Supported catalyst with strong coupling bimetallic nanoparticle active center, preparation method and application of supported catalyst in selective dehydrogenation of isopropanol

Abstract

The invention discloses a supported catalyst with a strong-coupling bimetallic nanoparticle active center, a preparation method of the supported catalyst and application of the supported catalyst in selective dehydrogenation of isopropanol. The preparation method comprises the following steps: mixing a dimethyl sulfoxide solution containing acetylacetone metal salt A and acetylacetone metal salt B with a dimethyl sulfoxide solution containing a carrier powder sample, carrying out ultrasonic treatment to a transparent colloid shape, drying, and roasting to obtain the supported catalyst with the strong coupling bimetallic nanoparticle active center. The prepared catalyst shows excellent catalytic efficiency in the selective dehydrogenation reaction of isopropanol, the yield of acetone in an isopropanol dehydrogenation product can be kept at 90% or above at a wide temperature window (100-200 DEG C), and the acetone generation rate of the catalyst at 200 DEG C is increased by 10.5 times compared with that of a traditional Pd-based catalyst.

Description

Technical Field

[0001] The invention belongs to the technical field of air pollution control, and particularly relates to a supported catalyst with strongly coupled bimetallic nanoparticle active centers, a preparation method and application thereof in selective dehydrogenation of isopropanol. Background Art

[0002] Alcohols such as isopropanol and ethanol are widely used as solvents. Such volatile organic compounds (VOCs) are characteristic pollutants in the packaging, printing, pharmaceutical and other industries. The selective oxidation of alcohol small molecules into aldehydes or ketones can not only provide a synthesis technology for key intermediates in the pharmaceutical and fine chemical industries, but also reduce CO due to its incomplete catalytic oxidation. 2 emissions, providing a theoretical basis for the coordinated 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 the C and H atoms, it is still a great challenge to achieve efficient activation and selective breakage of β-C–H bonds under mild conditions. Supported precious metal-based catalysts are widely used in catalytic oxidation reactions due to their excellent catalytic activity, but due to the uneven particle size distribution and coordination structure of their active centers, they can easily cause deep oxidation of alcohol organic compounds, resulting in reduced selectivity for high-value products. Taking the selective oxidation of alcohols as an example, supported precious metal-based catalysts exhibit high alcohol oxidation activity, but when the temperature rises, they often deeply oxidize alcohols to CO 2 . The high conversion rate of alcohol molecules at high temperature will also greatly reduce the selectivity and yield of selective oxidation products. In actual industrial production, even just because of temperature fluctuations, it is easy to destroy the stable and efficient production of selective oxidation products. Therefore, suppressing deep oxidation at high temperature and then maintaining ultra-high selectivity of selective oxidation products over a wider temperature range is very necessary to achieve a wide temperature window and remains a major challenge for supported precious metal-based catalysts. β-CH bond cleavage has been identified as the rate-determining step for the selective oxidation of alcohols, while deep oxidation is the rate-determining step for CO 2 The process requires the breaking of the CC bond. Therefore, the key countermeasure to this challenge is to design a catalyst that selectively promotes the activation of the CH bond while inhibiting the breaking of the CC bond. However, the bond energies of CH and CC are very close, and it is quite difficult to achieve the selective activation of CH alone. This requires the regulation of the physicochemical properties and active center structure of the catalyst to regulate the processes such as molecular adsorption-intermediate activation dehydrogenation-product rapid desorption, promote the selective dehydrogenation of isopropanol, and avoid its over-oxidation. Summary of the invention

[0003] In order to overcome the problems in the prior art that the molecular adsorption-intermediate activated dehydrogenation-product rapid desorption process is difficult to control and the selective dehydrogenation product of isopropanol is prone to over-oxidation, the purpose of the present invention is to provide a supported catalyst with a strongly coupled bimetallic nanoparticle active center and a preparation method and its application in the selective dehydrogenation of isopropanol.

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

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

[0006] A dimethyl sulfoxide solution containing acetylacetonate metal salt A and acetylacetonate metal salt B is mixed with a dimethyl sulfoxide solution containing a carrier powder sample, ultrasonicated to a transparent colloid state, dried, and calcined to obtain a supported catalyst with strongly coupled bimetallic nanoparticle active centers.

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

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

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

[0010] Furthermore, in the dimethyl sulfoxide solution containing acetylacetonate metal salt A and acetylacetonate metal salt B, the ratio of acetylacetonate 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°C, the calcination atmosphere is air or hydrogen-argon mixed gas, the calcination time is 2-6h, and the heating rate is 2-5°C·min -1 .

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

[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] The present invention proposes an in-situ activation and separation strategy for metal precursors, and through the non-polarization effect of acetylacetone metal salt in an organic solvent, group complexation is performed at low temperature and low pressure (-50°C, 50mbar), and the van der Waals force generated during the freeze-drying process of the organic solvent forms a bimetallic nanoparticle active center with a strong coupling effect. In the subsequent roasting process, the strong interaction between the interfaces of the bimetallic objects further accelerates the charge balance process inside the active center, greatly improving the activity and stability of the prepared catalyst. The technical method for preparing the catalyst involved in the present invention is simple and low in cost, greatly shortens the synthesis time and energy consumption, and can be prepared at the kilogram level, and the synthesis method has good application universality for a variety of metals and carriers.

[0018] The application of the supported catalyst with strong coupling bimetallic nanoparticle active center prepared by the present invention in the selective dehydrogenation reaction of isopropanol, through the strong coupling effect and synergistic catalytic effect between the bimetallic, synergistically realizes the selective activation of the CH bond of the isopropanol molecule and the rapid desorption of the acetone reaction intermediate, thereby avoiding the deep oxidation of the isopropanol molecule. It can keep the yield of acetone in the isopropanol dehydrogenation product above 90% under a wide temperature window (100-200° C.), and the acetone generation rate of the catalyst at 200° C. is increased by 10.5 times compared with the traditional Pd-based catalyst. The present invention breaks through the technical bottleneck of low efficiency of selective dehydrogenation of alcohol molecules by traditional Pd-based catalysts, and provides a scientific basis for resource utilization of high-concentration alcohol waste gas from industrial sources and coordinated control of pollution reduction and carbon reduction. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The PdO in Example 3 of the present invention x -MnO x / Al 2 O 3 High-angle annular dark field scanning transmission (HAADF-STEM) image of the catalyst, where (a) is a low magnification and (b) is a high magnification.

[0020] Figure 2 The PdO of Example 3 of the present invention x -MnO x / Al 2 O 3 X-ray diffraction (XRD) spectrum of catalyst.

[0021] Figure 3The PdO of Example 3 of the present invention x -MnO x / Al 2 O 3 Activity spectrum of the catalyst for the selective dehydrogenation of isopropanol.

[0022] Figure 4 The PdO of Example 3 of the present invention x -MnO x / Al 2 O 3 and PdO of Comparative Example 1 x / Al 2 O 3 Comparison of acetone production rates over selective dehydrogenation of isopropanol catalyzed by catalysts.

[0023] Figure 5 PdO in the present invention x -MnO x / Al 2 O 3 Schematic diagram of the mechanism of selective dehydrogenation of isopropanol catalyzed by catalysts.

[0024] Figure 6 PdO in the present invention x -MnO x / Al 2 O 3 Activity diagram of the catalyst for selective dehydrogenation of ethanol, where (a) is the ethanol conversion rate diagram and (b) is the acetaldehyde selectivity diagram. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0026] The invention discloses a method for preparing a supported catalyst with a strongly coupled bimetallic nanoparticle active center. The non-polarization effect of acetylacetone metal salt in an organic solvent causes the metal salt to undergo group complexation at low temperature and low pressure (-50°C, 50 mbar), and forms a bimetallic nanoparticle active center with a strongly coupled effect as a result of the van der Waals force generated during the freeze drying of the organic solvent. The selective activation of the CH bond of the isopropanol molecule and the rapid desorption of the acetone reaction intermediate are achieved through the strong coupling effect and synergistic catalytic effect between the bimetallics, thereby avoiding the deep oxidation of the isopropanol molecule. The catalyst prepared by the invention exhibits excellent catalytic efficiency in the selective dehydrogenation reaction of isopropanol. The catalyst can maintain the yield of acetone in the isopropanol dehydrogenation product at more than 90% in a wide temperature window (100-200°C). The acetone generation rate of the catalyst at 200°C is 10.5 times higher than that of the traditional Pd-based catalyst. The synthesis method has good universality of application to a variety of metals and carriers.

[0027] Specifically, the method for preparing a supported catalyst having strongly coupled bimetallic nanoparticle active centers of the present invention specifically comprises the following steps:

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

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

[0030] (3) quickly adding the solution obtained in step (1) to the solution obtained in step (2), and mixing them evenly under ultrasonic oscillation, with the ultrasonic power set to 40% and the temperature set to 15-20° C.;

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

[0032] (5) The solid powder obtained in step 4 is calcined at a temperature of 350-550°C, the calcination atmosphere is air or a hydrogen-argon mixture, the calcination time is 2-6h, and the heating rate is 2-5°C·min -1 , obtaining a supported catalyst with strongly coupled bimetallic nanoparticle active centers.

[0033] The supported catalyst with strongly coupled bimetallic nanoparticle active centers prepared by the present invention has a high temperature at 200°C and a space velocity of 36000-45000h -1 Under the 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%, showing excellent isopropanol selective dehydrogenation efficiency.

[0034] The following are specific embodiments.

[0035] Example 1 Preparation of PtO using a bimetallic in-situ activation and separation strategy x -MnO x / SiO 2 catalyst

[0036] Accurately weigh 0.039g of platinum acetylacetonate and 0.072g of manganese acetylacetonate and dissolve them in 15mL of dimethyl sulfoxide under ultrasonic oscillation, and record the mixed solution as solution 1; disperse 0.5g of silica carrier powder in 12mL of dimethyl sulfoxide and mix them thoroughly under ultrasonic oscillation, and record the mixed solution as solution 2. Quickly add solution 1 to solution 2 and mix them evenly under ultrasonic oscillation, with the ultrasonic power set to 40% and the temperature set to 15°C; wait for the mixed solution to present a transparent colloid state, and then freeze-dry the mixed solution; the freeze-drying pressure is set to 50mbar and the temperature is set to -50°C; after the sample is completely dried, the obtained powder sample is calcined, the sample calcination temperature is 350°C, the calcination atmosphere is a hydrogen-argon mixture, the calcination time is 4h, and the heating rate is 3°C·min -1 , and finally obtain PtO x -MnO x / SiO 2 catalyst.

[0037] Example 2 Preparation of PdO using a bimetallic in-situ activation and separation strategy x -CuO x / Al 2 O 3 catalyst

[0038] Accurately weigh 0.028g of palladium acetylacetonate and 0.069g of copper acetylacetonate and dissolve them in 20mL of dimethyl sulfoxide under ultrasonic oscillation, and record the mixed solution as solution 1; disperse 0.5g of aluminum oxide carrier powder in 12mL of dimethyl sulfoxide and mix them thoroughly under ultrasonic oscillation, and record the mixed solution as solution 2. Quickly add solution 1 to solution 2 and mix them evenly under ultrasonic oscillation. The ultrasonic power is set to 40% and the temperature is set to 20°C; after the mixed solution presents a transparent colloid state, freeze-dry the mixed solution; the freeze-drying pressure is set to 50mbar and the temperature is set to -50°C; after the sample is completely dried, the obtained powder sample is calcined. The sample calcination temperature is 400°C, the calcination atmosphere is a hydrogen-argon mixture, the calcination time is 4h, and the heating rate is 3°C·min -1 , and finally PdO x -CuO x / Al 2 O 3 catalyst.

[0039] Example 3 Preparation of PdO using a bimetallic in-situ activation and separation strategy x -MnO x / Al 2 O 3 catalyst

[0040] Accurately weigh 0.028g of acetylacetonate palladium and 0.072g of acetylacetonate manganese, dissolve in 30mL of dimethyl sulfoxide under ultrasonic oscillation, and record the mixed solution as solution 1; disperse 0.5g of silica carrier powder in 15mL of dimethyl sulfoxide, and mix them thoroughly under ultrasonic oscillation, and record the mixed solution as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic oscillation, with the ultrasonic power set to 40% and the temperature set to 20°C; wait for the mixed solution to present a transparent colloid state, and then freeze-dry the mixed solution; the freeze-drying pressure is set to 50mbar and the temperature is set to -50°C; after the sample is completely dried, the obtained powder sample is calcined, the sample calcination temperature is 500°C, the calcination atmosphere is a hydrogen-argon mixture, the calcination time is 5h, and the heating rate is 2°C·min -1 , and finally PdO x -MnO x / Al 2 O 3 catalyst.

[0041] See also Figure 1 ,Depend on Figure 1 The HAADF-STEM image shows that PdO x -MnO x / Al2 O 3 PdO exists on the catalyst surface x -MnO x Strongly coupled bimetallic active centers, where the particle size of the bimetallic active centers is approximately 3-4nm.

[0042] See also Figure 2 ,Depend on Figure 2 From the XRD spectrum, it can be seen that the characteristic peaks of the carrier are obvious, PdO x -MnO x The strongly coupled bimetallic active centers are highly dispersed on the catalyst surface.

[0043] Comparative Example 1: Traditional PdO x / Al 2 O 3 Catalyst preparation

[0044] Accurately weigh 0.028g of acetylacetonate palladium and dissolve it in 15mL of dimethyl sulfoxide under ultrasonic oscillation, and record the mixed solution as solution 1; disperse 0.5g of silica carrier powder in 10mL of dimethyl sulfoxide and mix it thoroughly under ultrasonic oscillation, and record the mixed solution as solution 2. Quickly add solution 1 to solution 2 and mix evenly under ultrasonic oscillation, set the ultrasonic power to 40% and the temperature to 15°C; wait for the mixed solution to present a transparent colloid, and then freeze-dry the mixed solution; the freeze-drying pressure is set to 50mbar and the temperature is set to -50°C; after the sample is completely dried, the obtained powder sample is calcined, the sample calcination temperature is 550°C, the calcination atmosphere is a hydrogen-argon mixture, the calcination time is 6h, and the heating rate is 5°C·min -1 , and finally PdO x / SiO 2 catalyst.

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

[0046] The performance of the catalyst for the selective catalytic dehydrogenation of isopropanol was evaluated in a fixed bed reactor (id=6 mm). 50 mg of PdO prepared in Example 3 was added to the reactor. x -MnO x / Al 2 O 3 The catalyst (40-60 mesh) was mixed with quartz sand in a mass ratio of 1:5 to avoid local overheating during the reaction and heated at 300 °C at 20 mL min -1The raw gas mixture was composed of 10000ppm isopropanol (1.0vol%) + 20.0vol% O 2 +N 2 (balance gas) composition, of which 10000ppm isopropanol is composed of N 2 The air flow was generated by blowing off the isopropanol in a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol can be calculated according to the Antoine equation. -1 The total flow rate reaches 36000mL·g -1 ·h -1 The space velocity (SV) of the catalyst was 1.33 W / m. The 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 detected three times under steady-state reaction conditions after being kept at a given temperature for at least 30 min and the average value was taken. In addition, at least three independent measurements were performed on samples from different batches to verify the accuracy and repeatability of the test.

[0047] See also Figure 3 ,Depend on Figure 3 The test results of the selective catalytic dehydrogenation activity of isopropanol show that PdO x -MnO x / Al 2 O 3 The catalyst exhibited excellent isopropanol catalytic conversion efficiency and acetone selectivity at 200°C and a space velocity of 36000-45000 h -1 Under the condition of oxygen volume concentration of 10-20%, complete conversion of 10000ppm isopropanol can be achieved, and the selectivity of product acetone is greater than 95%.

[0048] See also Figure 4 ,Depend on Figure 4 The comparison of acetone generation rate shows that PdO x -MnO x / Al 2 O 3 The acetone generation rate of the catalyst at 200° C. is increased by 10.5 times compared with the traditional Pd-based catalyst in Comparative Example 1.

[0049] See also Figure 5 ,Depend on Figure 5 The mechanism diagram shows that PdO x -MnO x The strong coupling and synergistic catalytic effect between the two metals synergistically achieve the selective activation of the CH bonds of the isopropanol molecules and the rapid desorption of the acetone reaction intermediates, thereby avoiding the deep oxidation of the isopropanol molecules.

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

[0051] The ethanol dehydrogenation catalytic performance of the catalyst samples was tested in a fixed bed reactor under normal pressure. Specifically, 100 mg of PdO prepared in Example 3 was firstly x -MnO x / Al 2 O 3 The catalyst was mixed with 400 mg of quartz sand and loaded into a U-shaped reactor tube, the inlet and outlet of which were slightly blocked with quartz wool. The mixed gas generated by the gas mixing device consisted of ethanol and nitrogen (30 mL min -1 ), wherein the ethanol feed was supplied by a syringe pump at 9.5 h -1 The mass time space velocity (WHSV) of the catalyst bed was controlled by a mass flow controller. The temperature was measured by a K-type thermocouple reaching the center of the catalyst bed. The exhaust gas products were monitored online by a gas chromatograph (HP 5890GC) equipped with a TCD and FID detector. The products were analyzed by GC-MS (Agilent, 7890B-5977A).

[0052] See also Figure 6 In (a) and (b), Figure 6 The selective catalytic dehydrogenation activity test of ethanol showed that PdO x -MnO x / Al 2 O 3 The catalyst exhibits excellent 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 acetylacetonate and 0.0005 mol of ferric acetylacetonate and dissolve them in 15 mL of dimethyl sulfoxide under ultrasonic oscillation, and record the mixed solution as solution 1; disperse 0.5 g of silica carrier powder in 10 mL of dimethyl sulfoxide and mix them thoroughly under ultrasonic oscillation, and record the mixed solution as solution 2. Quickly add solution 1 to solution 2 and mix them evenly under ultrasonic oscillation, with the ultrasonic power set to 40% and the temperature set to 15°C; after the mixed solution presents a transparent colloid state, freeze-dry the mixed solution; the freeze-drying pressure is set to 50 mbar and the temperature is set to -50°C; after the sample is completely dried, the obtained powder sample is calcined, the sample calcination temperature is 350°C, the calcination atmosphere is a hydrogen-argon mixed gas, the calcination time is 3h, and the heating rate is 5°C·min -1, and finally a supported catalyst with strongly coupled bimetallic nanoparticle active centers was obtained.

[0055] Example 7

[0056] Accurately weigh 0.0001 mol of ruthenium acetylacetonate and 0.0007 mol of nickel acetylacetonate and dissolve them in 20 mL of dimethyl sulfoxide under ultrasonic oscillation, and record the mixed solution as solution 1; disperse 0.5 g of silica carrier powder in 12 mL of dimethyl sulfoxide and mix them thoroughly under ultrasonic oscillation, and record the mixed solution as solution 2. Quickly add solution 1 to solution 2 and mix them evenly under ultrasonic oscillation, with the ultrasonic power set to 40% and the temperature set to 18°C; wait for the mixed solution to present a transparent colloid state, and then freeze-dry the mixed solution; the freeze-drying pressure is set to 50 mbar and the temperature is set to -50°C; after the sample is completely dried, the obtained powder sample is calcined, the sample calcination temperature is 480°C, the calcination atmosphere is a hydrogen-argon mixture, the calcination time is 2h, and the heating rate is 4°C·min -1 , and finally a supported catalyst with strongly coupled bimetallic nanoparticle active centers was obtained.

[0057] Example 8

[0058] Accurately weigh 0.0001 mol of acetylacetonate palladium and 0.001 mol of acetylacetonate chromium, dissolve in 30 mL of dimethyl sulfoxide under ultrasonic oscillation, and record the mixed solution as solution 1; disperse 0.5 g of silica carrier powder in 15 mL of dimethyl sulfoxide, and mix them thoroughly under ultrasonic oscillation, and record the mixed solution as solution 2. Quickly add solution 1 to solution 2 and mix them evenly under ultrasonic oscillation, with the ultrasonic power set to 40% and the temperature set to 20°C; wait for the mixed solution to present a transparent colloid state, and then freeze-dry the mixed solution; the freeze-drying pressure is set to 50 mbar and the temperature is set to -50°C; after the sample is completely dried, the obtained powder sample is calcined, the sample calcination temperature is 450°C, the calcination atmosphere is a hydrogen-argon mixture, the calcination time is 3h, and the heating rate is 5°C·min -1 , and finally a supported catalyst with strongly coupled bimetallic nanoparticle active centers was obtained.

[0059] Example 9

[0060] Same as Example 8, except that chromium acetylacetonate is replaced by lanthanum acetylacetonate.

[0061] Example 10

[0062] Same as Example 8, except that chromium acetylacetonate is replaced by cerium acetylacetonate.

[0063] Embodiment 11

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

[0065] Example 12

[0066] Same as Example 8, except that chromium acetylacetonate is replaced by zinc acetylacetonate.

[0067] Embodiment 13

[0068] Same as Example 8, except that chromium acetylacetonate is replaced by zirconium acetylacetonate.

[0069] Embodiment 14

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

[0071] Embodiment 15

[0072] Same as Example 8, except that chromium acetylacetonate is replaced by tin acetylacetonate.

[0073] Example 16

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

[0075] Embodiment 17

[0076] The performance of the catalyst for the selective catalytic dehydrogenation of isopropanol was evaluated in a fixed bed reactor (id=6 mm). 50 mg of PdO prepared in Example 3 was added to the reactor. x -MnO x / Al 2 O 3 The catalyst (40-60 mesh) was mixed with quartz sand in a mass ratio of 1:5 to avoid local overheating during the reaction and heated at 300 °C at 20 mL min -1 The raw gas mixture was composed of 10000ppm isopropanol (1.0vol%) + 10.0vol% O 2 +N 2 (balance gas) composition, of which 10000ppm isopropanol is composed of N 2 The air flow was generated by blowing off the isopropanol in a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol can be calculated according to the Antoine equation. -1 The total flow rate reaches 36000mL·g -1 ·h -1The 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 under steady-state reaction conditions after being kept at a given temperature for at least 30 minutes and the average value was taken.

[0077] Embodiment 18

[0078] The performance of the catalyst for the selective catalytic dehydrogenation of isopropanol was evaluated in a fixed bed reactor (id=6 mm). 50 mg of PdO prepared in Example 3 was added to the reactor. x -MnO x / Al 2 O 3 The catalyst (40-60 mesh) was mixed with quartz sand in a mass ratio of 1:5 to avoid local overheating during the reaction and heated at 300 °C at 20 mL min -1 The raw gas mixture was composed of 10000ppm isopropanol (1.0vol%) + 15.0vol% O 2 +N 2 (balance gas) composition, of which 10000ppm isopropanol is composed of N 2 The air flow was generated by blowing off the isopropanol in a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol can be calculated according to the Antoine equation. -1 The total flow rate reaches 45000mL·g -1 ·h -1 The 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 under steady-state reaction conditions after being kept at a given temperature for at least 30 minutes and the average value was taken.

[0079] Embodiment 19

[0080] The performance of the catalyst for the selective catalytic dehydrogenation of isopropanol was evaluated in a fixed bed reactor (id=6 mm). 50 mg of PdO prepared in Example 3 was added to the reactor. x -MnO x / Al 2 O 3 The catalyst (40-60 mesh) was mixed with quartz sand in a mass ratio of 1:5 to avoid local overheating during the reaction and heated at 300 °C at 20 mL min -1The raw gas mixture was composed of 10000ppm isopropanol (1.0vol%) + 12.0vol% O 2 +N 2 (balance gas) composition, of which 10000ppm isopropanol is composed of N 2 The air flow was generated by blowing off the isopropanol in a 20°C constant temperature water bath. The saturated vapor pressure of isopropanol can be calculated according to the Antoine equation. -1 The total flow rate reaches 20000mL·g -1 ·h -1 The 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 under steady-state reaction conditions after being kept at a given temperature for at least 30 minutes and the average value was taken.

[0081] In the present invention, a strongly coupled bimetallic nanoparticle active center is constructed on the surface of the carrier through in-situ activation and separation strategies of metal precursors at low temperatures. Through the strong coupling effect and synergistic catalytic effect between the bimetallics, the selective activation of the CH bond of the isopropanol molecule and the rapid desorption of the acetone reaction intermediate are synergistically achieved, thereby avoiding the deep oxidation of the isopropanol molecule. The catalyst prepared by the invention exhibits excellent catalytic efficiency in the selective dehydrogenation reaction of isopropanol, which can keep the yield of acetone in the isopropanol dehydrogenation product above 90% under a wide temperature window (100-200°C), and the acetone generation rate of the catalyst at 200°C is increased by 10.5 times compared with the traditional Pd-based catalyst. The present invention breaks through the technical bottleneck of the low efficiency of the selective dehydrogenation of alcohol molecules by traditional Pd-based catalysts, provides a scientific basis for the resource utilization of high-concentration alcohol waste gas from industrial sources and the coordinated control of pollution reduction and carbon reduction, and the synthesis method has good application universality for a variety of metals and carriers.

[0082] The above description is only for the best embodiment of the present invention, but it should not be understood as limiting the claims. The present invention is not limited to the above embodiments, and its specific structure is allowed to be changed. However, all changes made within the protection scope of the independent claims of the present invention are within the protection scope of the present invention.

[0083] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

Claims

1. A method for preparing a supported catalyst having strongly coupled bimetallic nanoparticle active centers, characterized in that: The following steps are involved: A dimethyl sulfoxide solution containing acetylacetonate metal salt A and acetylacetonate metal salt B is mixed with a dimethyl sulfoxide solution containing a carrier powder sample, ultrasonicated to a transparent colloid state, dried, and calcined to obtain a supported catalyst with strongly coupled bimetallic nanoparticle active centers.

2. The method for preparing a supported catalyst having strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that: The acetylacetonate metal salt A is platinum acetylacetonate, palladium acetylacetonate, rhodium acetylacetonate or ruthenium acetylacetonate.

3. The method for preparing a supported catalyst having strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that: The acetylacetonate metal salt B is manganese acetylacetonate, iron acetylacetonate, nickel acetylacetonate, chromium acetylacetonate, lanthanum acetylacetonate, cerium acetylacetonate, cobalt acetylacetonate, copper acetylacetonate, zinc acetylacetonate, zirconium acetylacetonate, indium acetylacetonate, tin acetylacetonate or molybdenum acetylacetonate.

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

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

6. The method for preparing a supported catalyst having strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that: The carrier is carbon nitride, silicon dioxide, aluminum oxide or titanium dioxide.

7. The method for preparing a supported catalyst having 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.

8. The method for preparing a supported catalyst having strongly coupled bimetallic nanoparticle active centers according to claim 1, characterized in that: The calcination temperature is 350-550°C, the calcination atmosphere is air or hydrogen-argon mixed gas, the calcination time is 2-6h, and the heating rate is 2-5°C·min -1 .

9. A supported catalyst having strongly coupled bimetallic nanoparticle active centers prepared by the preparation method according to any one of claims 1 to 8.

10. Use of a supported catalyst having strongly coupled bimetallic nanoparticle active centers prepared by the preparation method according to any one of claims 1 to 8 in the selective catalytic dehydrogenation of isopropanol.

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