A nickel-carbon composite material, its preparation method and application

Abstract

The present invention relates to the technical field of microwave absorption materials, and in particular to a nickel-carbon composite material, a preparation method thereof, and an application thereof. The preparation method of the carbon-nickel composite material includes: calcining a raw material containing a nickel salt under an inert atmosphere condition to obtain a carbon-nickel composite material; wherein, the nickel salt includes nickel acetate salt. The present invention also relates to the preparation and application of a nickel-carbon composite material and a metal-doped composite material thereof. The present invention has advantages such as a simple synthesis method, good microwave absorption and heating effects, and a significant effect on catalytically breaking chemical bonds, can achieve good catalytic effects, has broad development prospects and excellent economic benefits, and has far-reaching industrial application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of wave absorbing materials, and in particular to a nickel-carbon composite material and a preparation method and application thereof. Background Art

[0002] Absorbing materials can absorb or weaken the incident electromagnetic waves and convert them into heat or other ways to dissipate the electromagnetic wave energy. Currently, more research is applied to the development of civilian electromagnetic radiation protection and military stealth, and less research is done on microwave absorption heating catalytic reactions. At present, traditional microwave catalysis is to mechanically mix non-absorbent catalysts with absorbing carriers and then heat them for catalysis. This heating method is actually still heating the catalyst for catalytic reaction by heat conduction, which does not have a good heating catalytic effect and increases energy consumption.

[0003] In recent years, the research on microwave absorbing materials has also made some progress, but the catalytic benefits and sintering of microwave absorbing materials at high temperatures still face huge challenges. Due to the characteristics of microwave heating, it is easy to cause the local temperature of the catalyst to be too high, which will cause the catalyst to sinter and deactivate. At present, there is an urgent need to prepare a microwave absorbing material that can resist sintering for large-scale production. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a preparation method and application of a nickel-carbon composite material.

[0005] The present invention aims at the catalytic performance and sintering problems of microwave catalysts, and prepares a composite material of carbon-wrapped nickel, and a nickel-carbon and doped metal composite material obtained by carrying out other metal loading modification on the composite material. The preparation method is simple, and large-scale production can be carried out. It has a good catalytic decomposition effect in the decomposition of low-carbon alcohols, polycarbon hydrocarbons and other substances.

[0006] In a first aspect, the present invention provides a method for preparing a carbon-nickel composite material, comprising: calcining a raw material containing a nickel salt under an inert atmosphere to obtain a carbon-nickel composite material; wherein the nickel salt comprises nickel acetate.

[0007] The preparation method of the present invention is simple, has the possibility of large-scale production, and has a good catalytic decomposition effect on the decomposition of low-carbon alcohols, polycarbon hydrocarbons and other substances. The catalyst carbon-nickel and other metal compound composite materials obtained by the present invention not only have excellent microwave absorption and heating effects, but also can wrap nickel element to prevent nickel from being oxidized, can be stored for a long time under normal temperature and pressure conditions, and elemental nickel and other metal composites can have a good catalytic effect. The nickel-carbon composite material provided by the present invention is used for microwave heating catalysis, has good microwave absorption capacity, can effectively prevent catalyst sintering, and has good catalytic decomposition of low-carbon alcohols and polycarbon hydrocarbons and other substances.

[0008] Preferably, the nickel salt is nickel acetate with crystal water or nickel acetate without crystal water, preferably nickel acetate tetrahydrate.

[0009] More preferably, it further includes the step of metal doping to obtain a nickel-carbon metal-doped composite material;

[0010] Preferably, the preparation method includes: calcining the compound containing the doped metal and the nickel salt under an inert atmosphere condition to obtain a nickel-carbon metal-doped composite material;

[0011] Or, impregnating the doped metal on the carbon-nickel composite material to obtain a nickel-carbon metal-doped composite material.

[0012] More preferably, it includes: mixing and grinding the compound of the doped metal with the nickel salt, and then performing anaerobic decomposition preparation. Preferably, under an inert atmosphere condition, the temperature is raised by programmed temperature control. After reaching the set temperature, it is maintained for the set time, and then gradually cooled to room temperature to obtain a nickel-carbon metal-doped composite material; preferably, the grinding time is 25-30 min.

[0013] Preferably, the initial temperature of the programmed temperature control is room temperature, the heating rate is controlled at 1-20 °C / min, the final temperature reached is 400-1000 °C, it is maintained for 1-3 h, the cooling rate is 1-20 °C / min, and the flow rate of the inert gas is 10-100 mL / min;

[0014] More preferably, the initial temperature is room temperature, the heating control rate is between 5-10 °C / min, the final temperature reached is between 400-600 °C, it is maintained for 1-3 h, the cooling rate is between 2-10 °C / min, and the flow rate of the inert gas is 10-50 mL / min.

[0015] It is found through experimental research in the present invention that when preferably using nickel acetate tetrahydrate for decomposition under an inert atmosphere, by adjusting the heating rate to 5 °C / min, heating to 550 °C, maintaining for 2 h, and the cooling rate to 5 °C / min, the wave-absorbing performance of the nickel-carbon composite material can be improved, the morphology of the material can be improved to obtain a nanomaterial with more uniform and smaller particle sizes, the microwave absorption performance of the material can be enhanced, and the catalytic effect is more excellent.

[0016] Preferably, it includes: mixing the solution of the compound containing the doped metal with the nickel-carbon composite material, performing ultrasonic treatment, and impregnating the doped metal on the carbon-nickel composite material to obtain a nickel-carbon metal-doped composite material;

[0017] Preferably, an aqueous solution or an ethanol solution of a compound containing a doped metal is mixed with the nickel-carbon composite material, and ultrasonic treatment is carried out for 20 to 50 minutes, preferably 25 to 30 minutes, and then vacuum drying is carried out at 40 to 80 °C for 24 to 72 hours under an inert atmosphere, and then decomposition is carried out under controlled heating under inert conditions to obtain a nickel-carbon metal-doped composite material;

[0018] And / or, the decomposition conditions include: programmed temperature control with an initial temperature of room temperature, a controlled heating rate of 1 to 20 °C / min, a final temperature reached of 200 to 1000 °C, held for 1 to 3 hours, a cooling rate of 1 to 20 °C / min, and an inert gas flow rate of 10 to 100 mL / min;

[0019] More preferably, the initial temperature is room temperature, the heating control rate is between 1 and 10 °C / min, the final temperature reached is between 200 and 1000 °C, after holding for 1 to 3 hours, the cooling rate is between 2 and 10 °C / min, and the inert gas flow rate is 10 to 50 mL / min. In the present invention, the final temperature can be determined according to the decomposition temperature of the impregnated metal compound.

[0020] In the present invention, the obtained nickel-carbon composite material is used to obtain a nickel-carbon and metal-doped composite material by an impregnation method, which is beneficial to improving the effect under preferred conditions.

[0021] Further preferably, the doped metal includes one or more of cerium, zirconium, copper, iron, cobalt, zinc, calcium, sodium, magnesium, palladium, platinum, gold, and silver; and / or, the mass fraction loading of the doped metal is 0 to 20%, preferably 0.1 to 10%.

[0022] In the present invention, combining a doped metal on the basis of a specific nickel-carbon composite material has a better catalytic effect, and the catalytic activity is greatly improved after further loading the above other metals in the present invention.

[0023] According to the present invention, the nickel-carbon composite material and the nickel-carbon composite material loaded with other metals, namely the nickel-carbon metal-doped composite material, have a good catalytic decomposition effect on lower alcohols, lower hydrocarbons, aldehydes, ketones, and ether compounds. Further preferably, loading doped metals such as cerium, zirconium, copper, iron, zinc, cobalt, platinum, and palladium has a very good decomposition effect on the decomposition of lower-carbon compounds.

[0024] In the present invention, the calculation method of the mass fraction loading of the doped metal is the percentage of the mass of the loaded metal atoms to the mass of the nickel atoms. The supported catalysts obtained by the above two methods in the present invention can both be reduced by hydrogen.

[0025] As a preference, it further includes a step of reducing the nickel-carbon composite material by hydrogen. The obtained metal oxide in the present invention is reduced by hydrogen to obtain a nickel-carbon and other metal single-component composite material.

[0026] In a second aspect, the present invention also provides a nickel-carbon composite material obtained by the preparation method of the nickel-carbon composite material.

[0027] The carbon-nickel and other metal compound composite material of the present invention has the carbon not only having an excellent wave absorbing and heating effect, but also can wrap the nickel element to prevent the nickel from being oxidized, and can be preserved for a long time under normal temperature and pressure conditions. The elemental nickel and other metal composite materials can have a good catalytic effect.

[0028] Preferably, the carbon-nickel composite nanoparticles have a particle size of 20 to 200 nm, and preferably, the carbon in the nickel-carbon composite material encapsulates a single nickel.

[0029] In a third aspect, the present invention also provides the use of the nickel-carbon composite material in a microwave heating catalytic reaction.

[0030] The beneficial effect of the present invention is at least that: the nickel-carbon composite material and the metal-loaded nickel-carbon composite material provided by the present invention have the advantages of simple synthesis method, good microwave absorption heating effect, and significant catalytic breaking chemical bond effect. Different metals can be used for loading modification for different reactants to achieve good catalytic effect, and have broad development prospects and excellent economic benefits, and have far-reaching industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 The XRD diagram of the nickel-carbon composite material in the embodiment;

[0033] Figure 2 This is a SEM image of the nickel-carbon composite material in the embodiment;

[0034] Figure 3 TEM image of the nickel-carbon composite material in the embodiment;

[0035] Figure 4 TEM image of the nickel-carbon composite material in the embodiment. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the invention clearer, the technical solution in the embodiments of the invention is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the invention, not all of the embodiments. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0037] Unless otherwise specified, the raw materials and reagents used in the following examples are all commercially available. If no specific techniques or conditions are specified in the examples, they are all conventional methods or the techniques or conditions described in the literature in this field, or according to the product instructions. If the manufacturers of the reagents and instruments are not specified, they are all conventional products that can be purchased through regular channels.

[0038] In the embodiment of the present invention, the microwave device adopts a single-mode heating method. The feeding method is a bubbling method, using an inert gas to bring a small amount of liquid reactants into the microwave reactor, and the product gas after the reaction directly enters the chromatographic analysis. The raw materials were purchased from Aladdin.

[0039] The present invention will be further described below with reference to the embodiments.

[0040] Example 1

[0041] This embodiment provides a method for preparing a nickel-carbon composite material, which is as follows:

[0042] Take 30g of nickel acetate tetrahydrate and grind it thoroughly for 30min to make it into finer particles. Put it into a tube furnace, pass Ar flow rate 30mL / min, initial temperature 30℃, heating rate 5℃ / min, after reaching 550℃, keep it for 1.5h, and cool it to room temperature at 5℃ / min to obtain a nickel-carbon composite material. Figure 1 The XRD diagram of the nickel-carbon composite material in the embodiment, as shown in the figure, the three more obvious diffraction peaks are all diffraction peaks of Ni single substance; Figure 2 This is a scanning electron microscope image of the nickel-carbon composite material, showing that the material is a bulk nanomaterial; Figure 3 , 4 The transmission electron microscope image of the nickel-carbon composite material shows that the material has a two-layer structure, the outer layer is a carbon structure, and the inner layer is a single nickel. Figure 4 The more obvious lattice fringes with lighter colors on the outside have been verified to be graphite, while the lattice fringes with darker colors on the inside are nickel.

[0043] Application Example 1

[0044] Catalytic reaction of methanol on nickel-carbon composites under microwave conditions

[0045] Take the nickel-carbon composite material of Example 1 as a catalyst and a microwave absorber, put it into a microwave fixed-bed reactor, add 2.5 g of the nickel-carbon composite material, and control the mass space velocity of the methanol catalytic reaction to be 0.5 g / (g·h), and conduct reaction tests at 80 °C, 100 °C, and 130 °C.

[0046] The following Table C1-C6 refers to C1-C6 alkane and alkene organic compounds

[0047] Table 1 Reaction test results

[0048]

[0049] Catalytic reaction of nickel-carbon composite material on methanol under microwave conditions

[0050] Take the nickel-carbon composite material of Example 1 as a catalyst and a microwave absorber, put it into a microwave fixed-bed reactor, add 2.5 g of the nickel-carbon composite material, and control the mass space velocity of the methanol catalytic reaction to be 0.5 g / (g·h), and conduct a stability reaction test at 100 °C for 10 h. The following Table C1-C6 refers to C1-C6 alkane and alkene organic compounds.

[0051] Table 2 Reaction test results

[0052]

[0053]

[0054] Application Example 2

[0055] Catalytic reaction of nickel-carbon composite material on ethanol under microwave conditions

[0056] Take the nickel-carbon composite material of Example 1 as a catalyst and a microwave absorber, put it into a microwave fixed-bed reactor, add 2.5 g of the nickel-carbon composite material, and control the mass space velocity of the ethanol catalytic reaction to be 0.5 g / (g·h), and conduct reaction tests at 70 °C, 100 °C, and 130 °C. The test results are shown in the following table, where C1-C6 in the table refers to C1-C6 alkane and alkene organic compounds.

[0057] Table 3 Reaction test results

[0058]

[0059] Example 2

[0060] This example provides a preparation method of a nickel-carbon and cerium-zirconium oxide composite material, which is as follows:

[0061] Take 30 g of nickel acetate tetrahydrate, 0.122 g of zirconium hydroxide, and 0.104 g of cerium hydroxide, and mix and grind the three for 30 min to make them evenly mixed. Put them into a tube furnace, introduce Ar at a flow rate of 30 mL / min, with an initial temperature of 30 °C and a heating rate of 5 °C / min. After reaching 550 °C, hold for 1.5 h, and then cool to room temperature at 5 °C / min to obtain a nickel-carbon and zirconium oxide and cerium oxide composite material. The loadings of zirconium and cerium are both 1 wt.%.

[0062] Application Example 3

[0063] Catalytic reaction of nickel-carbon and zirconium oxide-cerium oxide composite material on methanol under microwave conditions

[0064] Take the nickel-carbon composite material of Example 2 as a catalyst and a microwave absorber, put it into a microwave fixed-bed reactor, add 2.5 g of the nickel-carbon composite material, and control the mass space velocity of the methanol catalytic reaction to be 0.5 g / (g·h). Conduct reaction tests at 80 °C, 100 °C, and 130 °C. The test results are shown in the following table, where C1-C6 refers to C1-C6 alkane and alkene organic compounds.

[0065] Table 4 Reaction test results

[0066]

[0067] Application Example 4

[0068] Catalytic reaction of nickel-carbon and zirconium oxide-cerium oxide composite material on ethanol under microwave conditions

[0069] Take the nickel-carbon composite material of Example 1 as a catalyst and a microwave absorber, put it into a microwave fixed-bed reactor, add 2.5 g of the nickel-carbon composite material, and control the mass space velocity of the ethanol catalytic reaction to be 0.5 g / (g·h). Conduct reaction tests at 70 °C, 100 °C, and 130 °C. The test results are shown in the following table, where C1-C6 refers to C1-C6 alkane and alkene organic compounds.

[0070] Table 5 Reaction test results

[0071]

[0072] Comparative Example 1

[0073] This comparative example uses the same preparation method as the nickel-carbon composite material in Example 1, except that the raw material is changed to zinc acetate tetrahydrate. The specific operation is as follows: Take 30 g of zinc acetate tetrahydrate and grind it thoroughly for 30 min to make it into finer particles. Put it into a tube furnace, introduce Ar at a flow rate of 30 mL / min, with an initial temperature of 30 °C and a heating rate of 5 °C / min. After reaching 550 °C, hold for 1.5 h, and then cool to room temperature at 5 °C / min to obtain a zinc-carbon-containing composite material.

[0074] It was found that when the composite material obtained in Comparative Example 1 was placed in a microwave reactor, its microwave absorption ability was poor and it could not effectively perform microwave absorption heating, so it could not be used as a microwave absorber to heat and catalyze the reaction of substances.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. Application of a nickel-carbon composite material in a microwave heating catalytic reaction, characterized in that, The preparation method of the carbon-nickel composite material includes: under the condition of an inert atmosphere, calcining the raw material containing nickel salt to obtain the carbon-nickel composite material; wherein, the nickel salt is nickel acetate tetrahydrate; it also includes a step of metal doping, and the doping metal is selected from one or more of cerium, zirconium, copper, palladium, platinum, gold, and silver; the heating rate is controlled between 5 and 10 °C / min, the final temperature reached is between 550 and 600 °C, maintained for 2 to 3 h, the cooling rate is between 5 and 10 °C / min, and the flow rate of the inert gas is 10 to 50 mL / min.

2. The application according to claim 1, wherein The preparation method includes: calcining the compound containing the doping metal and the nickel salt under the condition of an inert atmosphere to obtain a nickel-carbon-metal doped composite material; or, impregnating the doping metal on the carbon-nickel composite material to obtain a nickel-carbon-metal doped composite material.

3. The application according to claim 2, wherein It includes: Mixing and grinding the compound of the doping metal with the nickel salt, then under the condition of an inert atmosphere, heating by program temperature control, after reaching the set temperature, maintaining for the set time, and then gradually cooling to room temperature to obtain a nickel-carbon-metal doped composite material.

4. The application according to claim 1, characterized in that It includes: Mixing the solution of the compound containing the doping metal with the carbon-nickel composite material, performing ultrasonic treatment, impregnating the doping metal on the carbon-nickel composite material to obtain a nickel-carbon-metal doped composite material.

5. The application according to claim 4, characterized in that, Mixing the aqueous solution or ethanol solution of the compound containing the doping metal with the carbon-nickel composite material, performing ultrasonic treatment for 20 to 50 min, then drying in vacuum at 40 to 80 °C for 24 to 72 h under an inert atmosphere, and then performing controlled heating and decomposition under an inert condition to obtain a nickel-carbon-metal doped composite material.

6. The application according to claim 5, wherein It also includes a step of hydrogen reduction of the carbon-nickel composite material.

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