A propane catalytic combustion catalyst, its preparation method and use

Abstract

This invention relates to a propane catalytic combustion catalyst, its preparation method, and its applications. The propane catalytic combustion catalyst comprises a support and active nanoparticles supported on the support; the active nanoparticles comprise an active agent and an active metal supported on the surface of the active agent; the active metal comprises any one or a combination of at least two of Pt, Pd, or Rh; the active agent comprises a transition metal oxide; and the support comprises dendritic mesoporous silica. The propane catalytic combustion catalyst provided by this invention has advantages such as high activity, high stability, and strong water resistance, and its preparation method is simple, showing promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of environmental catalysis technology, specifically to a propane catalytic combustion catalyst, its preparation method, and its applications. Background Technology

[0002] Volatile organic compounds (VOCs) are a class of organic compounds widely present in indoor and outdoor environments. They are characterized by high vapor pressure at normal temperature and pressure, and their tendency to volatilize into gases. VOCs include hydrocarbons, halogenated hydrocarbons, oxygen-containing organic compounds, nitrogen-containing organic compounds, and sulfur-containing organic compounds, primarily originating from industrial processes, traffic exhaust, indoor building materials, household products, and plant emissions. With the increasing use of liquefied petroleum gas (LPG) and liquefied natural gas (LNG), the emission of light hydrocarbons is growing, posing a potential threat to air quality and potentially harming human health.

[0003] Propane is a typical VOC (accounting for about 4% of total VOCs). Due to the thermal and chemical stability of the propane molecule, the CH bond is difficult to break, thus requiring relatively high temperatures to degrade propane. Therefore, how to efficiently catalyze the combustion of propane at lower temperatures is of great significance for reducing VOC pollution.

[0004] CN104383925A discloses a method for preparing a catalyst for the catalytic combustion elimination of propane. This method employs a co-precipitation method to dope metal species into nickel oxide, wherein NiO-MnO... x Nickel oxide exhibits the best activity for catalytic combustion of propane, but it is prone to sintering and is extremely susceptible to deactivation under moisture conditions.

[0005] CN112958086A discloses a catalyst for propane catalytic combustion and its preparation method. The catalyst uses γ-Al2O3 as a support, and after constructing a MgAl2O4 spinel layer on the surface of Al2O3 by a stepwise loading method, Pd-Pt active components are loaded, and then a rare earth oxide protective layer is introduced on its surface to achieve a "sandwich" configuration. However, the preparation method of this catalyst is complicated and the catalytic combustion activity of propane is poor.

[0006] CN116174016A discloses a platinum-based catalyst for propane catalytic combustion and its preparation method. The platinum-based catalyst for propane catalytic combustion is in the form of foam, and the support is a foam-shaped monolithic all-silica molecular sieve. The preparation method of this catalyst is complex, the production cost is high, and it is difficult to apply in practice.

[0007] Therefore, current propane catalytic combustion catalysts struggle to simultaneously possess high activity, high stability, and strong water resistance. Furthermore, their preparation processes are cumbersome, production costs are high, and industrial-scale production is difficult. Thus, providing a catalyst suitable for propane catalytic combustion that exhibits high activity, high stability, and strong water resistance is a pressing issue that needs to be addressed. Summary of the Invention

[0008] To address the above problems, the present invention aims to provide a propane catalytic combustion catalyst, its preparation method, and its applications. Compared with the prior art, the propane catalytic combustion catalyst provided by the present invention has advantages such as high activity, high stability, and strong water resistance, and its preparation method is simple and has good application prospects.

[0009] To achieve this objective, the present invention adopts the following technical solution:

[0010] In a first aspect, the present invention provides a propane catalytic combustion catalyst, the propane catalytic combustion catalyst comprising a support and active nanoparticles supported on the support;

[0011] The active nanoparticles include an active additive and an active metal loaded on the surface of the active additive;

[0012] The active metal includes any one or a combination of at least two of Pt, Pd, or Rh;

[0013] The active additives include transition metal oxides;

[0014] The carrier comprises dendritic mesoporous silica.

[0015] The propane catalytic combustion catalyst provided by this invention improves catalytic activity through the synergistic effect of active metals and active additives. On the other hand, by using dendritic mesoporous silica as a support, the active metals and active additives are confined within the channels of the dendritic mesoporous silica, and the size of the active nanoparticles is controlled, which can further improve the activity, stability and water resistance of the catalyst.

[0016] Preferably, the particle size of the active nanoparticles is ≤5nm, for example, it can be 5nm, 4nm, 3nm, 2nm or 1nm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the active nanoparticles are loaded within the pores of the carrier.

[0018] Preferably, the carrier comprises dendritic mesoporous silica KCC-1.

[0019] Preferably, the diameter of the dendritic mesoporous silica KCC-1 is 550-750nm, for example, it can be 550nm, 560nm, 580nm, 600nm, 620nm, 640nm, 660nm, 680nm, 700nm, 720nm, 740nm or 750nm, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0020] Preferably, the mass of the active metal accounts for 0.1-2% of the mass of the propane catalytic combustion catalyst, for example, it can be 0.1%, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8% or 2%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 1-2%.

[0021] Preferably, the transition metal oxide contains any one or a combination of at least two of the transition metal elements selected from Ce, Ti, Nb, W, Co, Zr, or La, with cerium being the most preferred.

[0022] In this invention, the transition metal oxide can interact with noble metals to form a special noble metal-oxide interface (such as Pt-O-Ce), which can serve as a new active site, thereby enhancing catalytic activity. This invention preferably uses cerium as the transition metal because cerium oxide has a stronger oxygen storage and release capacity than oxides of elements such as Ti, Nb, W, Co, Zr, or La, thus further enhancing catalytic activity and reducing T. 90 temperature.

[0023] Preferably, the active additive accounts for 1-10% of the mass of the propane catalytic combustion catalyst, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable, preferably 3-10%.

[0024] In this invention, it is preferable to control the percentage of the mass of the active additive to the mass of the propane catalytic combustion catalyst. This can further enhance the catalytic activity, avoiding both excessive additives that may clog some pores and affect the contact between the reactants and active sites in the catalytic process, and insufficient additives that may result in too few noble metal-oxide interfaces, which would be detrimental to further enhancing the catalytic activity.

[0025] In a second aspect, the present invention provides a method for preparing a propane catalytic combustion catalyst as described in the first aspect of the present invention, the preparation method comprising the following steps:

[0026] (1) Mix the precursor of the active metal and the metal salt of the active auxiliary in a solvent, then add the carrier and stir, and then vacuum dry and grind in sequence to obtain powder;

[0027] (2) The powder obtained in step (1) is calcined to obtain a propane catalytic combustion catalyst.

[0028] The preparation method provided by this invention first mixes the precursor of the active metal and the metal salt of the active agent in a solvent. The solvent can dissolve various metal salts to form a salt solution. By stirring, the salt solution is fully mixed with the support and enters the pores of the support. After removing the solvent by vacuum drying, the metal salt remains in the pores of the support. Then, by calcination, active nanoparticles are formed and loaded in the pores, thereby enhancing the interaction between the active metal and the active agent and improving the catalytic activity, stability and water resistance of the catalyst.

[0029] Preferably, the precursor of the active metal in step (1) includes any one or a combination of at least two of the following: Pt precursor, Pd precursor, or Rh precursor.

[0030] Preferably, the Pt precursor includes any one or a combination of at least two of platinum nitrate, chloroplatinic acid, tetrahydroplatinum nitrate, or platinum acetylacetonate.

[0031] Preferably, the Pd precursor comprises any one or a combination of at least two of palladium nitrate, sodium tetrachloropalladium, or tetraamminepalladium nitrate.

[0032] Preferably, the Rh precursor comprises any one or a combination of at least two of rhodium nitrate, rhodium chloride, or ammonium rhodium chloronitrate.

[0033] Preferably, the metal salt of the active agent includes any one or a combination of at least two of the transition metal nitrates, acetates, sulfates or ammonium salts.

[0034] Preferably, the solvent includes any one or a combination of at least two of water, ethanol, ethylene glycol, or glycerol, with ethylene glycol being the most preferred.

[0035] In this invention, ethylene glycol is preferred as the solvent, which can further enhance the catalytic activity of the catalyst. This is because ethylene glycol has two hydroxyl groups, which can form stable complexes with metal salts. After drying, the metal salts still exist in the form of complexes. During the subsequent calcination process, ethylene glycol can play a protective role to prevent the metal particles from agglomerating.

[0036] Preferably, the volume ratio of the solvent to the mass ratio of the carrier is (2-4):1 mL / g, for example, it can be 2:1 mL / g, 2.2:1 mL / g, 2.4:1 mL / g, 2.6:1 mL / g, 2.8:1 mL / g, 3:1 mL / g, 3.2:1 mL / g, 3.4:1 mL / g, 3.6:1 mL / g or 3.8:1 mL / g, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] In this invention, it is preferable to control the volume ratio of the solvent to the mass of the carrier within a specific range because too little solvent may result in the metal salt not being completely dissolved; too much solvent may result in the carrier not being able to completely absorb the solvent, which in turn may prevent some of the salt solution from entering the pores.

[0038] Preferably, ultrasound is performed during the mixing process described in step (1).

[0039] Preferably, the power of the ultrasound is 150-250W, for example, it can be 150W, 160W, 170W, 180W, 190W, 200W, 210W, 220W, 230W, 240W or 250W, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0040] Preferably, the temperature of the ultrasound is 10-40℃, for example, it can be 10℃, 12℃, 14℃, 16℃, 18℃, 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, 32℃, 34℃, 36℃, 38℃ or 40℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0041] Preferably, the ultrasound duration is 0.5-1 hour, for example, 0.5 hours, 0.6 hours, 0.7 hours, 0.8 hours, 0.9 hours or 1 hour, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the stirring time is 10-12 hours, for example, 10 hours, 10.5 hours, 11 hours, 11.5 hours or 12 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, the vacuum drying temperature is 70-90℃, for example, it can be 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, 82℃, 84℃, 86℃, 88℃ or 90℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0044] Preferably, the vacuum drying time is 10-12 hours, for example, 10 hours, 10.5 hours, 11 hours, 11.5 hours or 12 hours, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Preferably, the heating rate of calcination in step (2) is 5-10℃ / min, for example, it can be 5℃ / min, 6℃ / min, 7℃ / min, 8℃ / min, 9℃ / min or 10℃ / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] In this invention, the calcination apparatus is not particularly limited and any apparatus used for catalyst calcination in the art can be used, such as a tube furnace.

[0047] Preferably, the final temperature of the calcination is 400-500℃, for example, it can be 400℃, 410℃, 420℃, 430℃, 440℃, 450℃, 460℃, 470℃, 480℃, 490℃ or 500℃, but is not limited to the listed values, and other unlisted values ​​within the range are also applicable.

[0048] Preferably, the calcination holding time is 4-6 hours, for example, it can be 4 hours, 4.2 hours, 4.4 hours, 4.6 hours, 4.8 hours, 5 hours, 5.2 hours, 5.4 hours, 5.6 hours, 5.8 hours or 6 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0049] Preferably, the calcination is carried out under an inert atmosphere.

[0050] Preferably, the inert atmosphere comprises argon.

[0051] As a preferred embodiment of the second aspect of the present invention, the preparation method includes the following steps:

[0052] (1) Mix the precursor of the active metal and the metal salt of the active auxiliary in a solvent until dissolved. During the mixing process, the mixture is ultrasonicated for 0.5-1h at a power of 150-250W and a temperature of 10-40℃. Then, a carrier is added and stirred for 10-12h. After that, the mixture is vacuum dried for 10-12h at a temperature of 70-90℃. Finally, the mixture is ground to obtain powder.

[0053] The precursor of the active metal includes any one or a combination of at least two of Pt precursor, Pd precursor, or Rh precursor; the Pt precursor includes any one or a combination of at least two of platinum nitrate, chloroplatinic acid, tetraammineplatinum nitrate, or platinum acetylacetonate; the Pd precursor includes any one or a combination of at least two of palladium nitrate, sodium tetrachloropalladiumate, or tetraamminepalladium nitrate; the Rh precursor includes any one or a combination of at least two of rhodium nitrate, rhodium chloride, or ammonium rhodium chlorochlorate; the metal salt of the active auxiliary includes any one or a combination of at least two of transition metal nitrate, acetate, sulfate, or ammonium salt; the solvent includes any one or a combination of at least two of water, ethanol, ethylene glycol, or glycerol; and the volume ratio of the solvent to the mass of the carrier is (2-4):1 mL / g.

[0054] (2) The powder obtained in step (1) is heated to an end temperature of 400-500℃ at a rate of 5-10℃ / min under an argon atmosphere and kept at that temperature for 4-6h to obtain a propane catalytic combustion catalyst.

[0055] Thirdly, the present invention provides the use of a propane catalytic combustion catalyst as described in the first aspect of the present invention, said propane catalytic combustion catalyst being used in the reaction of catalytic combustion of propane and complete oxidation to carbon dioxide and water.

[0056] The propane catalytic combustion catalyst provided by this invention can reduce the reaction temperature at which propane is completely converted into carbon dioxide and water, and has high stability, catalytic activity and water resistance.

[0057] Preferably, the temperature of the propane catalytic combustion is ≤380℃, for example, 380℃, 350℃, 340℃, 330℃, 320℃, 310℃, 300℃, 290℃, 280℃, 270℃, 260℃ or 250℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable. Preferably, it is ≤300℃, and more preferably ≤270℃.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] (1) The propane catalytic combustion catalyst provided by the present invention uses dendritic mesoporous silica as a support, making full use of its high specific surface area and special pore advantages to confine the active metal and active additive in the pores of dendritic mesoporous silica and form active nanoparticles. The special pores of the support can enhance the interaction between the active metal and the active additive, and improve the catalytic activity, stability and water resistance of the catalyst.

[0060] (2) The propane catalytic combustion catalyst provided by this invention can completely convert propane into CO2 and H2O at a relatively low temperature, exhibiting good catalytic degradation effect and capable of reducing the T of the propane catalytic combustion reaction. 90 The temperature can be reduced to below 380℃, and under better conditions it can reach below 300℃, and under even better conditions it can reach below 270℃.

[0061] (3) The preparation method provided by the present invention is simple, low in cost, and has good application prospects. Attached Figure Description

[0062] Figure 1 This is a TEM image of the propane catalytic combustion catalyst described in Example 1 of the present invention.

[0063] Figure 2 This is a graph showing the conversion rate results of the stability test of the propane catalytic combustion catalyst described in Example 1 of this invention;

[0064] Figure 3 This is a graph showing the conversion rate of the propane catalytic combustion catalyst described in Example 1 of this invention during a water resistance test. Detailed Implementation

[0065] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0066] Example 1

[0067] This embodiment provides a propane catalytic combustion catalyst, which includes a support and active nanoparticles loaded on the support. The active nanoparticles include an active additive and an active metal loaded on the surface of the active additive. The active nanoparticles are loaded in the pores of the support. The support is dendritic mesoporous silica. The active metal is Pt. The active additive is cerium dioxide. The propane catalytic combustion catalyst contains 1% Pt and 7% cerium dioxide by mass percentage, and is denoted as Pt-7CeO2 / KCC-1.

[0068] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst, the preparation method comprising the following steps:

[0069] (1) Mix 0.0216g of tetraammineplatinum nitrate and 0.1920g of cerium nitrate hexahydrate in 3mL of ethylene glycol until dissolved. During the mixing process, sonicate for 0.75h at a power of 200W and a temperature of 25℃. Then add 1g of dendritic mesoporous silica KCC-1 and stir for 12h. The volume ratio of ethylene glycol to the mass of KCC-1 is 3:1mL / g. Afterward, vacuum dry at a temperature of 80℃ for 12h, and then grind to obtain powder.

[0070] (2) The powder obtained in step (1) is calcined in a tube furnace under an argon atmosphere at a rate of 5°C / min to a final temperature of 400°C and held for 4 hours to obtain a propane catalytic combustion catalyst.

[0071] The TEM image of the propane catalytic combustion catalyst obtained in this embodiment is as follows: Figure 1 As shown, from Figure 1 It can be seen that the active nanoparticles formed by the noble metals Pt and CeO2 are all confined within the internal pores of the dendritic carrier.

[0072] Example 2

[0073] This embodiment provides a propane catalytic combustion catalyst, which includes a support and active nanoparticles loaded on the support. The active nanoparticles include an active additive and an active metal loaded on the surface of the active additive. The active nanoparticles are loaded in the pores of the support. The support is dendritic mesoporous silica. The active metal is Pt. The active additive is cerium dioxide. The propane catalytic combustion catalyst contains 1% Pt and 5% cerium dioxide by mass percentage, and is denoted as Pt-5CeO2 / KCC-1.

[0074] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst, the preparation method comprising the following steps:

[0075] (1) Mix 0.0211g of tetraammineplatinum nitrate and 0.1342g of cerium nitrate hexahydrate in 2mL of ethylene glycol until dissolved. During the mixing process, sonicate for 0.5h at a power of 150W and a temperature of 28℃. Then add 1g of dendritic mesoporous silica KCC-1 and stir for 10h. The volume ratio of ethylene glycol to the mass of KCC-1 is 2:1mL / g. Afterward, vacuum dry at a temperature of 70℃ for 10h, and then grind to obtain powder.

[0076] (2) The powder obtained in step (1) is calcined in a tube furnace under an argon atmosphere at a rate of 8°C / min to a final temperature of 450°C and held for 4 hours to obtain a propane catalytic combustion catalyst.

[0077] Example 3

[0078] This embodiment provides a propane catalytic combustion catalyst, which includes a support and active nanoparticles loaded on the support. The active nanoparticles include an active additive and an active metal loaded on the surface of the active additive. The active nanoparticles are loaded in the pores of the support. The support is dendritic mesoporous silica. The active metal is Pt. The active additive is cerium dioxide. The propane catalytic combustion catalyst contains 1% Pt and 10% cerium dioxide by mass percentage, and is denoted as Pt-10CeO2 / KCC-1.

[0079] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst, the preparation method comprising the following steps:

[0080] (1) Mix 0.0233g of tetraammineplatinum nitrate and 0.2835g of cerium nitrate hexahydrate in 4mL of ethylene glycol until dissolved. During the mixing process, sonicate for 1h at a power of 200W and a temperature of 25℃. Then add 1g of dendritic mesoporous silica KCC-1 and stir for 12h. The volume ratio of ethylene glycol to the mass of KCC-1 is 4:1mL / g. Afterward, vacuum dry at a temperature of 90℃ for 12h, and then grind to obtain powder.

[0081] (2) The powder obtained in step (1) is calcined in a tube furnace under an argon atmosphere at a rate of 10°C / min to a final temperature of 500°C and held for 6 hours to obtain a propane catalytic combustion catalyst.

[0082] Example 4

[0083] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 1 is that the propane catalytic combustion catalyst contains 0.1% Pt and 3% cerium dioxide by mass percentage, denoted as 0.1Pt-3CeO2 / KCC-1.

[0084] Example 5

[0085] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 1 is that the propane catalytic combustion catalyst contains 2% Pt and 10% cerium dioxide by mass percentage, denoted as 2Pt-10CeO2 / KCC-1.

[0086] Example 6

[0087] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 1 is that the propane catalytic combustion catalyst contains 1% Pt and 3% cerium dioxide by mass percentage, denoted as Pt-3CeO2 / KCC-1.

[0088] Example 7

[0089] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 1 is that the propane catalytic combustion catalyst contains 1% Pt and 1% cerium dioxide by mass percentage, denoted as Pt-1CeO2 / KCC-1.

[0090] Example 8

[0091] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 1 is that Pt is replaced with Pd. The propane catalytic combustion catalyst contains 1% Pd and 7% cerium dioxide by mass percentage, and is denoted as Pd-7CeO2 / KCC-1.

[0092] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 1 is that tetraammineplatinum nitrate is replaced with sodium tetrachloropalladium, and the amount of sodium tetrachloropalladium and cerium nitrate hexahydrate added is adjusted so that the mass percentage of Pd in ​​the propane catalytic combustion catalyst is 1% and the mass percentage of cerium dioxide is 7%.

[0093] Example 9

[0094] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 1 is that Pt is replaced with Rh. The propane catalytic combustion catalyst contains 1% Rh and 7% cerium dioxide by mass percentage, and is denoted as Rh-7CeO2 / KCC-1.

[0095] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 1 is that tetraammineplatinum nitrate is replaced with ammonium rhodium chloronurate, and the amount of ammonium rhodium chloronurate and cerium nitrate hexahydrate added is adjusted so that the mass percentage of Rh in the propane catalytic combustion catalyst is 1% and the mass percentage of cerium dioxide is 7%.

[0096] Example 10

[0097] This embodiment provides a method for preparing a propane catalytic combustion catalyst. The only difference between this method and Example 1 is that ethylene glycol is replaced with an equal volume of water. The resulting propane catalytic combustion catalyst is denoted as Pt-7CeO2 / KCC-1-H2O.

[0098] Example 11

[0099] This embodiment provides a method for preparing a propane catalytic combustion catalyst. The only difference between this method and Example 1 is that ethylene glycol is replaced with an equal volume of ethanol. The resulting propane catalytic combustion catalyst is denoted as Pt-7CeO2 / KCC-1-C2H5OH.

[0100] Example 12

[0101] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 2 is that cerium dioxide is replaced with titanium dioxide. The propane catalytic combustion catalyst contains 1% Pt and 5% titanium dioxide by mass percentage, and is denoted as Pt-5TiO2 / KCC-1.

[0102] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 2 is that cerium nitrate hexahydrate is replaced with titanium sulfate, and the amount of tetraammineplatinum nitrate and titanium sulfate is adjusted so that the mass percentage of Pt in the propane catalytic combustion catalyst is 1% and the mass percentage of titanium dioxide is 5%.

[0103] Example 13

[0104] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that of Example 2 is that cerium dioxide is replaced with niobium pentoxide. The propane catalytic combustion catalyst contains 1% Pt and 5% niobium pentoxide by mass percentage, and is denoted as Pt-5Nb2O5 / KCC-1.

[0105] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 2 is that cerium nitrate hexahydrate is replaced with ammonium niobate oxalate hydrate, and the amount of tetraammineplatinum nitrate and ammonium niobate oxalate hydrate is adjusted so that the mass percentage of Pt in the propane catalytic combustion catalyst is 1% and the mass percentage of niobium pentoxide is 5%.

[0106] Example 14

[0107] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that in Example 2 is that cerium dioxide is replaced with tungsten trioxide. The propane catalytic combustion catalyst contains 1% Pt and 5% tungsten trioxide by mass percentage, and is denoted as Pt-5WO3 / KCC-1.

[0108] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 2 is that cerium nitrate hexahydrate is replaced with ammonium metatungstate, and the amount of tetraammineplatinum nitrate and ammonium metatungstate is adjusted so that the mass percentage of Pt in the propane catalytic combustion catalyst is 1% and the mass percentage of tungsten trioxide is 5%.

[0109] Example 15

[0110] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that of Example 2 is that cerium dioxide is replaced with zirconium dioxide. The propane catalytic combustion catalyst contains 1% Pt and 5% zirconium dioxide by mass percentage, and is denoted as Pt-5ZrO2 / KCC-1.

[0111] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 2 is that cerium nitrate hexahydrate is replaced with zirconium nitrate, and the amount of tetraammineplatinum nitrate and zirconium nitrate is adjusted so that the mass percentage of Pt in the propane catalytic combustion catalyst is 1% and the mass percentage of zirconium dioxide is 5%.

[0112] Example 16

[0113] This embodiment provides a propane catalytic combustion catalyst. The only difference between the propane catalytic combustion catalyst and that of Example 2 is that cerium dioxide is replaced with lanthanum trioxide. The propane catalytic combustion catalyst contains 1% Pt and 5% lanthanum trioxide by mass percentage, and is denoted as Pt-5La2O3 / / KCC-1.

[0114] This embodiment also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 2 is that cerium nitrate hexahydrate is replaced with lanthanum nitrate hexahydrate, and the amount of tetraammineplatinum nitrate and lanthanum nitrate hexahydrate added is adjusted so that the mass percentage of Pt in the propane catalytic combustion catalyst is 1% and the mass percentage of lanthanum trioxide is 5%.

[0115] Example 17

[0116] This embodiment provides a method for preparing a propane catalytic combustion catalyst. The preparation method is the same as in Example 1 except that the volume of ethylene glycol is adjusted to 6 mL, and the volume ratio of ethylene glycol to the mass of KCC-1 is 6:1 mL / g. The resulting propane catalytic combustion catalyst is denoted as Pt-7CeO2 / KCC-1-(6:1).

[0117] Example 18

[0118] This embodiment provides a method for preparing a propane catalytic combustion catalyst. The preparation method is the same as in Example 1 except that the volume of ethylene glycol is adjusted to 1 mL, and the volume ratio of ethylene glycol to the mass of KCC-1 is 1:1 mL / g. The resulting propane catalytic combustion catalyst is denoted as Pt-7CeO2 / KCC-1-(1:1).

[0119] Comparative Example 1

[0120] This comparative example provides a propane catalytic combustion catalyst, which differs from the one in Example 1 only in that the propane catalytic combustion catalyst does not contain any active additives, that is, the active nanoparticles are only particles containing active metals, and the propane catalytic combustion catalyst contains 1% Pt by mass percentage, denoted as Pt / KCC-1.

[0121] This comparative example also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 1 is that cerium nitrate hexahydrate is not added in the mixing in step (1), and the amount of tetraammineplatinum nitrate added is adjusted so that the mass percentage of Pt in the propane catalytic combustion catalyst is 1%.

[0122] Comparative Example 2

[0123] This comparative example provides a propane catalytic combustion catalyst, which differs from that of Example 1 only in that the support is cerium dioxide, the active nanoparticles are loaded on cerium dioxide, and the propane catalytic combustion catalyst contains 1% Pt by mass percentage, with the balance being cerium dioxide, denoted as Pt / CeO2.

[0124] This comparative example also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 1 is that in step (1), dendritic mesoporous silica KCC-1 is replaced with cerium dioxide.

[0125] Comparative Example 3

[0126] This comparative example provides a propane catalytic combustion catalyst, which differs from that of Example 1 only in that the support is silicon dioxide, the active nanoparticles are loaded on silicon dioxide, and the propane catalytic combustion catalyst contains 1% Pt, 7% cerium dioxide, and the balance is silicon dioxide by mass percentage, denoted as Pt-7CeO2 / SiO2.

[0127] This comparative example also provides a method for preparing the above-mentioned propane catalytic combustion catalyst. The difference between the preparation method and Example 1 is that in step (1), dendritic mesoporous silica KCC-1 is replaced with silica.

[0128] Stability test:

[0129] Taking Example 1 as an example, the stability of the propane catalytic combustion catalyst prepared in Example 1 was tested. The test method was as follows: the gas composition was propane and air, with a propane volume percentage of 1%, a space velocity of 60000 mL / (h·g), and a fixed-bed reactor temperature of 275℃. The reaction was carried out continuously for 50 h. The propane concentration at the outlet of the fixed bed was analyzed by chromatography, and the propane conversion rate was calculated. The propane conversion rate within 50 h was as follows: Figure 2 As shown, from Figure 2 As can be seen, the conversion rate of propane remained at around 93% as the reaction time increased, indicating that the propane catalytic combustion catalyst provided by this invention has high stability.

[0130] Water resistance test:

[0131] Taking Example 1 as an example, the propane catalytic combustion catalyst prepared in Example 1 was subjected to a water resistance test. The test method was as follows: First, the reaction was carried out at a temperature of 275°C with a gas composition of propane and air, and the volume percentage of propane was 1%. Then, the reaction was continued at 275°C with the gas composition changed to propane, water vapor, and air, with the volume percentage of propane being 1% and the volume percentage of water vapor being 5%. The conversion rate curve of propane during the above process is shown in the figure. Figure 3 As shown, from Figure 3 As can be seen, the conversion rate of propane remained at about 93% when no steam was introduced. When steam was introduced, the conversion rate of propane dropped from 93% to 86%, but after about 40 minutes, the conversion rate of propane recovered to about 93%. The conversion rate remained stable at 93% until the steam was introduced. This shows that the propane catalytic combustion catalyst provided by the present invention has strong water resistance.

[0132] Catalytic activity test:

[0133] The propane catalytic combustion catalysts prepared in Examples 1-18 and Comparative Examples 1-3 were tested for propane catalytic combustion. The test method was as follows: the catalytic performance was tested in a fixed-bed reactor under the conditions of propane and air with a volume percentage of 1% propane and a space velocity of 60,000 mL / (h·g). The propane concentration at the outlet of the fixed bed was analyzed by chromatography and the propane conversion rate was calculated. When the conversion rate reached 90%, the corresponding reaction temperature T was recorded. 90 The results are shown in Table 1.

[0134] Table 1

[0135]

[0136]

[0137] The following points can be observed from the data in Table 1:

[0138] (1) As can be seen from the data in Examples 1-18, the propane catalytic combustion catalyst provided by the present invention has strong low-temperature catalytic activity and can accelerate the propane catalytic combustion reaction to T 90 The temperature can be reduced to below 380℃, and under better conditions it can reach below 300℃, and under even better conditions it can reach below 270℃.

[0139] (2) A comprehensive comparison of the data from Examples 1 and 7, and Examples 4 and 6, shows that the only difference between Example 7 and Example 1 is that the mass percentage of the active additive is outside the preferred range of this invention; the only difference between Example 4 and Example 6 is that the content of the active metal is outside the preferred range of this invention; and the difference between Example 1 and Example 6 is that the content of the active metal is outside the preferred range of this invention. 90 The temperature was significantly lower than in Example 7, and the temperature in Example 6 was significantly lower than that in Example 6. 90 The temperature was significantly lower than in Example 4, which shows that the present invention preferably controls the mass percentage of active metal and active additive to further enhance catalytic activity.

[0140] (3) A comprehensive comparison of the data from Examples 1 and 8-9, and Examples 2 and 12-16, shows that the only difference between Examples 8-9 and Example 1 is that the active metals are Pd and Rh, respectively. The only difference between Examples 12-16 and Example 2 is that the active additives are titanium dioxide, niobium pentoxide, tungsten trioxide, zirconium dioxide, and lanthanum trioxide, respectively. The T in Example 1... 90 The temperature was significantly lower than in Examples 8-9, and T in Example 2 was significantly lower. 90 The temperature was significantly lower than that in Examples 12-16, which shows that the present invention can further enhance catalytic activity by preferentially controlling the types of active metals and active additives.

[0141] (4) A comprehensive comparison of the data from Examples 1 and 10-11, 17-18 shows that the only difference between Examples 10-11 and Example 1 is that water and ethanol are used as solvents, respectively. The only difference between Examples 17-18 and Example 1 is that the mass ratio of ethylene glycol to the carrier is not within the preferred range of this invention. In Example 1, T... 90 The temperature was significantly lower than that in Examples 10-11 and 17-18. Therefore, it can be seen that the present invention preferably uses ethylene glycol as a solvent and controls the mass ratio of ethylene glycol to the support, which can further promote the loading of active nanoparticles in the pores of the support, thereby further enhancing the catalytic activity.

[0142] (5) A comprehensive comparison of the data from Example 1 and Comparative Examples 1-3 shows that the only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not contain any active additives; the only difference between Comparative Example 2 and Example 1 is that cerium dioxide is used as a carrier; and the only difference between Comparative Example 3 and Example 1 is that silicon dioxide is used as a carrier. The T in Example 1... 90 The temperature was significantly lower than that of Comparative Examples 1-3, demonstrating that the present invention, by employing active nanoparticles composed of active metals and active additives and loading them within the pores of dendritic mesoporous silica, can significantly enhance catalytic activity and reduce Tg. 90 temperature.

[0143] In summary, the propane catalytic combustion catalyst and its preparation method provided by the present invention use dendritic mesoporous silica as a support, and load active metals and active additives into active nanoparticles within its pores. By utilizing the special pores of the support to enhance the interaction between the active metals and active additives, the catalytic activity, stability and water resistance of the catalyst can be improved.

[0144] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A propane catalytic combustion catalyst, characterized in that, The propane catalytic combustion catalyst includes a support and active nanoparticles supported on the support; The active nanoparticles include an active additive and an active metal loaded on the surface of the active additive; The active metal includes Pt; The active additives include transition metal oxides; The carrier comprises dendritic mesoporous silica KCC-1; The transition metal oxide contains Ce as the transition metal element. The active additive accounts for 5-10% of the mass of the propane catalytic combustion catalyst; The propane catalytic combustion catalyst is prepared by the following method, which includes the following steps: (1) Mix the precursor of the active metal and the metal salt of the active auxiliary in a solvent, then add the carrier and stir, and then vacuum dry and grind in sequence to obtain powder; (2) The powder obtained in step (1) is calcined to obtain a propane catalytic combustion catalyst; The solvent is ethylene glycol; The volume ratio of the solvent to the mass of the carrier is (2-4):1 mL / g.

2. The propane catalytic combustion catalyst according to claim 1, characterized in that, The particle size of the active nanoparticles is ≤5nm.

3. The propane catalytic combustion catalyst according to claim 1, characterized in that, The active nanoparticles are loaded within the pores of the carrier.

4. The propane catalytic combustion catalyst according to claim 1, characterized in that, The diameter of the dendritic mesoporous silica KCC-1 is 550-750 nm.

5. The propane catalytic combustion catalyst according to claim 1, characterized in that, The mass of the active metal accounts for 0.1-2% of the mass of the propane catalytic combustion catalyst.

6. A method for preparing a propane catalytic combustion catalyst as described in any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Mix the precursor of the active metal and the metal salt of the active auxiliary in a solvent, then add the carrier and stir, and then vacuum dry and grind in sequence to obtain powder; The precursor of the active metal includes a Pt precursor; (2) The powder obtained in step (1) is calcined to obtain a propane catalytic combustion catalyst; The solvent is ethylene glycol; The volume ratio of the solvent to the mass of the carrier is (2-4):1 mL / g.

7. The preparation method according to claim 6, characterized in that, The Pt precursor includes any one or a combination of at least two of platinum nitrate, chloroplatinic acid, tetrahydroplatinum nitrate, or platinum acetylacetonate.

8. The preparation method according to claim 6, characterized in that, The metal salt of the active agent includes any one or a combination of at least two of the transition metal nitrates, acetates, sulfates, or ammonium salts.

9. The preparation method according to claim 6, characterized in that, Ultrasound is performed during the mixing process described in step (1).

10. The preparation method according to claim 9, characterized in that, The power of the ultrasound is 150-250W.

11. The preparation method according to claim 9, characterized in that, The temperature of the ultrasound is 10-40℃.

12. The preparation method according to claim 9, characterized in that, The duration of the ultrasound is 0.5-1 hour.

13. The preparation method according to claim 6, characterized in that, The stirring time is 10-12 hours.

14. The preparation method according to claim 6, characterized in that, The vacuum drying temperature is 70-90℃.

15. The preparation method according to claim 6, characterized in that, The vacuum drying time is 10-12 hours.

16. The preparation method according to claim 6, characterized in that, The heating rate of calcination in step (2) is 5-10℃ / min.

17. The preparation method according to claim 6, characterized in that, The final temperature of the calcination is 400-500℃.

18. The preparation method according to claim 6, characterized in that, The calcination holding time is 4-6 hours.

19. The preparation method according to claim 6, characterized in that, The calcination is carried out under an inert atmosphere.

20. The preparation method according to claim 19, characterized in that, The inert atmosphere includes argon.

21. The preparation method according to claim 6, characterized in that, The preparation method includes the following steps: (1) Mix the precursor of the active metal and the metal salt of the active auxiliary in a solvent until dissolved. During the mixing process, the mixture is ultrasonicated for 0.5-1h at a power of 150-250W and a temperature of 10-40℃. Then, a carrier is added and stirred for 10-12h. After that, the mixture is vacuum dried for 10-12h at a temperature of 70-90℃. Finally, the mixture is ground to obtain powder. The precursor of the active metal includes a Pt precursor, which includes any one or a combination of at least two of platinum nitrate, chloroplatinic acid, tetraammineplatinum nitrate, or platinum acetylacetonate. The metal salt of the active agent includes any one or a combination of at least two of transition metal nitrates, acetates, sulfates, or ammonium salts. The solvent is ethylene glycol, and the volume ratio of the solvent to the mass of the carrier is (2-4):1 mL / g. (2) The powder obtained in step (1) is heated to an end temperature of 400-500℃ at a rate of 5-10℃ / min under an argon atmosphere and kept at that temperature for 4-6h to obtain a propane catalytic combustion catalyst.

22. Use of a propane catalytic combustion catalyst as described in any one of claims 1-5, characterized in that, The propane catalytic combustion catalyst is used for the catalytic combustion of propane and the complete oxidation to carbon dioxide and water.

23. The use according to claim 22, characterized in that, The temperature for propane catalytic combustion is ≤380℃.

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