Greenhouse gas reforming conversion catalyst based on carbon-hydrogen bond selective editing and preparation method and application thereof

Abstract

The invention discloses a greenhouse gas reforming conversion catalyst based on carbon-hydrogen bond selective editing and a preparation method and application thereof.The catalyst comprises active metal components Ni and Cu and a SiO2 carrier, Ni and Cu are loaded on the SiO2 carrier under the coulomb force effect, and the loading mass ratio of Ni to Cu in the catalyst is 2.56: 0.06; the preparation method comprises the following steps: dissolving nickel salt and copper salt in a solvent, adding stronger ammonia water, and stirring to form a first solution; dispersing SiO2 powder in a solvent to form a second solution; mixing and stirring the first solution and the second solution, centrifuging, taking precipitate, grinding, and calcining to obtain a final product. The catalyst can achieve dual purposes of photocatalytic hydrogen production and thermocatalytic combustible synthesis gas production by activating carbon-hydrogen bonds of methane.

Description

Technical Field

[0001] The present invention belongs to the technical field of solar fuel, and in particular relates to a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, and a preparation method and application thereof. Background Art

[0002] Converting greenhouse gases CO2 and CH4 into synthesis gas has bilateral advantages in mitigating the greenhouse effect and providing green raw materials for synthetic chemicals and fuels. Unfortunately, due to the large bond dissociation energy and low polarizability of CH4 and CO2, greenhouse gas upgrading undergoes an endothermic uphill reaction at 298K with a Gibbs free energy of up to +170kJ / mol, so high operating temperatures (>700℃) are usually required. Plasmonic metal nanostructures are gaining more and more attention as photocatalysts because they can react with light-driven reactions under milder conditions than traditional thermal catalysis. The strong interaction between light and plasmonic nanostructures provides the required energy conversion for photocatalytic conversion. However, in traditional technical solutions, the process of preparing photocatalysts usually requires the use of precious metals. Therefore, it is technically difficult to prepare a catalyst that does not require the use of precious metals and has excellent photocatalytic activity. Summary of the invention

[0003] Purpose of the invention: The present invention aims to provide a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds that does not contain precious metals and has good photocatalytic activity. It can absorb ultraviolet-visible light to reach the temperature required for the reaction and excite active metal high-energy hot electrons, thereby accelerating the first step that determines the reaction rate. * The first CH bond of CH4 is cracked, and the activation energy of the reaction is reduced at the same time, so as to realize the photothermal driven catalytic methane dry reforming to produce hydrogen. By continuously introducing gaseous reactants, stable and efficient hydrogen production can be achieved in the photothermal reactor; the present invention also aims to provide a method for preparing the greenhouse gas reforming conversion catalyst based on the selective editing of carbon-hydrogen bonds; the present invention also aims to provide the application of the greenhouse gas reforming conversion catalyst based on the selective editing of carbon-hydrogen bonds.

[0004] Technical solution: The greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds described in the present invention uses SiO2 as a carrier, nickel and copper as active metal components, Ni and Cu are loaded on the SiO2 carrier by Coulomb force, and the loading mass ratio of Ni and Cu in the catalyst is 2.56:0.06. Among them, the silica carrier and the nickel-copper alloy produce a strong metal-carrier interaction, which effectively disperses the metal active sites. The catalytic activity and resistance to carbon deposition of the catalyst are attributed to the synergistic effect of the photogenerated carrier and photothermal conversion. A small amount of copper can promote the injection of metal hot electrons induced by the local surface plasmon effect (LSPR) generated by photoexcited Ni into the antibonding orbit of the reactant, accelerating the first step that determines the reaction rate.* The first CH bond of CH4 is cleaved, and at the same time, the catalyst induces * The formation of CHO intermediates, thus avoiding * The complete cracking of CH4 and subsequent coke deposition demonstrate that this selective C-H bond editing method achieves the orderly conversion of CH4 and CO2 with the synergistic effects of high conversion, high efficiency and high stability.

[0005] The method for preparing the greenhouse gas reforming conversion catalyst based on the selective editing of carbon-hydrogen bonds comprises the following steps:

[0006] Nickel salt and copper salt are dissolved in a solvent, and concentrated ammonia water is added and stirred to form a first solution; SiO2 powder is dispersed in the solvent to form a second solution; the first solution and the second solution are mixed and stirred, and the precipitate is taken out after centrifugation, ground, and calcined to obtain the final product.

[0007] Furthermore, after adding concentrated aqueous ammonia, the pH of the solution was adjusted to 9-12, and then the stirring was continued for 0-5 hours.

[0008] Furthermore, the first solution and the second solution are mixed and stirred for 0-5 hours, the rotation speed during centrifugation is controlled to be 2000-10000 r / min, and the obtained precipitate is washed with water and ethanol for 1-5 times.

[0009] Furthermore, the calcination process includes: heating the ground catalyst precursor in a tube furnace to 600-700°C at a heating rate of 2-3°C / min, keeping the temperature for 0.5-1 hour, and cooling to room temperature along with the furnace.

[0010] The catalyst can be applied to the preparation of synthesis gas by dry reforming of CO2 source and light alkane source, the method is carried out in a photothermal reactor, and the application method comprises the following steps:

[0011] The catalyst is placed in a reaction crucible, and a mixed gas of methane, carbon dioxide and nitrogen is continuously transported through the pipeline of the reactor to purge the air in the pipeline. The xenon lamp is turned on to irradiate ultraviolet-visible light to simulate sunlight for concentrated irradiation. The light shines directly on the surface of the catalyst. After absorbing sunlight, the catalyst quickly heats up to the temperature required for the reaction, and photothermal coupled methane dry reforming is carried out to produce hydrogen.

[0012] Furthermore, in the method, the volume ratio of methane, carbon dioxide and nitrogen introduced into the reaction tube is 30.2% / 30.4% / 39.6%, and the total flow rate of the mixed gas is 50-100 ml / min.

[0013] Furthermore, the focused irradiation provides 3-5W of power on the catalyst surface without using other heating equipment, and the spot diameter of the focused illumination is 5-6mm.

[0014] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: the catalyst does not require the use of precious metals and has excellent photocatalytic activity; the catalytic activity and carbon deposition resistance of the catalyst of the present invention are attributed to the synergistic effect of the photogenerated carrier and photothermal conversion, wherein a small amount of copper can promote the injection of metal hot electrons induced by the local surface plasmon effect (LSPR) generated by photoexcited Ni into the antibonding orbit of the reactant, accelerating the first step that determines the reaction rate, * The first CH bond of CH4 is cleaved, and at the same time, the catalyst induces * The formation of CHO intermediates, thus avoiding * The complete cracking of CH4 and subsequent coke deposition demonstrate that this selective C-H bond editing method achieves the orderly conversion of CH4 and CO2 with the synergistic effects of high conversion, high efficiency and high stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the reaction mechanism diagram of photothermal driven methane dry reforming;

[0016] Figure 2 This is a simplified diagram of the photothermal driven methane dry reforming reaction process;

[0017] Figure 3 This is a TEM image of the NiCu / SiO2 photothermal driven methane dry reforming catalyst;

[0018] Figure 4 This is the XRD pattern of the photothermal driven methane dry reforming catalyst;

[0019] Figure 5 This is the H2-TPR spectrum of the photothermal driven methane dry reforming catalyst;

[0020] Figure 6 This is a comparison chart of the comprehensive performance of photothermal coupling of photothermal driven methane dry reforming catalysts;

[0021] Figure 7 This is a comparison chart of the photothermal coupled synthesis gas yield of photothermal driven methane dry reforming catalyst;

[0022] Figure 8 This is the stability diagram of NiCu / SiO2, a photothermal driven methane dry reforming catalyst;

[0023] Fig. 9 This is the CH4-TPD spectrum of the photothermal driven methane dry reforming catalyst;

[0024] Fig.10 It is the UV-Vis-NIR absorption spectrum of the photothermal driven methane dry reforming catalyst;

[0025] Fig.11This is a comparison chart of the greenhouse gas conversion rate and spectral absorption rate ratio of the photothermal driven methane dry reforming catalyst under light irradiation of different wavelengths;

[0026] Fig.12 This is the DFT calculation result of the key step of the photothermal driven methane dry reforming catalyst;

[0027] Fig.13 This is the DFT calculation result of the excited state of NiCu / SiO2 catalyst for photothermal driven methane dry reforming;

[0028] Fig.14 The figure is a comparison chart of the catalytic effects of the catalyst of the present invention and the catalyst of the prior art. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0030] Example

[0031] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0032] (1) dissolving 0.15 g of nickel nitrate hexahydrate and 0.0019 g of copper nitrate hexahydrate in 20 ml of deionized water, and stirring the mixture under magnetic stirring at room temperature for 30 min to form a first solution;

[0033] (2) Add concentrated aqueous ammonia to the mixed solution in (1) while stirring until the pH is 11.5, and then continue stirring for 1 hour;

[0034] (3) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0035] (4) Pour the solution in (2) into (3) and stir for 3 h;

[0036] (5) The mixed solution obtained in (4) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0037] (6) The precipitate obtained in (5) was dried at 80°C overnight and then ground to obtain a NiCu / SiO2-E catalyst precursor.

[0038] The NiCu / SiO2-E catalyst precursor was heated to 600°C at a heating rate of 2°C / min in a tubular furnace in a 10% H2, 90% N2 atmosphere, kept warm for 0.5 hours, and cooled to room temperature with the furnace to obtain a NiCu / SiO2-E catalyst with a loading mass ratio of Ni and Cu in the catalyst of 2.56:0.06.

[0039] like Figure 2As shown in the figure, photothermal driven methane dry reforming hydrogen production is carried out in a photothermal reactor, and the catalyst is placed in a special reaction crucible. During the reaction, the gas distribution system continuously introduces a mixture of methane, carbon dioxide, and nitrogen into the reactor, and the xenon lamp is turned on to irradiate ultraviolet-visible light to the catalyst surface. At this time, the catalyst absorbs sunlight to reach the reaction temperature for photothermal coupled methane dry reforming hydrogen production.

[0040] The activity test of the catalyst used for photothermal driven methane dry reforming hydrogen production in this embodiment was carried out (the photothermal driven methane dry reforming reaction mechanism diagram is as follows Figure 1 The specific test method is as follows:

[0041] (1) Weigh 0.010 g of NiCu / SiO2-E catalyst and place it in a reaction crucible;

[0042] (2) A mixed gas of methane, carbon dioxide, and nitrogen is continuously delivered through the pipeline of the reactor to purge the air in the pipeline;

[0043] (3) The volume ratio of methane, carbon dioxide and nitrogen introduced into the reaction tube is 30.2% / 30.4% / 39.6%, and the total flow rate of the mixed gas is 50 ml / min.

[0044] (4) Turn on the xenon lamp to irradiate ultraviolet-visible light to simulate sunlight for concentrated irradiation, with a light intensity of 3.3 W and a spot size of 6 mm, which just irradiates the surface of the catalyst Ni / SiO2-E;

[0045] (5) After absorbing solar energy, the catalyst NiCu / SiO2-E rapidly heats up to the required reaction temperature of 500°C, and performs photothermal coupled methane dry reforming to produce hydrogen;

[0046] (6) The reaction gas was passed into a gas chromatograph for detection, and the H2 yield was 17.9 mmol / min / g cat , CO production rate is 27.3mmol / min / g cat .

[0047] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this embodiment is 26.6 mmol / min / g. cat ,CO yield was 38.3mmol / min / g cat .

[0048] like Figure 3 As shown, the nanoscale bright spots are nickel-copper metal particles with a particle size of about 2nm. Figure 4 XRD spectrum of the catalyst. The catalyst carrier is silica. Due to the high dispersion and small particle size of the nickel-copper alloy, no sharp signal can be detected.

[0049] Comparative Example 1

[0050] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0051] (1) dissolving 0.15 g of nickel nitrate hexahydrate in 20 ml of deionized water and stirring magnetically at room temperature for 30 min to form a first solution;

[0052] (2) Add concentrated aqueous ammonia to the mixed solution in (1) while stirring until the pH is 11.5, and then continue stirring for 1 hour;

[0053] (3) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0054] (4) Pour the solution in (2) into (3) and stir for 3 h;

[0055] (5) The mixed solution obtained in (4) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0056] (6) The precipitate obtained in (5) was dried at 80°C overnight and then ground to obtain a Ni / SiO2 catalyst precursor.

[0057] (7) The Ni / SiO2 catalyst precursor was heated to 600°C at a heating rate of 2°C / min in a tubular furnace in a 10% H2, 90% N2 atmosphere, kept at this temperature for 0.5 hours, and cooled to room temperature to obtain a Ni / SiO2-E catalyst.

[0058] The activity test of the catalyst for photothermal driven methane dry reforming to produce hydrogen in this comparative example was carried out, and the specific test method was the same as that in the embodiment.

[0059] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this comparative example is 17.9 mmol / min / g. cat , CO production rate is 27.3mmol / min / g cat .

[0060] Comparative Example 2

[0061] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0062] (1) dissolving 0.15 g of nickel nitrate hexahydrate and 0.0014 g of copper nitrate hexahydrate in 20 ml of deionized water, and stirring the mixture under magnetic stirring at room temperature for 30 min to form a first solution;

[0063] (2) Add concentrated aqueous ammonia to the mixed solution in (1) while stirring until the pH is 11.5, and then continue stirring for 1 hour;

[0064] (3) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0065] (4) Pour the solution in (2) into (3) and stir for 3 h;

[0066] (5) The mixed solution obtained in (4) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0067] (6) The precipitate obtained in (5) was dried at 80°C overnight and then ground to obtain a NiC / SiO2-E catalyst precursor.

[0068] (7) The NiCu / SiO2-E catalyst precursor was heated to 600°C at a heating rate of 2°C / min in a tubular furnace in a 10% H2, 90% N2 atmosphere, kept at this temperature for 0.5 hours, and cooled to room temperature with the furnace to obtain a NiCu / SiO2-E catalyst. The loading mass ratio of Ni and Cu in the catalyst was 2.53:0.05.

[0069] The activity of the catalyst used for photothermal driven methane dry reforming to produce hydrogen in this comparative example was tested, and the specific testing method is the same as that in the example below.

[0070] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this comparative example is 17.4 mmol / min / g. cat , CO production rate is 26.2mmol / min / g cat .

[0071] Comparative Example 3

[0072] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0073] (1) dissolving 0.15 g of nickel nitrate hexahydrate and 0.00285 g of copper nitrate hexahydrate in 20 ml of deionized water, and stirring the mixture under magnetic stirring for 30 min at room temperature to form a first solution;

[0074] (2) Add concentrated aqueous ammonia to the mixed solution in (1) while stirring until the pH is 11.5, and then continue stirring for 1 hour;

[0075] (3) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0076] (4) Pour the solution in (2) into (3) and stir for 3 h;

[0077] (5) The mixed solution obtained in (4) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0078] (6) The precipitate obtained in (5) was dried at 80°C overnight and then ground to obtain a NiCu / SiO2-E catalyst precursor.

[0079] (7) The NiCu / SiO2-E catalyst precursor was heated to 600°C in a tube furnace in a 10% H2, 90% N2 atmosphere at a heating rate of 2°C / min, kept at this temperature for 0.5 hours, and cooled to room temperature with the furnace to obtain Ni3Cu 0.075 / SiO2-E catalyst, the loading mass ratio of Ni and Cu in the catalyst is 2.54:0.07.

[0080] The activity of the catalyst used for photothermal driven methane dry reforming to produce hydrogen in this comparative example was tested, and the specific testing method is the same as that in the example below.

[0081] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this comparative example is 16.3 mmol / min / g. cat , CO production rate is 25.2mmol / min / g cat .

[0082] Comparative Example 4

[0083] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0084] (1) dissolving 0.15 g of nickel nitrate hexahydrate and 0.038 g of copper nitrate hexahydrate in 20 ml of deionized water, and stirring the mixture under magnetic stirring at room temperature for 30 min to form a first solution;

[0085] (2) Add concentrated aqueous ammonia to the mixed solution in (1) while stirring until the pH is 11.5, and then continue stirring for 1 hour;

[0086] (3) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0087] (4) Pour the solution in (2) into (3) and stir for 3 h;

[0088] (5) The mixed solution obtained in (4) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0089] (6) The precipitate obtained in (5) was dried at 80°C overnight and then ground to obtain a NiCu / SiO2-E catalyst precursor.

[0090] (7) The Ni3Cu1 / SiO2-E catalyst precursor was heated to 600°C at a heating rate of 2°C / min in a tubular furnace in a 10% H2, 90% N2 atmosphere, kept at this temperature for 0.5 hours, and cooled to room temperature with the furnace to obtain a NiCu / SiO2-E catalyst. The loading mass ratio of Ni and Cu in the catalyst was 2.68:1.12.

[0091] The activity of the catalyst used for photothermal driven methane dry reforming to produce hydrogen in this comparative example was tested, and the specific testing method is the same as that in the example below.

[0092] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this comparative example is 7.9 mmol / min / g. cat , CO production rate is 10.0mmol / min / g cat .

[0093] Comparative Example 5

[0094] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0095] (1) dissolving 0.15 g of nickel nitrate hexahydrate and 0.076 g of copper nitrate hexahydrate in 20 ml of deionized water, and stirring the mixture under magnetic stirring at room temperature for 30 min to form a first solution;

[0096] (2) Add concentrated aqueous ammonia to the mixed solution in (1) while stirring until the pH is 11.5, and then continue stirring for 1 hour;

[0097] (3) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0098] (4) Pour the solution in (2) into (3) and stir for 3 h;

[0099] (5) The mixed solution obtained in (4) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0100] (6) The precipitate obtained in (5) was dried at 80°C overnight and then ground to obtain a NiCu / SiO2-E catalyst precursor.

[0101] (7) The NiCu / SiO2-E catalyst precursor was heated to 600°C at a heating rate of 2°C / min in a tubular furnace in a 10% H2, 90% N2 atmosphere, kept at this temperature for 0.5 hours, and cooled to room temperature with the furnace to obtain a NiCu / SiO2-E catalyst. The loading mass ratio of Ni and Cu in the catalyst was 2.79:2.18.

[0102] The activity of the catalyst used for photothermal driven methane dry reforming to produce hydrogen in this comparative example was tested, and the specific testing method is the same as that in the example below.

[0103] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this comparative example is 3.9 mmol / min / g. cat , CO production rate is 4.8mmol / min / g cat .

[0104] Comparative Example 6

[0105] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0106] (1) dissolving 0.15 g of nickel nitrate hexahydrate and 0.114 g of copper nitrate hexahydrate in 20 ml of deionized water, and stirring the mixture under magnetic stirring at room temperature for 30 min to form a first solution;

[0107] (2) Add concentrated aqueous ammonia to the mixed solution in (1) while stirring until the pH is 11.5, and then continue stirring for 1 hour;

[0108] (3) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0109] (4) Pour the solution in (2) into (3) and stir for 3 h;

[0110] (5) The mixed solution obtained in (4) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0111] (6) The precipitate obtained in (5) was dried at 80°C overnight and then ground to obtain a NiCu / SiO2-E catalyst precursor.

[0112] (7) The Ni3Cu3 / SiO2-E catalyst precursor was heated to 600°C at a heating rate of 2°C / min in a tubular furnace in a 10% H2, 90% N2 atmosphere, kept at this temperature for 0.5 hours, and cooled to room temperature with the furnace to obtain a NiCu / SiO2-E catalyst. The loading mass ratio of Ni and Cu in the catalyst was 2.84:2.67.

[0113] The activity of the catalyst used for photothermal driven methane dry reforming to produce hydrogen in this comparative example was tested, and the specific testing method is the same as that in the example below.

[0114] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this comparative example is 2.4 mmol / min / g.cat , CO production rate is 2.9mmol / min / g cat .

[0115] Comparative Example 7

[0116] A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, which is specifically prepared by the following method:

[0117] (1) dissolving 0.15 g of nickel nitrate hexahydrate and 0.0019 g of copper nitrate hexahydrate in 20 ml of deionized water, and stirring the mixture under magnetic stirring at room temperature for 30 min to form a first solution;

[0118] (2) Weigh 1 g of SiO2 powder and disperse it in deionized water, and sonicate for 0.5 h;

[0119] (3) Pour the solution in (1) into (2) and stir for 3 h;

[0120] (4) The mixed solution obtained in (3) was centrifuged at 6000 r / min, and the obtained precipitate was washed five times with water and ethanol;

[0121] (5) The precipitate obtained in (4) was dried at 80°C overnight and then ground to obtain Ni3Cu 0.06 / SiO2-I catalyst precursor.

[0122] (6) Ni3Cu 0.06 The / SiO2-I catalyst precursor was heated to 600°C in a tube furnace with a 10% H2, 90% N2 atmosphere at a heating rate of 2°C / min, kept at this temperature for 0.5 hours, and cooled to room temperature to obtain Ni3Cu 0.06 / SiO2-I catalyst.

[0123] The activity of the catalyst used for photothermal driven methane dry reforming to produce hydrogen in this comparative example was tested, and the specific testing method is the same as that in the example below.

[0124] According to the gas chromatograph detection and calculation, the H2 yield of the catalyst for photothermal coupled methane dry reforming hydrogen production in this comparative example is 0.7 mmol / min / g. cat , CO production rate is 1.2mmol / min / g cat .

[0125] like Figure 4 As shown in Figure 2, the sample prepared by electrostatic adsorption has no obvious diffraction peaks except for silicon dioxide, and has a higher temperature hydrogen reduction peak ( Figure 5 ), indicating that the electrostatic adsorption method can provide a stronger metal-support interaction, which is beneficial to the dispersion of active metals. Figure 6-7As shown, the NiCu / SiO2-E catalyst synthesized when the nickel loading mass is 3% of the silica and the mass ratio Ni:Cu=2.56:0.06 shows great advantages in terms of reaction gas conversion rate, carbon deposition resistance, hydrogen-carbon ratio and sunlight-fuel conversion efficiency. Its reaction stability is also very good ( Figure 8 ). CH4-TPD shows that the addition of copper can inhibit the carbon accumulation caused by excessive CH4 cracking ( Fig. 9 ). However, with the continuous increase of copper content, the methane decomposition peak becomes weaker or even almost disappears, indicating that methane is difficult to decompose. The high activity of the catalyst with a mass ratio of Ni:Cu = 2.56:0.06 may be due to its unique selectivity in the methane cracking process: while activating the first CH bond of CH4, it inhibits the breakage of subsequent CH bonds, thereby preventing carbon accumulation due to excessive cracking of CH4. Figure 10-11 As shown in the figure, the catalyst has strong light absorption ability, especially in the visible light band of 520nm, it shows excellent light absorption ability and catalytic performance. This is because the hot electrons generated by the plasmon effect of the catalyst with a mass ratio of Ni:Cu=2.56:0.06 under the irradiation of this band enhance the dry reforming reaction. And the first principle calculation shows that ( Figure 12-13 ), the activation energy of the first step of methane cracking is lower than that of Ni / SiO2-E when the mass ratio Ni:Cu=2.56:0.06, and the activation energy of the breakage of the following three CH bonds is higher. The activation energy of *CH oxidation to *CHO on the catalyst with the mass ratio Ni:Cu=2.56:0.06 is lower than the activation energy of *CH dissociation to *C, indicating that a small amount of copper can promote the cracking of methane and promote the orderly reaction of dry reforming. Excited state calculations show that light can accelerate the first step of methane cracking and inhibit the deep cracking of methane. Fig.14 As shown, the catalytic activity of the catalyst described in the present application at a low temperature below 600° C. is significantly higher than that of conventional catalysts in the prior art. The present invention can provide theoretical guidance for future light-heat coupling experiments.

Claims

1. A greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds, characterized in that: The catalyst comprises active metal components Ni and Cu and a SiO2 carrier, wherein the Ni and Cu are loaded on the SiO2 carrier by Coulomb force, and the loading mass ratio of Ni to Cu in the catalyst is 2.56:0.

06.

2. A method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds according to claim 1, characterized in that: The following steps are involved: Nickel salt and copper salt are dissolved in a solvent, and concentrated ammonia water is added and stirred to form a first solution; SiO2 powder is dispersed in the solvent to form a second solution; the first solution and the second solution are mixed and stirred, and the precipitate is taken out after centrifugation, ground, and calcined to obtain the final product.

3. The method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds according to claim 2, characterized in that: After adding concentrated ammonia water, the pH of the solution was adjusted to 9-12, and then stirring was continued for 0-5h.

4. The method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds according to claim 2, characterized in that: The mixing and stirring time of the first solution and the second solution is 0-5h.

5. The method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds according to claim 2, characterized in that: The rotation speed during centrifugation is controlled at 2000-10000 r / min, and the obtained precipitate is washed 1-5 times with water and ethanol.

6. The method for preparing a greenhouse gas reforming conversion catalyst based on selective editing of carbon-hydrogen bonds according to claim 2, characterized in that: The calcination process includes: placing the ground catalyst precursor in a tube furnace and heating it to 600-700°C at a heating rate of 2-3°C / min, keeping the temperature for 0.5-1 hour, and cooling it to room temperature along with the furnace.

7. Use of the catalyst according to claim 1 in preparing synthesis gas by dry reforming of CO2 source and light alkane source.

8. Use of the catalyst according to claim 7 in preparing synthesis gas by dry reforming of CO2 source and light alkane source, characterized in that: Application methods include: The catalyst is placed in a reaction crucible, and a mixed gas of methane, carbon dioxide and nitrogen is continuously transported through the pipeline of the reactor to purge the air in the pipeline. The xenon lamp is turned on to irradiate ultraviolet-visible light to simulate sunlight for concentrated irradiation. The light shines directly on the surface of the catalyst. After absorbing sunlight, the catalyst quickly heats up to the temperature required for the reaction, and photothermal coupled methane dry reforming is carried out to produce hydrogen.

9. Use of the catalyst according to claim 8 in preparing synthesis gas by dry reforming of CO2 source and light alkane source, characterized in that: The volume ratio of methane, carbon dioxide and nitrogen is 30.2% / 30.4% / 39.4%, and the total flow rate of the mixed gas is 50-100 ml / min.

10. Use of the catalyst according to claim 8 in preparing synthesis gas by dry reforming of CO2 source and light alkane source, characterized in that: The power of the simulated sunlight focused on the catalyst surface is 3-5W, and the diameter of the focused illumination spot is 5-6mm.

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