Method for preparing propylene through direct dehydrogenation of propane and catalyst and preparation method thereof

Abstract

The invention provides a method for preparing propylene through direct dehydrogenation of propane, a platinum-tin hybrid nano-structure catalyst and a preparation method thereof. The catalyst comprises a carrier SBA-15, a 2D amorphous semiconductor MeOx packaged in a pore channel of the carrier, a metal active component Pt anchored on the 2D amorphous semiconductor / carrier and an auxiliary agent Sn, the metal active component Pt and the auxiliary agent Sn are marked as PtSn / at-MeOx / SBA-15, MeOx is selected from one of ZrO2, Nb2O5, Y2O3 and Dy2O3, the auxiliary agent Sn exists in a SnOx state, and the carrier SBA-15 and the 2D amorphous semiconductor MeOx packaged in the pore channel of the carrier are marked as at-MeOx / SBA-15; wherein MeOx in the at-MeOx / SBA-15 is packaged in a pore channel of the carrier in a single-layer form through a precipitation method or a microwave irradiation method to form a MeOx semiconductor film layer, an active component Pt and an auxiliary agent Sn in the catalyst PtSn / at-MeOx / SBA-15 are anchored on the at-MeOx / SBA-15 in a nano-particle form through a photocatalytic reduction method, and the active component Pt and the MeOx semiconductor film layer have a synergistic effect. The catalyst provided by the invention is low in Pt content, Sn exists in a SnOx state, and the catalyst has excellent propane dehydrogenation propylene preparation activity and good stability.

Description

Technical Field

[0001] The invention belongs to the technical field of catalysts, and specifically relates to a method for preparing propylene by direct dehydrogenation of propane and a platinum-tin hybrid nanostructured catalyst and a preparation method thereof. Background Art

[0002] In the petrochemical industry, propylene is an important chemical intermediate and chemical raw material, mainly used to produce important chemicals such as polypropylene, acrylonitrile, carbonyl synthesis, propylene oxide, acrolein, acrylic acid and other derivatives. However, traditional propylene production methods such as steam cracking and catalytic cracking can no longer meet the chemical industry's demand for propylene.

[0003] With people's attention to and exploitation of shale gas, the production of propane has been greatly improved, and direct dehydrogenation of propane has naturally received more attention. At present, the industrial direct dehydrogenation process of propane can be divided into two types: direct dehydrogenation of propane and oxidative dehydrogenation of propane. The direct dehydrogenation processes of propane are the Oleflex process and the Catofin process, which account for more than 90% of the direct dehydrogenation capacity of propane that has been put into production worldwide. The reactor used in the Oleflex process is a moving bed, the reaction temperature is 580℃~650℃, the single-pass conversion rate is 30%~40%, the selectivity is 89%~91%, and the catalyst used is Pt-Sn / Al 2 O 3 The characteristics of this process technology are high selectivity and stability for propylene, but the Pt-based catalyst is expensive, the purity of the reaction raw gas is high, and the catalyst is prone to carbon deposition during the reaction. The reactor used in the Catofin process is a fixed bed, the reaction temperature is 560℃~650℃, the single-pass conversion rate is 48%~65%, the propylene selectivity is 85%~90%, and the catalyst used is CrOx / Al 2 O 3 This process technology is characterized by high dehydrogenation activity and relatively loose operating conditions, but Cr-based catalysts, as heavy metal catalysts, will have an impact on the environment.

[0004] The Pt particles in the precious metal Pt catalyst are prone to agglomeration at high temperatures and carbon deposition on the catalyst surface, which can easily lead to catalyst deactivation. In order to reduce the catalyst deactivation rate, it is usually necessary to add hydrogen or inert gas to the feed, which undoubtedly reduces the thermodynamic limit of propane single-pass conversion rate and propylene productivity. It is still a challenge to develop a catalyst with high activity and stability to obtain a higher monopropylene yield than the existing process. Summary of the invention

[0005] The purpose of the present invention is to improve a catalyst with the expression of PtSn / @-MeOx / SBA-15, which is a PtSn-2D amorphous semiconductor hybrid nanostructure catalyst, has a simple preparation process, mild preparation conditions, a low content of active component Pt in the catalyst, and can reduce economic costs, and the auxiliary agent Sn is SnO x It exists in a state and has excellent propane dehydrogenation activity and stability.

[0006] In order to achieve the above object, the present invention provides a platinum-tin hybrid nanostructure catalyst for direct dehydrogenation of propane to propylene, comprising a carrier SBA-15, a 2D amorphous semiconductor MeO encapsulated in the pores of the carrier SBA-15, x and the metal active component Pt and the auxiliary agent Sn anchored on the 2D amorphous semiconductor / support, denoted as PtSn / @-MeO x / SBA-15, MeO x Selected from ZrO 2 , Nb 2 O 5 , Y 2 O 3 and Dy 2 O 3 In one of the above, the auxiliary agent Sn is SnO x The carrier SBA-15 and the 2D amorphous semiconductor MeO encapsulated in the pores of the carrier exist. x Denoted as @-MeO x / SBA-15; wherein the @-MeO x / MeO in SBA-15 x It is a two-dimensional amorphous metal oxide, and is encapsulated in the pores of the carrier SBA-15 in the form of a single layer by precipitation or microwave irradiation to form MeO x Semiconductor film layer, the catalyst PtSn / @-MeO x The active component Pt and the auxiliary agent Sn in SBA-15 are anchored in the @-MeO in the form of nanoparticles by photocatalytic reduction. x / SBA-15, the active component Pt and the MeO x There is a synergistic effect among the semiconductor film layers.

[0007] Preferably, based on the total mass of the catalyst as 100%, the catalyst PtSn / @-MeO x The mass content of Pt in SBA-15 is 0.1-3%, and the molar ratio of the active component Pt to the auxiliary agent Sn is 1:(1 / 3-2); x The total mass of @-MeO / SBA-15 is 100%, x / MeO in SBA-15 x The mass content is 5-15%.

[0008] More preferably, the catalyst PtSn / @-MeO x The mass content of Pt in / SBA-15 is 0.5-1.0%, and the molar ratio of the active component Pt to the auxiliary agent Sn is 1:1.

[0009] More preferably, the @-MeO x / MeO in SBA-15 x The MeO was spontaneously dispersed in the pores of the carrier SBA-15 in the form of a monolayer. x Semiconductor film layer, the @-MeO x / MeO in SBA-15 x The mass content is 10%.

[0010] The present invention also provides a method for preparing a platinum-tin hybrid nanostructure catalyst for direct dehydrogenation of propane to propylene, comprising the following steps: step (1) treating a metal oxide MeO by precipitation or microwave irradiation; x MeO is encapsulated in the pores of the carrier SBA-15 in a single layer x Semiconductor film layer, @-MeO x / SBA-15, MeO x It is a two-dimensional amorphous metal oxide, in which MeO x Selected from ZrO 2 , Nb 2 O 5 , Y 2 O 3 and Dy 2 O 3 Step (2) using a photocatalytic reduction method to anchor the active component Pt and the auxiliary agent Sn in the form of nanoparticles in the @-MeO x / SBA-15, and the catalyst PtSn / @-MeO was obtained x / SBA-15, wherein the active component Pt and the MeO x The semiconductor film has a synergistic effect, and the auxiliary agent Sn is SnO x The state exists.

[0011] Preferably, the catalyst is pretreated after step (2), specifically, the catalyst PtSn / @-MeO prepared in step 2) is treated with x / SBA-15 is filled into a micro fixed bed reactor, and an inert gas with a content of 10-40 vol% is introduced for pretreatment for 30-120 minutes, wherein the pretreatment temperature is 500-580°C.

[0012] Preferably, in step (1), the @-MeO x The total mass of @-MeO / SBA-15 is 100%, x / MeO in SBA-15 x The mass content is 5 to 15%; in step (2), based on the total mass of the catalyst as 100%, the catalyst PtSn / @-MeO x The mass content of Pt in / SBA-15 is 0.1-3%, and the molar ratio of the active component Pt to the auxiliary agent Sn is 1:(1 / 3-2).

[0013] More preferably, the catalyst PtSn / @-MeO x The mass content of Pt in / SBA-15 is 0.5-1.0%, and the molar ratio of the active component Pt to the auxiliary agent Sn is 1:1.

[0014] More preferably, the @-MeO x / MeO in SBA-15 x The MeO was spontaneously dispersed in the pores of the carrier SBA-15 in the form of a monolayer. x Semiconductor film layer, the @-MeO x / MeO in SBA-15 x The mass content is 10%.

[0015] In a specific embodiment, @-ZrO is prepared 2 / SBA-15 is a precipitation method, specifically: ZrOCl 2 8H 2 O was dissolved in deionized water, stirred at room temperature until mixed evenly, then SBA-15 molecular sieve and deionized water were added, and the mixture was stirred evenly, and the pH was adjusted to 9-10 with a precipitant, and the mixture was sealed with a plastic wrap, and stirred for 30 minutes, and then allowed to stand for aging. The aged mixture was washed, solid-liquid separated, dried, and calcined to obtain the @-ZrO 2 / SBA-15.

[0016] Preferably, the precipitant is a 50 g / ml ammonia solution.

[0017] Preferably, the @-ZrO is prepared 2 The drying conditions in the method of / SBA-15 include: a drying temperature of 80 to 120°C and a drying time of 12 to 24 hours.

[0018] Preferably, the @-ZrO is prepared 2 The calcination conditions in the method of / SBA-15 include: the calcination temperature is 600°C and the calcination time is 2 to 3 hours.

[0019] In a specific embodiment, the preparation of @-Nb 2 O 5 The method of SBA-15 is a precipitation method, specifically: C 10 H 5 NbO 20 Dissolve in deionized water, stir at room temperature until mixed evenly, then add SBA-15 molecular sieve and deionized water, stir at room temperature until mixed evenly, and then oscillate and disperse in an ultrasonic cleaner under the protection of plastic wrap for 30 to 45 minutes. After the completion of the ultrasonic wave, adjust the pH value to 9 to 10 with a precipitant, cover with plastic wrap, heat and stir in a constant temperature water bath at 60 to 100° C. for 40 to 60 minutes, then take out and stand at room temperature for 20 to 24 hours for aging and crystallization. The aged mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Nb 2 O 5 / SBA-15.

[0020] Preferably, the precipitant is a 50 g / ml ammonia solution.

[0021] Preferably, the preparation of the @-Nb 2 O 5 The drying conditions in the method of / SBA-15 include: a drying temperature of 80 to 120°C and a drying time of 12 to 24 hours.

[0022] Preferably, the @-Nb is prepared by precipitation method. 2 O 5 The calcination conditions in the method of / SBA-15 include: the calcination temperature is 600°C and the calcination time is 2 to 3 hours.

[0023] In a specific embodiment, the preparation of @-Y 2 O 3 / SBA-15 is a microwave irradiation method, specifically: the metal oxide precursor Y(NO 3 ) 3 6H 2 O is dissolved in deionized water and stirred evenly, and then molecular sieve SBA-15 is added to the solution. After stirring at room temperature until the mixture is evenly mixed, the mixture is shaken and dispersed in an ultrasonic cleaner under the protection of a plastic wrap for 30 to 45 minutes. After the ultrasonication is completed, the pH is adjusted to 7 to 8 with a precipitant. The obtained solution is irradiated in a microwave reaction device. The microwave power of the microwave reaction device is 200 to 400 W, and the irradiation time is 10 to 20 minutes. After the reaction is completed, the mixture is cooled to room temperature. The cooled mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Y 2 O 3 / SBA-15.

[0024] Preferably, the precipitating agent is an aqueous ammonia solution of 50 g / ml.

[0025] Preferably, in the method for preparing the @-Y 2 O 3 / SBA-15, the drying conditions include: the drying temperature is 80 - 120 °C, and the drying time is 12 - 24 h.

[0026] Preferably, in the method for preparing the @-Y 2 O 3 / SBA-15, the calcination conditions include: the calcination temperature is 700 °C, and the calcination time is 2 - 3 h.

[0027] Preferably, the method for preparing @-Dy 2 O 3 / SBA-15 is the microwave irradiation method. Specifically: Dissolve the metal oxide precursor Dy(NO 3 ) 3 ·6H 2 O in deionized water, stir evenly, then add the molecular sieve SBA-15 into the solution, stir at room temperature until evenly mixed, and then disperse it in an ultrasonic cleaner for 30 - 45 min under the protection of plastic wrap. After the ultrasonic treatment, adjust the pH to the target value of 9 - 10 with a precipitating agent. The obtained solution is irradiated in a microwave reaction device. The microwave power of the microwave reaction device is 200 - 400 W, and the irradiation time is 10 - 20 min. After the reaction is completed, cool it to room temperature. The cooled mixture is washed, solid-liquid separated, dried, and calcined to obtain the @-Dy 2 O 3 / SBA-15.

[0028] Preferably, the precipitating agent is an aqueous ammonia solution of 50 g / ml.

[0029] Preferably, in the method for preparing the @-Dy 2 O 3 / SBA-15, the drying conditions include: the drying temperature is 80 - 120 °C, and the drying time is 12 - 24 h.

[0030] Preferably, in the method for preparing the @-Dy 2 O 3 / SBA-15, the calcination conditions include: the calcination temperature is 600 °C, and the calcination time is 2 - 3 h.

[0031] In a specific embodiment, the photocatalytic reduction method is specifically: taking the @-MeO prepared in step (1) x / SBA-15 is added to water and anhydrous methanol, and ultrasonically dispersed evenly; then chloroplatinic acid solution and tin chloride solution are added, and ultrasonic oscillation is continued for a preset time; then the mixture is placed under an ultraviolet lamp and stirred under light conditions, and the stirred solution is filtered and vacuum dried to obtain the catalyst PtSn / @-MeOx / SBA-15.

[0032] Preferably, in the photocatalytic reduction method, the preset time of ultrasonic oscillation is 10 to 20 minutes, and stirring is performed under ultraviolet light for 12 hours; the temperature of vacuum drying is 75° C. to 85° C., and the time of vacuum drying is 8 to 12 hours.

[0033] The present invention also provides a method for producing propylene by direct dehydrogenation of propane, the method comprising using a pretreated catalyst PtSn / @-MeO x / SBA-15 catalyzes direct dehydrogenation of propane gas to produce propylene, the reaction pressure is normal pressure, and the reaction temperature is 500-580°C; the catalyst PtSn / @-MeO x / SBA-15 includes a carrier SBA-15, a 2D amorphous semiconductor MeO encapsulated in the pores of the carrier SBA-15 x and the metal active component Pt and the auxiliary agent Sn anchored on the 2D amorphous semiconductor / support, denoted as PtSn / @-MeO x / SBA-15, MeO x Selected from ZrO 2 , Nb 2 O 5 , Y 2 O 3 and Dy 2 O 3 In one of the above, the auxiliary agent Sn is SnO x The carrier SBA-15 and the 2D amorphous semiconductor MeO encapsulated in the pores of the carrier exist. x , denoted as @-MeO x / SBA-15; wherein the @-MeO x / MeO in SBA-15 x It is a two-dimensional amorphous metal oxide, and is encapsulated in the pores of the carrier SBA-15 in the form of a single layer by precipitation or microwave irradiation to form MeO x Semiconductor film layer, the catalyst PtSn / @-MeO x The active component Pt and the auxiliary agent Sn in SBA-15 are anchored in the @-MeO in the form of nanoparticles by photocatalytic reduction. x / SBA-15, the active component Pt and the MeO x There is a synergistic effect among the semiconductor film layers.

[0034] In a specific embodiment, @-ZrO is prepared 2 / SBA-15 is a precipitation method, specifically: ZrOCl 2 8H 2 O was dissolved in deionized water, stirred at room temperature until mixed evenly, then SBA-15 molecular sieve and deionized water were added, and the mixture was stirred evenly, and the pH was adjusted to 9-10 with a precipitant, and the mixture was sealed with a plastic wrap, and stirred for 30 minutes, and then allowed to stand for aging. The aged mixture was washed, solid-liquid separated, dried, and calcined to obtain the @-ZrO 2 / SBA-15.

[0035] In a specific embodiment, the preparation of @-Nb 2 O 5 The method of SBA-15 is a precipitation method, specifically: C 10 H 5 NbO 20 Dissolve in deionized water, stir at room temperature until mixed evenly, then add SBA-15 molecular sieve and deionized water, stir at room temperature until mixed evenly, and then oscillate and disperse in an ultrasonic cleaner under the protection of plastic wrap for 30 to 45 minutes. After the completion of the ultrasonic wave, adjust the pH value to 9 to 10 with a precipitant, cover with plastic wrap, heat and stir in a constant temperature water bath at 60 to 100° C. for 40 to 60 minutes, then take out and stand at room temperature for 20 to 24 hours for aging and crystallization. The aged mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Nb 2 O 5 / SBA-15.

[0036] In a specific embodiment, the preparation of @-Y 2 O 3 The method of / SBA-15 is microwave irradiation method, specifically: the metal oxide precursor Y(NO 3 ) 3 6H 2 O is dissolved in deionized water and stirred evenly, and then molecular sieve SBA-15 is added to the solution. After stirring at room temperature until the mixture is evenly mixed, the mixture is shaken and dispersed in an ultrasonic cleaner under the protection of a plastic wrap for 30 to 45 minutes. After the ultrasonication is completed, the pH is adjusted to 7 to 8 with a precipitant. The obtained solution is irradiated in a microwave reaction device. The microwave power of the microwave reaction device is 200 to 400 W, and the irradiation time is 10 to 20 minutes. After the reaction is completed, the mixture is cooled to room temperature. The cooled mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Y 2 O 3 / SBA-15.

[0037] In a specific embodiment, the preparation of @-Dy2 O 3 The method of / SBA-15 is microwave irradiation method, specifically: the metal oxide precursor Dy(NO 3 ) 3 6H 2 O is dissolved in deionized water and stirred evenly, and then molecular sieve SBA-15 is added to the solution. After stirring at room temperature until the mixture is evenly mixed, the mixture is shaken and dispersed in an ultrasonic cleaner under the protection of a plastic wrap for 30 to 45 minutes. After the ultrasonication is completed, the pH is adjusted to a target value of 9 to 10 with a precipitant. The obtained solution is irradiated in a microwave reaction device. The microwave power of the microwave reaction device is 200 to 400 W, and the irradiation time is 10 to 20 minutes. After the reaction is completed, the mixture is cooled to room temperature. The cooled mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Dy 2 O 3 / SBA-15.

[0038] In a specific embodiment, the photocatalytic reduction method is specifically: the @-MeO x / SBA-15 is added to water and anhydrous methanol, and ultrasonically dispersed uniformly; then chloroplatinic acid solution and tin chloride solution are added, and ultrasonic oscillation is continued for a preset time; then the solution is placed under an ultraviolet lamp and stirred under light conditions, and the stirred solution is filtered and vacuum dried to obtain the catalyst PtSn / @-MeO x / SBA-15.

[0039] Preferably, in the photocatalytic reduction method, the preset time of ultrasonic oscillation is 10 to 20 minutes, and stirring is performed under ultraviolet light for 12 hours; the temperature of vacuum drying is 75° C. to 85° C., and the drying time is 8 to 12 hours.

[0040] In a specific embodiment, the propane content in the propane gas is 100 vol%, and the gas weight hourly space velocity of the propane is 5 to 18 h -1 ; The catalyst PtSn / @-MeO x The pretreatment method of / SBA-15 is: the catalyst PtSn / @-MeO x / SBA-15 is filled into a micro fixed bed reactor, and an inert gas with a content of 10-40 vol% is introduced for pretreatment for 30-120 minutes, wherein the pretreatment temperature is 500-580°C.

[0041] Preferably, the inert gas is argon.

[0042] Preferably, the propane gas weight hourly space velocity is 14h -1 .

[0043] The beneficial effects of the present invention include at least:

[0044] 1. Catalyst PtSn / @-MeO provided by the present invention x / SBA-15, Pt is the active component, Sn is the auxiliary agent and Sn is in the form of SnO x State exists, SBA-15 is the carrier, MeO x It is a 2D amorphous semiconductor encapsulated in the pores of the carrier SBA-15. x Selected from ZrO 2 , Nb 2 O 5 , Y 2 O 3 and Dy 2 O 3 One of the @-MeO x / MeO in SBA-15 x It is a two-dimensional amorphous metal oxide, which is spontaneously dispersed and encapsulated in the pores of SBA-15 molecular sieve in the form of a single layer by precipitation or microwave irradiation to form MeO x Semiconductor film layer, active component Pt and auxiliary agent Sn in the form of nanoparticles are anchored in the @-MeO by photocatalytic reduction method. x / SBA-15, the active component Pt and the MeO x The semiconductor film layer has a synergistic effect; thus, the present invention makes full use of the semiconductor metal oxide MeO x The photocatalytic reduction properties of the catalyst are realized by uniformly loading Pt and Sn on the 2D amorphous semiconductor / carrier in the form of nanoparticles under ultraviolet light to form a hybrid composite nanostructured catalyst. The active component Pt has a low loading and a small amount of Sn, and Sn is in the form of SnO x The existence of the catalyst in this state makes the catalyst have excellent propane dehydrogenation activity and stability.

[0045] 2. Catalyst PtSn / @-MeO provided by the present invention x / SBA-15 has a simple preparation process, mild preparation conditions, high efficiency and environmental protection, and has good industrial application prospects.

[0046] 3. Catalyst PtSn / @-MeO provided by the present invention x / SBA-15 has high stability. Specifically, on the one hand, it can maintain good activity after being recycled for 2 to 4 times without showing obvious deactivation; on the other hand, when the reaction time is 960 min to 1200 min, the propane conversion rate is still high and the propylene selectivity is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The catalyst prepared in Example 1 is PtSn / @-10% ZrO 2 / SBA-15 and carrier ZrO 2 / SBA-15, SBA-15 and ZrO 2 XRD pattern of

[0048] Figure 2 The propane conversion rate and propane selectivity of the catalysts prepared in Examples 1 to 4 and Comparative Example 1 in the catalytic direct dehydrogenation of propane to propylene reaction versus time are plotted;

[0049] Figure 3 The propane conversion rate and propane selectivity of the catalysts prepared in Example 1, Examples 5 to 7 and Comparative Examples 2 to 3 in the catalytic direct dehydrogenation of propane to propylene reaction versus time are plotted;

[0050] Figure 4 The catalyst prepared in Example 8 is PtSn / @-10%Nb 2 O 5 / SBA-15 and carrier Nb 2 O 5 / SBA-15, SBA-15 and Nb 2 O 5 XRD pattern of

[0051] Figure 5 The propane conversion rate and propane selectivity of the catalysts prepared in Examples 8 to 11 and Comparative Example 4 in the catalytic direct dehydrogenation of propane to propylene reaction versus time;

[0052] Figure 6 The propane conversion rate and propane selectivity of the catalysts prepared in Example 8, Example 12 to Example 14 and Comparative Example 2 and Comparative Example 5 in the catalytic direct dehydrogenation of propane to propylene reaction versus time are plotted;

[0053] Figure 7 The catalyst prepared in Example 15 is PtSn / @-10%Y 2 O 3 / XPS chart of SBA-15;

[0054] Figure 8 The catalyst prepared in Example 15 is PtSn / @-10%Y 2 O 3 / SBA-15 and vector Y 2 O 3 / SBA-15, SBA-15 and Y 2 O 3 XRD pattern of

[0055] Fig. 9The propane conversion rate and propane selectivity versus time curve of the catalysts prepared in Examples 15 to 18 and Comparative Example 6 in the catalytic direct dehydrogenation of propane to propylene reaction;

[0056] Fig.10 The propane conversion rate and propane selectivity of the catalysts prepared in Example 15, Example 19 to Example 20 and Comparative Example 2 and Comparative Example 7 in the catalytic direct dehydrogenation of propane to propylene reaction versus time;

[0057] Fig.11 The catalyst prepared in Example 21 is PtSn / @-10%Dy 2 O 3 / XPS chart of SBA-15;

[0058] Fig.12 The catalyst prepared in Example 21 is PtSn / @-10% Dy 2 O 3 / SBA-15 and carrier Dy 2 O 3 / SBA-15, SBA-15 and Dy 2 O 3 XRD pattern of

[0059] Fig.13 Catalysts PtSn / @-10% MeO prepared in Example 15 and Example 21 x / TEM image of SBA-15;

[0060] Fig.14 The propane conversion rate and propane selectivity versus time curve of the catalysts prepared in Examples 21 to 24 and Comparative Example 8 in the catalytic direct dehydrogenation of propane to propylene reaction;

[0061] Fig.15 The propane conversion rate and propane selectivity versus time curve of the catalysts prepared in Example 21, Example 25 to Example 26 and Comparative Example 2 and Comparative Example 9 in the catalytic direct dehydrogenation of propane to propylene reaction;

[0062] Fig.16 This is a graph showing the cycle performance of the catalyst prepared in Example 1 for direct dehydrogenation of propane;

[0063] Fig.17 This is a graph showing the cycle performance of the catalyst prepared in Example 8 for direct dehydrogenation of propane;

[0064] Fig.18 This is a graph showing the cycle performance of the catalyst prepared in Example 15 for direct dehydrogenation of propane;

[0065] Fig.19This is a graph showing the cycle performance of the catalyst prepared in Example 21 for direct dehydrogenation of propane;

[0066] Fig. 20 This is a graph showing the stability performance of the catalyst prepared in Example 1 for direct dehydrogenation of propane;

[0067] Fig.21 This is a graph showing the stability performance of the catalyst prepared in Example 8 for direct dehydrogenation of propane;

[0068] Fig. 22 This is a graph showing the stability performance of the catalyst prepared in Example 15 for direct dehydrogenation of propane;

[0069] Fig.23 This is a graph showing the stability performance of the catalyst prepared in Example 21 for the direct dehydrogenation reaction of propane. DETAILED DESCRIPTION

[0070] The present invention is described in detail below with reference to the accompanying drawings and embodiments, but the present invention can be implemented in many different ways as limited and covered by the claims.

[0071] Embodiment 1 to Embodiment 7

[0072] PtSn nanoparticles and 2D amorphous metal oxide ZrO 2 Preparation of hybrid nanostructured catalysts

[0073] Example 1

[0074] 1. @-ZrO 2 Preparation of SBA-15:

[0075] Step 1.1, weigh a certain amount of ammonia solution, and prepare it into a 50g / ml ammonia solution as a precipitant.

[0076] Step 1.2, take a beaker, add 10 ml of deionized water, weigh 0.2905 g ZrOCl 2 8H 2 O is dissolved in deionized water and stirred evenly at room temperature to obtain a zirconium solution.

[0077] Step 1.3, add 1 g of SBA-15 carrier (ZrO 2 Theoretical calculated mass content is 10%) and 50ml of deionized water and stirred. After stirring evenly, slowly add the precipitant solution prepared in step 1.1, adjust the pH to 10, and after completing the pH adjustment, continue stirring for more than 30min, and let the solution stand and age for 24h.

[0078] Step 1.4, the aged mixed solution was filtered and washed, the solid was dried in a drying oven at 80°C for 12 h, and then the dried sample was placed in a muffle furnace and calcined at 600°C for 2 h to obtain the @-ZrO2 / SBA-15, recorded as 10% ZrO 2 / SBA-15.

[0079] 2. Catalyst PtSn / @-ZrO 2 Preparation of SBA-15:

[0080] Step 2.1: prepare the @-10% ZrO 2 / SBA-15 (0.366 g) was dissolved in 10 ml of anhydrous methanol, and a certain amount of deionized water was added to 100 ml. The mixture was stirred evenly at room temperature and ultrasonically vibrated for 15 min to obtain a mixed solution.

[0081] Step 2.2: After the ultrasound is completed, use a pipette to take 0.5 ml of chloroplatinic acid solution (containing 0.0074 g / ml platinum) (molecular formula H 2 PtCl 6 ) and 3 ml of tin chloride solution (0.0014 g / ml) were dropped into the mixed solution, the mixed solution was fixed to 100 ml, and ultrasonic shaking was continued for 30 min.

[0082] Step 2.3, the mixed solution after ultrasonic oscillation was irradiated with ultraviolet light for 12 hours under magnetic stirring, and then taken out and filtered after 12 hours, washed until the filtrate was neutral, and placed in a vacuum drying oven and dried at 80°C for 12 hours to obtain the catalyst PtSn / @-10%ZrO 2 SBA-15, where the catalyst is PtSn / @-10% ZrO 2 The molar ratio of Pt to Sn in / SBA-15 is 1:1, and the mass content of Pt is 1%.

[0083] Embodiment 2:

[0084] Same as Example 1, except that the volume of the tin chloride solution added in step 2.2 is 1 ml, and the molar ratio of platinum to tin is 3:1, denoted as Pt 3 Sn / @-10%ZrO 2 / SBA-15.

[0085] Embodiment 3:

[0086] Same as Example 1, except that the volume of the tin chloride solution added in step 2.2 is 1.5 ml, and the molar ratio of platinum to tin is 2:1, denoted as Pt 2 Sn / @-10%ZrO 2 / SBA-15.

[0087] Embodiment 4:

[0088] Same as Example 1, except that the volume of the tin chloride solution added in step 2.2 is 6 ml, and the molar ratio of platinum to tin is 1:2, denoted as PtSn 2 / @-10%ZrO 2 / SBA-15.

[0089] Embodiment 5:

[0090] Same as Example 1, except that the catalyst is PtSn / @-ZrO 2 SBA-15 ZrO 2 The mass fraction of ZrO is 5%, recorded as PtSn / @-5%ZrO 2 / SBA-15.

[0091] Embodiment 6:

[0092] Same as Example 1, except that the catalyst is PtSn / @-ZrO 2 / ZrO in SBA-15 2 The mass fraction of ZrO is 15%, recorded as PtSn / @-15%ZrO 2 / SBA-15.

[0093] Embodiment 7:

[0094] Same as Example 1, except that the catalyst is PtSn / @-ZrO 2 / ZrO in SBA-15 2 The mass fraction of ZrO is 20%, recorded as PtSn / @-20%ZrO 2 / SBA-15.

[0095] Comparative Example 1:

[0096] Same as Example 1, except that no tin chloride solution is added in step 2.2, recorded as Pt / @-10% ZrO 2 / SBA-15.

[0097] Comparative Example 2:

[0098] The same as Example 1, except that the catalyst does not carry a metal oxide film layer, and the active component platinum and the auxiliary agent tin are directly loaded on the molecular sieve SBA-15, which is recorded as PtSn / SBA-15.

[0099] Comparative Example 3:

[0100] Same as Example 1, except that platinum tin is directly loaded on the metal oxide ZrO 2 , denoted as PtSn / ZrO 2 .

[0101] Figure 1The catalyst prepared in Example 1 is PtSn / @-10% ZrO 2 / SBA-15 and carrier ZrO 2 / SBA-15, SBA-15 and ZrO 2 The XRD pattern of Figure 1 It can be seen that the spectrum has not changed significantly, indicating that the metal oxide ZrO 2 Does not exist in crystalline form.

[0102] Catalyst activity evaluation

[0103] The present invention investigates the effects of catalysts prepared in different embodiments / comparative examples on the performance of direct dehydrogenation of propane.

[0104] The catalyst performance of the propane dehydrogenation reaction device is evaluated by a micro-reaction fixed bed, and a quartz tube with an inner diameter of 8mm, a wall thickness of 4mm, and a tube length of 60cm is used as a microreactor. Before filling the catalyst, the quartz wool used for support is placed in the U-shaped card slot of the quartz tube. After filling the catalyst prepared by the embodiment / comparative example, a certain amount of quartz wool is loaded to ensure that the catalyst is not dispersed by the airflow during pretreatment and reaction. The bed height is about 1.2cm. After the catalyst is prepared, the reaction tube is loaded into the heating furnace of the fixed bed to ensure that the thermocouple for measuring the temperature is located above the bed. After installing the reaction tube, insulation equipment, and upper and lower sealing nuts, the air tightness of the device is checked. If there is no air leakage, the experimental operation can be carried out.

[0105] In the present invention, the reaction gas is pure propane, that is, the content of propane is 100 vol%, and the analysis is performed using an Agilent 6820 gas chromatograph, wherein the loaded catalyst is 100 mg; the propane reaction gas flow rate is 12 ml / min, that is, the weight hourly space velocity is 14 h -1 ;Activity test conditions: normal pressure, 550℃.

[0106] Before the reaction performance test, the catalyst was pretreated by introducing a mixed gas of hydrogen and argon. The pretreated catalyst was switched to propane feed gas under the protection of argon for reaction. The pretreatment conditions were as follows: the pretreatment temperature was 550°C (programmed temperature control was used in the reaction), the pretreatment time was 1h, and the volume ratio of hydrogen to argon in the pretreatment gas was 1:4, that is, 20% H 2 / 80%Ar.

[0107] It should be noted that when programmed temperature control is used in the reaction, specifically when the temperature is increased, the temperature range from room temperature to 100°C needs to be increased at a rate of 2°C / min, and after the temperature reaches 100°C, it can be increased at a rate of 5°C / min.

[0108] The catalyst activity is expressed by propane conversion and propylene selectivity or propylene yield and propylene selectivity:

[0109] in:

[0110]

[0111] Refers to propane conversion rate;

[0112] S j (%): refers to the selectivity of the generated product;

[0113] Y j (%): refers to propylene yield;

[0114] z j and n j are the number of carbon atoms and the number of moles of gaseous carbon-containing product j, respectively. propane is the number of moles of unconverted propane in the product stream.

[0115] z j and n j : are the number of carbon atoms and the number of moles of gaseous carbon-containing product j, respectively.

[0116] The initial activity data of the catalysts prepared in Examples 1 to 7 and Comparative Examples 1 to 3 in the direct dehydrogenation reaction of propane are summarized to obtain Table 1.

[0117] Table 1 Effect of catalysts prepared in different embodiments / comparative examples on propane dehydrogenation reaction performance

[0118] catalyst Propane conversion rate (%) Propylene selectivity (%) Example 1 <![CDATA[PtSn / @-10%ZrO 2 / SBA-15]]> 25.42 96.96 Example 2 <![CDATA[Pt 3 Sn / @-10%ZrO 2 / SBA-15]]> 24.36 97.14 Example 3 <![CDATA[Pt 2 Sn / @-10%ZrO 2 / SBA-15]]> 25.07 96.61 Example 4 <![CDATA[PtSn 2 / @-10%ZrO 2 / SBA-15]]> 22.75 98.20 Example 5 <![CDATA[PtSn / @-5%ZrO 2 / SBA-15]]> 23.23 97.53 Example 6 <![CDATA[PtSn / @-15%ZrO 2 / SBA-15]]> 25.11 96.37 Example 7 <![CDATA[PtSn 2 / @-20%ZrO 2 / SBA-15]]> 23.22 96.08 Comparative Example 1 <![CDATA[Pt / @-10%ZrO 2 / SBA-15]]> 21.15 86.45 Comparative Example 2 PtSn / SBA-15 9.38 94.40 Comparative Example 3 <![CDATA[PtSn / ZrO 2 ]]> 17.15 86.54

[0119] Table 1 examines the effects of the catalysts prepared in Examples 1 to 7 and Comparative Examples 1 to 3 on the performance of propane dehydrogenation reactions.

[0120] From the catalytic activity data of Comparative Example 1, it can be seen that the Pt / @-10% ZrO 2 / SBA-15 catalyst deactivates very quickly when the reaction gas feed is pure propane, and the propylene selectivity is only about 86%. Comparison of the catalytic activity data of Examples 1 to 4 and Comparative Example 1 shows that after adding the additive Sn to the catalyst, the catalyst deactivation is effectively suppressed, the propane conversion rate and the propylene selectivity are improved, and the catalyst Pt 3 Sn / @-ZrO 2The test results of / SBA-15 show that the propylene selectivity is increased by nearly 10% compared to when Sn is not added, and the initial propane conversion rate is also increased, which indicates that the presence of Sn effectively reduces the acid sites on the catalyst and improves the dispersion of the active component Pt. When Pt:Sn=1:1, it has the highest propane conversion rate and propylene selectivity, the initial propane conversion rate is 25.42%, and the propylene selectivity remains at around 97%. When too much tin is added, the excess tin is partially reduced during the pretreatment process, resulting in a decrease in activity.

[0121] Comparison of the catalytic activity data of Example 1, Example 5 to Example 7, and Comparative Example 2 and Comparative Example 3 shows that when the platinum-tin particles are directly loaded on SBA-15, the initial conversion rate of propane is only 9.38%, and the initial selectivity of propylene is 94.40%, which decreases over time. 2 When the initial conversion of propane is 17.15%, the initial selectivity of propylene is 86.54%. 2 After being encapsulated in the SBA-15 pores to form a monolayer dispersed film, the activity of the catalyst was greatly improved, and the propane conversion rate and propylene selectivity were increased. 2 The highest propylene yield was obtained when the loading amount was 10%. 2 When the loading is 15%, the activity is almost the same as that of the catalyst with 10% loading. The reason may be that when the loading is 15%, ZrO 2 It is dispersed in SBA-15 in a multi-layered state, without blocking the pores, but only brings more acid sites, and the addition of tin effectively covers the acid sites.

[0122] The relationship between propane conversion rate and propane selectivity and time in the direct dehydrogenation of propane to propylene by the catalysts prepared in Examples 1 to 4 and Comparative Example 1 is plotted as a curve graph, as shown in FIG. Figure 2 As shown; the relationship between propane conversion and propane selectivity and time in the catalytic direct dehydrogenation of propane to propylene by the catalysts prepared in Example 1, Example 5 to Example 7 and Comparative Examples 2 to 3 is plotted as a curve graph, as shown Figure 3 As shown. Figure 2 and Figure 3 It can be seen that the propane conversion rate and propylene selectivity corresponding to each catalyst change little with the increase of time. At the same time, when Pt:Sn=1:1, it has the highest propane conversion rate and propylene selectivity.

[0123] Embodiment 8 to Embodiment 14

[0124] PtSn nanoparticles and 2D amorphous metal oxides Nb 2 O 5Preparation of hybrid nanostructured catalysts

[0125] Example 8

[0126] 1. The @-Nb 2 O 5 Preparation of SBA-15:

[0127] Step 1.1, weigh a certain amount of ammonia solution, and prepare it into a 50g / ml ammonia solution as a precipitant.

[0128] Step 1.2, take a beaker, add 20ml of deionized water, weigh 0.2705gC 10 H 5 NbO 20 The powder is dissolved in deionized water and stirred to obtain a niobium solution.

[0129] Step 1.3, add 1g of SBA-15 carrier (Nb 2 O 5 Theoretical calculated mass content is 10%) and 80ml of deionized water, stir evenly at room temperature, and then oscillate and disperse in an ultrasonic cleaner under the protection of plastic wrap for 30 minutes. After the ultrasonic is completed, slowly drop the precipitant solution prepared in step 1.1 to adjust the pH to 9-10, heat and stir in a constant temperature water bath at 80℃ for 60min, then take out and stand at room temperature for 24h to age and crystallize.

[0130] Step 1.4, the aged mixed solution was filtered and washed, and the solidified product was dried in a vacuum drying oven at 80°C for 12 hours. Finally, the obtained solid powder was placed in a muffle furnace and calcined at 600°C for 2 hours to obtain the @-Nb 2 O 5 / SBA-15, denoted as 10% Nb 2 O 5 / SBA-15.

[0131] 2. Catalyst PtSn / @-Nb 2 O 5 Preparation of SBA-15:

[0132] Step 2.1: The @-10% Nb prepared in step 1.4 2 O 5 / SBA-15 (0.366 g) was dissolved in 10 ml of anhydrous methanol, and a certain amount of deionized water was added to 100 mL. The mixture was stirred evenly at room temperature and ultrasonically vibrated for 15 min to obtain a mixed solution.

[0133] Step 2.2: After the ultrasound is completed, use a pipette to take 0.5 ml of chloroplatinic acid solution (containing 0.0074 g / ml platinum) (molecular formula H 2 PtCl6 ) and 3 ml of tin chloride solution (0.0014 g / ml) were dropped into the mixed solution, the mixed solution was fixed to 100 ml, and ultrasonic shaking was continued for 30 min.

[0134] Step 2.3, the mixed solution after ultrasonic oscillation was irradiated with ultraviolet light for 12 hours under magnetic stirring, and then taken out and filtered after 12 hours, washed until the filtrate was neutral, and placed in a vacuum drying oven and dried at 80°C for 12 hours to obtain the catalyst PtSn / @-10%Nb 2 O 5 / SBA-15, where the catalyst is PtSn / @-10%Nb 2 O 5 The molar ratio of Pt to Sn in / SBA-15 is 1:1, and the mass content of Pt is 1%.

[0135] Embodiment 9:

[0136] Same as Example 8, except that the volume of the tin chloride solution added in step 2.2 is 1 ml, and the molar ratio of platinum to tin is 3:1, denoted as Pt 3 Sn / @-10%Nb 2 O 5 / SBA-15.

[0137] Embodiment 10:

[0138] Same as Example 8, except that the volume of the tin chloride solution added in step 2.2 is 1.5 ml, and the molar ratio of platinum to tin is 2:1, denoted as Pt 2 Sn / @-10%Nb 2 O 5 / SBA-15.

[0139] Embodiment 11:

[0140] Same as Example 8, except that the volume of the tin chloride solution added in step 2.2 is 6 ml, and the molar ratio of platinum to tin is 1:2, denoted as PtSn 2 / @-10%Nb 2 O 5 / SBA-15.

[0141] Embodiment 12:

[0142] Same as Example 8, except that the catalyst is PtSn / @-Nb 2 O 5 SBA-15 in Nb 2 O 5 The mass fraction is 5%, recorded as PtSn / @-5%Nb 2 O 5 / SBA-15.

[0143] Embodiment 13:

[0144] Same as Example 8, except that the catalyst is PtSn / @-Nb 2 O 5 SBA-15 in Nb 2 O 5 The mass fraction is 15%, recorded as PtSn / @-15%Nb 2 O 5 / SBA-15.

[0145] Embodiment 14:

[0146] Same as Example 8, except that the catalyst is PtSn / @-Nb 2 O 5 / SBA-15 in Nb 2 O 5 The mass fraction of Nb is 20%, recorded as PtSn / @-20%Nb 2 O 5 / SBA-15.

[0147] Comparative Example 4:

[0148] Same as Example 8, except that no tin chloride solution is added in step 2.2, recorded as Pt / @-10%Nb 2 O 5 / SBA-15.

[0149] Comparative Example 5:

[0150] Same as Example 8, except that the platinum tin is directly loaded on the metal oxide Nb 2 On O5, denoted as PtSn / Nb 2 O5.

[0151] Figure 4 The catalyst prepared in Example 8 is PtSn / @-10%Nb 2 O 5 / SBA-15 and carrier Nb 2 O 5 / SBA-15, SBA-15 and Nb 2 O 5 The XRD pattern of Figure 4 It can be seen that the spectrum has not changed significantly, indicating that the metal oxide Nb 2 O 5 Does not exist in crystalline form.

[0152] The catalytic activities of the catalysts prepared in Examples 8 to 14 and Comparative Examples 4 and 5 were evaluated according to the catalyst activity evaluation method described above. The evaluation results are shown in Table 2.

[0153] Table 2 Effect of catalysts prepared in different embodiments / comparative examples on propane dehydrogenation reaction performance

[0154] catalyst Propane conversion rate (%) Propylene selectivity (%) Example 8 <![CDATA[PtSn / @-10%Nb 2 SHE 5 / SBA-15]]> 25.64 96.22 Example 9 <![CDATA[Pt 3 Sn / @-10%Nb 2 O 5 / SBA-15]]> 19.98 96.06 Example 10 <![CDATA[Pt 2 Sn / @-10%Nb 2 O 5 / SBA-15]]> 21.25 97.14 Embodiment 11 <![CDATA[PtSn 2 / @-10%Nb 2 O 5 / SBA-15]]> 21.09 93.20 Example 12 <![CDATA[PtSn / @-5%Nb 2 SHE 5 / SBA-15]]> 24.39 96.99 Example 13 <![CDATA[PtSn / @-15%Nb 2 SHE 5 / SBA-15]]> 20.8 96.87 Embodiment 14 <![CDATA[PtSn 2 / @-20%Nb 2 O 5 / SBA-15]]> 18.06 95.94 Comparative Example 4 <![CDATA[Pt / @-10%Nb 2 SHE 5 / SBA-15]]> 14.92 95.40 Comparative Example 2 PtSn / SBA-15 9.38 94.40 Comparative Example 5 <![CDATA[PtSn / Nb 2 THE 5 ]]> 3.83 65.39

[0155] From the catalytic activity data of Comparative Example 4, it can be seen that when the catalyst is loaded with platinum only, the initial conversion rate of propane is only 14.91% and the initial propylene selectivity is 95%. After three hours of reaction, the conversion rate drops to about 10%, and the propylene selectivity also gradually decreases with the passage of time. From the catalytic activity data of Examples 8 to 11, it can be seen that the addition of Sn in the catalyst changes the electronic surface properties of Pt and forms a Pt-Sn active interface. With the increase in the loading amount of the auxiliary agent Sn, due to the interaction between Pt-Sn, it helps to increase the dispersion of Pt and the number of active sites, and the reaction activity of the catalyst is greatly improved. When the molar ratio of platinum to tin is 1:1, the catalyst has the best reaction activity, the initial conversion rate is as high as 25.64%, close to the thermodynamic limit (about 82% of the equilibrium conversion rate), and the propylene selectivity is maintained at about 96% during the reaction.

[0156] Comparison of the catalytic activity data of Example 8, Example 12 to Example 14, and Comparative Example 2 and Comparative Example 5 shows that when the platinum-tin particles are directly loaded on the molecular sieve SBA-15, the initial propylene conversion rate is 9.38% and the propylene selectivity is 94.40%, both of which decrease over time. 2 O 5 The load is Nb encapsulated in the SBA-15 channel. 2 O 5 The membrane layer and the PtSn nanoparticles anchored on its surface formed a special hybrid nanostructure. The interaction between the two resulted in a catalyst conversion rate of 24.22% and a propylene selectivity of more than 95% in the 180-minute test. 2 O 5 PtSn / @-Nb at 10% loading 2 O 5 / SBA-15 catalyst has the best activity, with a propylene conversion rate of up to 25.64% and a propylene selectivity of more than 96% throughout the process. 2 O 5 As the loading increases, the propane conversion rate decreases. When the loading increases to 20%, the propylene selectivity is almost the same as when the loading is 15%, but the propane conversion rate decreases significantly. The possible reason is that Nb 2 O 5 The loading was too high, which blocked the pores of SBA-15. For better comparison, PtSn nanoparticles directly loaded on Nb 2 O5 From the catalytic performance of the above catalysts, it can be seen that when the carrier is a pure oxide or a molecular sieve carrier, the propane conversion is very small, the initial conversion rate is less than 10%, and the selectivity for propylene is very poor. As the reaction proceeds, the conversion rate and selectivity show a continuous downward trend. It is inferred that when PtSn nanoparticles are directly loaded on pure oxide or molecular sieve carriers, no special hybrid nanostructure is formed.

[0157] The relationship between propane conversion rate and propane selectivity and time in the direct dehydrogenation of propane to propylene by the catalysts prepared in Examples 8 to 11 and Comparative Example 4 is plotted as a curve graph, as shown in FIG. Figure 5 As shown; the relationship between propane conversion and propane selectivity and time in the catalytic direct dehydrogenation of propane to propylene reaction of the catalysts prepared in Example 8, Example 12 to Example 14, and Comparative Example 2 and Comparative Example 5 is plotted as a curve graph, as shown Figure 6 As shown. Figure 5 and Figure 6 It can be seen that the propane conversion rate and propylene selectivity corresponding to each catalyst change little with the increase of time. At the same time, when Pt:Sn=1:1, it has the highest propane conversion rate and propylene selectivity.

[0158] Embodiment 15 to Embodiment 20

[0159] PtSn Nanoparticles and 2D Amorphous Metal Oxide Y 2 O 3 Preparation of hybrid nanostructured catalysts

[0160] Embodiment 15

[0161] 1. The @-Y 2 O 3 Preparation of SBA-15:

[0162] Step 1.1, weigh a certain amount of ammonia solution, and prepare it into a 50g / ml ammonia solution as a precipitant.

[0163] Step 1.2, add 150 ml of deionized water to a three-necked flask, weigh 0.3769 g of metal oxide precursor Y(NO 3 ) 3 6H 2 O is dissolved in deionized water and stirred to obtain a yttrium solution.

[0164] Step 1.3, add 1g of SBA-15 carrier (Y 2 O 3Theoretical calculated mass content is 10%), after stirring at room temperature, slowly drop the precipitant solution prepared in step 1.1 to adjust the pH to 7-8, and continue stirring for more than 15 minutes after the pH adjustment is completed.

[0165] Step 1.4, the stirred solution was transferred to a microwave reaction device, the power of the microwave reaction device was adjusted to 400W, and after microwave heating reaction for 16 minutes, the reaction solution was taken out, cooled to room temperature, and then solid-liquid separation was performed. The solid was washed with anhydrous ethanol and deionized water until the pH was neutral, and then placed in an 80°C drying oven for 12 hours. Finally, the dried powder was placed in a 700°C muffle furnace and calcined for 2 hours to obtain the @-Y 2 O 3 / SBA-15, recorded as 10%Y 2 O 3 / SBA-15.

[0166] 2. Catalyst PtSn / @-Y 2 O 3 Preparation of SBA-15:

[0167] Step 2.1: The @-10% Y prepared in step 1.4 2 O 3 / SBA-15 (0.366 g) was dissolved in 10 ml of anhydrous methanol, and a certain amount of deionized water was added to 100 mL. The mixture was stirred evenly at room temperature and ultrasonically vibrated for 15 min to obtain a mixed solution.

[0168] Step 2.2: After the ultrasound is completed, use a pipette to take 0.5 ml of chloroplatinic acid solution (containing 0.0074 g / ml platinum) (molecular formula H 2 PtCl 6 ) and 3 ml of tin chloride solution (0.0014 g / ml) were dropped into the mixed solution, the mixed solution was fixed to 100 ml, and ultrasonic shaking was continued for 30 min.

[0169] Step 2.3, the mixed solution after ultrasonic oscillation was irradiated with ultraviolet light for 12 hours under magnetic stirring, and then taken out and filtered after 12 hours, washed until the filtrate was neutral, and placed in a vacuum drying oven and dried at 80°C for 12 hours to obtain the catalyst PtSn / @-10%Y 2 O 3 / SBA-15, where catalyst PtSn / @-10%Y 2 O 3 The molar ratio of Pt to Sn in / SBA-15 is 1:1, and the mass content of Pt is 1%.

[0170] Embodiment 16:

[0171] Same as Example 15, except that the volume of the tin chloride solution added in Step 2.2 is 1 ml and the molar ratio of platinum to tin is 3:1, denoted as Pt 3 Sn / @-10%Y 2 O 3 / SBA-15

[0172] Example 17:

[0173] Same as Example 15, except that the volume of the tin chloride solution added in Step 2.2 is 1.5 ml and the molar ratio of platinum to tin is 2:1, denoted as Pt 2 Sn / @-10%Y 2 O 3 / SBA-15

[0174] Example 18:

[0175] Same as Example 15, except that the volume of the tin chloride solution added in Step 2.2 is 6 ml and the molar ratio of platinum to tin is 1:2, denoted as PtSn 2 / @-10%Y 2 O 3 / SBA-15

[0176] Example 19:

[0177] Same as Example 15, except for the catalyst PtSn / @-Y 2 O 3 / SBA-15, where the mass fraction of the metal oxide Y 2 O 3 is 5%, denoted as PtSn / @-5%Y 2 O 3 / SBA-15

[0178] Example 20:

[0179] Same as Example 15, except for the catalyst PtSn / @-Y 2 O 3 / SBA-15, where the mass fraction of the metal oxide Y 2 O 3 is 15%, denoted as PtSn / @-15%Y 2 O 3 / SBA-15

[0180] Comparative Example 6:

[0181] Same as Example 15, except that no tin chloride solution is added in Step 5, denoted as Pt / @-10%Y 2 O 3 / SBA-15

[0182] Comparative Example 7:

[0183] Same as Example 15, except that platinum tin is directly loaded on the metal oxide Y 2 O 3 , denoted as PtSn / Y 2 O 3 .

[0184] Figure 7 The catalyst prepared in Example 15 is PtSn / @-10%Y 2 O 3 / XPS graph of SBA-15, from Figure 7 It can be seen that the proportion of electron-deficient Pt is very high, indicating that x There is a strong interfacial electronic effect between them. Sn only exists in a +4 valence state, indicating that Sn is SnO on the 2D amorphous metal oxide film. x It exists stably in the form of and plays a good promoting role in the catalyst.

[0185] Figure 8 The catalyst prepared in Example 15 is PtSn / @-10%Y 2 O 3 / SBA-15 and vector Y 2 O 3 / SBA-15, SBA-15 and Y 2 O 3 The XRD pattern of Figure 8 It can be seen that the spectrum has not changed significantly, indicating that the metal oxide Nb 2 O 5 Does not exist in crystalline form.

[0186] Fig.13 Catalysts PtSn / @-10% MeO prepared in Example 15 and Example 21 x / TEM image of SBA-15, from Fig.13 It can be seen that the pore structure of SBA-15 does not change with the loading of metal oxides and the anchoring of PtSn nanoparticles, and Pt and Sn are evenly dispersed on the catalyst.

[0187] The catalytic activities of the catalysts prepared in Examples 15 to 20 and Comparative Examples 6 and 7 were evaluated according to the catalyst activity evaluation method described above. The evaluation results are shown in Table 3.

[0188] Table 3 Effect of catalysts prepared in different embodiments / comparative examples on propane dehydrogenation reaction performance

[0189]

[0190]

[0191] From the catalytic activity data of Comparative Example 6, it can be seen that when the catalyst is loaded with only platinum, the initial conversion rate of propane is only 24.17% and it is rapidly deactivated in a short time, and the initial propylene selectivity is less than 80%, and the conversion rate drops to about 10% after three hours of reaction. Comparing the catalytic activity data of Examples 15 to 18 with the catalytic activity data of Comparative Example 6, it can be seen that the addition of Sn significantly improves the reaction activity and stability of the catalyst. When the molar ratio of platinum to tin is 1:1, the catalyst has the best reaction activity, the initial conversion rate is as high as 26.49%, close to the thermodynamic limit (about 84% of the equilibrium conversion rate), and the propylene selectivity is maintained at about 97% during the reaction.

[0192] Comparison of the catalytic activity data of Example 15, Example 19 to Example 20, and Comparative Example 2 and Comparative Example 7 shows that when the platinum-tin particles are directly loaded on the SBA-15 carrier, the initial propylene yield is only 9.38%. 2 O 3 The load is packaged in the SBA-15 channel. 2 O 3 The membrane layer and the PtSn nanoparticles anchored on its surface form a special hybrid nanostructure. The interaction between the two greatly improves the catalyst performance. When the loading is 5%, the catalyst has good activity and the initial propylene yield is 24.56%. 2 O 3 PtSn / @-Y at 10% loading 2 O 3 / SBA-15 catalyst has the best activity, with a propylene yield of up to 25.55%. 2 O 3 As the loading increases, the selectivity of propylene decreases, which may be due to the increase in acid sites on the catalyst. 2 O 3 From the catalytic performance of the above catalysts, it can be seen that when the carrier is a pure oxide or a molecular sieve carrier, the propane conversion is very small, the initial yield is less than 10%, and the selectivity for propylene is very poor. As the reaction proceeds, the conversion rate and selectivity both show a downward trend.

[0193] The relationship between propane conversion rate and propane selectivity and time in the direct dehydrogenation of propane to propylene by the catalysts prepared in Examples 15 to 18 and Comparative Example 6 is plotted as a curve graph, as shown in FIG. Fig. 9As shown; the relationship between propane conversion and propane selectivity and time in the catalytic direct dehydrogenation of propane to propylene reaction of the catalysts prepared in Example 15, Example 19 to Example 20, and Comparative Example 2 and Comparative Example 7 is plotted as a curve graph, as shown Fig.10 As shown. Fig. 9 and Fig.10 It can be seen that the propane conversion rate and propylene selectivity corresponding to each catalyst change little with the increase of time. At the same time, when Pt:Sn=1:1, it has the highest propane conversion rate and propylene selectivity.

[0194] Example 21 to Example 26

[0195] PtSn nanoparticles and 2D amorphous metal oxides Dy 2 O 3 Preparation of hybrid nanostructured catalysts

[0196] Embodiment 21

[0197] 1. The @-Dy 2 O 3 Preparation of SBA-15:

[0198] Step 1.1, weigh a certain amount of ammonia solution, and prepare it into a 50g / ml ammonia solution as a precipitant.

[0199] Step 1.2, add 150 ml of deionized water to a three-necked flask, weigh 0.272 g of metal oxide precursor Dy(NO 3 ) 3 6H 2 O is dissolved in deionized water and stirred to obtain a dysprosium solution.

[0200] Step 1.3, add 1g of SBA-15 carrier (Dy 2 O 3 Theoretical calculated mass content is 10%), after stirring at room temperature, slowly drop the precipitant solution prepared in step 1.1 to adjust the pH to 9-10, and continue stirring for more than 15 minutes after the pH adjustment is completed.

[0201] Step 1.4, the stirred solution was transferred to a microwave reaction device, the power of the microwave reaction device was adjusted to 400W, and the microwave heating reaction was performed for 16 minutes, the reaction solution was taken out, cooled to room temperature, and then solid-liquid separation was performed, the solid was washed with anhydrous ethanol and deionized water until the pH was neutral, and then placed in an 80°C drying oven for 12 hours, and finally the dried solid powder was placed in a 600°C muffle furnace for calcination for 2 hours to obtain the @-Dy 2 O 3 / SBA-15, recorded as 10% Dy 2 O3 / SBA-15.

[0202] 2. Catalyst PtSn / @-Dy 2 O 3 Preparation of SBA-15:

[0203] Step 2.1: The @-10% Dy prepared in step 1.4 2 O 3 / SBA-15 (0.366 g) was dissolved in 10 ml of anhydrous methanol, and a certain amount of deionized water was added to 100 mL. The mixture was stirred evenly at room temperature and ultrasonically vibrated for 15 min to obtain a mixed solution.

[0204] Step 2.2: After the ultrasound is completed, use a pipette to take 0.5 ml of chloroplatinic acid solution (containing 0.0074 g / ml platinum) (molecular formula H 2 PtCl 6 ) and 3 ml of tin chloride solution (0.0014 g / ml) were dropped into the mixed solution, the mixed solution was fixed to 100 ml, and ultrasonic shaking was continued for 30 min.

[0205] Step 2.3, the mixed solution after ultrasonic oscillation was irradiated with ultraviolet light for 12 hours under magnetic stirring, and then taken out and filtered after 12 hours, washed until the filtrate was neutral, and placed in a vacuum drying oven and dried at 80°C for 12 hours to obtain the catalyst PtSn / @-10%Dy 2 O 3 / SBA-15, where the catalyst is PtSn / @-10%Dy 2 O 3 The molar ratio of Pt to Sn in / SBA-15 is 1:1, and the mass content of Pt is 1%.

[0206] Embodiment 22:

[0207] Same as Example 21, except that the volume of the tin chloride solution added in step 2.2 is 1 ml, and the molar ratio of platinum to tin is 3:1, denoted as Pt 3 Sn / @-10%Dy 2 O 3 / SBA-15.

[0208] Embodiment 23:

[0209] Same as Example 21, except that the volume of the tin chloride solution added in step 2.2 is 1.5 ml, and the molar ratio of platinum to tin is 2:1, denoted as Pt 2 Sn / @-10%Dy 2 O 3 / SBA-15.

[0210] Embodiment 24:

[0211] Same as Example 21, except that the volume of the tin chloride solution added in step 2.2 is 6 ml, and the molar ratio of platinum to tin is 1:2, denoted as PtSn 2 / @-10%Dy 2 O 3 / SBA-15.

[0212] Embodiment 25:

[0213] Same as Example 21, except that the catalyst is PtSn / @-Dy 2 O 3 / Metal Oxide Dy in SBA-15 2 O 3 The mass fraction of PtSn is 5%, recorded as PtSn / @-5%Dy 2 O 3 / SBA-15.

[0214] Embodiment 26:

[0215] Same as Example 21, except that the catalyst is PtSn / @-Dy 2 O 3 / Metal Oxide Dy in SBA-15 2 O 3 The mass fraction of Dy is 15%, recorded as PtSn / @-15%Dy 2 O 3 / SBA-15.

[0216] Comparative Example 8:

[0217] Same as Example 21, except that no tin chloride solution is added in step 5, recorded as Pt / @-10%Dy 2 O 3 / SBA-15.

[0218] Comparative Example 9:

[0219] Same as Example 21, except that the platinum tin is directly loaded on the metal oxide Dy 2 O 3 , recorded as PtSn / Dy 2 O 3 .

[0220] Fig.11 The catalyst prepared in Example 21 is PtSn / @-10%Dy 2 O 3 / XPS graph of SBA-15, from Fig.11 It can be seen that the proportion of electron-deficient Pt is very high, indicating that xThere is a strong interfacial electronic effect between them. Sn only exists in a +4 valence state, indicating that Sn is SnO on the 2D amorphous metal oxide film. x It exists stably in the form of and plays a good promoting role in the catalyst.

[0221] Fig.12 The catalyst prepared in Example 21 is PtSn / @-10% Dy 2 O 3 / SBA-15 and carrier Dy 2 O 3 / SBA-15, SBA-15 and Dy 2 O 3 The XRD pattern of Fig.12 It can be seen that the spectrum has not changed significantly, indicating that the metal oxide Nb 2 O 5 Does not exist in crystalline form.

[0222] Fig.13 Catalysts PtSn / @-10% MeO prepared in Example 15 and Example 21 x / TEM image of SBA-15, from Fig.13 It can be seen that the pore structure of SBA-15 does not change with the loading of metal oxides and the anchoring of PtSn nanoparticles, and Pt and Sn are evenly dispersed on the catalyst.

[0223] The catalytic activities of the catalysts prepared in Examples 21 to 26 and Comparative Examples 8 and 9 were evaluated according to the catalyst activity evaluation method described above. The evaluation results are shown in Table 4.

[0224] Table 4 Effect of catalysts prepared in different embodiments / comparative examples on propane dehydrogenation reaction performance

[0225]

[0226]

[0227] From the catalytic activity data of comparative example 8, it can be seen that when Sn is not added, the performance of the catalyst is not good, and the propane conversion rate decreases with the increase of reaction time. Comparing the catalytic activity data of implementation 21 to embodiment 24 and comparative example 8, it can be seen that with the addition of Sn, the propane conversion rate is significantly improved. With the continued addition of Sn, the catalytic activity reaches a peak when the molar ratio of platinum to tin is 1:1. When the molar ratio of platinum to tin is 1:2, the excessive addition of Sn leads to an increase in the acidity of the catalyst and a slight decrease in activity. PtSn / @-Dy 2 O 3 / SBA-15 catalyst has the best reaction performance, with an initial propane conversion rate of 26.65% (about 85% of the equilibrium conversion rate) and a propylene selectivity of more than 97%. As the reaction proceeds, the final selectivity remains stable at around 97%. Similarly, no matter what molar ratio of platinum and tin exists, the catalyst has good stability.

[0228] Comparison of the catalytic activity data of Example 21, Example 25-Example 26, and Comparative Example 2 and Comparative Example 9 shows that when the platinum-tin particles are directly loaded on the SBA-15 carrier, the initial propylene yield is only 9.38%. 2 O 3 The load is packaged in the SBA-15 channel. 2 O 3 The membrane layer and the PtSn nanoparticles anchored on its surface form a special hybrid nanostructure. The interaction between the two greatly improves the catalyst performance. When the loading is 5%, the catalyst has good activity and the initial propylene yield is 25.98%. 2 O 3 PtSn / @-Dy at 10% loading 2 O 3 / SBA-15 catalyst has the best activity, with a propylene yield of up to 26.65%. 2 O 3 As the loading increases, the selectivity of propylene decreases, which may be due to the increase in acid sites on the catalyst. 2 O 3 From the catalytic performance of the above catalysts, it can be seen that when the carrier is a pure oxide or a molecular sieve carrier, the propane conversion is very small, the initial yield is less than 10%, and the selectivity for propylene is very poor. As the reaction proceeds, the conversion rate and selectivity both show a downward trend.

[0229] The relationship between propane conversion rate and propane selectivity and time in the direct dehydrogenation of propane to propylene by the catalysts prepared in Examples 21 to 24 and Comparative Example 8 is plotted as a curve graph, as shown in FIG. Fig.13 As shown; the relationship between propane conversion and propane selectivity and time in the catalytic direct dehydrogenation of propane to propylene reaction of the catalysts prepared in Example 21, Example 25 to Example 26, and Comparative Example 2 and Comparative Example 9 is plotted as a curve graph, as shown Fig.14 As shown. Fig.13 and Fig.14 It can be seen that the propane conversion rate and propylene selectivity corresponding to each catalyst change little with the increase of time. At the same time, when Pt:Sn=1:1, it has the highest propane conversion rate and propylene selectivity.

[0230] Comparative Example 10

[0231] Same as Example 15, except that the metal oxide precursor is 0.2408 g In(NO 3 ) 3 6H 2 O, pH precipitation range 9-10, calcination temperature 600℃, recorded as PtSn / @-10%In 2 O 3 / SBA-15.

[0232] Comparative Example 11

[0233] Step 1: Prepare sample 10% VO by impregnation method x / SBA-15: Weigh the metal oxide precursor and dissolve 0.1447g ammonium metavanadate in 50mL deionized water, then add 1g SBA-15 molecular sieve, stir in a 60℃ water bath until evaporated, and dry in an oven at 80℃. Then place it in a muffle furnace for calcination, and heat it to 600℃ at 10℃ / min for 6h to obtain the sample 10%VO x / SBA-15.

[0234] Step 2: The metal oxide-coated support 10% VO x / SBA-15 is dissolved in 10ml of anhydrous methanol, and a certain amount of deionized water is added to 100mL, stirred evenly, and ultrasonicated for 15min. After the ultrasonication is completed, 0.5ml of chloroplatinic acid solution (containing 0.0074g / ml of platinum) and 3ml of tin chloride solution (0.0014g / ml) are added with a pipette, and the solution is fixed to 100ml, and the ultrasonication is continued for 30min. After the ultrasonication is completed, the solution is irradiated with ultraviolet light for 12h under magnetic stirring. After 12h, it is taken out and filtered. Finally, it is placed in a vacuum drying oven at 80℃ and dried for 12h to obtain a platinum-tin catalyst hybridized with PtSn nanoparticles and 2D amorphous metal oxide nanostructures, recorded as PtSn / @10%VO x / SBA-15.

[0235] Comparative Example 12

[0236] Same as Example 8, except that 0.2805 g of ferric nitrate nonahydrate as a precursor of the metal oxide was added in step 1.2, and the solvent was HNO 3 Solution; step 1.3 adjusts the pH precipitation range to 8-9; step 1.4 is calcined at 600°C for 4h, recorded as PtSn / @-10%FeO x / SBA-15.

[0237] Comparative Example 13

[0238] Step 1: Preparation of 10% TiO by sol-gel method 2 / SBA-15 sample: Weigh 1g of SBA-15 and add it to isopropanol (the mass ratio of SBA-15 to isopropanol is 1:15). After it is completely dissolved, put it into an ultrasonic cleaner for ultrasonic treatment for 2 hours to make the molecular sieve SBA-15 evenly dispersed in isopropanol. Then, add 0.4770g of butyl titanate dropwise while stirring, slowly add 1mL of water after 1 hour, and stir for an additional 2 hours to complete the hydrolysis of butyl titanate. After the hydrolysis is completed, the prepared material is recovered by filtering and washing, rinsed with anhydrous ethanol and deionized water, and after filtering, the filter cake is transferred to a culture dish, dried in an 80°C drying oven overnight, and finally calcined at 500°C in a muffle furnace for 4 hours.

[0239] Step 2: The sample coated with metal oxide prepared in step 1 is 10% TiO 2 / SBA-15 was dissolved in 10ml of anhydrous methanol, and a certain amount of deionized water was added to 100mL, stirred evenly, and ultrasonicated for 15min. After the ultrasonication was completed, 0.5ml of chloroplatinic acid solution (containing 0.0074g / ml of platinum) and 3ml of tin chloride solution (0.0014g / ml) were added with a pipette, and the solution was fixed to 100ml, and the ultrasonication was continued for 30min. After the ultrasonication was completed, the solution was irradiated with ultraviolet light for 12h under magnetic stirring. After 12h, it was taken out and filtered. Finally, it was placed in a vacuum drying oven at 80℃ and dried for 12h to obtain a platinum-tin catalyst hybridized with PtSn nanoparticles and 2D amorphous metal oxide nanostructures, recorded as PtSn / @10%TiO 2 / SBA-15.

[0240] Comparative Example 14

[0241] Same as Example 15, except that the metal oxide precursor is 0.3032 g of gallium nitrate hydrate, the pH precipitation range is 9-10, the calcination temperature is 550° C., and the calcination time is 4 h, recorded as PtSn / @-10%Ga 2 O 3 / SBA-15.

[0242] The catalytic activities of the catalysts prepared in Comparative Examples 10 to 14 were evaluated according to the catalyst activity evaluation method described above. The evaluation results are shown in Table 5.

[0243] Table 5 Effect of catalysts prepared in different embodiments / comparative examples on propane dehydrogenation reaction performance

[0244]

[0245] It can be seen from Table 5 that compared with other metal oxides (In 2 O3 , V 2 O 5 , Fe 2 O 3 , TiO 2 , Ga 2 O 3 ) semiconductor hybrid nanostructure catalyst, preparation example (1 / 8 / 15 / 21) PtSn nanoparticles and 2D amorphous metal oxide (ZrO 2 , Nb 2 O 5 , Y 2 O 3 or Dy 2 O 3 ) hybrid nanostructured catalyst has better activity, PtSn nanoparticles and MeO x (ZrO 2 , Nb 2 O 5 , Y 2 O 3 or Dy 2 O 3 )2D amorphous metal oxides have synergistic catalysis and produce strong interfacial electronic effects. Coating a monolayer of dispersed metal oxide film in the pores of molecular sieve SBA-15 can well optimize the catalytic performance of PDH. 2 O 3 PtSn / @-10%Dy 2 O 3 / SBA-15 catalyst has the best activity, with a conversion rate of 85% of the equilibrium conversion rate. The deactivation coefficient calculated through long-term stability test data is only 0.0110, which is much lower than that of conventional catalysts. This type of PtSn nanoparticles and 2D amorphous metal oxide hybrid nanostructured catalyst has excellent activity and excellent stability.

[0246] Example 27 to Example 30

[0247] Catalyst Cyclic Stability Test

[0248] Embodiment 27

[0249] The catalyst prepared in Example 1 was subjected to a cyclic stability test.

[0250] According to the catalyst activity evaluation method provided above, the catalyst PtSn / @-10% ZrO prepared in Example 1 was used. 2 / SBA-15 was used for multiple cycles, each time for 7 hours. After the experiment, the catalyst was collected and calcined in a muffle furnace at 500℃ for 2h to eliminate carbon deposits. The results of multiple cycles are detailed in Fig.16 .

[0251] Embodiment 28

[0252] The catalyst prepared in Example 8 was subjected to a cyclic stability test.

[0253] According to the catalyst reaction activity method provided above, the catalyst PtSn / @-10%Nb prepared in Example 8 was used. 2 O 5 / SBA-15 was used for multiple cycles, each time for 7 hours. After the experiment, the catalyst was collected and calcined in a muffle furnace at 500℃ for 2h to eliminate carbon deposits. The results of multiple cycles are detailed in Fig.17 .

[0254] Embodiment 29

[0255] The catalyst prepared in Example 15 was subjected to a cycle stability test.

[0256] According to the catalyst activity evaluation method provided above, the catalyst PtSn / @-10%Y prepared in Example 15 was used. 2 O 3 / SBA-15 was used for multiple cycles, each time for 7 hours. After the experiment, the catalyst was collected and calcined in a muffle furnace at 500℃ for 2h to eliminate carbon deposits. The results of multiple cycles are detailed in Fig.18 .

[0257] Embodiment 30

[0258] The catalyst prepared in Example 21 was subjected to a cyclic stability test.

[0259] According to the catalyst reaction activity method provided above, the catalyst PtSn / @-10%Dy prepared in Example 21 was used. 2 O 3 / SBA-15 was used for multiple cycles, each time for 7 hours. After the experiment, the catalyst was collected and calcined in a muffle furnace at 500℃ for 2h to eliminate carbon deposits. The results of multiple cycles are detailed in Fig.19 .

[0260] from Figure 16 to Figure 19 It can be seen that the PtSn nanoparticles and 2D amorphous metal oxide hybrid nanostructure catalyst have good regenerative performance, and the catalyst can be repeatedly recycled by simple calcination treatment. 2 O 3 / SBA-15 with PtSn / @-10%Dy 2 O 3 / SBA-15 catalyst showed only a slight decrease after four cycles of regeneration.

[0261] Example 31 to Example 33

[0262] Catalyst stability testing

[0263] Embodiment 31

[0264] The stability of the catalyst prepared in Example 1 was tested

[0265] According to the catalyst activity evaluation method provided above, the catalyst PtSn / @-10% ZrO prepared in Example 1 was used. 2 / SBA-15 for catalytic reaction, the reaction time is 960 minutes, from Fig. 20 It can be seen that the catalyst PtSn / @-10%ZrO 2 / SBA-15 has good stability performance and can maintain good catalytic activity even after the catalytic reaction time reaches 960 minutes.

[0266] Embodiment 32

[0267] The stability of the catalyst prepared in Example 8 was tested

[0268] According to the catalyst activity evaluation method provided above, the catalyst prepared in Example 8 was used. 2 O 5 / SBA-15 was used for catalytic reaction, and the reaction time was 1200 minutes. Fig.21 It can be seen that the catalyst PtSn / @-10%Nb 2 O 5 / SBA-15 has good stability performance and still maintains good catalytic activity after the catalytic reaction time reaches 1200 minutes.

[0269] Embodiment 33

[0270] The stability of the catalyst prepared in Example 15 was tested

[0271] According to the catalyst activity evaluation method provided above, the catalyst prepared in Example 15 was used. 2 O 3 / SBA-15 was used for catalytic reaction, and the reaction time was 1200 minutes. Fig. 22 It can be seen that the catalyst PtSn / @-10%Y 2 O 3 / SBA-15 has good stability performance and still maintains good catalytic activity after the catalytic reaction time reaches 1200 minutes.

[0272] Embodiment 32

[0273] The stability of the catalyst prepared in Example 21 was tested

[0274] According to the catalyst activity evaluation method provided above, the catalyst prepared in Example 21 was used. 2 O 3 / SBA-15 was used for catalytic reaction, and the reaction time was 1200 minutes. Fig.23 It can be seen that the catalyst PtSn / @-10%Dy 2 O 3 / SBA-15 has good stability performance and still maintains good catalytic activity after the catalytic reaction time reaches 1200 minutes.

[0275] from Figure 20 to Figure 23 It can be seen that the PtSn-like nanoparticles and 2D amorphous metal oxide hybrid nanostructure catalysts have good stability performance, and the catalytic activity is still good after the catalytic reaction time reaches 1200 minutes. 2 O 3 The PtSn hybrid nanostructured catalyst has the best stability, and the calculated deactivation coefficient is only 0.0110.

[0276] In summary, the synergistic effect between PtSn nanoparticles and 2D amorphous metal oxides effectively improves the catalyst activity. The experimental results of the embodiments and comparative examples show that when the platinum-tin ratio is 1:1 and the metal oxide loading is 10%, the highest propane conversion rate can reach 26.65 (about 85% of the equilibrium conversion rate). In contrast, the catalysts PtSn / SBA-15 and PtSn / MeO prepared in the comparative examples without this special structure have a higher propane conversion rate than the catalysts PtSn / SBA-15 and PtSn / MeO x The initial conversion rate was less than 10%.

[0277] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A platinum-tin hybrid nanostructured catalyst for direct dehydrogenation of propane to propylene, characterized in that: The invention comprises a carrier SBA-15, and a 2D amorphous semiconductor MeO encapsulated in the pores of the carrier SBA-15. x and the metal active component Pt and the auxiliary agent Sn anchored on the 2D amorphous semiconductor / support, denoted as PtSn / @-MeO x / SBA-15, MeO x One of ZrO2, Nb2O5, Y2O3 and Dy2O3, wherein the auxiliary agent Sn is SnO x The carrier SBA-15 and the 2D amorphous semiconductor MeO encapsulated in the pores of the carrier exist. x Denoted as @-MeO x / SBA-15; wherein the @-MeO x / MeO in SBA-15 x It is a two-dimensional amorphous metal oxide, and is encapsulated in the pores of the carrier SBA-15 in the form of a single layer by precipitation or microwave irradiation to form MeO x Semiconductor film layer, the catalyst PtSn / @-MeO x The active component Pt and the auxiliary agent Sn in SBA-15 are anchored in the @-MeO in the form of nanoparticles by photocatalytic reduction. x / SBA-15, the active component Pt and the MeO x There is a synergistic effect among the semiconductor film layers.

2. The platinum-tin hybrid nanostructured catalyst for direct dehydrogenation of propane to propylene according to claim 1, characterized in that: Taking the total mass of the catalyst as 100%, the catalyst PtSn / @-MeO x The mass content of Pt in SBA-15 is 0.1-3%, and the molar ratio of the active component Pt to the auxiliary agent Sn is 1:(1 / 3-2); x The total mass of @-MeO / SBA-15 is 100%, x / MeO in SBA-15 x The mass content is 5-15%.

3. The platinum-tin hybrid nanostructured catalyst for direct dehydrogenation of propane to propylene according to claim 2, characterized in that: The @-MeO x / MeO in SBA-15 x The MeO was spontaneously dispersed in the pores of the carrier SBA-15 in the form of a monolayer. x Semiconductor film layer, the @-MeO x / MeO in SBA-15 x The mass content is 10%; the molar ratio of the active component Pt to the auxiliary agent Sn is 1:

1.

4. A method for preparing a platinum-tin hybrid nanostructured catalyst for direct dehydrogenation of propane to propylene, characterized in that: The steps include: Step (1), by precipitation method or microwave irradiation method, the metal oxide MeO x MeO is encapsulated in the pores of the carrier SBA-15 in a single layer x Semiconductor film layer, @-MeO x / SBA-15, MeO x It is a two-dimensional amorphous metal oxide, in which MeO x One selected from ZrO2, Nb2O5, Y2O3 and Dy2O3; Step (2), using a photocatalytic reduction method to anchor the active component Pt and the auxiliary agent Sn in the form of nanoparticles on the @-MeO x / SBA-15, and the catalyst PtSn / @-MeO was obtained x / SBA-15, wherein the active component Pt and the MeO x The semiconductor film has a synergistic effect, and the auxiliary agent Sn is SnO x The state exists.

5. The method for preparing a platinum-tin hybrid nanostructured catalyst for direct dehydrogenation of propane to propylene according to claim 4, characterized in that: The method for preparing @-ZrO2 / SBA-15 is a precipitation method, specifically: dissolving ZrOCl2·8H2O in deionized water, stirring at room temperature until the mixture is uniformly mixed, then adding SBA-15 molecular sieve and deionized water, continuing to stir uniformly, adjusting the pH to 9-10 with a precipitant, covering with a plastic wrap, continuing to stir for 30 minutes, standing for aging, and washing, solid-liquid separation, drying, and calcining the aged mixed solution to obtain the @-ZrO2 / SBA-15; The method for preparing @-Nb2O5 / SBA-15 is a precipitation method, specifically: C 10 H5B 20 Dissolve in deionized water, stir at room temperature until mixed evenly, then add SBA-15 molecular sieve and deionized water, stir at room temperature until mixed evenly, and then oscillate and disperse in an ultrasonic cleaner under the protection of plastic wrap for 30 to 45 minutes. After the completion of ultrasound, adjust the pH value to 9 to 10 with a precipitant, cover with plastic wrap, heat and stir in a constant temperature water bath at 60 to 100° C. for 40 to 60 minutes, then take out and stand at room temperature for 20 to 24 hours for aging and crystallization. The aged mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Nb2O5 / SBA-15; The method for preparing @-Y2O3 / SBA-15 is a microwave irradiation method, specifically: dissolving the metal oxide precursor Y(NO3)3·6H2O into deionized water, stirring evenly, then adding the molecular sieve SBA-15 to the solution, stirring at room temperature until the mixture is evenly mixed, and then oscillating and dispersing in an ultrasonic cleaner under the protection of a plastic wrap for 30 to 45 minutes, adjusting the pH to 7 to 8 with a precipitant after the ultrasonication, and irradiating the obtained solution in a microwave reaction device, wherein the microwave power of the microwave reaction device is 200 to 400 W, the irradiation time is 10 to 20 minutes, and the temperature is cooled to room temperature after the reaction is completed. The cooled mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Y2O3 / SBA-15; The method for preparing @-Dy2O3 / SBA-15 is a microwave irradiation method, specifically: dissolving the metal oxide precursor Dy(NO3)3·6H2O into deionized water, stirring evenly, then adding the molecular sieve SBA-15 to the solution, stirring at room temperature until the mixture is evenly mixed, and then oscillating and dispersing in an ultrasonic cleaner under the protection of plastic wrap for 30 to 45 minutes, and adjusting the pH to a target value of 9 to 10 with a precipitant after the ultrasonication is completed. The obtained solution is irradiated in a microwave reaction device, the microwave power of the microwave reaction device is 200 to 400 W, the irradiation time is 10 to 20 minutes, and the temperature is cooled to room temperature after the reaction is completed. The cooled mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Dy2O3 / SBA-15.

6. The method for preparing a platinum-tin hybrid nanostructured catalyst for direct dehydrogenation of propane to propylene according to claim 4, characterized in that: The photocatalytic reduction method is specifically as follows: adding the @-MeOx / SBA-15 prepared in step (1) to water and anhydrous methanol, and uniformly dispersing by ultrasonication; then adding chloroplatinic acid solution and tin chloride solution, and continuing ultrasonic oscillation for a preset time; then placing under an ultraviolet lamp, stirring under light conditions, filtering the stirred solution, and vacuum drying to obtain the catalyst PtSn / @-MeO x / SBA-15.

7. A method for preparing propylene by direct dehydrogenation of propane, characterized in that: The method comprises using a pretreated catalyst PtSn / @-MeO x / SBA-15 catalyzes direct dehydrogenation of propane gas to produce propylene, the reaction pressure is normal pressure, and the reaction temperature is 500-580°C; the catalyst PtSn / @-MeO x / SBA-15 includes a carrier SBA-15, a 2D amorphous semiconductor MeO encapsulated in the pores of the carrier SBA-15 x and the metal active component Pt and the auxiliary agent Sn anchored on the 2D amorphous semiconductor / support, denoted as PtSn / @-MeO x / SBA-15, MeO x One of ZrO2, Nb2O5, Y2O3 and Dy2O3, wherein the auxiliary agent Sn is SnO x The carrier SBA-15 and the 2D amorphous semiconductor MeO encapsulated in the pores of the carrier exist. x Denoted as @-MeO x / SBA-15; wherein the @-MeO x / MeO in SBA-15 x It is a two-dimensional amorphous metal oxide, and is encapsulated in the pores of the carrier SBA-15 in the form of a single layer by precipitation or microwave irradiation to form MeO x Semiconductor film layer, the catalyst PtSn / @-MeO x The active component Pt and the auxiliary agent Sn in SBA-15 are anchored in the @-MeO in the form of nanoparticles by photocatalytic reduction. x / SBA-15, the active component Pt and the MeO x There is a synergistic effect among the semiconductor film layers.

8. The method for preparing propylene by direct dehydrogenation of propane according to claim 7, characterized in that: The method for preparing @-ZrO2 / SBA-15 is a precipitation method, specifically: dissolving ZrOCl2·8H2O in deionized water, stirring at room temperature until the mixture is uniformly mixed, then adding SBA-15 molecular sieve and deionized water, continuing to stir uniformly, adjusting the pH to 9-10 with a precipitant, covering with a plastic wrap, continuing to stir for 30 minutes, standing for aging, and washing, solid-liquid separation, drying, and calcining the aged mixed solution to obtain the @-ZrO2 / SBA-15; The method for preparing @-Nb2O5 / SBA-15 is a precipitation method, specifically: C 10 H5B 20 Dissolve in deionized water, stir at room temperature until mixed evenly, then add SBA-15 molecular sieve and deionized water, stir at room temperature until mixed evenly, and then oscillate and disperse in an ultrasonic cleaner under the protection of plastic wrap for 30 to 45 minutes. After the completion of ultrasound, adjust the pH value to 9 to 10 with a precipitant, cover with plastic wrap, heat and stir in a constant temperature water bath at 60 to 100° C. for 40 to 60 minutes, then take out and stand at room temperature for 20 to 24 hours for aging and crystallization. The aged mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Nb2O5 / SBA-15.

9. The method for preparing propylene by direct dehydrogenation of propane according to claim 7, characterized in that: The method for preparing @-Y2O3 / SBA-15 is a microwave irradiation method, specifically: dissolving the metal oxide precursor Y(NO3)3·6H2O into deionized water, stirring evenly, then adding the molecular sieve SBA-15 to the solution, stirring at room temperature until the mixture is evenly mixed, and then oscillating and dispersing in an ultrasonic cleaner under the protection of a plastic wrap for 30 to 45 minutes, adjusting the pH to 7 to 8 with a precipitant after the ultrasonication, and irradiating the obtained solution in a microwave reaction device, wherein the microwave power of the microwave reaction device is 200 to 400 W, the irradiation time is 10 to 20 minutes, and the temperature is cooled to room temperature after the reaction is completed. The cooled mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Y2O3 / SBA-15; The method for preparing @-Dy2O3 / SBA-15 is a microwave irradiation method, specifically: dissolving the metal oxide precursor Dy(NO3)3·6H2O into deionized water, stirring evenly, then adding the molecular sieve SBA-15 to the solution, stirring at room temperature until the mixture is evenly mixed, and then oscillating and dispersing in an ultrasonic cleaner under the protection of plastic wrap for 30 to 45 minutes, and adjusting the pH to a target value of 9 to 10 with a precipitant after the ultrasonication is completed. The obtained solution is irradiated in a microwave reaction device, the microwave power of the microwave reaction device is 200 to 400 W, the irradiation time is 10 to 20 minutes, and the temperature is cooled to room temperature after the reaction is completed. The cooled mixed solution is washed, solid-liquid separated, dried, and calcined to obtain the @-Dy2O3 / SBA-15.

10. The method for preparing propylene by direct dehydrogenation of propane according to claim 7, characterized in that: The propane content in the propane gas is 100 vol%, and the gas weight hourly space velocity of the propane is 5 to 18 h -1 The pretreatment method of the catalyst PtSn / @-MeOx / SBA-15 is as follows: the catalyst PtSn / @-MeOx / SBA-15 is filled into a micro fixed bed reactor, and an inert gas with a content of 10 to 40 vol% is introduced for pretreatment for 30 to 120 minutes, wherein the pretreatment temperature is 500 to 580°C.

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