Co-C catalytic material and preparation method and application thereof
By using photothermal synergistic catalysis with Co-C catalytic materials, the problems of high energy consumption and byproduct formation in the selective oxidation of cyclohexane were solved, achieving a low-energy-consumption, high-selectivity, and high-conversion cyclohexane oxidation reaction.
Patent Information
- Application Number
- CN202511180427.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-22
- Publication Date
- 2026-01-13
AI Technical Summary
Existing technologies for the selective oxidation of cyclohexane to cyclohexanone and cyclohexanol suffer from high energy consumption and byproduct formation, making it difficult to reduce energy consumption while maintaining high selectivity and conversion rate.
Using Co-C catalytic materials, photothermal synergistic catalysis is achieved through Co-C materials with strong light absorption capacity. Cyclohexane oxidation is carried out at room temperature by utilizing the photothermal effect. Furthermore, the microreactor system is enhanced by continuous flow photothermal strengthening to improve mass and heat transfer, thereby achieving high selectivity and conversion rate.
It achieves efficient oxidation of cyclohexane under low energy consumption conditions, resulting in high KA oil selectivity and conversion rate, and reducing operating costs.
Smart Images
Figure CN121314637A_ABST
Abstract
Description
Technical Field
[0001] This invention discloses a composite catalytic material; specifically, a Co-C catalytic material. This invention also discloses the preparation method and application of the catalyst, belonging to the field of catalyst technology. Background Technology
[0002] The selective oxidation of cyclohexane to cyclohexanone and cyclohexanol (KA oil) presents a significant challenge in catalytic engineering and modern chemical processes. The inherent chemical stability of the CH bond in cyclohexane requires harsh reaction conditions, typically involving temperatures of 150–170 °C and pressures of approximately 10–20 atmospheres in industrial settings. These conditions often lead to the formation of unwanted byproducts, reducing overall process selectivity and increasing operating costs. Therefore, achieving high selectivity while maintaining optimal conversion remains a primary goal in the research of cyclohexane catalytic oxidation.
[0003] Semiconductor catalysis technology can overcome the technical bottleneck of this reaction. Carbon materials have excellent visible light absorption capabilities, and Co-C doped with Co has excellent light absorption capabilities across the entire spectrum, enabling the reaction to proceed at room temperature and improving the selectivity of photothermal synergistic catalysis for cyclohexane oxidation. Summary of the Invention
[0004] The technical problem this invention aims to solve is to construct a catalyst with controllable absorption capacity for different wavelengths of light, covering the entire solar radiation band, by regulating the material structure; to construct a molecular-level precise heating system using photothermal relaxation; to delay the recombination of photogenerated electrons and holes using a built-in electric field; to achieve low-temperature and efficient air oxidation of cyclohexane under no external heating conditions; and to enhance mass and heat transfer through a continuous flow photothermal enhanced microreactor system, thereby achieving high cyclohexane conversion and high KA oil selectivity; and to develop a low-energy-consumption, environmentally friendly, and intrinsically safe catalytic process with high activity, controllable conversion.
[0005] The first objective of this invention is to provide a method for preparing Co-C catalytic materials.
[0006] The second objective of this invention is to provide a Co-C photothermal catalytic material prepared by the above-described preparation method.
[0007] A third objective of this invention is to provide a method for catalyzing the photocatalytic oxidation of cyclohexane using the Co-C catalytic material.
[0008] Therefore, the first technical solution provided by the present invention is as follows:
[0009] A method for preparing a Co-C catalytic material includes the following steps:
[0010] S1. Preparation of ZIF-67:
[0011] The cobalt source and ligand were added to the solvent and dispersed evenly. The mixture was then stirred for 8-12 hours. After stirring, the mixture was allowed to stand for 6-18 hours. The solution was then centrifuged, washed, and dried to obtain ZIF-67.
[0012] The molar ratio of the cobalt source and the ligand is 1:1.5-1:2;
[0013] S2. Preparation of Co-C
[0014] ZIF-67 was placed in a tube furnace and calcined at 800-900℃ for 4-6 hours under an argon atmosphere. The black product after calcination was Co-C.
[0015] Furthermore, in the above-mentioned method for preparing a Co-C catalytic material, the cobalt source in S1 is cobalt nitrate hexahydrate.
[0016] Furthermore, in the above-mentioned method for preparing a Co-C catalytic material, the ligand in S1 is 2-methylimidazole; and the solvent is methanol.
[0017] Furthermore, in the above-mentioned method for preparing a Co-C catalytic material, the stirring reaction time in S1 is 10 hours.
[0018] Furthermore, in the above-mentioned method for preparing a Co-C catalytic material, the static reaction time in S1 is 12 hours.
[0019] Furthermore, in the above-mentioned method for preparing a Co-C catalytic material, the calcination temperature in step S2 is 850℃.
[0020] Furthermore, in the above-mentioned method for preparing a Co-C catalytic material, the calcination time in S2 is 5 hours.
[0021] The second technical solution provided by this invention is a Co-C catalytic material prepared by the method provided in the first technical solution.
[0022] The final technical solution of the present invention is to provide the above-mentioned Co-C catalytic material for photothermal catalytic cyclohexane oxidation reaction.
[0023] The present invention provides a method for photothermal catalytic oxidation of cyclohexane, comprising the following steps in sequence:
[0024] 1) Weigh out the Co-C photothermal catalyst material and dissolve it in cyclohexane and acetone;
[0025] 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.0-2.0 MPa;
[0026] 3) React at 100-150℃ under xenon lamp irradiation for 6-10 hours;
[0027] 4) After the reaction is complete, wait for the reactor to cool to room temperature, then measure the conversion rate and selectivity;
[0028] The ratio of the Co-C photothermal catalytic material to cyclohexane is 30 mg: 15 mL.
[0029] The volume ratio of cyclohexane to acetonitrile is 2:1.
[0030] Compared with the prior art, the beneficial effects of the present invention are mainly reflected in:
[0031] 1. The technical solution provided by this invention, based on the excellent light absorption ability of carbon materials themselves, produces Co-C materials with the characteristics of full-spectrum absorption by doping with Co atoms, which have extremely high utilization rate of sunlight.
[0032] 2. The technical solution provided by this invention utilizes the principle of photothermal relaxation, in which Co-C material absorbs light energy and converts it into heat energy, reaching a maximum temperature of 230.5℃. This achieves photothermal synergistic catalysis of cyclohexane reaction at room temperature, opening up new avenues for future room temperature light-induced reactions. Attached Figure Description
[0033] Figure 1 TEM images of the Co-C-1, Co-C-2, Co-C-3, and Co-C-4 photothermal catalytic materials provided in Examples 1, 2, 3, and 4.
[0034] Figure 2 HRSEM images and mapping diagrams of the Co-C-3 photothermal catalytic material provided in Example 3;
[0035] Figure 3 XRD patterns of the Co-C-1, Co-C-2, Co-C-3, Co-C-4, and Co-C-5 photothermal catalytic materials provided in Examples 1, 2, 3, 4, and 5;
[0036] Figure 4 The UV-Vis spectrum of the Co-C-3 photothermal catalytic material provided in Example 3;
[0037] Figure 5 Infrared thermal imaging of the Co-C-3 photothermal catalytic material provided in Example 3 under xenon lamp illumination in the wavelength range of 350-800 nm;
[0038] Figure 6 Infrared thermal imaging of the Co-C-3 photothermal catalytic material provided in Example 3 under xenon lamp illumination in the wavelength range of 350-2500nm. Detailed Implementation
[0039] The claims of the present invention will be further described in detail below with reference to specific embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention.
[0040] Unless otherwise specified, the reagents, methods and equipment used in this invention are conventional reagents, methods and equipment in this technical field, and the temperatures not explicitly limited are all room temperature.
[0041] Example 1
[0042] This embodiment provides a method for preparing a Co-C-1 photothermal catalytic material, including the following steps:
[0043] 1) Synthesis of ZIF-67
[0044] 3 mmol of cobalt nitrate hexahydrate and 10 mmol of 2-methylimidazole were added to 10 mL of methanol, respectively, and the mixture was sonicated at 33 kHz for 3 min to disperse it into a clear solution. Then, the cobalt nitrate hexahydrate methanol solution was added dropwise to the 2-methylimidazole methanol solution (dropwise addition time 5 min), and the reaction was stirred for 10 h. After standing for 12 h, the mixture was washed three times with methanol and dried to obtain ZIF-67.
[0045] 2) Synthesis of Co-C-1
[0046] The ZIF-67 from step 1) was placed in a tube furnace and calcined at 850°C for 5 hours under an argon atmosphere. After calcination, it was cooled to room temperature to obtain the Co-C-1 photothermal catalytic material.
[0047] Example 2
[0048] This embodiment provides a method for preparing a Co-C-2 photothermal catalytic material, including the following steps:
[0049] 1) Synthesis of ZIF-67
[0050] 3 mmol of cobalt nitrate hexahydrate and 20 mmol of 2-methylimidazole were added to 10 mL of methanol, respectively, and the mixture was sonicated at 33 kHz for 3 min to disperse it into a clear solution. Then, the cobalt nitrate hexahydrate methanol solution was added dropwise to the 2-methylimidazole methanol solution (dropwise addition time 5 min), and the reaction was stirred for 10 h. After standing for 12 h, the mixture was washed three times with methanol and dried to obtain ZIF-67.
[0051] 2) Synthesis of Co-C-2
[0052] The ZIF-67 from step 1) was placed in a tube furnace and calcined at 850°C for 5 hours under an argon atmosphere. After calcination, it was cooled to room temperature to obtain the Co-C-2 photothermal catalytic material.
[0053] Example 3
[0054] This embodiment provides a method for preparing a Co-C-3 photothermal catalytic material, including the following steps:
[0055] 1) Synthesis of ZIF-67
[0056] 3 mmol of cobalt nitrate hexahydrate and 30 mmol of 2-methylimidazole were added to 10 mL of methanol, respectively, and the mixture was sonicated at 33 kHz for 3 min to disperse it into a clear solution. Then, the cobalt nitrate hexahydrate methanol solution was added dropwise to the 2-methylimidazole methanol solution (dropwise addition time 5 min), and the reaction was stirred for 10 h. After standing for 12 h, the mixture was washed three times with methanol and dried to obtain ZIF-67.
[0057] 2) Synthesis of Co-C-3
[0058] The ZIF-67 from step 1) was placed in a tube furnace and calcined at 850°C for 5 hours under an argon atmosphere. After calcination, it was cooled to room temperature to obtain the Co-C-3 photothermal catalytic material.
[0059] Example 4
[0060] This embodiment provides a method for preparing a Co-C-4 photothermal catalytic material, including the following steps:
[0061] 1) Synthesis of ZIF-67
[0062] 3 mmol of cobalt nitrate hexahydrate and 40 mmol of 2-methylimidazole were added to 10 mL of methanol, respectively, and the mixture was sonicated at 33 kHz for 3 min to disperse it into a clear solution. Then, the cobalt nitrate hexahydrate methanol solution was added dropwise to the 2-methylimidazole methanol solution (dropwise addition time 5 min), and the reaction was stirred for 10 h. After standing for 12 h, the mixture was washed three times with methanol and dried to obtain ZIF-67.
[0063] 2) Synthesis of Co-C-4
[0064] The ZIF-67 from step 1) was placed in a tube furnace and calcined at 850°C for 5 hours under an argon atmosphere. After calcination, it was cooled to room temperature to obtain the Co-C-4 photothermal catalytic material.
[0065] Example 5
[0066] This embodiment provides a method for preparing a Co-C-5 photothermal catalytic material, including the following steps:
[0067] 1) Synthesis of ZIF-67
[0068] 3 mmol of cobalt nitrate hexahydrate and 50 mmol of 2-methylimidazole were added to 10 mL of methanol, respectively, and the mixture was sonicated at 33 kHz for 3 min to disperse it into a clear solution. Then, the cobalt nitrate hexahydrate methanol solution was added dropwise to the 2-methylimidazole methanol solution (dropwise addition time 5 min), and the reaction was stirred for 10 h. After standing for 12 h, the mixture was washed three times with methanol and dried to obtain ZIF-67.
[0069] 2) Synthesis of Co-C-5
[0070] The ZIF-67 from step 1) was placed in a tube furnace and calcined at 850°C for 5 hours under an argon atmosphere. After calcination, it was cooled to room temperature to obtain the Co-C-5 photothermal catalytic material.
[0071] Comparative Example 1
[0072] This comparative example provides a method for preparing C catalytic materials, including the following steps:
[0073] 1) Synthesis of ZIF-8
[0074] 3 mmol of zinc nitrate hexahydrate and 50 mmol of 2-methylimidazole were added to 10 mL of methanol, respectively, and the mixture was sonicated at 33 kHz for 3 min to disperse it into a clear solution. Then, the cobalt nitrate hexahydrate methanol solution was added dropwise to the 2-methylimidazole methanol solution (dropwise addition time 5 min), and the reaction was stirred for 10 h. After standing for 12 h, the mixture was washed three times with methanol and dried to obtain ZIF-8.
[0075] 2) Synthesis of C
[0076] ZIF-8 from step 1) was placed in a tube furnace and calcined at 850°C for 5 hours under an argon atmosphere. After calcination, it was cooled to room temperature to obtain material C.
[0077] To better understand this application, the experimental results of the embodiments are further analyzed and explained below with reference to the accompanying drawings.
[0078] TEM images of the photothermal catalytic materials Co-C-1 (1a), Co-C-2 (1b), Co-C-3 (1c), and Co-C-4 (1d) provided in Examples 1, 2, 3, and 4 are available for reference. Figure 1 ;from Figure 1 It can be seen that different ratios of cobalt nitrate hexahydrate and 2-methylimidazole have a significant impact on the morphology of the material. Figure 1 Co in a) and 1b) shows stacking, while the morphology in 1d) is inconsistent. Figure 1 c) Co has the best distribution and the reactive sites are evenly distributed.
[0079] HRSEM and mapping images of the Co-C-3 photothermal catalytic material provided in Example 3 are shown below. Figure 2 ;exist Figure 2 In (a) and (b), Co atoms can be observed distributed on the surface of the cubic structure, indicating that Co has been successfully doped into C. Furthermore, Figure 2 (c) and (d) show that Co and C elements are uniformly distributed on the sample, further proving the successful preparation of Co-C materials.
[0080] XRD images of the Co-C-1, Co-C-2, Co-C-3, Co-C-4, and Co-C-5 photothermal catalytic materials provided in Examples 1, 2, 3, 4, and 5 are available for reference. Figure 3 ;pass Figure 3 By comparing the standard card of Co atoms (PDF#15-0806), it can be seen that the Co-C series of materials all have the characteristic diffraction peaks of Co-C, and there is a small diffraction peak near 25°, indicating that the sample contains carbon, which further demonstrates the successful preparation of the material.
[0081] The UV-Vis spectra of the Co-C-3 photothermal catalytic material provided in Example 3 under different stirring reaction times are shown in the attached image. Figure 4 ;pass Figure 4 It can be clearly seen that the material has good absorption in ultraviolet, visible and near-infrared light, which also indicates that the material will have good photothermal generation capabilities.
[0082] The infrared thermal image of the Co-C photothermal catalytic material provided in Example 3 under xenon lamp illumination in the wavelength range of 350-800 nm is shown in the figure. Figure 5 ,from Figure 5 It can be seen that Co-C can rapidly heat up under light irradiation in the 350-800nm range, eventually stabilizing at around 160℃, with a maximum heating temperature of 133.9℃. This indicates that the strong absorption capacity of Co-C in the ultraviolet and visible light bands is used for photothermal generation. However, since Co-C also has strong absorption in the visible light band, we infer that broadening the wavelength of the light source would yield better results.
[0083] The infrared thermal image of the Co-C photothermal catalytic material provided in Example 3 under xenon lamp illumination in the wavelength range of 350-2500 nm is shown in the figure. Figure 6 As can be seen, Co-C materials have better utilization of light across the entire wavelength range and can rapidly heat up within 30 seconds, with the highest temperature reaching 230.5℃.
[0084] Application Example 1
[0085] This application example uses the Co-C-1 photothermal catalytic material provided in Example 1 to catalyze the photothermal catalytic reaction of cyclohexane. The reaction process specifically includes the following steps:
[0086] 1) Weigh 30 mg of Co-C-1 photothermal catalyst and dissolve it in 15 mL of cyclohexane and 7.5 mL of acetone;
[0087] 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.5 MPa;
[0088] 3) React at room temperature under xenon lamp irradiation for 16 hours;
[0089] 4) After the reaction was complete, the reactor was allowed to cool to room temperature. The resulting solution was then analyzed by gas chromatography, yielding a conversion rate of 2.28% and a selectivity of 96.43%.
[0090] Application Example 2
[0091] This application example uses the Co-C-2 photothermal catalytic material provided in Example 2 to catalyze the photothermal catalytic reaction of cyclohexane. The reaction process specifically includes the following steps:
[0092] 1) Weigh 30 mg of Co-C-2 photothermal catalyst and dissolve it in 15 mL of cyclohexane and 7.5 mL of acetone;
[0093] 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.5 MPa;
[0094] 3) React at room temperature under xenon lamp irradiation for 16 hours;
[0095] 4) After the reaction was complete, the reactor was allowed to cool to room temperature. The resulting solution was then analyzed by gas chromatography, yielding a conversion rate of 4.94% and a selectivity of 98.30%.
[0096] Application Example 3
[0097] This application example uses the Co-C-3 photothermal catalytic material provided in Example 3 to catalyze the photothermal catalytic reaction of cyclohexane. The reaction process specifically includes the following steps:
[0098] 1) Weigh 30 mg of Co-C-3 photothermal catalyst and dissolve it in 15 mL of cyclohexane and 7.5 mL of acetone;
[0099] 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.5 MPa;
[0100] 3) React at room temperature under xenon lamp irradiation for 16 hours;
[0101] 4) After the reaction was complete, the reactor was allowed to cool to room temperature. The resulting solution was then analyzed by gas chromatography, yielding a conversion rate of 5.99% and a selectivity of 98.74%.
[0102] Application Example 4
[0103] This application example uses the Co-C-4 photothermal catalytic material provided in Example 4 to catalyze the photothermal catalytic reaction of cyclohexane. The reaction process specifically includes the following steps:
[0104] 1) Weigh 30 mg of Co-C-4 photothermal catalyst and dissolve it in 15 mL of cyclohexane and 7.5 mL of acetone;
[0105] 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.5 MPa;
[0106] 3) React at room temperature under xenon lamp irradiation for 16 hours;
[0107] 4) After the reaction was complete, the reactor was allowed to cool to room temperature. The resulting solution was then analyzed by gas chromatography, yielding a conversion rate of 5.38% and a selectivity of 98.49%.
[0108] Application Example 5
[0109] This application example uses the Co-C-5 photothermal catalytic material provided in Example 5 to catalyze the photothermal catalytic reaction of cyclohexane. The reaction process specifically includes the following steps:
[0110] 1) Weigh 30 mg of Co-C-5 photothermal catalyst and dissolve it in 15 mL of cyclohexane and 7.5 mL of acetone;
[0111] 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.5 MPa;
[0112] 3) React at room temperature under xenon lamp irradiation for 16 hours;
[0113] 4) After the reaction was complete, the reactor was allowed to cool to room temperature. The resulting solution was then analyzed by gas chromatography, and the conversion rate was found to be 4.7%, with a selectivity of 98.36%.
[0114] Comparative Application Example 1
[0115] In this comparative application example, catalyst C catalyzes the photothermal catalytic reaction of cyclohexane. The reaction process specifically includes the following steps:
[0116] 1) Weigh 30 mg of C photothermal catalyst material and dissolve it in 15 mL of cyclohexane and 7.5 mL of acetone;
[0117] 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.5 MPa;
[0118] 3) React at room temperature under xenon lamp irradiation for 16 hours;
[0119] 4) After the reaction was completed, the reactor was cooled to room temperature. The solution after the reaction was taken out and the conversion rate and selectivity were measured by gas chromatography.
[0120] The above application examples and comparative application examples show that, under the same conditions, Co-C-1, Co-C-2, Co-C-3, Co-C-4, Co-C-5, and C exhibit the highest conversion rate of cyclohexane oxidation via photothermal catalysis of Co-C-3, reaching 5.99%, which meets the standards for industrial production.
Claims
1. A method for preparing a Co-C catalytic material, characterized in that, The steps are as follows: S1. Preparation of ZIF-67: The cobalt source and ligand were added to the solvent and dispersed evenly. The mixture was then stirred for 8-12 hours. After stirring, the mixture was allowed to stand for 6-18 hours. The solution was then centrifuged, washed, and dried to obtain ZIF-67. The molar ratio of the cobalt source and the ligand is 1:1.5-1:2; S2. Preparation of Co-C ZIF-67 was placed in a tube furnace and calcined at 800-900℃ for 4-6 hours under an argon atmosphere. The black product after calcination was Co-C.
2. The method for preparing a Co-C catalytic material according to claim 1, characterized in that, The cobalt source mentioned in S1 is cobalt nitrate hexahydrate.
3. The method for preparing a Co-C catalytic material according to claim 1, characterized in that, The ligand in S1 is 2-methylimidazole; the solvent in S1 is methanol.
4. The method for preparing a Co-C catalytic material according to claim 1, characterized in that, The stirring reaction time described in S1 is 10 hours.
5. The method for preparing a Co-C catalytic material according to claim 1, characterized in that, The static reaction time described in S1 is 12 hours.
6. The method for preparing a Co-C catalytic material according to claim 1, characterized in that, The calcination temperature described in S2 is 850℃.
7. The method for preparing a Co-C catalytic material according to claim 1, characterized in that, The calcination time described in S2 is 5 hours.
8. A Co-C catalytic material, characterized in that, Prepared using the method described in any one of claims 1-7.
9. The Co-C catalytic material according to claim 8 is used as a catalyst for the photothermal catalytic oxidation of cyclohexane.
10. A method for photothermal catalytic oxidation of cyclohexane, characterized in that, The steps are as follows: 1) Weigh the Co-C photothermal catalytic material according to claim 8 and dissolve it in cyclohexane and acetonitrile; 2) Pour the solution prepared in step 1) into the photothermal reactor, seal the reactor, and fill it with dry air at 1.0-2.0 MPa; 3) React at 100-150℃ under xenon lamp irradiation for 6-10 hours; 4) After the reaction is complete, wait for the reactor to cool to room temperature, then measure the conversion rate and selectivity; The ratio of the Co-C photothermal catalytic material to cyclohexane is 2 mg: 0.8-1.2 mL.
11. The method for photothermal catalytic oxidation of cyclohexane according to claim , characterized in that, The volume ratio of cyclohexane to acetonitrile is 2:1.