Carbon nanotube hybrid material
By growing CNTs on a catalyzed carbonaceous substrate, the problems of uneven dispersion and safety hazards of carbon nanotubes in the prior art are solved, and the material performance and cost reduction are improved.
Patent Information
- Application Number
- CN202380075885.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-09
- Filing Date
- 2023-10-26
- Publication Date
- 2025-06-13
AI Technical Summary
Existing physical mixing methods lead to uneven dispersion of carbon nanotubes in the carrier matrix, and there are safety risks during the processing, making it difficult to optimize the CNT load to maintain a balance between material performance and cost.
Using an improved method, by growing CNTs on a catalytic carbonaceous substrate, using lignin or water-soluble lignin derivatives as biosource synthesis media, avoiding the use of organic solvents and non-lignin-derived surfactants, to form a catalytic carbonaceous substrate to support uniform growth of CNTs.
The uniform growth of carbon nanotubes on carbonic substrates is achieved, which improves the conductivity, mechanical properties and chemical strength of the material, reduces production costs, and avoids the risk of using harmful chemicals.
Smart Images
Figure CN120152938A_ABST
Abstract
Description
[0001] Cross-reference to related applications
[0002] This application claims priority to Indian Patent Application No. 202211060980, filed on October 26, 2022, and U.S. Provisional Application No. 63 / 431,368, filed on December 9, 2022, the disclosures of both of which are incorporated herein by reference. BACKGROUND OF THE INVENTION
[0003] Carbon black is an amorphous form of carbon used as a pigment or reinforcing filler in rubber and plastic products. Due to the graphite microcrystalline nature of the carbon black, it imparts some electrostatic properties to non-conductive materials and thus finds applications in many fields such as conductive polymers, inks, paints, and antistatic coatings. For some applications, another form of nanostructured carbon, such as carbon nanotubes (CNTs), can be combined with carbon black to improve the conductivity, mechanical properties, and chemical strength of the final product.
[0004] CNTs are formed by rolling a single-atom-thick sheet of carbon to form cylinders with diameters in the nanometer range and lengths up to several micrometers. Due to the excellent chemical, mechanical, thermal, and optical properties of CNTs, they can be used in composite materials and microelectronics. However, due to cost, it may be desirable to optimize the CNT loading to maintain a balance between material performance and cost. The performance of CNT composites typically depends on the uniform mixing of different nanostructures in the host matrix.
[0005] Existing physical mixing methods often result in non-uniform dispersion and have only a small impact on the final properties. Additionally, mixing two nanoscale components in a host matrix may pose safety hazards during processing. Incorporating carbon nanotubes on the surface of a carbon structure facilitates the obtaining of a single synergistic material. SUMMARY OF THE INVENTION
[0006] The present disclosure relates to an improved method for growing CNTs on a catalytic carbonaceous substrate using various feed gases. Preparation of the disclosed composite materials involves generating catalytic carbon as a support for the growth of CNTs on the support. The method utilizes a green approach, synthesizing catalytic carbon from biogenic sources such as lignin or suitable water-soluble lignin derivatives without using organic solvents. In contrast, many existing wet impregnation methods typically use harsh acidic conditions, expensive surfactants, or require multi-step processing to uniformly disperse the catalyst on the carbon support. Different from the disclosed method, existing methods are either expensive or cumbersome.
[0007] On the one hand, a method for manufacturing a carbon nanotube hybrid material comprises: (a) dispersing a carbonaceous substrate in a medium comprising water and one or more of the following: (i) lignin and a first base; or (ii) a water-soluble lignin derivative; wherein the medium does not contain an organic solvent and a non-lignin-derived surfactant; (b) contacting the medium with a metal salt and a second base; (c) forming catalytic sites on the carbonaceous substrate from the metal salt to provide a catalyzed carbonaceous substrate; and (d) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate.
[0008] In a further aspect, the method comprises: (a) dispersing a carbonaceous substrate in a medium comprising water and one or more of the following: (i) lignin and a first base; or (ii) a water-soluble lignin derivative; (b) contacting the medium with a metal salt and a second base; (c) obtaining a solid from the medium, the solid comprising the carbonaceous substrate with the metal salt loaded thereon; (d) calcining the solid to convert the metal salt to a metal oxide; (e) reducing the metal oxide to its corresponding elemental metal to form a catalyzed carbonaceous substrate; and (f) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate.
[0009] Also described is a carbon nanotube hybrid material manufactured by any of the disclosed methods. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The foregoing summary of the invention and the following detailed description of the disclosure can be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the disclosure, the drawings show some but not all of the alternative embodiments. The disclosure is not limited to the precise arrangements and instrumentalities shown. The following drawings, which are incorporated in and constitute a part of the specification, help to explain the principles of the disclosure.
[0011] Figures 1A-C Shows SEM images (Figure 1A: 500 nm scale, Figure 1B: 2 μm scale, Figure 1C: 10 μm scale) of a hybrid material manufactured using carbon monoxide (CO, H 2 and N 2 ) as the feed gas by a nickel catalyst deposited on Raven PFEB (Birla Carbon, Marietta GA, USA).
[0012] Figure 2 is a hybrid material manufactured by a nickel catalyst deposited on a Raven PFEB substrate and the corresponding I d / I gA Raman spectrum with a ratio of 1.01.
[0013] Figures 3A-C SEM images of exemplary hybrid materials made from nickel catalysts deposited on Raven PFEB, hybrid materials made from nickel-cobalt catalysts deposited on Raven PFEB, and hybrid materials made from cobalt-molybdenum catalysts deposited on Raven PFEB are shown, where the HRTEM magnification insets show the carbon nanotube morphology (Figure 3A: 2 μm scale, Figure 3B: 5 μm scale, Figure 3C: 2 μm scale).
[0014] Figure 4 Shows the use of ethylene (ethylene, H 2 and N 2 ) as the feed gas, and the HRTEM image of the hybrid material made from the nickel catalyst deposited on Raven PFEB (Example 2). ( Figure 4 10 nm scale).
[0015] Figure 5 Shows the use of carbon monoxide (CO, H 2 and N 2 ) as the feed gas, and the SEM image of the hybrid material made from the Ni catalyst deposited on graphite (Example 3). ( Figure 5 10 μm scale).
[0016] Figure 6 Shows the use of water-soluble lignin derivatives and ethylene (ethylene, H 2 and N 2 ) as the feed gas, and the TEM image of the carbon-CNT hybrid material prepared on Ni-loaded Raven PFEB (Example 4) ( Figure 6 20 nm scale). Detailed Description
[0017] One aspect of the method includes the following steps: (a) dispersing a carbonaceous substrate in a medium that includes water and one or more of the following: (i) lignin and a first base; or (ii) a water-soluble lignin derivative; (b) contacting the medium with a metal salt and a second base; (c) forming catalytic sites on the carbonaceous substrate from the metal salt to provide a catalyzed carbonaceous substrate; and (d) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate.
[0018] One advantage of the method is that the medium can be free of organic solvents and non-lignin-derived surfactants. Generally, since the process involves water-soluble metal salts, organic solvents are not required. In addition to any other volatile organic solvents such as dichloromethane, chloroform, and other solvents known to those skilled in the art, specific examples of unwanted organic solvents include alcohols such as ethanol, propanol, isopropanol, etc. In some aspects, the method as a whole does not involve the use of organic solvents, that is, organic solvents are not used in any step of the process.
[0019] Another advantage of the method is that it can avoid the use of non-lignin-derived surfactants and is thus environmentally friendly and sustainable. For example, the medium can be free of non-lignin-derived nonionic surfactants, non-lignin-derived zwitterionic surfactants, non-lignin-derived cationic or amphoteric surfactants. In a specific example, the medium can be free of Triton surfactants, including Triton-X-100.
[0020] The method is applicable to various carbonaceous substrates. Examples include natural graphite, synthetic graphite, graphene, carbon black, carbon fiber, or activated carbon. In one aspect, the carbonaceous substrate is carbon black. A specific example is Raven PFEB carbon black (Birla Carbon, Marietta, Georgia, USA). In another aspect, the carbonaceous substrate is graphite.
[0021] Generally, the first base can be any base suitable for providing a medium pH in the range of 8 to 12. Suitable first bases include ammonia, carbonate, bicarbonate, or hydroxide bases. Specific examples include sodium hydroxide, ammonium bicarbonate, and potassium hydroxide.
[0022] When using water-soluble lignin derivatives, such as anionic lignin derivatives, no first base is required to dissolve the lignin derivative in the medium. Examples of suitable anionic lignin derivatives include lignosulfonates, which are generally water-soluble anionic polyelectrolyte polymers and by-products produced from wood pulp using sulfite pulping. For water-soluble lignin derivatives, although no first base is required to dissolve the derivative in the aqueous medium, a second base can be used to precipitate the metal salt and thus load the metal salt onto the carbonaceous substrate. A combination of lignin and the first base and water-soluble lignin derivatives can also be used.
[0023] The second base and any first base can be the same or different. Suitable examples of the second base include ammonia, carbonate, bicarbonate, or hydroxide bases. Specific examples include sodium hydroxide, ammonium bicarbonate, and potassium hydroxide. In one aspect, when used with lignin, the first base can be a hydroxide base such as sodium hydroxide or potassium hydroxide, and the second base used in the metal salt loading step can be an ammonia base such as ammonium bicarbonate.
[0024] A variety of metal salts can be used as precursors for metal oxides, and once the carbonaceous substrate is loaded with the metal salt, the metal oxide will form upon calcination of the carbonaceous substrate. On the one hand, the metal salt is a d-block transition metal salt. In a further aspect, the metal salt is of iron. On the other hand, the metal salt is non-iron. In a further aspect, the metal salt is a salt of iron, nickel, molybdenum, copper or cobalt. A metal salt with any suitable anion is contemplated. On the one hand, the metal salt is a transition metal nitrate, transition metal acetate, transition metal citrate, transition metal chloride or any hydrate or combination of these salts.
[0025] On the one hand, forming catalytic sites on the carbonaceous substrate from the metal salt involves converting the metal salt to a metal oxide and then reducing the metal oxide to its corresponding elemental metal. Thus, the term "catalyzed carbonaceous substrate" refers to a carbon-based substrate having a catalyst formed or deposited on the substrate.
[0026] In a specific aspect, for example, the method comprises: (a) dispersing a carbonaceous substrate in a medium comprising water and one or more of the following: (i) lignin and a first base; or (ii) a water-soluble lignin derivative; (b) contacting the medium with a metal salt and a second base; (c) obtaining a solid from the medium, the solid comprising the carbonaceous substrate loaded with the metal salt; (d) calcining the solid to convert the metal salt to a metal oxide; (e) reducing the metal oxide to its corresponding elemental metal to form a catalyzed carbonaceous substrate; and (f) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate. As described above, the dispersion may be free of organic solvents, free of non-lignin-derived surfactants, or both.
[0027] On the one hand, the calcination can be carried out at a temperature in the range of 400 °C to 650 °C. "Calcination" refers to the heat treatment of a solid whereby the solid is raised to a high temperature without melting, thereby converting the metal salt to a metal oxide. In a further aspect, prior to calcination, the solid can be obtained from the medium by filtering the solid from the medium, washing the solid and drying the solid at a temperature below 100 °C, followed by the calcination step. In a further aspect, the metal oxide can be reduced to its corresponding elemental metal using hydrogen. In a further aspect, the catalyzed carbonaceous substrate can be exposed to a carbon-containing gas at a temperature in the range of 600 °C to 1200 °C, such as 600 °C to 1000 °C, 600 °C to 800 °C or in a specific aspect at about 700 °C. Generally, the disclosed method can be carried out in any suitable reactor, such as a fluidized bed reactor, a rotary reactor or a tubular reactor.
[0028] A variety of carbon-containing gases and their mixtures are considered. For example, the carbon-containing gas can include carbon monoxide, ethylene, acetylene, methane, benzene, xylene, carbon dioxide, or a combination thereof. Other co-gases can be used with any carbon-containing gas such as hydrogen, nitrogen, etc. A non-limiting example of a carbon-containing gas is ethylene, hydrogen, and nitrogen, which can be used, for example, in a volume % ratio of 10:10:80 (ethylene:H 2 :N 2 ). Another example of a carbon-containing gas is carbon monoxide, hydrogen, and nitrogen, which can be used, for example, in a volume % ratio of 40:40:20 (CO:H 2 :N 2 ).
[0029] In some aspects, the yield % of carbon nanotubes formed on a carbonaceous substrate can be in the range of about 100 - 500% (by weight of the carbonaceous substrate).
[0030] Also described is a carbon nanotube hybrid material manufactured by any of the embodiments of the disclosed methods.
[0031] Another advantage of the described methods is that, in some aspects, the methods do not require the use of non-catalytic materials at any step of the process, including, for example, during steps involving the growth of carbon nanotubes. It has been found that the described methods allow carbon nanotubes to grow thinly and uniformly on a carbonaceous substrate without depositing non-catalytic materials other than metal oxides on the carbonaceous substrate, which are ultimately reduced to the corresponding metals to form a catalyzed carbonaceous substrate. In other words, it has been observed that any interaction between the catalyst sites and the carbonaceous substrate itself does not interfere with the growth of carbon nanotubes. Specific non-catalytic materials that can be excluded from the process include aluminum, aluminum salts, hydrates of aluminum salts, glass, silicates, silanes, etc.
[0032] Similarly, the disclosed methods do not require coating a polymer on the carbonaceous substrate prior to forming carbon nanotubes on the substrate. For example, a barrier coating of furfuryl alcohol polymer is not required on the carbonaceous substrate.
[0033] Exemplary aspects
[0034] The following exemplary aspects of the present disclosure, while non-limiting, are specifically considered.
[0035] Aspect (1): A method for manufacturing a carbon nanotube hybrid material, the method comprising: (a) dispersing a carbonaceous substrate in a medium, the medium comprising water and one or more of the following: (i) lignin and a first base; or (ii) a water-soluble lignin derivative; wherein the medium does not contain an organic solvent and a non-lignin-derived surfactant; (b) contacting the medium with a metal salt and a second base; (c) forming catalytic sites on the carbonaceous substrate from the metal salt to provide a catalyzed carbonaceous substrate; and (d) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate.
[0036] Aspect (2): The method according to aspect (1), wherein the carbonaceous substrate comprises natural graphite, synthetic graphite, graphene, carbon black, carbon fiber, or activated carbon.
[0037] Aspect (3): The method according to any one of the preceding aspects, wherein the first base provides a medium pH in the range of 8 to 12.
[0038] Aspect (4): The method according to any one of the preceding aspects, wherein the first base is ammonia, a carbonate, a bicarbonate, or a hydroxide base.
[0039] Aspect (5): The method according to any one of the preceding aspects, wherein the first base is sodium hydroxide.
[0040] Aspect (6): The method according to any one of the preceding aspects, wherein the second base is ammonia, a carbonate, a bicarbonate, or a hydroxide base.
[0041] Aspect (7): The method according to any one of the preceding aspects, wherein the second base is sodium hydroxide.
[0042] Aspect (8): The method according to any one of the preceding aspects, wherein the second base is ammonium bicarbonate.
[0043] Aspect (9): The method according to any one of the preceding aspects, wherein the water-soluble lignin derivative is an anionic lignin derivative.
[0044] Aspect (10): The method according to any one of the preceding aspects, wherein the water-soluble lignin derivative is lignosulfonate.
[0045] Aspect (11): The method according to any one of the preceding aspects, wherein the metal salt is a d-block transition metal salt.
[0046] Aspect (12): The method according to any one of the preceding aspects, wherein the metal salt is iron-based or non-iron-based.
[0047] Aspect (13): The method according to any one of the preceding aspects, wherein the metal salt is a salt of iron, nickel, molybdenum, or cobalt or a combination thereof.
[0048] Aspect (14): The method according to any one of the preceding aspects, wherein forming the catalytic sites on the carbonaceous substrate by the metal salt comprises converting the metal salt into a metal oxide and then reducing the metal oxide to its corresponding elemental metal.
[0049] Aspect (15): The method according to any one of the preceding aspects, wherein the carbon-containing gas comprises ethylene, acetylene, methane, benzene, xylene, carbon dioxide, or a combination thereof.
[0050] Aspect (16): A carbon nanotube hybrid material manufactured by the method according to any one of the preceding aspects.
[0051] Aspect (17): A method for manufacturing a carbon nanotube hybrid material, the method comprising: (a) dispersing a carbonaceous substrate in a medium, the medium comprising water and one or more of the following: (i) lignin and a first base; or (ii) a water-soluble lignin derivative; (b) contacting the medium with a metal salt and a second base; (c) obtaining a solid from the medium, the solid comprising the carbonaceous substrate loaded with the metal salt; (d) calcining the solid to convert the metal salt into a metal oxide; (e) reducing the metal oxide to its corresponding elemental metal to form a catalyzed carbonaceous substrate; and (f) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate.
[0052] Aspect (18): The method according to aspect (17), wherein the dispersion does not contain an organic solvent.
[0053] Aspect (19): The method according to aspect (17) or (18), wherein the dispersion does not contain a non-lignin-derived surfactant.
[0054] Aspect (20): The method according to any one of aspects (17) to (19), wherein the carbonaceous substrate comprises natural graphite, synthetic graphite, graphene, carbon black, carbon fiber, or activated carbon.
[0055] Aspect (21): The method according to any one of aspects (17) to (20), wherein the first base provides a medium pH in the range of 8 to 12.
[0056] Aspect (22): The method according to any one of aspects (17) to (21), wherein the first base is ammonia, carbonate, bicarbonate, or a hydroxide base.
[0057] Aspect (23): The method according to any one of aspects (17) to (22), wherein the first base is sodium hydroxide.
[0058] Aspect (24): The method according to any one of aspects (17) to (23), wherein the second base is ammonia, a carbonate, a hydrogencarbonate or a hydroxide base.
[0059] Aspect (25): The method according to any one of aspects (17) to (24), wherein the second base is sodium hydroxide.
[0060] Aspect (26): The method according to any one of aspects (17) to (25), wherein the second base is ammonium hydrogencarbonate.
[0061] Aspect (27): The method according to any one of aspects (17) to (26), wherein the water-soluble lignin derivative is an anionic lignin derivative.
[0062] Aspect (28): The method according to any one of aspects (17) to (27), wherein the water-soluble lignin derivative is lignosulphonate.
[0063] Aspect (29): The method according to any one of aspects (17) to (28), wherein the metal salt is a d-block transition metal salt.
[0064] Aspect (30): The method according to any one of aspects (17) to (29), wherein the metal salt is non-ferrous.
[0065] Aspect (31): The method according to any one of aspects (17) to (30), wherein the metal salt is a salt of nickel, molybdenum or cobalt or a combination thereof.
[0066] Aspect (32): The method according to any one of aspects (17) to (31), wherein the calcination is carried out at a temperature in the range of 400 °C to 650 °C.
[0067] Aspect (33): The method according to any one of aspects (17) to (32), wherein the solid is obtained from the medium by filtering the solid from the medium, washing the solid and drying the solid at a temperature of less than 100 °C.
[0068] Aspect (34): The method according to any one of aspects (17) to (33), wherein the metal oxide is reduced to its corresponding elemental metal using hydrogen.
[0069] Aspect (35): The method according to any one of aspects (17) to (34), wherein the catalyzed carbonaceous substrate is exposed to the carbon-containing gas at a temperature in the range of 600 °C to 1200 °C.
[0070] Aspect (36): The method according to any one of aspects (17) to (35), wherein the carbon-containing gas comprises ethylene, acetylene, methane, benzene, xylene, carbon dioxide, or a combination thereof.
[0071] Aspect (37): A carbon nanotube hybrid material produced by the method according to any one of the foregoing aspects.
[0072] Examples
[0073] The following examples further illustrate the present disclosure. The scope of the present disclosure and the claims is not limited by the scope of the following examples.
[0074] Example 1
[0075] An exemplary carbon nanotube hybrid material was produced according to the following method. Lignin was dissolved in an alkaline aqueous medium (0.0032 M NaOH, i.e., the first base), and carbon black was added. The mixture was stirred to disperse the carbon black in the medium. A nickel metal salt (Ni(NO 3 ) 2 ) and a base source, in this case NH 4 HCO 3 , i.e., the second base, were added dropwise together. The resulting mixture was stirred at 80 °C for three hours. Then, the solid carbon black substrate (loaded with the Ni metal salt on the substrate) was filtered from the aqueous medium and washed to remove impurities, including remaining lignin and lignin derivatives. The solid was dried at 80 °C under vacuum for 12 hours or at 80 °C without vacuum for 24 hours.
[0076] To prepare the catalyzed substrate, the dried solid was calcined at 600 °C for four hours in a nitrogen atmosphere. Then, the resulting catalyzed substrate was heated in a nitrogen atmosphere. Once the furnace temperature reached 700 °C, carbon monoxide and hydrogen were passed through the furnace while maintaining the furnace temperature at 680 °C - 1200 °C for a duration ranging from 10 minutes to 3 hours. Heating was turned off, the substrate was cooled in a nitrogen atmosphere, and the resulting carbon nanotube - carbon black hybrid substrate was collected. The yield % of CNT formation was found to be 264% (by weight of the carbonaceous substrate).
[0077] The carbon black substrate specifically used was Raven PFEB (Birla Carbon, Marietta, Georgia, USA). The loading rate of the nickel catalyst on the substrate was determined to be 18.24% (by weight of the substrate). SEM images of the hybrid material are shown in Figures 1A-C(A: 500 nm scale, B: 2 μm scale, C: 10 μm scale), indicating that uniform and thin carbon nanotubes grow on the carbon black, which appear as grape-like clusters in the SEM image. The Raman spectrum of the hybrid material is shown in Figure 2 .
[0078] Additional metal catalysts were also evaluated, and the yields are shown in Table 1. The corresponding SEM / HRTEM images of the Ni-Raven PFEB mixture, Ni-Co / Raven PFEB mixture, and Co-Mo / Raven PFEB mixture are shown in Figures 3A (2 μm scale), 3B (5 μm scale), and 3C (2 μm scale), respectively.
[0079] Table 1
[0080] Catalyst CNT yield % by substrate weight Ni on Raven PFEB 100 Ni-Co on Raven PFEB 209 Co-Mo on Raven PFEB 486
[0081] Example 2
[0082] In this example, ethylene was used as the carbon source. The catalyzed substrate prepared as described above was heated in a nitrogen atmosphere. Once the furnace temperature reached 700 °C, ethylene, hydrogen, and nitrogen (volume % 10:10:80) were passed through the furnace while maintaining the furnace temperature at 700 °C for a duration ranging from 30 minutes to 3 hours. Heating was turned off, and the substrate was cooled in a nitrogen atmosphere, and the resulting carbon nanotube-carbon black hybrid substrate was collected. The yield % of the carbonaceous material was found to be in the range of 300 - 500%. The resulting TEM images are shown in Figure 4 .
[0083] Example 3
[0084] In this example, graphite was used as the catalyst support. Ni was deposited on the graphite support using a lignin co-precipitation process in a similar manner as described previously. The catalyzed substrate was heated in a nitrogen atmosphere. Once the furnace temperature reached 700 °C, carbon monoxide, hydrogen, and nitrogen (volume % 40:40:20) were passed through the furnace while maintaining the furnace temperature at 700 °C for 3 hours. Heating was turned off, and the substrate was cooled in a nitrogen atmosphere, and the resulting carbon nanotube-carbon black hybrid substrate was collected. The yield % of the carbonaceous material was found to be in the range of 300 - 500%. The resulting SEM images are shown in Figure 5 .
[0085] Example 4
[0086] In this example, a water-soluble lignin derivative is used to disperse carbon black, Raven PFEB, in an aqueous medium. Catalyst deposition is carried out in a similar manner as described in the previous example. The catalyzed substrate is heated in a nitrogen atmosphere. Once the furnace temperature reaches 700 °C, ethylene, hydrogen, and nitrogen (in a volume % ratio of 10:10:80) are passed through the furnace while maintaining the furnace temperature at 700 °C for 3 hours. Heating is turned off, and the substrate is cooled in a nitrogen atmosphere, and the resulting carbon nanotube-carbon black hybrid substrate is collected. The yield % of the carbonaceous material is found to be in the range of 100 - 200%. The resulting TEM images are shown in Figure 6 the
[0087] The features and advantages of the present disclosure are apparent from the detailed description, and the claims cover all such features and advantages. For those skilled in the art, there will be many variations, and any variations equivalent to those described in the present disclosure fall within the scope of the present disclosure. Those skilled in the art will understand that the concepts on which the present disclosure is based can be used as a basis for the design of other methods and systems for carrying out several purposes of the present disclosure. Therefore, the claims should not be regarded as limited by the description or examples.
Claims
1. A method for manufacturing a carbon nanotube hybrid material, the method comprising: a) dispersing a carbonaceous substrate in a medium, the medium comprising water and one or more of the following: i) lignin and a first base; or ii) a water-soluble lignin derivative; wherein the medium does not contain an organic solvent and a non-lignin-derived surfactant; b) contacting the medium with a metal salt and a second base; c) forming catalytic sites on the carbonaceous substrate from the metal salt to provide a catalyzed carbonaceous substrate; and d) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate.
2. The method according to claim 1, wherein the carbonaceous substrate comprises natural graphite, synthetic graphite, graphene, carbon black, carbon fiber or activated carbon.
3. The method according to claim 1, wherein the first base provides a medium pH in the range of 8 to 12.
4. The method according to claim 1, wherein the first base is ammonia, a carbonate, a bicarbonate or a hydroxide base.
5. The method according to claim 1, wherein the first base is sodium hydroxide.
6. The method according to claim 1, wherein the second base is ammonia, a carbonate, a bicarbonate or a hydroxide base.
7. The method according to claim 1, wherein the second base is sodium hydroxide.
8. The method according to claim 1, wherein the second base is ammonium bicarbonate.
9. The method according to claim 1, wherein the water-soluble lignin derivative is an anionic lignin derivative.
10. The method according to claim 1, wherein the water-soluble lignin derivative is lignosulfonate.
11. The method according to claim 1, wherein the metal salt is a d-block transition metal salt.
12. The method according to claim 1, wherein the metal salt is iron-based or non-iron-based.
13. The method according to claim 1, wherein the metal salt is a salt of iron, nickel, molybdenum or cobalt or a combination thereof.
14. The method according to claim 1, wherein forming catalytic sites on the carbonaceous substrate from the metal salt comprises converting the metal salt into a metal oxide and then reducing the metal oxide to its corresponding elemental metal.
15. The method according to claim 1, wherein the carbon-containing gas comprises ethylene, acetylene, methane, benzene, xylene, carbon dioxide or a combination thereof.
16. A carbon nanotube hybrid material, which is manufactured by the method according to any one of the preceding claims.
17. A method for manufacturing a carbon nanotube hybrid material, the method comprising: a) dispersing a carbonaceous substrate in a medium, the medium comprising water and one or more of the following: i) lignin and a first base; or ii) a water-soluble lignin derivative; b) contacting the medium with a metal salt and a second base; c) obtaining a solid from the medium, the solid comprising the carbonaceous substrate loaded with the metal salt; d) calcining the solid to convert the metal salt into a metal oxide; e) reducing the metal oxide to its corresponding elemental metal to form a catalyzed carbonaceous substrate; and f) exposing the catalyzed carbonaceous substrate to a carbon-containing gas to grow carbon nanotubes on the catalyzed carbonaceous substrate.
18. The method according to claim 17, wherein the dispersion does not contain an organic solvent.
19. The method according to claim 17 or 18, wherein the dispersion does not contain a non-lignin-derived surfactant.
20. The method according to claim 17, wherein the carbonaceous substrate comprises natural graphite, synthetic graphite, graphene, carbon black, carbon fiber or activated carbon.
21. The method according to claim 17, wherein the first base provides a medium pH in the range of 8 to 12.
22. The method according to claim 17, wherein the first base is ammonia, carbonate, bicarbonate, hydroxide base.
23. The method according to claim 17, wherein the first base is sodium hydroxide.
24. The method according to claim 17, wherein the second base is ammonia, carbonate, bicarbonate or hydroxide base.
25. The method according to claim 17, wherein the second base is sodium hydroxide.
26. The method according to claim 17, wherein the second base is ammonium bicarbonate.
27. The method according to claim 17, wherein the water-soluble lignin derivative is an anionic lignin derivative.
28. The method according to claim 17, wherein the water-soluble lignin derivative is lignosulfonate.
29. The method according to claim 17, wherein the metal salt is a d-block transition metal salt.
30. The method according to claim 17, wherein the metal salt is non-ferrous.
31. The method according to claim 17, wherein the metal salt is a salt of nickel, molybdenum or cobalt or a combination thereof.
32. The method according to claim 17, wherein the calcination is carried out at a temperature in the range of 400 to 650.
33. The method according to claim 17, wherein the solid is obtained from the medium by filtering the solid from the medium, washing the solid and drying the solid at a temperature below 100.
34. The method according to claim 17, wherein the metal oxide is reduced to its corresponding elemental metal using hydrogen.
35. The method according to claim 17, wherein the catalyzed carbonaceous substrate is exposed to the carbon-containing gas at a temperature in the range of 600 to 1200.
36. The method according to claim 17, wherein the carbon-containing gas comprises ethylene, acetylene, methane, benzene, xylene, carbon dioxide or a combination thereof.
37. A carbon nanotube hybrid material, which is manufactured by the method according to any one of claims 17 to 36.