution A;

[0012] Add Cu-TCPP to the dispersion and mix thoroughly to form solution B.

[0013] Solution B was added to solution A and stirred continuously. After being fully mixed, the volume was fixed and the mixture was transferred to a reactor for heating and reaction. After the reaction, the precipitate was washed several times until a transparent supernatant was formed after centrifugation. The precipitate was dispersed again and dried on a rotary evaporator to collect the product PML-Cu.

[0014] Step (3) PML-Cu / Bi 12 O 17 Preparation of Br2 catalyst:

[0015] Bi 12 O 17 Br2 was dispersed in ethanol, and PML-Cu was added. The oil bath was continuously refluxed and stirred vigorously. The product was centrifuged and washed with deionized water and anhydrous ethanol several times. The precipitate was collected by centrifugation and vacuum dried to obtain the product PML-Cu / Bi. 12 O 17 Br2 catalyst.

[0016] In step (1), the content of Bi in the mannitol solution is 0.01-0.1 mol / L, the content of polyvinyl pyrrolidone in the mannitol solution is 1-20 g / L, the Br concentration in the Br source solution is 0.1-0.2 M; and the volume ratio of the mannitol solution to the Br source solution is 20:1-2:1;

[0017] The pH adjustment range is 10-13.5; the heating temperature is 90-180°C, and the time is 5-24 hours.

[0018] In step (2), the volume ratio of DMF to ETOH in the dispersion is 1:1-5:1;

[0019] In the fixed volume solution, the content of Cu(NO3)3·3H2O is 0.1-0.5 g / L, the content of formic acid is 0.1-0.5 v%, the content of polyvinylpyrrolidone is 0.5-2 g / L; and the content of Cu-TCPP is 0.1-0.5 g / L.

[0020] The reaction temperature is 60-120°C, and the reaction time is 1-6h.

[0021] In step (3), the amount of PML-Cu added is Bi 12 O 17 0.1-2% of Br2 mass;

[0022] The reflux reaction temperature is 50-150°C, and the reaction time is 5-24h.

[0023] The multi-active site porphyrin copper atomic layer PML-Cu / Bi obtained by the present invention 12 O 17 Br2 catalyst, the main structure is Bi 12 O 17 Br2 nanotube material, the surface of which is coated with PML-Cu with high-density dispersed Cu atoms.

[0024] PML-Cu / Bi prepared by the present invention 12 O 17 Br2 material is used for photocatalytic reduction of CO2 to produce CO.

[0025] The beneficial effects of the present invention are:

[0026] Compared with the existing technology, PML-Cu / Bi 12 O 17 The preparation of Br2 can realize the construction of high-density active sites on the surface of the photocatalyst, thereby significantly improving the photocatalytic CO2 reduction to CO performance of the material, with a selectivity of up to 100%, providing a new route for the preparation of carbon-based chemicals. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 PML-Cu / Bi in Example 1 12 O 17 X-ray diffraction (XRD) pattern of Br2 catalyst.

[0028] Figure 2 PML-Cu / Bi in Example 1 12 O 17 High-magnification transmission electron microscopy (HRTEM) image of Br2 catalyst.

[0029] Figure 3 PML-Cu / Bi in Example 1 12 O17 Generation rate diagram of CO produced by photocatalytic reduction of CO2 over Br2 catalyst.

[0030] Figure 4 PML-Cu / Bi in Example 1 12 O 17 Cyclic activity diagram of photocatalytic reduction of CO2 to CO production over Br2 catalyst. DETAILED DESCRIPTION

[0031] The present invention provides a multi-active site photocatalytic CO2 reduction porphyrin copper atomic layer PML-Cu / Bi 12 O 17 Br2 catalyst and preparation method thereof. The present invention is further described below in conjunction with the accompanying drawings and specific embodiments to enable those skilled in the art to better understand the present invention, but the scope of protection of the present invention is not limited to the following implementation contents.

[0032] Example 1:

[0033] Step (1)Bi 12 O 17 Preparation of Br2 material:

[0034] 0.243 g Bi(NO3)3·5H2O and 0.27 g polyvinylpyrrolidone were dissolved in 15 mL mannitol solution, 3 mL KBr solution 0.17 M was added and the pH of the reaction solution was adjusted to 13.

[0035] The reactants were transferred to a polytetrafluoroethylene-lined autoclave and heated to 160°C for 24 h. The sample was collected by centrifugation and washed with water and ethanol to remove impurities, and then dried under vacuum to obtain Bi 12 O 17 Br2 material.

[0036] Step (2) Preparation of Metalloporphyrin-Based Monoatomic Layer PML-Cu:

[0037] DMF and ETOH were prepared into a dispersion with a volume ratio of 3:1.

[0038] Add 2 mg of Cu(NO3)3·3H2O, 40 uL of formic acid and 10 mg of polyvinyl pyrrolidone to the dispersion, mix well and record it as solution A.

[0039] 5 mg of Cu-TCPP was added to the dispersion and mixed thoroughly, which was recorded as solution B.

[0040] Solution B was added to Solution A with continuous stirring. After thorough mixing, the volume was adjusted to 20 mL. The solution was then transferred to a reactor, heated to 80°C, and reacted for 2 hours. After the reaction, the precipitate was washed several times until a clear supernatant formed after centrifugation. The precipitate was redispersed and transferred to a round-bottom flask. The product, PML-Cu, was dried on a rotary evaporator and collected.

[0041] Step (3) PML-Cu / Bi 12 O 17 Preparation of Br2:

[0042] 60mg Bi 12 O 17 Br2 was dispersed in ethanol, and 0.3 mg of PML-Cu was added to form a mixture. The mixture was refluxed in an oil bath at 85°C and stirred vigorously for 12 hours. The product was washed with deionized water and anhydrous ethanol several times, and the precipitate was collected by centrifugation and dried in a vacuum drying oven. The resulting product was recorded as PML-Cu / Bi. 12 O 17 Br2 catalyst.

[0043] Figure 1 PML-Cu / Bi 12 O 17 XRD patterns of Br2 catalyst, PML-Cu / Bi 12 O 17 Br2 material has the same 12 O 17 Similar characteristic diffraction peaks to Br2 materials, Figure 1 The spectrum corresponds to Bi 12 O 17 Br2 crystal JCPDS#37-0701.

[0044] Figure 2 PML-Cu / Bi 12 O 17 HRTEM image of Br2 catalyst, Figure 2 The material in a is an ultra-thin nanotube structure. Figure 2 Middle b shows that the surface of the material has high-density dispersed Cu atoms.

[0045] Figure 3 PML-Cu / Bi 12 O 17 The generation rate diagram of CO produced by photocatalytic reduction of CO2 by Br2 catalyst, compared with PML-Cu and Bi 12 O 17 Br2, PML-Cu / Bi 12 O 17Br2 showed significantly improved photocatalytic CO2 reduction ability, with a CO production of 584.3 μmol g after 5 h of illumination. -1 .

[0046] Figure 4 PML-Cu / Bi 12 O 17 The cyclic activity diagram of the photocatalytic reduction of CO2 to CO by Br2 catalyst. After multiple cycles, the material can still maintain a good photocatalytic CO2 to CO generation ability.

[0047] Example 2:

[0048] Step (1)Bi 12 O 17 Preparation of Br2 material:

[0049] 0.485 g Bi(NO3)3·5H2O and 0.24 g polyvinylpyrrolidone were dissolved in 15 mL mannitol solution, 6 mL KBr solution 0.2 M was added and the pH of the reaction solution was adjusted to 13.5.

[0050] The reactants were transferred to a polytetrafluoroethylene-lined autoclave and heated to 120°C for 12 h. The sample was collected by centrifugation and washed with water and ethanol to remove impurities, and then dried under vacuum to obtain Bi 12 O 17 Br2 material.

[0051] Step (2) Preparation of Metalloporphyrin-Based Monoatomic Layer PML-Cu:

[0052] DMF and ETOH were prepared into a dispersion with a ratio of 5:1.

[0053] Add 4 mg of Cu(NO3)3·3H2O, 80 uL of formic acid and 20 mg of polyvinyl pyrrolidone to the dispersion, mix well and record it as solution A.

[0054] 10 mg of Cu-TCPP was added to the dispersion and mixed thoroughly, which was recorded as solution B.

[0055] Solution B was added to Solution A with continuous stirring. After thorough mixing, the volume was adjusted to 20 mL. The solution was then transferred to a reactor, heated to 90°C, and reacted for 4 hours. After the reaction, the precipitate was washed several times until a clear supernatant formed after centrifugation. The precipitate was redispersed and transferred to a round-bottom flask. The product, PML-Cu, was dried on a rotary evaporator and collected.

[0056] Step (3) PML-Cu / Bi 12 O 17 Preparation of Br2:

[0057] 100mg Bi12 O 17 Br2 was dispersed in ethanol, and 2 mg of PML-Cu was added to form a mixture. The mixture was refluxed in an oil bath at 80°C and stirred vigorously for 6 h. The product was washed with deionized water and anhydrous ethanol several times, and the precipitate was collected by centrifugation and dried in a vacuum drying oven. The resulting product was recorded as PML-Cu / Bi. 12 O 17 Br2 catalyst.

[0058] Example 3:

[0059] Step (1)Bi 12 O 17 Preparation of Br2 material:

[0060] 0.2 g Bi(NO3)3·5H2O and 0.2 g polyvinylpyrrolidone were dissolved in 15 mL mannitol solution, 6 mL KBr solution 0.1 M was added and the pH of the reaction solution was adjusted to 12.

[0061] The reactants were transferred to a polytetrafluoroethylene-lined autoclave and heated to 140°C for 16 h. The sample was collected by centrifugation and washed with water and ethanol to remove impurities, and then dried under vacuum to obtain Bi 12 O 17 Br2 material.

[0062] Step (2) Preparation of Metalloporphyrin-Based Monoatomic Layer PML-Cu:

[0063] Prepare a dispersion of DMF and ETOH in a ratio of 2:1. Add 2 mg of Cu(NO₃)₃·3H₂O, 40 μL of formic acid, and 30 mg of polyvinylpyrrolidone to the dispersion, mix well, and record it as solution A.

[0064] 8 mg of Cu-TCPP was added to the dispersion and mixed thoroughly, which was recorded as solution B.

[0065] Solution B was added to Solution A with continuous stirring. After thorough mixing, the volume was adjusted to 20 mL. The solution was then transferred to a reactor, heated to 120°C, and reacted for 1 hour. After the reaction, the precipitate was washed several times until a clear supernatant formed after centrifugation. The precipitate was redispersed and transferred to a round-bottom flask. The product, PML-Cu, was dried on a rotary evaporator and collected.

[0066] Step (3) PML-Cu / Bi 12 O 17 Preparation of Br2:

[0067] 20mg Bi 12 O 17Br2 was dispersed in ethanol, and 0.02 mg of PML-Cu was added to form a mixture. The mixture was refluxed in an oil bath at 90°C and stirred vigorously for 5 h. The product was washed with deionized water and anhydrous ethanol several times, and the precipitate was collected by centrifugation and dried in a vacuum drying oven. The resulting product was recorded as PML-Cu / Bi. 12 O 17 Br2 catalyst.

[0068] Example 4:

[0069] Step (1)Bi 12 O 17 Preparation of Br2 material:

[0070] 0.1 g Bi(NO3)3·5H2O and 0.1 g polyvinylpyrrolidone were dissolved in 15 mL mannitol solution, 1 mL KBr solution 0.2 M was added and the pH of the reaction solution was adjusted to 13.

[0071] The reactants were transferred to a polytetrafluoroethylene-lined autoclave and heated to 120°C for 10 h. The sample was collected by centrifugation and washed with water and ethanol to remove impurities, and then dried under vacuum to obtain Bi 12 O 17 Br2 material.

[0072] Step (2) Preparation of Metalloporphyrin-Based Monoatomic Layer PML-Cu:

[0073] Prepare a dispersion of DMF and ETOH in a ratio of 5:1. Add 2 mg of Cu(NO₃)₃·3H₂O, 60 μL of formic acid, and 10 mg of polyvinylpyrrolidone to the dispersion, mix well, and record it as solution A.

[0074] 7 mg of Cu-TCPP was added to the dispersion and mixed thoroughly, which was recorded as solution B.

[0075] Solution B was added to Solution A with continuous stirring. After thorough mixing, the volume was adjusted to 20 mL. The solution was then transferred to a reactor, heated to 60°C, and reacted for 5 hours. After the reaction, the precipitate was washed several times until a clear supernatant formed after centrifugation. The precipitate was redispersed and transferred to a round-bottom flask. The product, PML-Cu, was dried on a rotary evaporator and collected.

[0076] Step (3) PML-Cu / Bi 12 O 17 Preparation of Br2:

[0077] 120mg Bi 12 O 17Br2 was dispersed in ethanol, and 1.2 mg of PML-Cu was added to form a mixture. The mixture was refluxed in an oil bath at 100°C and stirred vigorously for 5 h. The product was washed with deionized water and anhydrous ethanol several times, and the precipitate was collected by centrifugation and dried in a vacuum oven. The obtained product was recorded as PML-Cu / Bi. 12 O 17 Br2 catalyst.

Claims

1. Multi-active site porphyrin copper atomic layer PML-Cu / Bi 12 O 17 The preparation method of Br2 catalyst is characterized in that: The following steps are involved: (1)Bi 12 O 17 Preparation of Br2 material: Bi(NO3)3·5H2O and polyvinylpyrrolidone were dissolved in mannitol solution, Br source solution was added and the pH of the reaction solution was adjusted. The reaction solution was transferred to a polytetrafluoroethylene-lined autoclave and heated at a constant temperature. The solution was collected by centrifugation, washed with water and anhydrous ethanol to remove impurities, and dried in vacuum to obtain Bi 12 O 17 Br2 materials; (2) Preparation of tetracarboxyphenylporphyrin copper Cu-TCPP based single atomic layer material PML-Cu: N,N-dimethylformamide DMF and anhydrous ethanol ETOH are prepared into a dispersion; Cu(NO3)3·3H2O, formic acid and polyvinylpyrrolidone were added to the dispersion and mixed to form solution A; Add Cu-TCPP to the dispersion and mix thoroughly to form solution B; Solution B was added to solution A and stirred continuously. After thorough mixing, the volume was fixed and the mixture was transferred to a reactor for heating and reaction. After the reaction, the precipitate was washed several times until a transparent supernatant was formed after centrifugation. The precipitate was redispersed and dried on a rotary evaporator to collect the product PML-Cu. (3)PML-Cu / Bi 12 O 17 Preparation of Br2 catalyst: Bi 12 O 17 Br2 was dispersed in ethanol, and PML-Cu was added. The mixture was continuously refluxed in an oil bath and stirred vigorously. The mixture was centrifuged, washed, and the precipitate was collected and dried under vacuum to obtain the product PML-Cu / Bi. 12 O 17 Br2 catalyst.

2. The preparation method according to claim 1, wherein In step (1), the content of Bi in the mannitol solution is 0.01-0.1 mol / L, the content of polyvinyl pyrrolidone in the mannitol solution is 1-20 g / L, the Br concentration in the Br source solution is 0.1-0.2 M; and the volume ratio of the mannitol solution to the Br source solution is 20:1-2:

1.

3. The preparation method according to claim 1, wherein In step (1), the pH of the reaction solution is adjusted in the range of 10-13.

5.

4. The preparation method according to claim 1, wherein In step (1), the heating temperature is 90-180° C., and the heating time is 5-24 h.

5. The preparation method according to claim 1, wherein In step (2), the volume ratio of DMF to ETOH in the dispersion is 1:1-5:

1.

6. The preparation method according to claim 1, wherein In step (2), in the solution after volume adjustment, the content of Cu(NO3)3·3H2O is 0.1-0.5g / L, the content of formic acid is 0.1-0.5v%, the content of polyvinylpyrrolidone is 0.5-2g / L; and the content of Cu-TCPP is 0.1-0.5g / L.

7. The preparation method according to claim 1, wherein In step (2), the reaction temperature is 60-120° C., and the reaction time is 1-6 h.

8. The preparation method according to claim 1, wherein In step (3), the amount of PML-Cu added is Bi 12 O 17 0.1-2% of the mass of Br2; the reflux temperature is 50-150°C, and the reflux time is 5-24h.

9. Multi-active site porphyrin copper atomic layer PML-Cu / Bi 12 O 17 Br2 catalyst, characterized in that Prepared by the method according to any one of claims 1 to 8, the main structure is Bi 12 O 17 Br2 nanotube material, the surface of which is coated with PML-Cu with high-density dispersed Cu atoms.

10. The multi-active site porphyrin copper atomic layer PML-Cu / Bi according to claim 9 12 O 17 Br2 catalyst is used for photocatalytic reduction of CO2 to produce CO.

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