A supported catalyst with strongly coupled bimetallic nanoparticle active centers and its preparation method, and its application in the selective dehydrogenation of isopropanol.

Abstract

This invention discloses a supported catalyst with strongly coupled bimetallic nanoparticle active centers, its preparation method, and its application in the selective dehydrogenation of isopropanol. The preparation method includes: mixing a dimethyl sulfoxide solution containing acetylacetone metal salt A and acetylacetone metal salt B with a dimethyl sulfoxide solution containing a support powder sample, sonicating until a transparent colloidal state is reached, drying, and calcining to obtain the supported catalyst with strongly coupled bimetallic nanoparticle active centers. The catalyst prepared by this invention exhibits excellent catalytic efficiency in the selective dehydrogenation reaction of isopropanol, maintaining the yield of acetone in the isopropanol dehydrogenation product above 90% over a wide temperature window (100-200℃). The acetone formation rate of this catalyst at 200℃ is 10.5 times higher than that of traditional Pd-based catalysts.

Description

Technical Field

[0001] This invention belongs to the field of air pollution control technology, and specifically relates to a supported catalyst with a strongly coupled bimetallic nanoparticle active center, its preparation method, and its application in the selective dehydrogenation of isopropanol. Background Technology

[0002] Isopropanol, ethanol, and other alcohols are widely used as solvents. These volatile organic compounds (VOCs) are characteristic pollutants in industries such as packaging, printing, and pharmaceuticals. The selective oxidation of small alcohol molecules to aldehydes or ketones not only provides key intermediate synthesis technologies for the pharmaceutical and fine chemical industries but also, due to its incomplete catalytic oxidation, can reduce CO2 emissions, providing a theoretical basis for the synergistic control of industrial waste gas pollution reduction and carbon reduction. However, due to the high bond energy of the C–H bond and the similar electronegativity of C and H atoms, achieving efficient activation and selective cleavage of the β-C–H bond under mild conditions remains a significant challenge. Supported noble metal-based catalysts are widely used in catalytic oxidation reactions due to their excellent catalytic activity. However, due to the heterogeneous particle size distribution and coordination structure of their active centers, they are prone to causing deep oxidation of alcohols, leading to a decrease in the selectivity of high-value products. Taking the selective oxidation of alcohols as an example, supported noble metal-based catalysts exhibit high alcohol oxidation activity, but at elevated temperatures, they often deeply oxidize alcohols to CO2. The high conversion rate of alcohol molecules at high temperatures also significantly reduces the selectivity and yield of selective oxidation products. In actual industrial production, even temperature fluctuations can easily disrupt the stable and efficient production of selective oxidation products. Therefore, suppressing deep oxidation at high temperatures and maintaining ultra-high selectivity of the selective oxidation products over a wider temperature range is essential for achieving a wide temperature window and remains a major challenge for supported noble metal-based catalysts. β-CH bond cleavage has been identified as the rate-determining step in the selective oxidation of alcohols, while deep oxidation to CO2 requires C / C bond cleavage. Therefore, a key strategy to address this challenge is to design catalysts that selectively promote CH bond activation while inhibiting C / C bond cleavage. However, the bond energies of CH and C / C are very close, making selective activation of CH alone quite difficult. This necessitates the regulation of the catalyst's physicochemical properties and active site structure to modulate processes such as molecular adsorption, intermediate activation and dehydrogenation, and rapid product desorption, thereby promoting the selective dehydrogenation of isopropanol and preventing its over-oxidation. Summary of the Invention

[0003] To overcome the problems of difficulty in controlling the molecular adsorption-intermediate activation dehydrogenation-product rapid desorption process in existing technologies, and the easy over-oxidation of the selective dehydrogenation products of isopropanol, the purpose of this invention is to provide a supported catalyst with a strongly coupled bimetallic nanoparticle active center, its preparation method, and its application in the selective dehydrogenation of isopropanol.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing a supported catalyst with strongly coupled bimetallic nanoparticle active centers includes the following steps:

[0006] A dimethyl sulfoxide solution containing acetylacetone metal salt A and acetylacetone metal salt B was mixed with a dimethyl sulfoxide solution containing the support powder sample, sonicated until a transparent colloidal state was formed, dried, and calcined to obtain a supported catalyst with strongly coupled bimetallic nanoparticle active centers.

[0007] Furthermore, the metal salt A of acetylacetone is platinum acetylacetone, palladium acetylacetone, rhodium acetylacetone, or ruthenium acetylacetone.

[0008] Furthermore, the metal salt B of acetylacetone is manganese acetylacetone, iron acetylacetone, nickel acetylacetone, chromium acetylacetone, lanthanum acetylacetone, cerium acetylacetone, cobalt acetylacetone, copper acetylacetone, zinc acetylacetone, zirconium acetylacetone, indium acetylacetone, tin acetylacetone, or molybdenum acetylacetone.

[0009] Furthermore, the molar ratio of acetylacetone metal salt A to acetylacetone metal salt B is 1:0.5-10.

[0010] Furthermore, in the dimethyl sulfoxide solution containing acetylacetone metal salt A and acetylacetone metal salt B, the ratio of acetylacetone metal salt A to dimethyl sulfoxide is 0.0001 mol: 15-30 mL.

[0011] Furthermore, the carrier is carbon nitride, silicon dioxide, aluminum oxide, or titanium dioxide.

[0012] Furthermore, in the dimethyl sulfoxide solution containing the carrier powder sample, the ratio of the carrier powder sample to dimethyl sulfoxide is 0.5 g: 10-15 mL.

[0013] Furthermore, the calcination temperature is 350-550℃, the calcination atmosphere is air or a hydrogen-argon mixture, the calcination time is 2-6 hours, and the heating rate is 2-5℃·min. -1 .

[0014] A supported catalyst with a strongly coupled bimetallic nanoparticle active center.

[0015] Application of a supported catalyst with strongly coupled bimetallic nanoparticle active centers in the selective catalytic dehydrogenation of isopropanol.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] This invention proposes an in-situ activation and separation strategy for metal precursors. Through the non-polarization of acetylacetone metal salts in organic solvents, group complexation occurs at low temperature and low pressure (-50℃, 50 mbar). The van der Waals forces generated during the freeze-drying process of the organic solvent further enhance this complexation, forming bimetallic nanoparticle active centers with strong coupling. Subsequent calcination further accelerates the charge balance process within the active centers through strong interactions at the bimetallic interface, significantly improving the activity and stability of the prepared catalyst. The catalyst preparation method described in this invention is simple, low-cost, and significantly reduces synthesis time and energy consumption. It allows for kilogram-scale production and exhibits good applicability to various metals and supports.

[0018] The supported catalyst with strongly coupled bimetallic nanoparticle active centers prepared in this invention is applied in the selective dehydrogenation reaction of isopropanol. Through the strong coupling and synergistic catalytic effect between the bimetals, it synergistically achieves selective activation of the CH bond in the isopropanol molecule and rapid desorption of the acetone reaction intermediate, thereby avoiding deep oxidation of the isopropanol molecule. It can maintain the yield of acetone in the isopropanol dehydrogenation product above 90% within a wide temperature window (100-200℃), and the acetone formation rate at 200℃ is 10.5 times higher than that of traditional Pd-based catalysts. This invention overcomes the technical bottleneck of low selective dehydrogenation efficiency of traditional Pd-based catalysts for alcohol molecules, providing a scientific basis for the resource utilization and synergistic control of pollution reduction and carbon reduction of high-concentration alcohol waste gas from industrial sources. Attached Figure Description

[0019] Figure 1 The middle part is PdO from Example 3 of this invention. x -MnO x High-angle annular dark-field scanning transmission (HAADF-STEM) images of the Al2O3 catalyst, where (a) is at low magnification and (b) is at high magnification.

[0020] Figure 2 The PdO in Example 3 of this invention x -MnO x / X-ray diffraction (XRD) pattern of Al2O3 catalyst.

[0021] Figure 3 The PdO in Example 3 of this invention x -MnO x / Active activity spectrum of Al2O3 catalyst for selective dehydrogenation of isopropanol.

[0022] Figure 4 The PdO in Example 3 of this invention x -MnO x / Al2O3 and PdO from Comparative Example 1 x / Comparison of acetone formation rates catalyzed by Al2O3 catalyst for selective dehydrogenation of isopropanol.

[0023] Figure 5 PdO in this invention x -MnO x / Schematic diagram of the selective dehydrogenation mechanism of isopropanol catalyzed by Al2O3 catalyst.

[0024] Figure 6 PdO in this invention x -MnO x / Active activity diagram of Al2O3 catalyst for selective dehydrogenation of ethanol, where (a) is the ethanol conversion diagram and (b) is the acetaldehyde selectivity diagram. Detailed Implementation

[0025] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0026] This invention discloses a method for preparing a supported catalyst with strongly coupled bimetallic nanoparticle active centers. Through the non-polarization of acetylacetone metal salt in an organic solvent, it undergoes group complexation at low temperature and low pressure (-50℃, 50 mbar). The van der Waals forces generated during the freeze-drying process of the organic solvent further enhance the formation of strongly coupled bimetallic nanoparticle active centers. Through the strong coupling and synergistic catalytic effect between the bimetals, the selective activation of the CH bond in isopropanol molecules and the rapid desorption of acetone reaction intermediates are synergistically achieved, thus avoiding deep oxidation of isopropanol molecules. The catalyst prepared by this invention exhibits excellent catalytic efficiency in the selective dehydrogenation reaction of isopropanol, maintaining the yield of acetone in the isopropanol dehydrogenation product above 90% over a wide temperature window (100-200℃). The acetone formation rate at 200℃ is 10.5 times higher than that of traditional Pd-based catalysts. Furthermore, this synthesis method has good applicability to various metals and supports.

[0027] Specifically, the method for preparing the supported catalyst with strongly coupled bimetallic nanoparticle active centers of the present invention includes the following steps:

[0028] (1) Disperse 0.0001 mol of acetylacetone metal salt A (which can be any one of platinum acetylacetone, palladium acetylacetone, rhodium acetylacetone and ruthenium acetylacetone) and 0.0005-0.001 mol of acetylacetone metal salt B (which can be any one of manganese acetylacetone, iron acetylacetone, nickel acetylacetone, chromium acetylacetone, lanthanum acetylacetone, cerium acetylacetone, cobalt acetylacetone, copper acetylacetone, zinc acetylacetone, zirconium acetylacetone, indium acetylacetone, tin acetylacetone and molybdenum acetylacetone) in 15-30 mL of dimethyl sulfoxide and dissolve them completely under ultrasonic vibration;

[0029] (2) Disperse 0.5g of carrier powder (which can be any one of carbon nitride, silicon dioxide, aluminum oxide and titanium dioxide) in 10-15mL of dimethyl sulfoxide and mix it thoroughly under ultrasonic vibration;

[0030] (3) Quickly add the solution obtained in step (1) to the solution obtained in step (2) and mix them evenly under ultrasonic vibration. The ultrasonic power is set to 40% and the temperature is set to 15-20℃.

[0031] (4) After the mixed solution in step (3) becomes a transparent colloidal state, the mixed solution is freeze-dried; the freeze-drying pressure is set to 50 mbar and the temperature is set to -50℃.

[0032] (5) The solid powder obtained in step 4 is subjected to calcination treatment. The calcination temperature of the sample is 350-550℃, the calcination atmosphere is air or hydrogen-argon mixture, the calcination time is 2-6h, and the heating rate is 2-5℃·min. -1 A supported catalyst with a strongly coupled bimetallic nanoparticle active center was obtained.

[0033] The supported catalyst with strongly coupled bimetallic nanoparticle active centers prepared in this invention exhibits excellent performance at 200℃ and a space velocity of 36000-45000 h⁻¹. -1 Under conditions of 10-20% oxygen volume concentration, complete conversion of 10,000 ppm isopropanol can be achieved, and the selectivity of the product acetone is greater than 95%, demonstrating excellent selective dehydrogenation efficiency of isopropanol.

[0034] The following are specific examples.

[0035] Example 1: Preparation of PtO using a bimetallic in-situ activation and separation strategy x -MnO x / SiO2 catalyst

[0036] Accurately weigh 0.039 g of platinum acetylacetone and 0.072 g of manganese acetylacetone, dissolve them in 15 mL of dimethyl sulfoxide under ultrasonic vibration, and designate this mixture as solution 1. Disperse 0.5 g of silica carrier powder in 12 mL of dimethyl sulfoxide and mix thoroughly under ultrasonic vibration, designating this mixture as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic vibration at 40% power and 15°C. After the mixture becomes a transparent colloid, freeze-dry it at 50 mbar pressure and -50°C. After the sample is completely dry, calcine the resulting powder sample at 350°C in a hydrogen-argon mixture for 4 h at a heating rate of 3°C / min. -1 Finally, PtO was obtained. x -MnO x / SiO2 catalyst.

[0037] Example 2: Preparation of PdO using a bimetallic in-situ activation and separation strategy x -CuO x / Al2O3 catalyst

[0038] Accurately weigh 0.028 g of palladium acetylacetone and 0.069 g of copper acetylacetone, dissolve them in 20 mL of dimethyl sulfoxide under ultrasonic vibration, and designate this mixture as solution 1. Disperse 0.5 g of alumina carrier powder in 12 mL of dimethyl sulfoxide and mix thoroughly under ultrasonic vibration, designating this mixture as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic vibration at 40% power and 20°C. After the mixture becomes a transparent colloid, freeze-dry it at 50 mbar pressure and -50°C. After the sample is completely dry, calcine the resulting powder sample at 400°C in a hydrogen-argon mixture for 4 h at a heating rate of 3°C / min. -1 Finally, PdO was obtained. x -CuO x / Al2O3 catalyst.

[0039] Example 3: PdO prepared using a bimetallic in-situ activation and separation strategy. x -MnO x / Al2O3 catalyst

[0040] Accurately weigh 0.028 g of palladium acetylacetone and 0.072 g of manganese acetylacetone, dissolve them in 30 mL of dimethyl sulfoxide under ultrasonic vibration, and designate this mixture as solution 1. Disperse 0.5 g of silica carrier powder in 15 mL of dimethyl sulfoxide and mix thoroughly under ultrasonic vibration, designating this mixture as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic vibration at 40% power and 20°C. After the mixture becomes a transparent colloid, freeze-dry it at 50 mbar pressure and -50°C. After the sample is completely dry, calcine the resulting powder sample at 500°C in a hydrogen-argon mixture for 5 h at a heating rate of 2°C / min. -1 Finally, PdO was obtained. x -MnO x / Al2O3 catalyst.

[0041] See Figure 1 ,Depend on Figure 1 The HAADF-STEM image shows that PdO x -MnO x PdO exists on the surface of the Al2O3 catalyst. x -MnO x Strongly coupled bimetallic active centers, wherein the particle size of the bimetallic active centers is approximately 3-4 nm.

[0042] See Figure 2 ,Depend on Figure 2 The XRD pattern shows that the characteristic peaks of the support are obvious, and PdO x -MnO x Strongly coupled bimetallic active centers are highly dispersed on the catalyst surface.

[0043] Comparative Example 1: Traditional PdO x Preparation of Al2O3 catalyst

[0044] Accurately weigh 0.028 g of palladium acetylacetone and dissolve it in 15 mL of dimethyl sulfoxide under ultrasonic vibration. This mixture is designated as solution 1. Disperse 0.5 g of silica carrier powder in 10 mL of dimethyl sulfoxide and mix thoroughly under ultrasonic vibration. This mixture is designated as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic vibration at 40% power and 15°C. After the mixture becomes a transparent colloid, freeze-dry it at 50 mbar pressure and -50°C. After the sample is completely dry, calcine the resulting powder sample at 550°C in a hydrogen-argon mixture for 6 hours at a heating rate of 5°C / min. -1 Finally, PdO was obtained. x / SiO2 catalyst.

[0045] Example 4: Isopropanol dehydrogenation performance test of a supported catalyst with strongly coupled bimetallic nanoparticle active centers.

[0046] The performance evaluation of the catalyst for the selective catalytic dehydrogenation of isopropanol was carried out in a fixed-bed reactor (id = 6 mm). 50 mg of PdO prepared in Example 3 was used. x -MnO x Al2O3 catalyst (40-60 mesh) was mixed with quartz sand at a mass ratio of 1:5 to avoid local overheating during the reaction process, and the mixture was reacted at 300℃ at a rate of 20 mL / min. -1 Oxygen flow rate was used for oxidation pretreatment for 1 hour to remove surface impurities. The feed gas mixture consisted of 10,000 ppm isopropanol (1.0 vol%) + 20.0 vol% O2 + N2 (equilibrium gas), where 10,000 ppm isopropanol was generated by stripping N2 gas from a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol could be calculated using the Antoine equation, by controlling the flow rate to 16.7 mL·min. -1 The total flow rate reached 36000 mL·g -1 ·h -1 The space velocity (SV) was measured. Reactants and products were detected online by gas chromatography (GC-2010, Shimadzu) using a flame ionization detector (FID) and a Stabilwax@-DB capillary column. For each measurement, all catalytic performance data were measured three times and averaged after holding at a given temperature for at least 30 minutes under steady-state reaction conditions. Furthermore, at least three independent measurements were performed on different batches of samples to verify the accuracy and repeatability of the tests.

[0047] See Figure 3 ,Depend on Figure 3The results of the selective catalytic dehydrogenation activity test of isopropanol show that PdO x -MnO x Al2O3 catalysts exhibit excellent catalytic conversion efficiency of isopropanol and selectivity for acetone at 200℃ and space velocities of 36,000-45,000 h⁻¹. -1 Under conditions of 10-20% oxygen volume concentration, complete conversion of 10,000 ppm isopropanol can be achieved, with a selectivity of acetone greater than 95%.

[0048] See Figure 4 ,Depend on Figure 4 A comparison of the acetone formation rates shows that PdO x -MnO x The Al2O3 catalyst at 200℃ increased the acetone production rate by 10.5 times compared with the conventional Pd-based catalyst in Comparative Example 1.

[0049] See Figure 5 ,Depend on Figure 5 As can be seen from the mechanism diagram, PdO x -MnO x The strong coupling and synergistic catalytic effect between the two metals work together to selectively activate the CH bond of the isopropanol molecule and rapidly desorb the acetone reaction intermediate, thereby avoiding the deep oxidation of the isopropanol molecule.

[0050] Example 5: Ethanol dehydrogenation performance test of a supported catalyst with strongly coupled bimetallic nanoparticle active centers.

[0051] The catalytic performance of the catalyst sample for ethanol dehydrogenation was tested in a fixed-bed reactor under normal pressure. Specifically, 100 mg of PdO prepared in Example 3 was first... x -MnO x The Al₂O₃ catalyst was mixed with 400 mg of quartz sand and loaded into a U-shaped reactor tube, with the inlet and outlet slightly plugged with quartz wool. The mixed gas produced by the gas mixing device consisted of ethanol and nitrogen (30 mL / min). -1 The mixture consists of ethanol, which is fed by an injection pump at a rate of 9.5 h / min. -1 Mass space-time velocity (WHSV) control was used, and nitrogen flow rate was controlled by a mass flow controller. Temperature was measured using a type K thermocouple reaching the center of the catalyst bed. Exhaust gas products were monitored online by a gas chromatograph (HP 5890GC) equipped with TCD and FID detectors. Products were analyzed by GC-MS (Agilent, 7890B-5977A).

[0052] See Figure 6 In (a) and (b), by Figure 6 The selective catalytic dehydrogenation activity test of ethanol showed that PdO x -MnOx Al2O3 catalysts exhibit superior ethanol conversion efficiency (greater than 13%) and acetaldehyde selectivity (75%-80%) compared to traditional Pd-based catalysts.

[0053] Example 6

[0054] Accurately weigh 0.0001 mol of rhodium acetylacetone and 0.0005 mol of iron acetylacetone, dissolve them in 15 mL of dimethyl sulfoxide under ultrasonic vibration, and designate this mixture as solution 1. Disperse 0.5 g of silica carrier powder in 10 mL of dimethyl sulfoxide and mix thoroughly under ultrasonic vibration, designating this mixture as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic vibration at 40% power and 15°C. After the mixture becomes a transparent colloid, freeze-dry it at 50 mbar pressure and -50°C. After the sample is completely dry, calcine the resulting powder sample at 350°C in a hydrogen-argon mixture for 3 h at a heating rate of 5°C / min. -1 Ultimately, a supported catalyst with a strongly coupled bimetallic nanoparticle active center was obtained.

[0055] Example 7

[0056] Accurately weigh 0.0001 mol of ruthenium acetylacetone and 0.0007 mol of nickel acetylacetone, dissolve them in 20 mL of dimethyl sulfoxide under ultrasonic vibration, and designate this mixture as solution 1. Disperse 0.5 g of silica carrier powder in 12 mL of dimethyl sulfoxide and mix thoroughly under ultrasonic vibration, designating this mixture as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic vibration at 40% power and 18°C. After the mixture becomes a transparent colloid, freeze-dry it at 50 mbar pressure and -50°C. After the sample is completely dry, calcine the resulting powder sample at 480°C in a hydrogen-argon mixture for 2 h at a heating rate of 4°C / min. -1 Ultimately, a supported catalyst with a strongly coupled bimetallic nanoparticle active center was obtained.

[0057] Example 8

[0058] Accurately weigh 0.0001 mol of palladium acetylacetone and 0.001 mol of chromium acetylacetone, dissolve them in 30 mL of dimethyl sulfoxide under ultrasonic vibration, and designate this mixture as solution 1. Disperse 0.5 g of silica carrier powder in 15 mL of dimethyl sulfoxide and mix thoroughly under ultrasonic vibration, designating this mixture as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic vibration at 40% power and 20°C. After the mixture becomes a transparent colloid, freeze-dry it at 50 mbar pressure and -50°C. After the sample is completely dry, calcine the resulting powder sample at 450°C in a hydrogen-argon mixture for 3 h at a heating rate of 5°C / min. -1 Ultimately, a supported catalyst with a strongly coupled bimetallic nanoparticle active center was obtained.

[0059] Example 9

[0060] Same as Example 8, except that chromium acetylacetone is replaced with lanthanum acetylacetone.

[0061] Example 10

[0062] Same as Example 8, except that chromium acetylacetone is replaced with cerium acetylacetone.

[0063] Example 11

[0064] Same as Example 8, except that chromium acetylacetonate is replaced with cobalt acetylacetonate.

[0065] Example 12

[0066] Same as Example 8, except that chromium acetylacetone is replaced with zinc acetylacetone.

[0067] Example 13

[0068] Same as Example 8, except that chromium acetylacetone is replaced with zirconium acetylacetone.

[0069] Example 14

[0070] Same as Example 8, except that chromium acetylacetonate is replaced with indium acetylacetonate.

[0071] Example 15

[0072] Same as Example 8, except that chromium acetylacetone is replaced with tin acetylacetone.

[0073] Example 16

[0074] Same as Example 8, except that chromium acetylacetonate is replaced with molybdenum acetylacetonate.

[0075] Example 17

[0076] The performance evaluation of the catalyst for the selective catalytic dehydrogenation of isopropanol was carried out in a fixed-bed reactor (id = 6 mm). 50 mg of PdO prepared in Example 3 was used. x -MnO x Al2O3 catalyst (40-60 mesh) was mixed with quartz sand at a mass ratio of 1:5 to avoid local overheating during the reaction process, and the mixture was reacted at 300℃ at a rate of 20 mL / min. -1 Oxygen flow rate was used for oxidation pretreatment for 1 hour to remove surface impurities. The feed gas mixture consisted of 10,000 ppm isopropanol (1.0 vol%) + 10.0 vol% O2 + N2 (equilibrium gas), where 10,000 ppm isopropanol was generated by stripping N2 gas from a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol could be calculated according to the Antoine equation by controlling the flow rate to 16.7 mL·min. -1 The total flow rate reached 36000 mL·g -1 ·h -1 The space velocity (SV) was measured. Reactants and products were detected online by gas chromatography (GC-2010, Shimadzu) using a flame ionization detector (FID) and a Stabilwax@-DB capillary column. For each measurement, all catalytic performance data were measured three times and averaged after holding at a given temperature for at least 30 minutes under steady-state reaction conditions.

[0077] Example 18

[0078] The performance evaluation of the catalyst for the selective catalytic dehydrogenation of isopropanol was carried out in a fixed-bed reactor (id = 6 mm). 50 mg of PdO prepared in Example 3 was used. x -MnO x Al2O3 catalyst (40-60 mesh) was mixed with quartz sand at a mass ratio of 1:5 to avoid local overheating during the reaction process, and the mixture was reacted at 300℃ at a rate of 20 mL / min. -1 Oxygen flow rate was used for oxidation pretreatment for 1 hour to remove surface impurities. The feed gas mixture consisted of 10,000 ppm isopropanol (1.0 vol%) + 15.0 vol% O2 + N2 (equilibrium gas), where 10,000 ppm isopropanol was generated by stripping N2 gas from a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol could be calculated using the Antoine equation, by controlling the flow rate to 16.7 mL·min. -1 The total flow rate reached 45000 mL·g -1 ·h -1The space velocity (SV) was measured. Reactants and products were detected online by gas chromatography (GC-2010, Shimadzu) using a flame ionization detector (FID) and a Stabilwax@-DB capillary column. For each measurement, all catalytic performance data were measured three times and averaged after holding at a given temperature for at least 30 minutes under steady-state reaction conditions.

[0079] Example 19

[0080] The performance evaluation of the catalyst for the selective catalytic dehydrogenation of isopropanol was carried out in a fixed-bed reactor (id = 6 mm). 50 mg of PdO prepared in Example 3 was used. x -MnO x Al2O3 catalyst (40-60 mesh) was mixed with quartz sand at a mass ratio of 1:5 to avoid local overheating during the reaction process, and the mixture was reacted at 300℃ at a rate of 20 mL / min. -1 Oxygen flow rate was used for oxidation pretreatment for 1 hour to remove surface impurities. The feed gas mixture consisted of 10,000 ppm isopropanol (1.0 vol%) + 12.0 vol% O2 + N2 (equilibrium gas), where 10,000 ppm isopropanol was generated by stripping N2 gas from a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol could be calculated using the Antoine equation, by controlling the flow rate to 16.7 mL·min. -1 The total flow rate reached 20000 mL·g -1 ·h -1 The space velocity (SV) was measured. Reactants and products were detected online by gas chromatography (GC-2010, Shimadzu) using a flame ionization detector (FID) and a Stabilwax@-DB capillary column. For each measurement, all catalytic performance data were measured three times and averaged after holding at a given temperature for at least 30 minutes under steady-state reaction conditions.

[0081] This invention constructs strongly coupled bimetallic nanoparticle active centers on the support surface through in-situ activation and separation of metal precursors at low temperatures. Through the strong coupling and synergistic catalytic effect between the two metals, selective activation of the CH bonds in isopropanol molecules and rapid desorption of acetone reaction intermediates are achieved, thus avoiding deep oxidation of isopropanol molecules. The catalyst prepared by this invention exhibits excellent catalytic efficiency in the selective dehydrogenation reaction of isopropanol, maintaining the yield of acetone in the isopropanol dehydrogenation product above 90% over a wide temperature window (100-200℃). The acetone formation rate of this catalyst at 200℃ is 10.5 times higher than that of traditional Pd-based catalysts. This invention overcomes the technical bottleneck of low selective dehydrogenation efficiency of traditional Pd-based catalysts for alcohol molecules, providing a scientific basis for the resource utilization and synergistic control of pollution reduction and carbon reduction of high-concentration alcohol waste gas from industrial sources. Furthermore, this synthesis method has good applicability to various metals and supports.

[0082] The above description only illustrates the preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. The present invention is not limited to the above embodiments, and variations in its specific structure are permitted. All modifications made within the scope of the independent claims of this invention are also within the scope of protection of this invention.

[0083] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

Claims

1. A method for preparing a supported catalyst with strongly coupled bimetallic nanoparticle active centers, characterized in that, Includes the following steps: A dimethyl sulfoxide solution containing acetylacetone metal salt A and acetylacetone metal salt B was mixed with a dimethyl sulfoxide solution containing a support powder sample, sonicated until a transparent colloidal state was formed, freeze-dried, and calcined to obtain a supported catalyst with a strongly coupled bimetallic nanoparticle active center. The carrier is carbon nitride, silicon dioxide, aluminum oxide, or titanium dioxide; The metal salt B of acetylacetone is manganese acetylacetone, iron acetylacetone, nickel acetylacetone, chromium acetylacetone, lanthanum acetylacetone, cerium acetylacetone, cobalt acetylacetone, copper acetylacetone, zinc acetylacetone, zirconium acetylacetone, indium acetylacetone, tin acetylacetone, or molybdenum acetylacetone. The metal salt A of acetylacetone is platinum acetylacetone, palladium acetylacetone, rhodium acetylacetone, or ruthenium acetylacetone.

2. The method for preparing the supported catalyst with strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that, The molar ratio of acetylacetone metal salt A to acetylacetone metal salt B is 1:0.5-10.

3. The method for preparing the supported catalyst with strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that, In a dimethyl sulfoxide solution containing acetylacetone metal salt A and acetylacetone metal salt B, the ratio of acetylacetone metal salt A to dimethyl sulfoxide is 0.0001 mol : 15-30 mL.

4. The method for preparing the supported catalyst with strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that, In the dimethyl sulfoxide solution containing the carrier powder sample, the ratio of the carrier powder sample to dimethyl sulfoxide is 0.5 g : 10-15 mL.

5. The method for preparing the supported catalyst with strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that, The calcination temperature is 350-550 ºC, the calcination atmosphere is air or a hydrogen-argon mixture, the calcination time is 2-6 h, and the heating rate is 2-5 ºC∙min. -1 .

6. A supported catalyst with a strongly coupled bimetallic nanoparticle active center prepared by the preparation method according to any one of claims 1-5.

7. The application of a supported catalyst with a strongly coupled bimetallic nanoparticle active center prepared by the preparation method according to any one of claims 1-5 in the selective catalytic dehydrogenation of isopropanol.

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