Array spiral carbon nanofiber sponge and preparation method thereof
Patent Information
- Application Number
- CN202510161147.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-13
- Publication Date
- 2025-05-16
Smart Images
Figure CN120004252A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to an array spiral carbon nanofiber sponge and a preparation method thereof, belonging to the technical field of carbon nanofiber materials. Background Art
[0002] The discovery of carbon nanofibers is a major breakthrough in the field of carbon material science. Since its discovery, its unique structure and excellent performance have triggered a wide and in-depth research boom in the scientific research community. In terms of structural characteristics, carbon nanofibers have a nearly perfect one-dimensional nanostructure. This unique structure gives it many excellent properties and lays the foundation for the research of spiral carbon nanofibers. Researchers have carried out all-round and multi-level research work on the structure, performance and preparation methods of carbon nanofibers. In the field of oil-water separation, spiral carbon nanofibers show unique advantages. Its special spiral structure and surface properties enable it to have different affinities and adsorption selectivity for oil and water, and can effectively adsorb and separate oil from oil-water mixtures, and can still maintain high separation efficiency and stability during multiple adsorption-desorption cycles; at the same time, the unique micromorphology and pore structure formed by the spiral structure help to build a continuous oil-water transmission channel, further improving the efficiency of oil-water separation. Chemical vapor deposition (CVD) is one of the most promising methods for preparing spiral carbon nanofibers. This method utilizes gaseous or vaporous substances to react in the gas phase or at a gas-solid interface to generate solid deposits for preparation, and the diameter, morphology and arrangement of the fibers can be effectively controlled by precisely controlling the reaction parameters and catalysts.
[0003] With the development of industry and the increasing prominence of environmental problems, the demand for efficient separation materials in the field of oil-water separation has become more urgent. Traditional oil-water separation methods have many limitations, such as low separation efficiency, high cost, and easy secondary pollution. Carbon nanofiber materials, due to their good chemical stability and controllable surface properties, have shown great application potential in the field of oil-water separation. However, the existing carbon nanofibers used in this field have the problem of being difficult to accurately control their structure and morphology during the preparation process, especially the difficulty in synthesizing spiral fibers in large quantities, which will show problems such as uneven pore distribution and large fluctuations in fiber diameter, which will affect the oil-water transmission and adsorption efficiency of carbon nanofibers. At the same time, the lack of structural strength also makes carbon nanofibers easy to deform or damage in high flow rate or long-term circulation environments, which will limit their practical application performance. Summary of the invention
[0004] In view of the fact that it is difficult to accurately control the structure and morphology of existing carbon nanofibers used in the field of oil-water separation during the preparation process, especially it is difficult to synthesize spiral fibers in large quantities, and they will show problems such as uneven pore distribution and large fluctuations in fiber diameter. The present invention proposes an array spiral carbon nanofiber sponge and a preparation method thereof, wherein nanometal is used as a catalyst to catalyze the vapor deposition of carbon-containing gas to form an array spiral carbon nanofiber self-supporting sponge block with a high elastic modulus. The structure of the array spiral carbon nanofiber sponge is a kinked spiral structure or a spring-like spiral structure. Under the action of stress, the array spiral carbon nanofiber self-supporting sponge block can maintain good shape stability and can quickly return to its original state after being compressed. Moreover, the array spiral carbon nanofiber self-supporting sponge block has excellent oil-water separation performance.
[0005] A spiral carbon nanofiber array sponge is prepared by reaction with nano metal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas. The spiral carbon nanofiber sponge is a self-supporting sponge block formed by spiral carbon nanofibers with diameters of 99 to 174 nm that are regularly entangled and arranged with each other. The structure of the spiral carbon nanofiber array sponge is a kinked spiral structure or a spring-like spiral structure.
[0006] The arrayed spiral carbon nanofibers have high defects, and the catalyst is embedded in the fibers, carrying functional groups C=C, CH, and OH. The arrayed spiral carbon nanofiber sponge has abundant pores, which makes it have a high porosity, can provide a larger specific surface area, and improve the efficiency of oil-water separation.
[0007] The array spiral carbon nanofiber sponge has a thickness of 1 to 3.5 cm and a length of 5 to 8 cm.
[0008] The preparation method of the array spiral carbon nanofiber sponge (see Figure 1 ), the specific steps are as follows:
[0009] (1) uniformly dispersing the nanometal precursor in ethanol to obtain a nanometal precursor dispersion, and directly drying the nanometal precursor dispersion to obtain a pretreated nanometal precursor;
[0010] (2) placing the pretreated nanometal precursor in a chemical vapor deposition tube furnace, uniformly heating the temperature to 280-400° C. and uniformly introducing a protective gas for 0.5-4 h;
[0011] (3) switching the protective gas to a carbon-containing organic molecular gas and uniformly passing it into a chemical vapor deposition tube furnace, and performing nano-metal catalytic vapor deposition at a temperature of 280 to 400° C. for 1.5 to 4 hours to promote the formation of spiral carbon nanofibers;
[0012] (4) Switch the carbon-containing gas to a protective gas and uniformly pass it into a chemical vapor deposition tube furnace, and uniformly cool it to room temperature to obtain an array-arranged spiral carbon nanofiber sponge. The array-arranged spiral carbon nanofiber sponge has large defects. The carbon atoms of the spiral carbon nanofibers are arranged in a sp 2 and sp 3 The hybrid combination forms a strong covalent bond, which makes the material have excellent chemical stability and can withstand the complex chemical environment in the oil-water mixture, and is not easy to react with acidic and alkaline substances or other chemical components therein; it also has good mechanical strength. When processing oil-water mixture, it can withstand external forces such as fluid scouring and stirring without structural damage.
[0013] Preferably, the nano-metal precursor in step (1) is an iron-based catalyst or a copper-based catalyst, and the concentration of the nano-metal precursor dispersion is 1 to 4 g / L.
[0014] Preferably, the drying temperature in step (1) is 60-80° C. and the drying time is 5-9 hours.
[0015] Preferably, the protective gas in step (2) is nitrogen or an inert gas, the flow rate is 40 to 80 mL / min, and the uniform heating rate is 1 to 10°C.
[0016] Preferably, the carbon-containing gas in step (3) is methane or acetylene, and the flow rate is 50 to 80 mL / min.
[0017] Preferably, the protective gas in step (4) is nitrogen or an inert gas, the flow rate is 40 to 80 mL / min, and the uniform cooling rate is 5 to 10° C. / min.
[0018] The array spiral carbon nanofiber sponge is used as an oil-water separation material in oil-water fluid separation.
[0019] The beneficial effects of the present invention are:
[0020] (1) The present invention uses nanometal as a catalyst and adopts chemical vapor deposition to prepare a spiral carbon nanofiber sponge with a diameter of 99 to 174 nm. The spiral carbon nanofiber sponge arranged in an array is a self-supporting sponge block with a regular winding arrangement (no additional support is required to maintain the shape and structure integrity); the preparation method is simple and convenient, with high yield, and good repeatability and scalability;
[0021] (2) The temperature and gas flow rate of the spiral carbon nanofiber sponge arranged in an array in the present invention can be adjusted during the reaction process to ensure the controllability of the diameter, length, arrangement and structure of the spiral carbon nanofibers to meet different application requirements;
[0022] (3) The arrayed spiral carbon nanofiber sponge obtained by the present invention has a large defect that the carbon atoms of the spiral carbon nanofibers are arranged in a sp 2 and sp 3 The hybrid combination forms a strong covalent bond, which makes the material have excellent chemical stability and can withstand the complex chemical environment in the oil-water mixture, and is not easy to react with acidic and alkaline substances or other chemical components; it also has good mechanical strength and can withstand external forces such as fluid scouring and stirring without structural damage when processing oil-water mixture;
[0023] (4) The spiral carbon nanofiber sponge of the present invention is suitable for various types of carbon sources and catalysts and has strong adaptability. The oil-water separation characteristics of the arrayed spiral carbon nanofibers are the result of the combined effects of their microstructure, material composition and molecular motion, laying a foundation for their wide application in the field of fluid separation. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 The present invention is a flow chart for preparing the arrayed helical carbon nanofibers;
[0025] Figure 2 Optical images of the array-arranged spiral carbon nanofiber sponges prepared in Example 1, Example 3, and Example 9;
[0026] Figure 3 10um scanning electron microscope analysis image of the array-arranged spiral carbon nanofiber sponge prepared in Example 2 and Example 4;
[0027] Figure 4 The single array-arranged spiral carbon nanofiber sponges prepared in Example 7 and Example 8 were subjected to transmission electron microscopy analysis;
[0028] Figure 5 X-ray diffraction (XRD) analysis was performed on the array-arranged spiral carbon nanofiber sponges prepared in Example 3 and Example 5;
[0029] Figure 6 The array-arranged spiral carbon nanofiber sponges prepared in Example 6 and Example 8 were analyzed using Raman spectroscopy technology;
[0030] Figure 7 Contact angle measurement and analysis were performed for the array-arranged spiral carbon nanofiber sponges prepared in Example 3 and Example 9;
[0031] Figure 8 The hydrophobic properties of the arrayed spring-shaped spiral carbon nanofiber sponge prepared in Example 4 were analyzed. DETAILED DESCRIPTION
[0032] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.
[0033] Example 1: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (twisted spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0034] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0035] (1) 10 mg of nanometal precursor (copper tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 1 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 80° C. for 5 h to obtain a pretreated nanometal precursor;
[0036] (2) Spreading the pretreated nanometal precursor flat in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 2°C / min to a temperature of 290°C and introducing argon uniformly for 4 hours, wherein the flow rate of argon is 80 mL / min; the copper tartrate precursor is decomposed into catalyst nanocopper;
[0037] (3) Switching argon gas to carbon-containing gas (acetylene) and uniformly passing it into a chemical vapor deposition tube furnace at a flow rate of 65 mL / min, and performing nano-metal (nano-copper) catalytic vapor deposition at a temperature of 290°C for 2.2 h to form twisted helical carbon nanofibers (TCNFs);
[0038] (4) The carbon-containing gas (acetylene) was switched to argon gas and introduced into a chemical vapor deposition tube furnace at a flow rate of 80 mL / min, and then cooled to room temperature at a cooling rate of 10 °C / min to obtain a kinked spiral carbon nanofiber sponge.
[0039] Example 2: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (twisted spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0040] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0041] (1) 10 mg of nanometal precursor (copper tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 3.3 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 60° C. for 9 h to obtain a pretreated nanometal precursor;
[0042] (2) Spreading the pretreated nano-metal precursor flat in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 5°C / min to a temperature of 280°C, and introducing argon uniformly for 0.5h, wherein the flow rate of argon is 50mL / min; the copper tartrate precursor is decomposed into catalyst nano-copper;
[0043] (3) Switching argon gas to carbon-containing gas (acetylene) and uniformly passing it into a chemical vapor deposition tube furnace at a flow rate of 40 mL / min, and performing nano-metal (nano-copper) catalytic vapor deposition at a temperature of 280°C for 1.5 h to form twisted helical carbon nanofibers (TCNFs);
[0044] (4) The carbon-containing gas (acetylene) was switched to argon gas and introduced into a chemical vapor deposition tube furnace at a flow rate of 50 mL / min, and then cooled to room temperature at a cooling rate of 5 °C / min to obtain an array-arranged kinked spiral carbon nanofiber sponge.
[0045] Example 3: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (twisted spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0046] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0047] (1) 10 mg of nanometal precursor (copper tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 1.67 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 70° C. for 7.5 h to obtain a pretreated nanometal precursor;
[0048] (2) Spreading the pretreated nano-metal precursor flat in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 8°C / min to a temperature of 310°C, and introducing nitrogen uniformly for 0.5h, wherein the flow rate of nitrogen is 50mL / min; the copper tartrate precursor is decomposed into catalyst nano-copper;
[0049] (3) Switching nitrogen to carbon-containing gas (acetylene) and uniformly passing it into a chemical vapor deposition tube furnace at a flow rate of 75 mL / min, and performing nanometal (nanocopper) catalytic vapor deposition at a temperature of 310°C for 1.5 h to form twisted helical carbon nanofibers (TCNFs);
[0050] (4) The carbon-containing gas (acetylene) was switched to nitrogen and introduced into a chemical vapor deposition tube furnace at a flow rate of 50 mL / min, and then cooled to room temperature at a cooling rate of 6 °C / min to obtain an array-arranged kinked spiral carbon nanofiber sponge.
[0051] Example 4: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (spring-like spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0052] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0053] (1) 10 mg of nanometal precursor (ferric tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 1.1 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 80° C. for 5.5 h to obtain a pretreated nanometal precursor;
[0054] (2) Spreading the pretreated nano-metal precursor in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 4°C / min to a temperature of 360°C and introducing argon uniformly for 2 hours, wherein the flow rate of argon is 65 mL / min; the ferric tartaric acid precursor is decomposed into catalyst nano-iron;
[0055] (3) Switching argon gas to carbon-containing gas (acetylene) and uniformly passing it into a chemical vapor deposition tube furnace at a flow rate of 80 mL / min, and performing nanometal (nanoiron) catalytic vapor deposition at a temperature of 360°C for 1.5 h to form spring-shaped spiral carbon nanofibers (SCNFs);
[0056] (4) The carbon-containing gas (acetylene) was switched to argon gas and introduced into a chemical vapor deposition tube furnace at a flow rate of 65 mL / min, and then cooled to room temperature at a cooling rate of 7 °C / min to obtain an array-arranged spring-shaped spiral carbon nanofiber sponge.
[0057] Example 5: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (spring-like spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0058] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0059] (1) 10 mg of nanometal precursor (copper tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 4 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 80° C. for 6 h to obtain a pretreated nanometal precursor;
[0060] (2) Spreading the pretreated nano-metal precursor flat in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 7°C / min to a temperature of 380°C, and introducing argon gas uniformly for 3 hours, wherein the flow rate of argon gas is 75 mL / min; the copper tartrate precursor is decomposed into catalyst nano-copper;
[0061] (3) Switching argon gas to carbon-containing gas (acetylene) and uniformly passing it into a chemical vapor deposition tube furnace at a flow rate of 60 mL / min, and performing nanometal (nanocopper) catalytic vapor deposition at a temperature of 380°C for 2 h to form spring-shaped spiral carbon nanofibers (SCNFs);
[0062] (4) The carbon-containing gas (acetylene) was switched to argon gas and introduced into a chemical vapor deposition tube furnace at a flow rate of 80 mL / min, and then cooled to room temperature at a cooling rate of 8 °C / min to obtain a spring-shaped spiral carbon nanofiber sponge.
[0063] Example 6: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (twisted spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0064] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0065] (1) 10 mg of nanometal precursor (copper tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 1.25 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 80° C. for 6 h to obtain a pretreated nanometal precursor;
[0066] (2) Spreading the pretreated nano-metal precursor in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 1°C / min to a temperature of 315°C, and introducing nitrogen uniformly for 3 hours, wherein the flow rate of nitrogen is 60 mL / min; the copper tartrate precursor is decomposed into catalyst nano-copper;
[0067] (3) Switching nitrogen to carbon-containing gas (acetylene) and passing it into a chemical vapor deposition tube furnace at a flow rate of 50 mL / min, and catalyzing the vapor deposition of nanometal (nanocopper) for 2 h at a temperature of 315 °C to form twisted helical carbon nanofibers (TCNFs);
[0068] (4) The carbon-containing gas (acetylene) was switched to nitrogen and introduced into a chemical vapor deposition tube furnace at a flow rate of 55 mL / min, and then cooled to room temperature at a cooling rate of 5 °C / min to obtain an array-arranged kinked spiral carbon nanofiber sponge.
[0069] Example 7: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (twisted spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0070] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0071] (1) 10 mg of nanometal precursor (ferric tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 2.5 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 70° C. for 5 h to obtain a pretreated nanometal precursor;
[0072] (2) Spreading the pretreated nano-metal precursor in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 10°C / min to a temperature of 305°C, and introducing argon uniformly for 4 hours, wherein the flow rate of argon is 80 mL / min; the tartaric acid iron precursor is decomposed into catalyst nano-iron;
[0073] (3) Switching argon gas to carbon-containing gas (acetylene) and uniformly passing it into a chemical vapor deposition tube furnace at a flow rate of 40 mL / min, and performing nanometal (nanoiron) catalytic vapor deposition at a temperature of 305°C for 1.5 h to form twisted helical carbon nanofibers (TCNFs);
[0074] (4) The carbon-containing gas (acetylene) was switched to argon gas and introduced into a chemical vapor deposition tube furnace at a flow rate of 75 mL / min, and then cooled to room temperature at a cooling rate of 6 °C / min to obtain a kinked spiral carbon nanofiber sponge.
[0075] Example 8: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (spring-like spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0076] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0077] (1) 10 mg of nanometal precursor (ferric tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 1.43 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 80° C. for 6 h to obtain a pretreated nanometal precursor;
[0078] (2) Spreading the pretreated nano-metal precursor in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 3°C / min to a temperature of 360°C, and introducing argon uniformly for 3.5 hours, wherein the flow rate of argon is 65 mL / min; the tartaric acid iron precursor is decomposed into catalyst nano-iron;
[0079] (3) Switching argon gas to carbon-containing gas (methane) and passing it into a chemical vapor deposition tube furnace at a flow rate of 40 mL / min, nanometal (nanoiron) catalyzed vapor deposition was performed at a temperature of 290°C for 4 h to form spring-shaped spiral carbon nanofibers (SCNFs);
[0080] (4) The carbon-containing gas (methane) was switched to argon gas and introduced into a chemical vapor deposition tube furnace at a flow rate of 60 mL / min, and then cooled to room temperature at a cooling rate of 6 °C / min to obtain an array-arranged spring-shaped spiral carbon nanofiber sponge.
[0081] Example 9: The array spiral carbon nanofiber sponge of this example is prepared by reacting nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas to obtain a spiral carbon nanofiber sponge with a high elastic modulus. The spiral carbon nanofiber sponge arranged in this array is a self-supporting sponge block (spring-like spiral structure) with a diameter of 99 to 174 nm and is regularly entangled with each other; the surface of the carbon array spiral carbon nanofiber sponge contains many defects, the catalyst is embedded in the fiber and carries organic functional groups C=C, CH, and OH;
[0082] A method for preparing an array spiral carbon nanofiber sponge, the specific steps are as follows:
[0083] (1) 10 mg of nanometal precursor (ferric tartrate precursor) was uniformly dispersed in ethanol to obtain a nanometal precursor dispersion with a concentration of 2.2 g / L, and the nanometal precursor dispersion was directly dried at a temperature of 75° C. for 6.5 h to obtain a pretreated nanometal precursor;
[0084] (2) Spreading the pretreated nano-metal precursor flat in a porcelain boat, and then placing it in a chemical vapor deposition tube furnace, heating it uniformly at a heating rate of 10°C / min to a temperature of 380°C and introducing argon uniformly for 1.5 hours, wherein the flow rate of argon is 80 mL / min; the tartaric acid iron precursor is decomposed into catalyst nano-iron;
[0085] (3) Switching argon gas to carbon-containing gas (methane) and uniformly passing it into a chemical vapor deposition tube furnace at a flow rate of 60 mL / min, and performing nanometal (nanoiron) catalytic vapor deposition at a temperature of 380°C for 1.5 h to form spring-shaped spiral carbon nanofibers (SCNFs);
[0086] (4) The carbon-containing gas (methane) was switched to argon gas and introduced into a chemical vapor deposition tube furnace at a flow rate of 60 mL / min, and then cooled to room temperature at a cooling rate of 8 °C / min to obtain an array-arranged spring-shaped spiral carbon nanofiber sponge.
[0087] The spiral carbon nanofiber sponges prepared in Example 1, Example 3 and Example 9 were analyzed by scanning electron microscope. Figure 2 As shown, the scale bar is 10um; it can be seen in the figure that the spiral carbon nanofibers are arranged in an orderly manner to form a clear array structure, indicating that the growth conditions are effectively controlled during the synthesis process;
[0088] The spiral carbon nanofiber sponges arranged in arrays prepared in Example 2 and Example 4 were subjected to scanning electron microscopy analysis at a higher magnification. Figure 3 As shown, the scale bar is 1um. Figure 3 It can be observed that the helical carbon nanofibers exhibit different helical structures, namely, kinked helical carbon nanofibers (TCNFs) and spring-like helical carbon nanofibers (SCNFs). Both have relatively smooth surfaces, can reach several microns in length, and may vary in different regions. The fiber diameter ranges from tens to hundreds of nanometers.
[0089] The single array-arranged spiral carbon nanofiber sponges prepared in Example 7 and Example 8 were analyzed by transmission electron microscopy. The results are as follows: Figure 4 As shown in the transmission electron microscopy analysis of TCNFs, the diffraction rings appear relatively blurred ( Figure 4 b), there are no ordered clusters near the middle of the fiber, and most of them are disordered clusters ( Figure 4 c), ordered clusters were observed only at the outer boundaries of the fibers ( Figure 4 d); No graphite fringes were observed in the high-resolution TEM images of SCNFs ( Figure 4 f), and the corresponding selected area electron diffraction (SAED) pattern shows the weakest diffraction ring, indicating that the graphitization degree of SCNFs is the lowest ( Figure 4 g and 4h), the results are also consistent with the XRD analysis;
[0090] The array-arranged spiral carbon nanofiber sponges prepared in Example 3 and Example 5 were subjected to X-ray diffraction (XRD) analysis. Figure 5 As shown in the figure, the physical structure of the spiral carbon nanofibers of the two structures arranged in the array can be determined. There is a characteristic peak at about 25°, which corresponds to the (0 0 2) plane, indicating that it has good graphitization properties; at the same time, CuO and Cu2O phases were found at 36° and 43°, because the catalyst used in the synthesis process is nano-copper, and the Cu phase is oxidized by oxygen in the air;
[0091] The spiral carbon nanofiber sponges arranged in arrays prepared in Example 6 and Example 8 were subjected to Raman spectroscopy analysis. Figure 6The characteristic peaks in the Raman spectrum mainly include G peak and D peak. The G peak of TCNFs and SCNFs is located at about 1580cm, while the D peak is located at about 1330cm. The ratio of the intensity of the D peak to the G peak is widely used as an important indicator for evaluating the degree of defects in materials. It is known from calculations that the I D / I G The values are 2.09 and 2.12, respectively, indicating that the two structures of the helical carbon nanofiber sponges have larger surface defects and amorphous degree;
[0092] The contact angle of the spiral carbon nanofiber sponge arranged in an array prepared in Example 3 and Example 9 was measured. The hydrophobicity of the spiral carbon nanofiber sponge arranged in an array was tested. Figure 7 ; The contact angle measurement experiment is mainly used to evaluate the wettability of the material surface. By measuring the contact angle, it is possible to intuitively determine whether the material surface is hydrophilic or hydrophobic. The contact angle of TCNFs was measured to be 124.0 degrees, indicating that it has good hydrophobic properties; while the contact angle of SCNFs is as high as 151.3 degrees, indicating that it has the characteristics of super-hydrophobic materials. By analyzing the oil-water separation characteristics of the array-arranged spiral carbon nanofiber sponge, its potential in fluid separation applications is explored;
[0093] The hydrophobic and oleophilic properties of the spring-shaped helical carbon nanofiber sponge arranged in an array in Example 4 are shown in Figure 8 When water drops are dripped into the spring-shaped spiral carbon nanofiber sponge, an obvious hydrophobic effect can be observed; this phenomenon occurs due to the curved spring-like structure inside the SCNFs, which exhibits excellent hydrophobicity; then oil drops are dripped into the sponge block to observe the surface of the sponge block, and it can be seen that the spring-shaped spiral carbon nanofiber sponge block has a strong ability to absorb oil in a short time; this characteristic reflects that the spring-shaped spiral carbon nanofiber sponge has both hydrophobic and oleophilic properties.
[0094] The specific implementation modes of the present invention are described in detail above, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.
Claims
1. An array spiral carbon nanofiber sponge, characterized in that: The spiral carbon nanofiber sponge is prepared by reacting with nanometal as a catalyst precursor under the inflow of protective gas and carbon-containing organic molecular gas. The spiral carbon nanofiber sponge is a self-supporting sponge block formed by spiral carbon nanofibers with a diameter of 99 to 174 nm that are regularly entangled with each other. The structure of the array of spiral carbon nanofiber sponges is a kinked spiral structure or a spring-like spiral structure.
2. The array spiral carbon nanofiber sponge according to claim 1, characterized in that: The array spiral carbon nanofiber sponge has a thickness of 1 to 3.5 cm and a length of 5 to 8 cm.
3. The method for preparing the array spiral carbon nanofiber sponge according to claim 1 or 2, characterized in that: The specific steps are as follows: (1) uniformly dispersing the nanometal precursor in ethanol to obtain a nanometal precursor dispersion, and directly drying the nanometal precursor dispersion to obtain a pretreated nanometal precursor; (2) placing the pretreated nanometal precursor in a chemical vapor deposition tube furnace, uniformly heating the temperature to 280-400° C. and uniformly introducing a protective gas for 0.5-4 h; (3) switching the protective gas to a carbon-containing organic molecular gas and uniformly passing it into a chemical vapor deposition tube furnace, and performing nano-metal catalytic vapor deposition at a temperature of 280 to 400° C. for 1.5 to 4 hours to promote the formation of spiral carbon nanofibers; (4) The carbon-containing gas is switched to a protective gas and introduced into a chemical vapor deposition tube furnace at a uniform speed, and then cooled to room temperature at a uniform speed to obtain an array-arranged spiral carbon nanofiber sponge.
4. The method for preparing the array spiral carbon nanofiber sponge according to claim 3, characterized in that: In step (1), the nano-metal precursor is an iron-based catalyst or a copper-based catalyst, and the concentration of the nano-metal precursor dispersion is 1 to 4 g / L.
5. The method for preparing the array spiral carbon nanofiber sponge according to claim 3, characterized in that: The drying temperature of step (1) is 60-80° C. and the drying time is 5-9 hours.
6. The method for preparing the array spiral carbon nanofiber sponge according to claim 3, characterized in that: In step (2), the protective gas is nitrogen or an inert gas, the flow rate is 40 to 80 mL / min, and the uniform heating rate is 1 to 10°C.
7. The method for preparing the array spiral carbon nanofiber sponge according to claim 3, characterized in that: The carbon-containing gas in step (3) is methane or acetylene, and the flow rate is 50-80 mL / min.
8. The method for preparing the array spiral carbon nanofiber sponge according to claim 3, characterized in that: In step (4), the protective gas is nitrogen or an inert gas, the flow rate is 40 to 80 mL / min, and the uniform cooling rate is 5 to 10° C. / min.
9. The arrayed spiral carbon nanofiber sponge according to claim 1 or 2 is used as an oil-water separation material in oil-water fluid separation.