A supported catalyst with sub-nano cluster active centers and its preparation method, and its application in the selective dehydrogenation of isopropanol.

Abstract

This invention discloses a supported catalyst with sub-nano cluster active centers, its preparation method, and its application in the selective dehydrogenation of isopropanol. The preparation method includes: uniformly mixing a noble metal precursor solution with a support, performing rotary evaporation using a stepwise depressurization vacuum extraction method, followed by a first calcination to obtain powder; subjecting the powder to plasma discharge treatment under a mixed gas of hydrogen and argon to obtain a sample; and then subjecting the sample to a second calcination. This invention utilizes the strong coupling and synergistic catalytic effects between uniformly coordinated metal atoms at the sub-nano cluster sites to synergistically achieve selective activation of the C-H bonds in isopropanol molecules and rapid desorption of acetone reaction intermediates, thereby avoiding deep oxidation of isopropanol molecules. This catalyst 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℃).

Description

Technical Field

[0001] This invention belongs to the field of air pollution control technology, and specifically relates to a supported catalyst with sub-nano cluster active centers, 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 still faces significant challenges. 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 alcohol organic compounds, leading to a decrease in the selectivity of high-value products.

[0003] Taking the selective oxidation of alcohols as an example, supported noble metal-based catalysts exhibit high activity in alcohol oxidation, but at elevated temperatures, they often lead to the deep oxidation of alcohols to CO2. The high conversion rate of alcohol molecules at high temperatures also significantly reduces the selectivity and yield of the 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 then 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 the deep oxidation to CO2 requires the breaking of C / C bonds. Therefore, the key strategy to address this challenge is to design catalysts that selectively promote CH bond activation while suppressing C / C bond cleavage. However, the bond energies of CH and C / C are very close, making it quite difficult to achieve selective activation of CH alone. Summary of the Invention

[0004] To overcome the technical problem that existing catalysts easily cause deep oxidation of alcohol organic compounds, leading to a decrease in the selectivity of high-value products, the purpose of this invention is to provide a supported catalyst with sub-nano cluster active centers, a preparation method, and its application in the selective dehydrogenation of isopropanol.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for preparing a supported catalyst with sub-nano cluster active centers includes the following steps:

[0007] After the noble metal precursor solution was mixed evenly with the carrier, rotary evaporation was performed using a step-down vacuum extraction method to obtain a solid.

[0008] The solid is dried and then calcined once to obtain a powder.

[0009] The powder was subjected to plasma discharge treatment in a mixed gas of hydrogen and argon to obtain a sample;

[0010] The sample was calcined a second time to obtain a supported catalyst with sub-nano cluster active centers.

[0011] Furthermore, the noble metal precursor is one of chloroplatinic acid, sodium chloropalladium, iridium chloride, ruthenium chloride, rhodium chloride, chloroauric acid, and silver chloride.

[0012] Furthermore, the carrier is one of silicon dioxide, aluminum oxide, PCN, titanium dioxide, and cerium dioxide.

[0013] Furthermore, the ratio of the precious metal precursor to the carrier is 0.0001 mol: 0.2-1.0 g.

[0014] Furthermore, the rotary evaporation process was carried out at a temperature of 60-65℃, a rotation speed of 120-140 rpm, and a vacuum descent rate of 10 mbar·min. -1 .

[0015] Furthermore, the initial roasting temperature is 350-400℃, the time is 2-3 hours, and the heating rate is 1-2.5℃·min. -1 .

[0016] Furthermore, the plasma discharge treatment voltage is 10-30kV, the current is 1-2A, and the time is 30-300min.

[0017] Furthermore, the secondary calcination temperature is 500-550℃, the calcination time is 3-4 hours, and the heating rate is 5℃·min. -1 The atmosphere for the secondary roasting was a mixture of hydrogen and argon, at a temperature of 5°C / min. -1 The heating rate is increased to 500-550℃.

[0018] A supported catalyst with sub-nano cluster active centers.

[0019] Application of a supported catalyst with sub-nano cluster active centers in the selective catalytic dehydrogenation of isopropanol.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention begins with the design and development of sub-nano cluster active centers with highly uniform particle size distribution and easily tunable coordination structures. First, a bottom-up synthesis strategy is employed, using a step-by-step depressurization vacuum extraction method and a two-step pyrolysis method to synthesize single-atom catalysts with uniform coordination structures. Then, utilizing the ionization effect of non-thermal plasma, under an external field, the aforementioned uniformly coordinated single-atom sites are induced to migrate and aggregate directionally on the support surface in a reducing atmosphere. The migration rate of metal atoms and the size of the aggregates are precisely controlled by adjusting the plasma discharge power and the external field treatment time. Through the strong coupling and synergistic catalytic effects between the uniformly coordinated metal atoms at the sub-nano cluster sites, the selective activation of the CH bonds in isopropanol molecules and the rapid desorption of acetone reaction intermediates are synergistically achieved, thereby avoiding deep oxidation of isopropanol molecules. The catalyst prepared by this invention exhibits excellent catalytic efficiency in the selective dehydrogenation of isopropanol. It maintains the yield of acetone in the isopropanol dehydrogenation product above 90% over a wide temperature window (100-200℃). The acetone formation rate at 180℃ is 18.3 times higher than that of traditional supported catalysts. This invention overcomes the technical bottleneck of low selective dehydrogenation efficiency of traditional supported noble metal-based catalysts for alcohol molecules, providing a scientific basis for the resource utilization and synergistic control of pollution reduction and carbon reduction in high-concentration alcohol waste gas from industrial sources. Furthermore, this synthesis method has good applicability to various noble metals and supports. Attached Figure Description

[0022] Figure 1 In this invention, Pd1 / SiO2 (before plasma treatment) and Pd nc High-angle annular dark-field scanning transmission (HAADF-STEM) images of Pd1 / SiO2 catalyst, where (a) is Pd1 / SiO2 (before plasma treatment) and (b) is Pd1 / SiO2. nc / SiO2 catalyst.

[0023] Figure 2 The Pd1 / Al2O3 (before plasma treatment) and Pd in ​​this invention nc High-angle annular dark-field scanning transmission (HAADF-STEM) images of Pd1 / Al2O3 catalyst, where (a) is Pd1 / Al2O3 (before plasma treatment) and (b) is Pd1 / Al2O3. nc / Al2O3 catalyst.

[0024] Figure 3 The Pt1 / CeO2 (before plasma treatment) and Pt in this invention nc High-angle annular dark-field scanning transmission (HAADF-STEM) images of Pt1 / CeO2 catalyst, where (a) is Pt1 / CeO2 (before plasma treatment) and (b) is Pt1 / CeO2.nc / CeO2 catalyst.

[0025] Figure 4 The Pd1 / TiO2 (before plasma treatment) and Pd in ​​this invention nc High-angle annular dark-field scanning transmission (HAADF-STEM) images of Pd1 / TiO2 catalyst, where (a) is Pd1 / TiO2 (before plasma treatment) and (b) is Pd1 / TiO2. nc / TiO2 catalyst.

[0026] Figure 5 Pd in ​​this invention nc / TiO2 catalyst catalytic selective dehydrogenation activity diagram of ethanol, where (a) is the isopropanol conversion diagram and (b) is the acetone selectivity diagram.

[0027] Figure 6 Pd in ​​this invention nc / TiO2 and Pd np Comparison of acetone formation rates for selective dehydrogenation of isopropanol catalyzed by TiO2 (traditional supported Pd-based catalyst) catalyst. Detailed Implementation

[0028] 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.

[0029] This invention constructs a supported noble metal-based catalyst with uniform active center particle size and coordination structure to regulate 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.

[0030] The present invention provides a method for preparing a supported catalyst with sub-nano cluster active centers. Starting with the design and development of sub-nano cluster active centers with highly uniform particle size distribution and easily tunable coordination structures, a bottom-up synthesis strategy is employed. Single-atom catalysts with uniform coordination structures are synthesized through a stepwise depressurization vacuum extraction method and a two-step pyrolysis method. Subsequently, utilizing the ionization effect of non-thermal plasma, under an external field, the aforementioned uniformly coordinated single-atom sites are induced to migrate and aggregate directionally on the support surface in a reducing atmosphere. The migration rate of metal atoms and the size of the aggregates are precisely controlled by adjusting the plasma discharge power and the external field treatment time. Through the strong coupling and synergistic catalytic effects between the uniformly coordinated metal atoms at the sub-nano cluster sites, the selective activation of the CH bonds in isopropanol molecules and the rapid desorption of acetone reaction intermediates are synergistically achieved, thereby avoiding deep oxidation of isopropanol molecules. The catalyst prepared by this invention exhibits excellent catalytic efficiency in the selective dehydrogenation reaction of isopropanol. It can maintain the yield of acetone in the dehydrogenation product of isopropanol above 90% within a wide temperature window (100-200℃). The acetone generation rate of this catalyst at 180℃ is 18.3 times higher than that of traditional supported catalysts.

[0031] The preparation method of the present invention specifically includes the following steps:

[0032] (1) Disperse 0.0001 mol of a noble metal precursor (which may be one of chloroplatinic acid, sodium chloropalladium, iridium chloride, ruthenium chloride, rhodium chloride, chloroauric acid and silver chloride) in 10-20 mL of deionized water under ultrasonic vibration.

[0033] (2) Add 0.2-1.0g of carrier (which can be one of silicon dioxide, aluminum oxide, PCN (polymer carbon nitride), titanium dioxide and cerium dioxide) to the mixed solution obtained in step (1), and mix evenly under ultrasonic magnetic stirring. The ultrasonic power is set to 40%, the temperature is set to 50-65℃, and the stirring speed is set to 800-1200rpm.

[0034] (3) The mixed solution obtained in step (2) was subjected to rotary evaporation using a step-by-step depressurization vacuum extraction method. The water temperature was set to 60-65℃, the rotation speed was set to 120-140 rpm, and the vacuum degree decrease rate was 10 mbar·min. -1 .

[0035] (4) Dry the solid powder obtained in step (3) at 60-80℃ for 6-12 hours.

[0036] (5) The solid sample obtained in step (4) is calcined at 350-400℃ in air for 2-3 hours, with a heating rate of 1-2.5℃·min. -1 .

[0037] (6) Place the solid powder obtained in step (5) into the glass tube of the plasma reactor and evacuate the reactor. Then, introduce a mixed gas of 20% hydrogen and 80% argon by volume into the reactor and maintain it for more than 60 minutes at a flow rate of 100-200 mL / min. -1 .

[0038] (7) Turn on the plasma discharge device in step (6), set the voltage to 10-30kV, the current to 1-2A, and the processing time to 30-300min.

[0039] (8) Disperse the solid powder obtained in step (7) in 30 mL of dimethyl sulfoxide, and ultrasonically wash it at 40-60 °C. After centrifugation, continue to ultrasonically wash the obtained sample twice with 30-50 mL of ethanol-deionized water mixed solution (ethanol to deionized water volume ratio of 3:1).

[0040] (9) Dry the sample obtained in step (8) at 60-80℃ for 6-12 hours.

[0041] (10) The sample obtained in step (9) is calcined at 500-550℃ in air atmosphere for 3-4 hours, with a heating rate of 1-2℃·min. -1 .

[0042] The supported catalyst with sub-nano cluster active centers prepared in this invention achieves selective activation of the CH bonds in isopropanol molecules and rapid desorption of acetone reaction intermediates through strong coupling and synergistic catalytic effects between metal atoms with uniform coordination structures at the sub-nano cluster sites, thereby avoiding deep oxidation of isopropanol molecules. The catalyst prepared in 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 180℃ is 18.3 times higher than that of conventional supported catalysts.

[0043] The following are specific examples.

[0044] Example 1: Pd with sub-nano cluster active centers nc Preparation of SiO2 catalyst

[0045] 0.0271 g of sodium chloropalladium was dispersed in 20 mL of deionized water under ultrasonic vibration, and 1.0 g of SiO2 support was added to the solution. The mixture was then stirred evenly under ultrasonic magnetic stirring with an ultrasonic power of 40%, a temperature of 60 °C, and a stirring speed of 1000 rpm. The mixture was then subjected to rotary evaporation using a step-down vacuum extraction method, with the water temperature set at 60 °C, the rotation speed at 130 rpm, and a vacuum decrease rate of 10 mbar·min⁻¹. -1 The resulting solid powder was then dried at 60°C for 12 hours and calcined at 350°C in air for 2 hours at a heating rate of 2.5°C / min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 150 mL / min. -1 A mixture of 20% hydrogen and 80% argon gas was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 60 minutes at a voltage of 20 kV and a current of 1 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 60 °C. After centrifugation, the sample was ultrasonically washed twice more with 30 mL of an ethanol-deionized water mixture and dried at 60 °C for 12 hours. Finally, the dried sample was calcined at 500 °C in air for 3 hours at a heating rate of 1 °C / min. -1 Pd is obtained nc / SiO2 catalyst.

[0046] See Figure 1 In (a) and (b), by Figure 1 HAADF-STEM images show that a bottom-up synthesis strategy was adopted, using a stepwise depressurization vacuum extraction method and a two-step pyrolysis method to synthesize a Pd1 / SiO2 single-atom catalyst with a uniform coordination structure. Subsequently, Pd1 / SiO2 catalysts with uniform sub-nano cluster active centers were successfully synthesized through non-thermal plasma treatment. nc / SiO2 catalyst.

[0047] Example 2: Pd with sub-nano cluster active centers nc Preparation of Al2O3 catalyst

[0048] 0.0271 g of sodium chloropalladate was dispersed in 20 mL of deionized water under ultrasonic vibration. 1.0 g of Al₂O₃ support was added to the solution, and the mixture was thoroughly mixed under ultrasonic magnetic stirring. The ultrasonic power was set to 40%, the temperature to 60 °C, and the stirring speed to 1000 rpm. The mixture was then subjected to rotary evaporation using a step-down vacuum extraction method. The water temperature was set to 60 °C, the rotation speed to 120 rpm, and the vacuum decrease rate to 10 mbar·min⁻¹. -1The resulting solid powder was then dried at 80°C for 12 hours and calcined at 400°C in air for 2 hours at a heating rate of 2.5°C / min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 150 mL / min. -1 A mixture of 20% hydrogen and 80% argon gas was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 120 minutes at a voltage of 20 kV and a current of 2 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 60 °C. After centrifugation, the sample was ultrasonically washed twice more with 30 mL of an ethanol-deionized water mixture and dried at 80 °C for 12 hours. Finally, the dried sample was calcined at 500 °C in air for 3 hours at a heating rate of 1 °C / min. -1 Pd is obtained nc / Al2O3 catalyst.

[0049] See Figure 2 In (a) and (b), by Figure 2 HAADF-STEM images show that a bottom-up synthesis strategy was adopted, using a stepwise depressurization vacuum extraction method and a two-step pyrolysis method to synthesize a Pd1 / Al2O3 single-atom catalyst with a uniform coordination structure. Subsequently, Pd1 / Al2O3 with uniform sub-nano cluster active centers was successfully synthesized through non-thermal plasma treatment. nc / Al2O3 catalyst.

[0050] Example 3: Pt with sub-nano cluster active centers nc Preparation of / CeO2 catalyst

[0051] 0.0410 g of chloroplatinic acid was dispersed in 20 mL of deionized water under ultrasonic vibration, and 1.0 g of CeO2 carrier was added to the solution. The mixture was then stirred evenly with ultrasonic magnetic stirring at 40% power, 65°C, and 1200 rpm. The mixture was then subjected to rotary evaporation using a step-down vacuum extraction method, with the water temperature set at 65°C, the rotation speed at 140 rpm, and the vacuum decrease rate at 10 mbar·min⁻¹. -1 The resulting solid powder was then dried at 80°C for 12 hours and calcined at 400°C in air for 3 hours at a heating rate of 2.5°C / min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 200 mL / min. -1A mixture of 20% hydrogen and 80% argon gas was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 120 minutes at a voltage of 30 kV and a current of 2 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 60 °C. After centrifugation, the sample was ultrasonically washed twice more with 50 mL of an ethanol-deionized water mixture and dried at 80 °C for 12 hours. Finally, the dried sample was calcined at 550 °C in air for 3 hours at a heating rate of 1 °C / min. -1 , obtain Pt nc / CeO2 catalyst.

[0052] See Figure 3 In (a) and (b), by Figure 3 HAADF-STEM images show that a bottom-up synthesis strategy was adopted, using a stepwise depressurization vacuum extraction method and a two-step pyrolysis method to synthesize a Pt1 / CeO2 single-atom catalyst with a uniform coordination structure. Subsequently, Pt with uniform sub-nano cluster active centers was successfully synthesized through non-thermal plasma treatment. nc / CeO2 catalyst.

[0053] Example 4: Pd with sub-nano cluster active centers nc Preparation of TiO2 catalyst

[0054] 0.0271 g of sodium chloropalladate was dispersed in 20 mL of deionized water under ultrasonic vibration. 1.0 g of TiO2 support was added to the solution, and the mixture was thoroughly mixed under ultrasonic magnetic stirring. The ultrasonic power was set to 40%, the temperature to 65 °C, and the stirring speed to 1200 rpm. The mixture was then subjected to rotary evaporation using a stepwise decreasing vacuum extraction method. The water temperature was set to 60 °C, the rotation speed to 120 rpm, and the vacuum decrease rate to 10 mbar·min⁻¹. -1 The resulting solid powder was then dried at 70°C for 12 hours and calcined at 350°C in air for 3 hours at a heating rate of 2°C / min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 200 mL / min. -1 A mixture of 20% hydrogen and 80% argon gas was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 200 minutes at a voltage of 30 kV and a current of 2 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 60 °C. After centrifugation, the sample was ultrasonically washed twice more with 40 mL of an ethanol-deionized water mixture and dried at 80 °C for 12 hours. Finally, the dried sample was calcined at 500 °C in air for 4 hours at a heating rate of 1 °C / min.-1 Pd is obtained nc / TiO2 catalyst.

[0055] See Figure 4 In (a) and (b), by Figure 4 HAADF-STEM images show that a bottom-up synthesis strategy was adopted, using a stepwise depressurization vacuum extraction method and a two-step pyrolysis method to synthesize a Pd1 / TiO2 single-atom catalyst with a uniform coordination structure. Subsequently, Pd1 / TiO2 catalysts with uniform sub-nano cluster active centers were successfully synthesized through non-thermal plasma treatment. nc / TiO2 catalyst.

[0056] See Figure 5 In (a) and (b), by Figure 5 The results of the selective catalytic dehydrogenation activity test of isopropanol show that Pd nc The TiO2 catalyst exhibits excellent isopropanol catalytic conversion efficiency and acetone selectivity at 180 °C 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 90%. This is mainly due to the strong coupling and synergistic catalytic effect between metal atoms in the uniform coordination structure at the sub-nano cluster sites, which synergistically achieve selective activation of the CH bond of the isopropanol molecule and rapid desorption of the acetone reaction intermediate, thereby avoiding deep oxidation of the isopropanol molecule.

[0057] See Figure 6 ,Depend on Figure 6 A comparison of acetone formation rates shows that Pd, with its uniform sub-nano cluster active centers, exhibits higher acetone formation rates. nc The acetone formation rate of TiO2 catalyst at 200℃ is higher than that of conventional Pd catalyst. np The TiO2 catalyst was improved by 18.3 times.

[0058] Example 5: Isopropanol dehydrogenation performance test of a supported catalyst with sub-nano cluster active centers

[0059] 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 catalyst (40-60 mesh) was mixed with silica sand at a mass ratio of 1:5 to avoid localized overheating during the reaction, and the mixture was reacted at 300 °C at a rate of 20 mL / min. -1Oxygen 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.

[0060] Example 6

[0061] 0.0001 mol of iridium chloride was dispersed in 10 mL of deionized water under ultrasonic vibration, and 0.2 g of SiO2 support was added to the solution. The mixture was then stirred evenly with ultrasonic magnetic stirring at 40% ultrasonic power, 65℃, and 1100 rpm. The mixture was then subjected to rotary evaporation using a step-down vacuum extraction method, with the water temperature set at 65℃, the rotation speed at 140 rpm, and the vacuum decrease rate at 10 mbar·min⁻¹. -1 The resulting solid powder was then dried at 60°C for 12 hours and calcined at 390°C in air for 2 hours at a heating rate of 1°C·min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 100 mL / min. -1 A mixture of 20% hydrogen and 80% argon gas was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 200 minutes at a voltage of 10 kV and a current of 1 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 40 °C. After centrifugation, the sample was ultrasonically washed twice more with 45 mL of an ethanol-deionized water mixture and dried at 70 °C for 10 hours. Finally, the dried sample was calcined at 540 °C in air for 2 hours at a heating rate of 1 °C / min. -1 Thus, a supported catalyst with sub-nano cluster active centers was obtained.

[0062] Example 7

[0063] 0.0001 mol of ruthenium chloride was dispersed in 13 mL of deionized water under ultrasonic vibration, and 1.0 g of CeO2 carrier was added to the solution. The mixture was then stirred evenly under ultrasonic magnetic stirring at 40% power, 50°C, and 900 rpm. The mixture was then subjected to rotary evaporation using a step-down vacuum extraction method at 65°C, 130 rpm, and a vacuum decrease rate of 10 mbar·min⁻¹. -1 The resulting solid powder was then dried at 80°C for 6 hours and calcined at 380°C in air for 2 hours at a heating rate of 1.5°C / min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 170 mL / min. -1 A 20% hydrogen-80% argon gas mixture was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 100 minutes at a voltage of 30 kV and a current of 2 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 50 °C. After centrifugation, the sample was ultrasonically washed twice more with 35 mL of an ethanol-deionized water mixture and dried at 80 °C for 6 hours. Finally, the dried sample was calcined at 530 °C in air for 3 hours at a heating rate of 2 °C / min. -1 Thus, a supported catalyst with sub-nano cluster active centers was obtained.

[0064] Example 8

[0065] 0.0001 mol of rhodium chloride was dispersed in 16 mL of deionized water under ultrasonic vibration. 0.5 g of PCN carrier was added to the solution, and the mixture was thoroughly mixed under ultrasonic magnetic stirring. The ultrasonic power was set to 40%, the temperature to 55℃, and the stirring speed to 1200 rpm. The mixture was then subjected to rotary evaporation using a step-down vacuum extraction method. The water temperature was set to 62℃, the rotation speed to 140 rpm, and the vacuum decrease rate to 10 mbar·min⁻¹. -1 The resulting solid powder was then dried at 70°C for 10 hours and calcined at 370°C in air for 3 hours at a heating rate of 2.0°C·min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 200 mL / min. -1A mixture of 20% hydrogen and 80% argon gas was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 300 minutes at a voltage of 25 kV and a current of 1 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 45 °C. After centrifugation, the sample was ultrasonically washed twice more with 40 mL of an ethanol-deionized water mixture and dried at 60 °C for 12 hours. Finally, the dried sample was calcined at 550 °C in air for 3 hours at a heating rate of 1 °C / min. -1 Thus, a supported catalyst with sub-nano cluster active centers was obtained.

[0066] Example 9

[0067] 0.0001 mol of silver chloride was dispersed in 20 mL of deionized water under ultrasonic vibration, and 0.8 g of TiO2 support was added to the solution. The mixture was then stirred evenly with ultrasonic magnetic stirring at 40% power, 65°C, and 800 rpm. The mixture was then subjected to rotary evaporation using a step-down vacuum extraction method at 63°C, 120 rpm, and a vacuum decrease rate of 10 mbar·min⁻¹. -1 The resulting solid powder was then dried at 65°C for 12 hours and calcined at 360°C in air for 3 hours at a heating rate of 2.5°C / min. -1 The calcined sample was placed inside the glass tube of the plasma reactor, and the reactor was evacuated. Then, the plasma was injected into the reactor at a rate of 120 mL / min. -1 A 20% hydrogen-80% argon gas mixture was introduced and maintained for at least 60 minutes. Then, the plasma discharge device was activated, and the sample was treated for 30 minutes at a voltage of 15 kV and a current of 1 A. The resulting solid powder was then dispersed in 30 mL of dimethyl sulfoxide and ultrasonically washed at 55 °C. After centrifugation, the sample was ultrasonically washed twice more with 50 mL of an ethanol-deionized water mixture and dried at 75 °C for 10 hours. Finally, the dried sample was calcined at 520 °C in air for 4 hours at a heating rate of 2 °C / min. -1 Thus, a supported catalyst with sub-nano cluster active centers was obtained.

[0068] The above description is only of the preferred embodiment 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 variations made within the scope of the independent claims of the present invention are also within the scope of protection of the present invention.

[0069] 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. Use of a supported catalyst having sub-nanocluster active centres in the selective catalytic dehydrogenation of isopropyl alcohol, characterised in that, The preparation method of the supported catalyst with sub-nanocluster active centers is as follows: After the noble metal precursor solution is mixed uniformly with the carrier, a solid is obtained by performing rotary evaporation treatment using a stepwise pressure reduction vacuum extraction method; wherein the temperature of the rotary evaporation treatment is 60-65 °C, the rotation speed is 120-140 rpm, and the vacuum degree reduction rate is 10 mbar min -1 ; The solid is dried and then subjected to a first firing to obtain a powder; the first firing is at a temperature of 350-400 °C for a time of 2-3 h, with a temperature increase rate of 1-2.5 °C / min min -1 ; The powder is subjected to plasma discharge treatment under a mixed gas of hydrogen and argon to obtain a sample; The sample is subjected to a second calcination to obtain a supported catalyst with sub-nanocluster active centers; the temperature of the second calcination is 500-550 °C, the calcination time is 3-4 h, and the temperature increase rate is 5 °C min -1 ; the atmosphere of the second calcination is a mixture of hydrogen and argon, and the temperature is increased to 500-550 °C at a temperature increase rate of 5 °C min -1 .

2. Use of the supported catalyst with sub-nanocluster active centres according to claim 1 for the selective catalytic dehydrogenation of isopropyl alcohol, characterised in that, The noble metal precursor is one of chloroplatinic acid, sodium chloroplatinate, iridium chloride, ruthenium chloride, rhodium chloride, chloroauric acid and silver chloride.

3. Use of the supported catalyst with sub-nanocluster active centres according to claim 1 for the selective catalytic dehydrogenation of isopropyl alcohol, characterised in that, The carrier is one of silicon dioxide, aluminum oxide, PCN, titanium dioxide and cerium dioxide.

4. Use of the supported catalyst with sub-nanocluster active centres according to claim 1 for the selective catalytic dehydrogenation of isopropanol, characterised in that, The dosage ratio of the noble metal precursor to the carrier is 0.0001 mol: 0.2-1.0 g.

5. Use of the supported catalyst with sub-nanocluster active centres according to claim 1 for the selective catalytic dehydrogenation of isopropanol, characterised in that, The voltage of the plasma discharge treatment is 10-30 kV, the current is 1-2 A, and the time is 30-300 min.

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