Interfacial catalysts with high specific surface area and high active site number, preparation and use

Abstract

The application provides an interface catalyst with high specific surface area and high active site number, and a preparation method and application thereof. The interface catalyst takes amorphous active carbon as a carrier, and deposits Fe2O3 and TiO2 two species of interfaces on the surface of the amorphous active carbon. The interface is Fe2O3-TiO2 interface, TiO2-Fe2O3 interface, Fe2O3-TiO2-Fe2O3 interface or TiO2-Fe2O3-TiO2 interface. The method adopts an atomic layer deposition method. The interface catalyst with high specific surface area and high active site number is used as a catalyst for thermal decomposition of ammonium perchlorate. The interface structure of the interface catalyst prepared by the application is accurately adjustable and has a high active site number, and the performance of the interface catalyst in catalyzing decomposition of ammonium perchlorate is much higher than that of the results reported in the current literature and patents. Compared with the prior art, the interface catalyst prepared by the application has the advantages of high active interface site number, environmental green friendliness, high activity in catalyzing ammonium perchlorate, etc. The preparation process of the bimetallic oxide interface catalyst is simple and convenient.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials and relates to an interface catalyst, in particular to an interface catalyst with a high specific surface area and a high number of active sites, and its preparation and application. Background Art

[0002] Ammonium perchlorate (AP) is the most commonly used oxidizer in composite propellants due to its unique thermal decomposition properties. The combustion behavior of AP directly impacts the performance of rocket propellant systems. Therefore, improving the combustion performance of AP and understanding its thermal decomposition behavior are crucial for enhancing the performance of solid rocket propellants. Currently, the addition of combustion catalysts is considered an effective method to improve the thermal decomposition efficiency of AP. Transition metal oxides, as combustion catalysts, can effectively promote the thermal decomposition of oxidizers and enhance the combustion performance of solid propellants. The catalytic effect of transition metal oxides on the thermal decomposition of AP is attributed to various factors, such as semiconductor properties (p-type or n-type semiconductors) and charge or electron transfer processes, but the actual catalytic mechanism remains uncertain. Typical transition metal oxides, such as Fe2O3, TiO2, MnO2, and Co2O3, exhibit excellent catalytic activity for the decomposition of AP. Among these transition metal oxides, Fe2O3 and TiO2 have been widely used due to their high efficiency, abundance, low cost, and non-toxicity.

[0003] In recent years, researchers have made great efforts to improve the catalytic activity of related metal oxides. The general strategies to improve activity mainly include particle size control, morphology modulation, multi-component, etc. Although these methods are effective for the activation of AP, the overall combustion performance of these catalysts is still far from satisfactory because they are prone to changes in particle size, morphology, state and dispersion during the reaction, and the performance after the change is significantly reduced. The development of efficient combustion catalysts with stable performance and maximum active sites is very promising. Considering that the catalytic process generally occurs at the interface between two metal oxides, it is crucial to regulate the interfacial electronic structure and geometric structure to effectively catalyze the decomposition of AP. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide an interfacial catalyst with a high specific surface area and a high number of active sites, as well as its preparation and application, to solve the technical problem in the existing technology that the specific surface area and the number of active sites of the interfacial catalyst need to be further improved.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] The invention discloses an interfacial catalyst with high specific surface area and high number of active sites. The interfacial catalyst uses amorphous activated carbon as a carrier and deposits an interface of two species, Fe2O3 and TiO2, on the surface of the amorphous activated carbon.

[0007] The interface is a Fe2O3-TiO2 interface, a TiO2-Fe2O3 interface, a Fe2O3-TiO2-Fe2O3 interface or a TiO2-Fe2O3-TiO2 interface.

[0008] The present invention also protects a method for preparing an interface catalyst with a high specific surface area and a high number of active sites as described above. The method uses atomic layer deposition to form an interface on a carrier by orderly depositing Fe2O3 species and TiO2 species in a periodic manner.

[0009] The steps of depositing the Fe2O3 species are as follows: firstly depositing an iron source, and then allowing the deposited ferrocene to react chemically with O2 to generate Fe2O3 species.

[0010] The deposition steps of the TiO2 species are as follows: firstly, a titanium source is deposited, and then the deposited titanium tetraisopropoxide is chemically reacted with H2O2 to generate TiO2 species.

[0011] The present invention also has the following technical features:

[0012] Specifically, the deposition step of the Fe2O3 species is step A. A complete step A includes:

[0013] Step A1: Under vacuum conditions, ferrocene is brought into the reaction chamber by bubbling an inert carrier gas for deposition. The deposition temperature is 350° C. to 400° C., the deposition time is 300 s, and the flow rate of the inert carrier gas is 40 to 100 ml / min.

[0014] In step A2, an inert carrier gas is introduced into the reaction chamber to blow away the unadsorbed ferrocene in the reaction chamber and the ferrocene physically adsorbed on the surface. The blowing time is 600 s and the flow rate of the inert carrier gas is 100-200 ml / min.

[0015] In Step A3, O2 is introduced into the reaction chamber to undergo a redox reaction with ferrocene. The O2 introduction time is 300 s and the flow rate is 25-60 ml / min.

[0016] In step A4, an inert carrier gas is introduced into the reaction chamber to blow the unreacted molecules and by-products out of the reaction chamber. The blowing time is 600 s and the flow rate of the inert carrier gas is 100-200 ml / min.

[0017] Specifically, the TiO2 species deposition step is step B. A complete step B includes:

[0018] Step B1, under vacuum conditions, lower the reaction chamber temperature to 150° C. and stabilize it, and bring titanium tetraisopropoxide into the reaction chamber by bubbling with an inert carrier gas for deposition. The deposition time is 300 s, and the flow rate of the inert carrier gas is 40 to 100 ml / min.

[0019] In step B2, an inert carrier gas is introduced into the reaction chamber to blow away the unadsorbed titanium tetraisopropoxide in the reaction chamber and the titanium tetraisopropoxide physically adsorbed on the surface. The blowing time is 600 s and the flow rate of the inert carrier gas is 100-200 ml / min.

[0020] In step B3, H2O2 is introduced into the reaction chamber by bubbling to undergo a redox reaction with titanium tetraisopropoxide. The introduction time of H2O2 is 300 s, and the flow rate is 25-60 ml / min.

[0021] Step B4: Introduce an inert carrier gas into the reaction chamber to blow the unreacted molecules and by-products out of the reaction chamber. The blowing time is 600 s and the flow rate of the inert carrier gas is 100-200 ml / min.

[0022] Preferably, in steps A and B, they can be combined according to actual needs, for example (AB) nc (Steps AB are performed alternately, A first, then B, and the whole process is repeated n times), (BA) nc (Steps AB are performed alternately, B first, then A, and the whole process is repeated n times), A xc -B yc (Advanced type: perform x cycles of step A, then y cycles of step B), B yc -A xc (First, perform step B for y times, and then perform step A for x times).

[0023] Preferably, the inert carrier gas is nitrogen or argon.

[0024] Preferably, the number of deposition cycles is 1 to 10 times.

[0025] More preferably, the number of deposition cycles is 1 to 5 times.

[0026] The present invention also protects the use of the interfacial catalyst with high specific surface area and high number of active sites as a catalyst for the thermal decomposition reaction of ammonium perchlorate.

[0027] Compared with the prior art, the present invention has the following technical effects:

[0028] (I) The interfacial structure of the interfacial catalyst prepared by the present invention is precisely adjustable and has a high number of active sites. Its performance in catalyzing the decomposition of ammonium perchlorate is much higher than the results reported in current literature and patents.

[0029] (II) Compared with the prior art, the interface catalyst prepared by the present invention has the advantages of high active interface sites, high environmental friendliness, high catalytic activity for ammonium perchlorate, etc. The preparation process of the bimetallic oxide interface catalyst is simple and convenient.

[0030] (III) Under the action of the interfacial catalyst prepared in the present invention, the pyrolysis peak temperature of AP is as low as 249°C to 296°C, which is significantly lower than the pyrolysis peak temperature of pure AP without any catalyst added, which is 438°C, and significantly lower than the lowest value reported in current literature and patents.

[0031] (IV) Under the action of the interfacial catalyst prepared by the present invention, the reaction rate constant is reduced from 0.0011s to 0.11s when no catalyst is added. -1 Improved to 5.1-5.3s -1 , an increase of 5000 times.

[0032] (V) The interfacial catalyst prepared in this invention significantly increased the heat release of AP, from 217.7 J / g in the absence of catalyst to 1567.8 J / g to 1573.5 J / g. This further demonstrates the promising application of bimetallic oxide interfacial catalysts in the catalytic decomposition of AP.

[0033] (VI) The method of the present invention has mild conditions for atomic layer deposition synthesis, and the experimental chemicals are all common chemicals in laboratories. The catalyst cost is low.

[0034] (VII) The catalyst of the present invention is easy to prepare, has good reproducibility, and is low in price, which greatly reduces the preparation cost of the catalyst and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is the transmission electron microscope TEM image of AC@Fe2O3@TiO2 catalyst.

[0036] Figure 2 This is the transmission electron microscopy (HRTEM) image of AC@Fe2O3@TiO2 catalyst.

[0037] Figure 3 Transmission electron microscope (STEM) image and EDX mapping image of AC@Fe2O3@TiO2 catalyst.

[0038] Figure 4 This is the transmission electron microscope TEM image of AC@TiO2@Fe2O3 catalyst.

[0039] Figure 5 This is the transmission electron microscopy (HRTEM) image of AC@TiO2@Fe2O3 catalyst.

[0040] Figure 6 Transmission electron microscope (STEM) image and EDX mapping image of AC@TiO2@Fe2O3 catalyst.

[0041] Figure 7 XPS spectra of AC@Fe2O3@TiO2 catalyst and AC@TiO2@Fe2O3 catalyst, where a represents AC@Fe2O3@TiO2 catalyst and b represents AC@TiO2@Fe2O3 catalyst;

[0042] Figure 8 These are the DSC spectra of thermal decomposition of ammonium perchlorate (AP) catalyzed by AC@Fe2O3@TiO2 catalyst and AC@TiO2@Fe2O3 catalyst.

[0043] Figure 9 This is the kinetic data diagram of thermal decomposition of ammonium perchlorate (AP) catalyzed by AC@Fe2O3@TiO2 catalyst and AC@TiO2@Fe2O3 catalyst.

[0044] Figure 10 AC(@Fe2O3@TiO2) nc (n=1~5) and AC(@TiO2@Fe2O3) nc DSC spectra of thermal decomposition of ammonium perchlorate (AP) catalyzed by (n=1~5) catalysts.

[0045] The specific contents of the present invention are further explained in detail below with reference to the embodiments. DETAILED DESCRIPTION

[0046] It should be noted that, unless otherwise specified, all materials and equipment in the present invention are those known in the art.

[0047] Surface and interface catalysis plays a crucial role in many reactions, including those in the chemical industry, electrochemistry, and combustion. In heterogeneous catalysis, the surface and interface of a catalyst are the sites where reactions occur: reactant molecules are adsorbed, activated, converted to products, and desorbed into the gas phase. Furthermore, charge interactions between two transition metal oxides primarily occur at the interface. Due to the complex interfacial effects of the resulting catalysts, understanding the intrinsic interactions between the two components is difficult. Controlled synthesis with well-defined, ordered, and uniform distribution of components is essential for exploring the structural properties and catalytic performance of different surfaces and interfaces. Using unique preparation methods such as atomic layer deposition (ALD), H-titanate@Fe2O3 composites with Fe2O3-H2Ti3O7 interfacial sites were previously prepared using ALD. It was discovered that the interface between the Fe2O3 nanoparticles and the H-titanate support may be the optimal active site for the thermal decomposition of AP. Catalysts with specific interfacial structures are achievable using ALD. Furthermore, the number of interfacial sites of the added catalyst is relatively high in the reaction. Therefore, the development of efficient combustion catalysts with the maximum number of interfacial sites is urgently needed. Therefore, loading interfacial catalysts on activated carbon supports with large specific surface area is a good choice.

[0048] The present invention relates to the preparation of a bimetallic oxide interface catalyst using high-surface-area AC (activated carbon) as a carrier based on atomic layer deposition technology, and its application in catalyzing the thermal decomposition reaction of ammonium perchlorate. The catalyst is prepared by combining Fe2O3 particles and a TiO2 film using atomic layer deposition technology to form a bimetallic oxide interface catalyst, specifically a Fe2O3-TiO2 interface, a TiO2-Fe2O3 interface, a Fe2O3-TiO2-Fe2O3 interface, or a TiO2-Fe2O3-TiO2 interface catalyst. The Fe2O3 and TiO2 film are sequentially deposited on the amorphous activated carbon using atomic layer deposition, and the deposition is performed at least once. Alternatively, the Fe2O3 and TiO2 species can be sequentially deposited on the amorphous activated carbon using atomic layer deposition in a specific arrangement sequence, and the deposition is performed 2 to 10 times.

[0049] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent modifications made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0050] Example 1:

[0051] This embodiment provides a method for preparing an interfacial catalyst with a high specific surface area and a high number of active sites. The interfacial catalyst is AC@Fe2O3-5c@TiO2-5c.

[0052] The method comprises the following steps:

[0053] In the first step, the amorphous activated carbon is spread flat on the sample table, then placed in the atomic layer deposition reaction chamber and the outlet is sealed, and a mechanical vacuum pump is used to evacuate the reaction chamber.

[0054] In the second step, the temperature was set and increased. The reaction chamber temperature was set to 350°C, the ferrocene storage tank temperature was set to 95°C, and the Inlet and Outlet temperatures were set to 120°C and 150°C, respectively.

[0055] The third step is to introduce a certain flow of inert carrier gas into the reaction chamber from the inlet of the atomic layer deposition equipment, and use a mechanical pump to evacuate the outlet to stabilize the vacuum degree in the reaction chamber within a certain range.

[0056] In the fourth step, ferrocene was injected into the reaction chamber by bubbling, with a ferrocene carrier gas flow rate of 40 ml / min, a total carrier gas flow rate of 100 ml / min, and an injection time of 300 s, so that the ferrocene AC surface was chemically adsorbed.

[0057] In the fifth step, an inert carrier gas was introduced into the reaction chamber to blow the iron source physically adsorbed on the AC surface away from the surface. The flow rate was 100 ml / min and the introduction time was 600 s.

[0058] In the sixth step, high-purity oxygen was injected into the reaction chamber through the inlet of the equipment. The oxygen flow rate was 25 ml, the total carrier gas flow rate was 100 ml / min, and the injection time was 300 s, so that the oxygen and the iron source adsorbed on the AC surface underwent redox reaction.

[0059] In the seventh step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the byproducts and excess oxygen molecules on the AC surface. The inert carrier gas was introduced for 600 s.

[0060] Step 8: Steps 4 to 7 constitute one cycle of iron oxide deposition. Repeat steps 4 to 7 to increase the number of iron oxide deposition cycles to 5, and AC@Fe2O3-5c is now prepared.

[0061] Step 9: Reset the temperature: the reaction chamber temperature is 150°C, the titanium tetraisopropoxide storage tank temperature is 45°C, and the Inlet and Outlet temperatures are set to 100°C.

[0062] In the tenth step, titanium tetraisopropoxide was injected into the reaction chamber by bubbling. The carrier gas flow rate of titanium tetraisopropoxide was 40 ml / min, the total carrier gas flow rate was 100 ml / min, and the injection time was 300 s, so that titanium tetraisopropoxide was chemically adsorbed on the surface of AC@Fe2O3-5c.

[0063] In the eleventh step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the titanium source physically adsorbed on the surface of AC@Fe2O3-5c. The introduction time was 600 s.

[0064] In the twelfth step, hydrogen peroxide vapor molecules were injected into the reaction chamber through the inlet of the equipment. The inert gas flow rate through the hydrogen peroxide path was 40 ml / min, the total carrier gas flow rate was 100 ml / min, and the injection time was 300 s, so that the hydrogen peroxide molecules underwent redox reaction with the titanium source adsorbed on AC@Fe2O3-5c.

[0065] In the thirteenth step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the by-products and excess hydrogen peroxide molecules on the sample surface. The introduction time was 600 s.

[0066] Step 14: Step 10 to Step 13 is one cycle of titanium dioxide deposition. Repeat Step 10 to Step 13, increase the number of cycles of titanium dioxide deposition to 5 cycles, and finally prepare

[0067] AC@Fe2O3-5c@TiO2-5c interfacial catalyst.

[0068] Figure 1 This is the transmission electron microscope TEM image of AC@Fe2O3@TiO2 catalyst. Figure 1 It can be seen that the deposition of Fe2O3 and TiO2 did not change the morphology of AC, and Fe2O3 and TiO2 species were not visible under low-magnification electron microscopy, indicating that these two species prepared by atomic layer deposition method are highly dispersed on AC.

[0069] Figure 2 This is the transmission electron microscope (HRTEM) image of the AC@Fe2O3@TiO2 catalyst. It can be seen that Fe2O3 is a particle and TiO2 is a thin film, in which Fe2O3 is distributed inside and TiO2 is on the outside, forming a closely contacted Fe2O3-TiO2 interface site.

[0070] Figure 3 Transmission electron microscopy (STEM) and EDX mapping images of the AC@Fe2O3@TiO2 catalyst show that Fe and Ti are evenly distributed on AC from the elemental distribution maps of Fe and Ti, further proving that Fe2O3 and TiO2 are highly dispersed on AC.

[0071] Example 2:

[0072] This embodiment provides a method for preparing an interfacial catalyst with a high specific surface area and a high number of active sites. The interfacial catalyst is AC@TiO2-5c@Fe2O3-5c.

[0073] The method comprises the following steps:

[0074] In the first step, the amorphous activated carbon is spread flat on the sample table, then placed in the atomic layer deposition reaction chamber and the outlet is sealed, and a mechanical vacuum pump is used to evacuate the reaction chamber.

[0075] The second step is to set the temperature. The reaction chamber temperature is 150°C, the titanium tetraisopropoxide storage tank temperature is 45°C, and the Inlet and Outlet temperatures are set to 100°C.

[0076] The third step is to introduce a certain flow of inert carrier gas into the reaction chamber from the inlet of the atomic layer deposition equipment, and use a mechanical pump to evacuate the outlet to stabilize the vacuum degree in the reaction chamber within a certain range.

[0077] In the fourth step, titanium tetraisopropoxide was injected into the reaction chamber by bubbling. The carrier gas flow rate of titanium tetraisopropoxide was 40 ml / min, the total carrier gas flow rate was 100 ml / min, and the injection time was 300 s, so that titanium tetraisopropoxide was chemically adsorbed on the AC surface.

[0078] In the fifth step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the titanium source physically adsorbed on the AC surface. The introduction time was 600 s.

[0079] In the sixth step, hydrogen peroxide vapor molecules are injected into the reaction chamber through the inlet of the equipment. The inert gas flow rate through the hydrogen peroxide path is 40 ml / min, the total carrier gas flow rate is 100 ml / min, and the injection time is 300 s, so that the hydrogen peroxide molecules undergo redox reaction with the titanium source adsorbed on the AC.

[0080] In the seventh step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the byproducts and excess hydrogen peroxide molecules on the sample surface. The introduction time was 600 s.

[0081] Step 8: Steps 4 to 7 constitute one cycle of titanium dioxide deposition. Repeat steps 4 to 7 to increase the number of titanium dioxide deposition cycles to 5, and AC@TiO2-5c is obtained.

[0082] Step 9: Set the temperature and increase the temperature. The reaction chamber temperature is 350°C, the ferrocene storage tank temperature is 95°C, and the Inlet and Outlet temperatures are 120°C and 150°C, respectively.

[0083] In the tenth step, ferrocene was injected into the reaction chamber by bubbling, with a ferrocene carrier gas flow rate of 40 ml / min, a total carrier gas flow rate of 100 ml / min, and an injection time of 300 s, so that ferrocene was chemically adsorbed on the surface of AC@TiO2-5c.

[0084] In the eleventh step, an inert carrier gas was introduced into the reaction chamber to blow the iron source physically adsorbed on the surface of AC@TiO2-5c away from its surface at a flow rate of 100 ml / min and the introduction time was 600 s.

[0085] In the twelfth step, high-purity oxygen was injected into the reaction chamber through the equipment inlet. The oxygen flow rate was 25 ml, the total carrier gas flow rate was 100 ml / min, and the injection time was 300 s, so that the oxygen underwent a redox reaction with the iron source adsorbed on the surface of AC@TiO2-5c.

[0086] In the thirteenth step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the byproducts and excess oxygen molecules on the AC surface. The introduction time was 600 s.

[0087] Step 14: Steps 10 to 13 are one cycle of iron oxide deposition. Repeat steps 10 to 13 to increase the number of iron oxide deposition cycles to 5, and finally prepare the AC@TiO2-5c@Fe2O3-5c interfacial catalyst.

[0088] Figure 4 This is the transmission electron microscope TEM image of AC@TiO2@Fe2O3 catalyst. Figure 4 It can be seen that the deposition of Fe2O3 and TiO2 did not change the morphology of AC, and Fe2O3 and TiO2 species were not visible under low-magnification electron microscopy, which also shows that the two species prepared by atomic layer deposition are highly dispersed on AC.

[0089] Figure 5 This is the transmission electron microscope (HRTEM) image of the AC@TiO2@Fe2O3 catalyst. It can be seen that Fe2O3 is particles and TiO2 is a thin film, in which TiO2 is distributed inside and Fe2O3 is on the outside, forming a closely contacted Fe2O3-TiO2 interface site.

[0090] Figure 6 The transmission electron microscope (STEM) image and EDX mapping image of AC@TiO2@Fe2O3 catalyst show that Fe and Ti are evenly distributed on AC from the element distribution map, which further proves that Fe2O3 and TiO2 are highly dispersed on AC.

[0091] Figure 7The XPS spectra of AC@Fe2O3@TiO2 and AC@TiO2@Fe2O3 catalysts (Fe 2p, Ti 2p, O1s), where a represents AC@Fe2O3@TiO2 and b represents AC@TiO2@Fe2O3. The peak of Fe 2p indicates that 711.4 eV is the standard peak of Fe2O3, proving that the valence state of the deposited Fe species is Fe 3+ From the Ti 2p peak, it can be seen that 458.7eV is the standard peak of TiO2. The above results prove that the deposited species are Fe2O3 and TiO2 species.

[0092] Example 3:

[0093] This embodiment provides a method for preparing an interfacial catalyst with high specific surface area and high number of active sites. The interfacial catalyst is AC(@Fe2O3@TiO2) nc (n=1-5).

[0094] The method comprises the following steps:

[0095] In the first step, the amorphous activated carbon is spread flat on the sample table, then placed in the atomic layer deposition reaction chamber and the outlet is sealed, and a mechanical vacuum pump is used to evacuate the reaction chamber.

[0096] In the second step, a certain flow of inert carrier gas is introduced into the reaction chamber from the inlet of the atomic layer deposition equipment, and a mechanical pump is used to evacuate the reaction chamber at the outlet to stabilize the vacuum degree in the reaction chamber within a certain range.

[0097] The third step is to set the temperature and increase the temperature. The reaction chamber temperature is 350°C, the ferrocene storage tank temperature is 95°C, and the Inlet and Outlet temperatures are 120°C and 150°C respectively.

[0098] In the fourth step, ferrocene was injected into the reaction chamber by bubbling, with a ferrocene carrier gas flow rate of 40 ml / min, a total carrier gas flow rate of 100 ml / min, and an injection time of 300 s, so that ferrocene was chemically adsorbed on the sample surface.

[0099] In the fifth step, an inert carrier gas is introduced into the reaction chamber to blow away the iron source physically adsorbed on the sample surface. The flow rate is 100 ml / min and the introduction time is 600 s.

[0100] In the sixth step, high-purity oxygen is injected into the reaction chamber through the equipment inlet. The oxygen flow rate is 25 ml, the total carrier gas flow rate is 100 ml / min, and the injection time is 300 s, so that the oxygen undergoes an oxidation-reduction reaction with the iron source adsorbed on the sample surface.

[0101] In the seventh step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the byproducts and excess oxygen molecules on the sample surface. The introduction time was 600 s.

[0102] Step 8. Reset the temperature: the reaction chamber temperature is 150°C, the titanium tetraisopropoxide storage tank temperature is 45°C, and the Inlet and Outlet temperatures are set to 100°C.

[0103] In the ninth step, titanium tetraisopropoxide was injected into the reaction chamber by bubbling. The carrier gas flow rate of titanium tetraisopropoxide was 40 ml / min, the total carrier gas flow rate was 100 ml / min, and the injection time was 300 s, so that titanium tetraisopropoxide was chemically adsorbed on the surface of AC@Fe2O3-5c.

[0104] In the tenth step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the titanium source physically adsorbed on the surface of the sample. The introduction time was 600 s.

[0105] In the eleventh step, hydrogen peroxide vapor molecules are injected into the reaction chamber through the inlet of the equipment. The inert gas flow rate through the hydrogen peroxide path is 40 ml / min, the total carrier gas flow rate is 100 ml / min, and the injection time is 300 s, so that the hydrogen peroxide molecules undergo redox reaction with the titanium source adsorbed on the sample.

[0106] In the twelfth step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the by-products and excess hydrogen peroxide molecules on the sample surface. The introduction time was 600 s.

[0107] In the thirteenth step, steps three to twelve are to first deposit one cycle of Fe2O3 and then one cycle of TiO2, and repeat steps three to twelve to increase the number of deposition cycles to prepare different AC (@Fe2O3@TiO2)nc (n=1, 2, 3, 4, 5) interface catalysts.

[0108] In the present invention, the inert carrier gas is high-purity nitrogen or high-purity argon.

[0109] Example 4:

[0110] This embodiment provides a method for preparing an interfacial catalyst with a high specific surface area and a high number of active sites. The interfacial catalyst is AC(@TiO2@Fe2O3) nc (n=1~5).

[0111] The method comprises the following steps:

[0112] In the first step, the amorphous activated carbon is spread flat on the sample table, then placed in the atomic layer deposition reaction chamber and the outlet is sealed, and a mechanical vacuum pump is used to evacuate the reaction chamber.

[0113] In the second step, a certain flow of inert carrier gas is introduced into the reaction chamber from the inlet of the atomic layer deposition equipment, and a mechanical pump is used to evacuate the reaction chamber at the outlet to stabilize the vacuum degree in the reaction chamber within a certain range.

[0114] The third step is to set the temperature: the reaction chamber temperature is 150°C, the titanium tetraisopropoxide storage tank temperature is 45°C, and the Inlet and Outlet temperatures are set to 100°C.

[0115] In the fourth step, titanium tetraisopropoxide was injected into the reaction chamber by bubbling. The carrier gas flow rate of titanium tetraisopropoxide was 40 ml / min, the total carrier gas flow rate was 100 ml / min, and the injection time was 300 s, so that titanium tetraisopropoxide was chemically adsorbed on the surface of AC@Fe2O3-5c.

[0116] In the fifth step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the titanium source physically adsorbed on the surface of the sample. The introduction time was 600 s.

[0117] In the sixth step, hydrogen peroxide vapor molecules are injected into the reaction chamber through the inlet of the equipment. The inert gas flow rate through the hydrogen peroxide path is 40 ml / min, the total carrier gas flow rate is 100 ml / min, and the injection time is 300 s, so that the hydrogen peroxide molecules undergo redox reaction with the titanium source adsorbed on the sample.

[0118] In the seventh step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the byproducts and excess hydrogen peroxide molecules on the sample surface. The introduction time was 600 s.

[0119] Step 8. Set the temperature and increase the temperature. The reaction chamber temperature is 350°C, the ferrocene storage tank temperature is 95°C, and the Inlet and Outlet temperatures are 120°C and 150°C, respectively.

[0120] In the ninth step, ferrocene was injected into the reaction chamber by bubbling, with a ferrocene carrier gas flow rate of 40 ml / min, a total carrier gas flow rate of 100 ml / min, and an injection time of 300 s, so that ferrocene was chemically adsorbed on the sample surface.

[0121] In the tenth step, an inert carrier gas is introduced into the reaction chamber to blow away the iron source physically adsorbed on the sample surface. The flow rate is 100 ml / min and the introduction time is 600 s.

[0122] In the eleventh step, high-purity oxygen is injected into the reaction chamber through the inlet of the equipment. The oxygen flow rate is 25 ml, the total carrier gas flow rate is 100 ml / min, and the injection time is 300 s, so that the oxygen undergoes a redox reaction with the iron source adsorbed on the sample surface.

[0123] In the twelfth step, an inert carrier gas with a flow rate of 100 ml / min was introduced into the reaction chamber to blow away the byproducts and excess oxygen molecules on the sample surface. The introduction time was 600 s.

[0124] Step 13: From step 3 to step 12, first deposit one cycle of TiO2 and then one cycle of Fe2O3. Repeat steps 3 to step 12 to increase the number of deposition cycles to prepare different ACs (@TiO2@Fe2O3). nc (n=1,2,3,4,5)interfacial catalyst.

[0125] In the present invention, the inert carrier gas is high-purity nitrogen or high-purity argon.

[0126] Example 5:

[0127] This embodiment provides an application of an interfacial catalyst with a high specific surface area and a high number of active sites for catalyzing the thermal decomposition reaction of ammonium perchlorate. The interfacial catalyst is:

[0128] AC@Fe2O3@TiO2, AC@TiO2@Fe2O3, AC(@Fe2O3@TiO2) nc (n=1~5) and AC(@TiO2@Fe2O3) nc (n=1~5).

[0129] 5 mg of interfacial catalyst was evenly mixed with 45 mg of ultrafine ammonium perchlorate (AP), and an appropriate amount of the above-mentioned evenly mixed sample was taken for thermal decomposition test experiment. The performance of its catalytic AP was tested by thermogravimetry and differential calorimetry (TG-DSC). The test atmosphere was high-purity Ar, the heating rate was 10℃ / min, and the test temperature range was 50-600℃. Under the action of the catalyst, the high-temperature decomposition peak temperature of AP was as low as 249℃~296℃, which was significantly lower than the high-temperature decomposition peak temperature of pure AP without any catalyst added, which was 438℃, and significantly lower than the lowest value reported in the current literature and patents. Under the action of this catalyst, the reaction rate constant was reduced from 0.0011s when no catalyst was added. -1 Improved to 0.32~5.1s -1 , increased by 5000 times. Under the action of this catalyst, the heat release of AP increased significantly, from 217.7J / g without catalyst to 747.6J / g~1574J / g.

[0130] Table 1 shows the AC@Fe2O3@TiO2, AC@TiO2@Fe2O3, AC(@Fe2O3@TiO2) nc and AC(@TiO2@Fe2O3) nc Catalyst (n=1-5) Peak temperature of AP decomposition catalyzed by the catalyst.

[0131] Table 1 Peak temperature of AP decomposition catalyzed by interfacial catalysts

[0132] Interfacial Catalyst Peak temperature of AP decomposition at high temperature (℃) Without catalyst (pure AP) 438 <![CDATA[AC@Fe2O3-5c@TiO2-5c]]> 285 <![CDATA[AC@TiO2-5c@Fe2O3-5c]]> 279 <![CDATA[AC(@Fe2O3@TiO2) 1c ]]> 296 <![CDATA[AC(@Fe2O3@TiO2) 2c ]]> 288 <![CDATA[AC(@Fe2O3@TiO2) 3c ]]> 286 <![CDATA[AC(@Fe2O3@TiO2) 4c ]]> 282 <![CDATA[AC(@Fe2O3@TiO2) 5c ]]> 273 <![CDATA[AC(@TiO2@Fe2O3) 1c ]]> 287 <![CDATA[AC(@TiO2@Fe2O3) 2c ]]> 287 <![CDATA[AC(@TiO2@Fe2O3) 3c ]]> 287 <![CDATA[AC(@TiO2@Fe2O3) 4c ]]> 264 <![CDATA[AC(@TiO2@Fe2O3) 5c ]]> 249

[0133] Figure 8 DSC spectra of thermal decomposition of ammonium perchlorate (AP) catalyzed by AC@Fe2O3@TiO2 catalyst and AC@TiO2@Fe2O3 catalyst; Figure 9 These are the thermal decomposition kinetic data of ammonium perchlorate (AP) catalyzed by AC@Fe2O3@TiO2 catalyst and AC@TiO2@Fe2O3 catalyst; A is the thermal decomposition data of pure AP; B is the thermal decomposition data of AP after adding AC@Fe2O3-5c@TiO2-5c; C is the thermal decomposition data of AP after adding AC@TiO2-5c@Fe2O3-5c.

[0134] From Table 1, Figure 8 and Figure 9 It can be seen that the pyrolysis peak temperature of pure AP without any catalyst is 438°C, the pyrolysis peak temperature of AP thermal decomposition catalyzed by AC@Fe2O3-5c@TiO2-5c is 285°C; the pyrolysis peak temperature of AP thermal decomposition catalyzed by AC@TiO2-5c@Fe2O3-5c is 279°C; AC@Fe2O3-5c@TiO2-5c and AC@TiO2-5c@Fe2O3-5c have similar pyrolysis peak temperatures, similar activation energy Ea, similar reaction rate constant k and similar heat release ΔH, indicating that the active site structure and number of the two catalysts are similar.

[0135] Figure 10 AC(@Fe2O3@TiO2) nc (n=1~5) and AC(@TiO2@Fe2O3) nc DSC spectra of thermal decomposition of ammonium perchlorate (AP) catalyzed by (n=1-5); A1-A5 are AC(@Fe2O3@TiO2) 1c ,AC(@Fe2O3@TiO2) 2c ,AC(@Fe2O3@TiO2) 3c ,AC(@Fe2O3@TiO2) 4c and AC(@Fe2O3@TiO2) 5c , B1~B5 are

[0136] AC(@TiO2@Fe2O3) 1c ,AC(@TiO2@Fe2O3) 2c ,AC(@TiO2@Fe2O3) 3c ,AC(@TiO2@Fe2O3)4c and AC(@TiO2@Fe2O3) 5c Using AC(@Fe2O3@TiO2) 1c The pyrolysis peak temperature of AP catalyzed by the catalyst is 296℃; AC(@Fe2O3@TiO2) 2c The high temperature decomposition peak temperature of AP catalyzed by the catalyst is 288℃; using AC (@Fe2O3@TiO2) 3c The high temperature decomposition peak temperature of AP catalyzed by the catalyst is 286℃; using AC (@Fe2O3@TiO2) 4c The pyrolysis peak temperature of AP catalyzed by the catalyst is 282℃; using AC(@Fe2O3@TiO2) 5c The high temperature decomposition peak temperature of AP catalyzed by the catalyst is 273℃; using AC (@TiO2@Fe2O3) 1c ,AC(@TiO2@Fe2O3) 2c and AC(@TiO2@Fe2O3) 3c The high temperature decomposition peak temperature of AP catalyzed by the catalyst is 287℃; using AC (@TiO2@Fe2O3) 4c The pyrolysis peak temperature of AP catalyzed by the catalyst is 264℃; using AC(@TiO2@Fe2O3) 5c The pyrolysis peak temperature of AP catalyzed by the catalyst is 249°C. It can be concluded that the pyrolysis peak temperature of AP under the action of the bimetallic oxide interface catalyst of the present invention is as low as 249°C to 296°C, which is significantly lower than the pyrolysis peak temperature of pure AP without any catalyst, which is 438°C, and significantly lower than the lowest value reported in current literature and patents. Under the action of this catalyst, the reaction rate constant is reduced from 0.0011s when no catalyst is added. -1 Improved to 5.1-5.3s -1 , increased by 5000 times. Under the action of this catalyst, the heat release of AP increased significantly, from 217.7J / g without catalyst to 1567.8J / g~1573.5J / g.

Claims

1. Application of interfacial catalysts with high specific surface area and high number of active sites as catalysts for the thermal decomposition reaction of ammonium perchlorate; The interface catalyst with high specific surface area and high number of active sites uses amorphous activated carbon as a carrier, and deposits the interface of two species, Fe2O3 and TiO2, on the surface of the amorphous activated carbon; The interface is a Fe2O3-TiO2 interface, a TiO2-Fe2O3 interface, a Fe2O3-TiO2-Fe2O3 interface or a TiO2-Fe2O3-TiO2 interface; Under the action of the interface catalyst with high specific surface area and high number of active sites, the peak temperature of high-temperature decomposition of ammonium perchlorate is as low as 249° C. to 296° C.; The method for preparing the interface catalyst with high specific surface area and high number of active sites adopts atomic layer deposition method, and the interface is formed by sequentially depositing Fe2O3 species and TiO2 species on the carrier in a periodic manner; The Fe2O3 species deposition step is step A. A complete step A includes: Step A1: Under vacuum conditions, ferrocene is introduced into the reaction chamber by bubbling an inert atmosphere for deposition. The deposition temperature is 350°C to 400°C, the deposition time is 300 s, and the flow rate of the inert atmosphere is 40 to 100 mL / min. Step A2: An inert atmosphere is introduced into the reaction chamber to blow away the unadsorbed ferrocene in the reaction chamber and the ferrocene physically adsorbed on the surface. The blowing time is 600 s and the flow rate of the inert atmosphere is 100-200 mL / min. Step A3: O2 is introduced into the reaction chamber to undergo a redox reaction with ferrocene. The O2 introduction time is 300 s at a flow rate of 25-60 mL / min. Step A4: introduce an inert atmosphere into the reaction chamber to blow out unreacted molecules and by-products in the reaction chamber. The blowing time is 600 s and the flow rate of the inert atmosphere is 100-200 mL / min. The TiO2 species deposition step is step B. A complete step B includes: Step B1, under vacuum conditions, lower the reaction chamber temperature to 150° C. and stabilize it, then introduce titanium tetraisopropoxide into the reaction chamber by bubbling an inert atmosphere for deposition. The deposition time is 300 s, and the flow rate of the inert atmosphere is 40-100 mL / min. Step B2: introducing an inert atmosphere into the reaction chamber to blow away the unadsorbed titanium tetraisopropoxide in the reaction chamber and the titanium tetraisopropoxide physically adsorbed on the surface. The blowing time is 600 s and the flow rate of the inert atmosphere is 100-200 mL / min. Step B3: bubbling H2O2 into the reaction chamber to react with titanium tetraisopropoxide for 300 s at a flow rate of 25-60 mL / min. Step B4: introduce an inert atmosphere into the reaction chamber to blow out the unreacted molecules and by-products in the reaction chamber. The blowing time is 600 s and the flow rate of the inert atmosphere is 100-200 mL / min.

2. The use according to claim 1, characterized in that The inert atmosphere is nitrogen or argon.

3. The use according to claim 1, characterized in that The number of cycles of the deposition is 1 to 10 times.

4. The use according to claim 1, wherein The number of cycles of the deposition is 1 to 5 times.

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