TiO2 loaded bimetallic catalyst as well as preparation method and application thereof

Abstract

The invention provides a TiO2 loaded bimetallic catalyst as well as a preparation method and application thereof. The TiO2 loaded bimetallic catalyst comprises a TiO2 carrier, and non-noble metal single atoms and noble metal particles which are loaded on the TiO2 carrier, the loading capacities of the non-noble metal single atoms and the noble metal particles are 0.1-1 wt% based on 100% of the mass of the TiO2 carrier. Tests show that the yield of formate obtained by carrying out hydrogenation reaction by using the TiO2-loaded bimetallic catalyst provided by the invention is high, the selectivity is 99% or above, and the formate has no attenuation after 6 cycles and has excellent CO poisoning resistance. In addition, the preparation method of the TiO2 loaded bimetallic catalyst provided by the invention is simple, mild in operation condition and low in cost, and is beneficial to realizing large-scale production.

Description

Technical Field

[0001] The invention belongs to the field of hydrogenation reaction catalysts, and specifically relates to a TiO2-loaded bimetallic catalyst and a preparation method and application thereof. Background Art

[0002] With the gradual reduction of fossil resources and the sharp increase in global energy consumption, how to efficiently reduce CO2 emissions has become a crucial issue. Therefore, the process of using hydroxide aqueous solution to capture CO2 to generate carbonates and selectively hydrogenating them into high-value-added chemicals has attracted widespread attention from scholars. For example, it is now possible to catalyze the direct conversion of carbonates into formate, but this process also has some key problems, such as complex catalyst preparation, high cost, harsh reaction conditions, catalyst recovery, low efficiency, low selectivity and stability. Therefore, how to catalyze hydrogenation at low cost, high activity and high selectivity has always been a technical difficulty that needs to be solved in this field.

[0003] At present, although homogeneous catalysts containing organometallic complexes of iron or ruthenium have been reported to catalyze the hydrogenation of carbonates to form formate in water, the reactivity of carbonate conversion is very limited and the catalyst cannot be recycled. At the same time, most heterogeneous catalysts have difficulty in converting carbonates into formate, and the storage conditions of supported metal particle catalysts are harsh and require activation treatment before the reaction, which is costly. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a TiO2-supported bimetallic catalyst and a preparation method and application thereof. The catalyst not only has high activity, selectivity and stability, but also has a simple preparation method and low cost.

[0005] To achieve this object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a TiO2-supported bimetallic catalyst, which includes a TiO2 carrier and non-precious metal single atoms and precious metal particles supported on the TiO2 carrier;

[0007] Taking the mass of the TiO2 carrier as 100%, the loading amounts of the non-precious metal single atoms and the precious metal particles are both 0.1-1 wt%.

[0008] Preferably, the non-noble metal in the non-noble metal single atom is selected from any one or more of nickel, cobalt, copper or iron.

[0009] Preferably, the precious metal in the precious metal particles is selected from any one or more of platinum, ruthenium, rhodium or palladium.

[0010] Preferably, the noble metal particles are spherical, and the average particle size of the noble metal particles is 1.5-2.5 nm.

[0011] In a second aspect, the present invention provides a method for preparing the above-mentioned TiO2-supported bimetallic catalyst, comprising the following steps:

[0012] The TiO2 carrier, noble metal salt, non-noble metal salt, alkaline substance and solvent are mixed, dried and calcined to obtain a TiO2-supported bimetallic catalyst.

[0013] Preferably, the non-noble metal salt is selected from any one or more of nickel salts, copper salts, cobalt salts or iron salts.

[0014] Preferably, the noble metal salt is selected from any one or more of platinum salt, ruthenium salt, rhodium salt or palladium salt.

[0015] Preferably, the alkaline substance is selected from aqueous ammonia.

[0016] Preferably, the solvent is selected from water.

[0017] Preferably, the ratio of the TiO2 carrier, the noble metal salt, the non-noble metal salt, the alkaline substance and the solvent is 100 mg: (0.1~1) mg: (0.1~1) mg: (20~200) μL: (25~50) mL.

[0018] Preferably, the mixing time is 10-24 h, the mixing is carried out under stirring conditions, and the stirring rate is 500-1000 r / min.

[0019] Preferably, the drying temperature is 80-120°C.

[0020] Preferably, the calcination is carried out in a reducing atmosphere, and the reducing atmosphere is selected from a hydrogen-argon mixed gas and / or a hydrogen-nitrogen mixed gas.

[0021] Preferably, the calcination temperature is 300-450° C. and the calcination time is 2-6 h.

[0022] In a third aspect, the present invention provides an application of the above-mentioned TiO2-loaded bimetallic catalyst in the hydrogenation reaction of a mixture of carbonate, bicarbonate or hydroxide aqueous solution and CO2 gas.

[0023] In a fourth aspect, the present invention provides a method for using the above-mentioned TiO2-supported bimetallic catalyst, comprising the following steps:

[0024] The above-mentioned TiO2-supported bimetallic catalyst is mixed with a mixture of carbonate, bicarbonate or hydroxide aqueous solution and CO2 gas, and then hydrogen is introduced under a protective gas atmosphere to carry out a hydrogenation reaction.

[0025] Preferably, the carbonate is selected from any one or more of sodium carbonate, potassium carbonate or ammonium carbonate.

[0026] Preferably, the bicarbonate is selected from any one or more of sodium bicarbonate, potassium bicarbonate or ammonium bicarbonate.

[0027] Preferably, the hydroxide in the aqueous hydroxide solution is selected from any one or more of sodium hydroxide, potassium hydroxide or ammonium hydroxide.

[0028] Preferably, the protective gas is argon and / or helium.

[0029] Preferably, the hydrogen is pure hydrogen or a mixed gas containing hydrogen.

[0030] Preferably, the hydrogenation reaction is carried out at a pressure of 1-5 MPa, a temperature of 100-500 °C, and a time of 1-5 h.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention provides a method for preparing a TiO2-supported bimetallic catalyst, wherein the TiO2 support, a noble metal salt, a non-noble metal salt, an alkaline substance and a solvent are mixed, dried and calcined to obtain the TiO2-supported bimetallic catalyst. The presence of the alkaline substance can generate hydroxyl radicals on the surface of the TiO2 support, thereby adsorbing non-noble metals and noble metals through electrostatic adsorption or chemical adsorption, wherein the non-noble metal can replace part of the Ti atoms to form non-noble metal single atoms coordinated with O, and the noble metal grows into small particles and is loaded on the support surface through the coordination bond between the noble metal and O. In the present invention, the non-noble metal single atoms and the noble metal particles can be uniformly dispersed and are not easy to aggregate. The catalyst has the advantages of high reactivity, good selectivity, strong stability, etc. in the selective catalysis of hydrogenation reactions such as mixtures of carbonate, bicarbonate or hydroxide aqueous solution and CO2 gas through its special and stable coordination environment and the synergistic effect between the loaded non-noble metal single atoms and the noble metal particles.

[0033] According to tests, the hydrogenation reaction using the TiO2-supported bimetallic catalyst provided by the present invention has a high yield of formate and a selectivity of more than 99%. There is no attenuation after six cycles, and the catalyst has excellent resistance to CO poisoning.

[0034] In addition, the preparation method of the TiO2-loaded bimetallic catalyst provided by the present invention is simple, the operating conditions are mild and the cost is low, which is conducive to large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1The X-ray diffraction pattern of the TiO2-based catalyst loaded with nickel atoms and platinum particles prepared in Example 1;

[0036] Figure 2 Spherical aberration-corrected transmission electron micrographs of different sizes of the TiO2-based catalyst loaded with nickel single atoms and platinum particles prepared in Example 1;

[0037] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the formate catalytic product of the TiO2-based catalyst loaded with nickel single atoms and platinum particles prepared in Example 1;

[0038] Figure 4 The yield result graph and selectivity result graph of the target product sodium formate which was repeatedly used in the sodium carbonate hydrogenation reaction by the TiO2-based catalyst loaded with nickel single atoms and platinum particles prepared in Example 1. DETAILED DESCRIPTION

[0039] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In view of the problems in the prior art that the catalyst for catalyzing the direct conversion of carbonate into formate is complex in preparation, high in cost, harsh in reaction conditions, difficult to recover, low in efficiency, low in selectivity and stability, the present invention provides a TiO2-supported bimetallic catalyst (abbreviated as: M SAs -M NPs / TiO2), which includes a TiO2 carrier and a non-precious metal single atom (abbreviated as: M Sas , where M represents a specific non-precious metal element) and precious metal particles (referred to as: M NPs , where M represents a specific precious metal element).

[0041] In the present invention, the TiO2 carrier is cheap and stable. The TiO2 carrier of the present invention is preferably a flaky TiO2 with a large specific surface area, which can provide more metal growth binding sites, making it easier to form non-precious metal single atoms and precious metal particles later.

[0042] In the present invention, the non-noble metal in the non-noble metal single atom is selected from any one or more of nickel, cobalt, copper or iron, preferably nickel.

[0043] In the present invention, the precious metal in the precious metal particles is selected from any one or more of platinum, ruthenium, rhodium or palladium, preferably platinum. At the same time, the precious metal particles are spherical, and the average particle size of the precious metal particles is 1.5-2.5 nm, preferably 1.8-2 nm.

[0044] If the loading amount of non-precious metal single atoms is too high, it will cause them to aggregate and cannot exist in the form of single atoms. For precious metal particles, if the loading amount is too high, the particle size will increase, so that the effective catalytic area is reduced, which is not conducive to subsequent practical applications. Therefore, in the present invention, based on the mass of the TiO2 carrier as 100%, the loading amount of the non-precious metal single atoms and the precious metal particles is 0.1~1 wt%, preferably 0.3~0.8 wt%. The present invention has no particular restrictions on the ratio of non-precious metal single atoms and precious metal particles, as long as the above-mentioned loading amount range is met.

[0045] In the present invention, the above-mentioned non-precious metal single atoms and precious metal particles can be evenly dispersed and are not easy to aggregate. The catalyst has the advantages of high reaction activity, good selectivity, strong stability, etc. in the selective catalysis of hydrogenation reactions of mixtures of carbonate, bicarbonate or hydroxide aqueous solutions and CO2 gas due to its special and stable coordination environment and the synergistic effect between the loaded non-precious metal single atoms and the precious metal particles.

[0046] The present invention also provides a method for preparing the above-mentioned TiO2-supported bimetallic catalyst, comprising the following steps:

[0047] The TiO2 carrier, noble metal salt, non-noble metal salt, alkaline substance and solvent are mixed, dried and calcined to obtain a TiO2-supported bimetallic catalyst.

[0048] In the present invention, the preparation of the above-mentioned TiO2 carrier is not particularly limited and can be prepared according to a preparation method well known to those skilled in the art.

[0049] Exemplarily, the TiO2 carrier is prepared according to the following method:

[0050] Tetrabutyl titanate is mixed with hydrofluoric acid, placed in a high-pressure reactor for reaction, and then cooled to room temperature. The centrifugal product is collected after centrifugation, and washed with a NaOH solution to remove fluoride ions. The product is collected after another centrifugation, and finally washed with water, washed with alcohol, and dried to obtain a product, which is recorded as a TiO2 carrier.

[0051] Wherein, the concentration of tetrabutyl titanate is 99 wt%, the concentration of hydrofluoric acid is 50 wt%, the dosage of tetrabutyl titanate and hydrofluoric acid is 20~30 mL and 2~5 mL; the concentration of the NaOH solution is 0.5~1.5 M. The reaction temperature of the autoclave is 160~200°C, preferably 170~180°C; the reaction time is 12~48 h, preferably 24~36 h. The speed of the centrifuge is 6000~12000 rpm, preferably 8000~10000 rpm; the time is 2~10 min, preferably 5~8 min. The temperature of the drying is 60~80°C, preferably 65~75°C.

[0052] In the above method, raw materials such as tetrabutyl titanate, hydrofluoric acid and NaOH solution may also be replaced by other commonly used substances in the art.

[0053] After the TiO2 support is obtained, according to the present invention, the TiO2 support, a noble metal salt, a non-noble metal salt, an alkaline substance and a solvent are mixed.

[0054] In the present invention, the noble metal salt is selected from any one or more of platinum salts, ruthenium salts, rhodium salts or palladium salts, such as chloroplatinic acid, ruthenium chloride, rhodium chloride, potassium chloropalladate, or other commonly used noble metal salts in the art.

[0055] In the present invention, the non-precious metal salt is selected from any one or more of nickel salts, copper salts, cobalt salts or iron salts, such as specifically nickel chloride, copper chloride, cobalt chloride, iron chloride, or other commonly used non-precious metal salts in the art.

[0056] In the present invention, the alkaline substance is preferably selected from ammonia water, which is used to generate hydroxyl radicals on the surface of the TiO2 carrier, and can be decomposed into gas in the subsequent heating process, so that other impurities will not be introduced.

[0057] In the present invention, the solvent is selected from water, preferably deionized water.

[0058] In the present invention, the mass ratio of TiO2 carrier to noble metal salt and non-noble metal salt and the amount of alkaline substance added affect the loading amount, dispersion and coordination environment of noble metal and non-noble metal, and further affect the hydrogenation catalytic activity.

[0059] Therefore, it is preferred that in the present invention, the ratio of the TiO2 carrier, the noble metal salt, the non-noble metal salt, the alkaline substance and the solvent is 100 mg:(0.1~1) mg:(0.1~1) mg:(20~200) μL:(25~50) mL, preferably 100 mg:(0.3~0.8) mg:(0.3~0.8) mg:(50~150) μL:(30~45) mL.

[0060] Specifically, in some embodiments of the present invention, the amount of the TiO2 carrier is 100 mg, the amount of ammonia water is 20-200 μL, the amount of non-precious metal salt and precious metal salt is 0.1-1 wt.% (compared to the amount of TiO2 carrier), and the amount of water is 25-50 mL.

[0061] In the present invention, the mixing is preferably carried out under stirring conditions, the stirring rate is 500-1000 r / min, preferably 600-800 r / min; the stirring time is 10-24 h, preferably 12-20 h. The stirring process affects the loading, dispersion and coordination environment of the precious metal and non-precious metal, and thus affects the hydrogenation catalytic activity.

[0062] In some embodiments of the present invention, it is preferred to disperse the TiO2 carrier into an aqueous solution, and then add an alkaline substance and an aqueous solution containing a noble metal salt and a non-noble metal salt, and stir at room temperature.

[0063] In the present invention, the room temperature is "10-30°C", preferably "15-25°C".

[0064] According to the present invention, after obtaining a mixed solution of TiO2 carrier, noble metal salt, non-noble metal salt, alkaline substance and solvent, it is dried and calcined in sequence to obtain a TiO2-loaded bimetallic catalyst.

[0065] In the present invention, the drying temperature is 80-120°C, preferably 90-110°C.

[0066] In the present invention, the calcination treatment is carried out in a reducing atmosphere, and the reducing atmosphere is selected from a hydrogen-argon mixed gas and / or a hydrogen-nitrogen mixed gas. During the calcination process, the non-precious metal is dispersed as a single atom on the surface of the TiO2 carrier, and the precious metal grows as small particles on the surface of the TiO2 carrier. The calcination temperature is 300-450°C, preferably 320-400°C; the time is 2-6h, preferably 3-4h. Among them, the calcination treatment affects the loading amount, dispersion and coordination environment of the precious metal and the non-precious metal, and thus affects the hydrogenation catalytic activity.

[0067] The preparation method of the TiO2-loaded bimetallic catalyst provided by the present invention is simple, low-cost, and is conducive to large-scale production.

[0068] In summary, in some embodiments of the present invention, the method for preparing the TiO2-supported bimetallic catalyst comprises the following steps:

[0069] Step (1): tetrabutyl titanate and hydrofluoric acid are mixed, placed in a high-pressure reactor for reaction, cooled to room temperature, centrifuged, and the centrifuged product is collected, washed with a NaOH solution to remove fluoride ions, centrifuged again, and the product is collected, and finally washed with water, washed with alcohol, and dried to obtain a product, which is recorded as TiO2-{001};

[0070] Step (2): Disperse the TiO2-{001} prepared in step (1) into an aqueous solution, then add ammonia water and an aqueous solution containing a metal salt, stir at room temperature, dry and calcine to obtain a non-precious metal single atom (M SAs ) and precious metal particles (M NPs ) coexistence product, denoted as M SAs -M NPs / TiO2.

[0071] In the present invention, the non-precious metal single atoms and the precious metal particles can be uniformly dispersed on the TiO2 carrier and are not easy to aggregate. Through its special and stable coordination environment and the synergistic effect between the loaded non-precious metal single atoms and the precious metal particles, the TiO2-loaded bimetallic catalyst has the advantages of high reaction activity, good selectivity, strong stability, etc. in the selective catalytic hydrogenation reaction of a mixture of carbonate, bicarbonate or hydroxide aqueous solution and CO2 gas.

[0072] Based on this, the present invention also provides an application of the above-mentioned TiO2-loaded bimetallic catalyst in the hydrogenation reaction of a mixture of carbonate, bicarbonate or hydroxide aqueous solution and CO2 gas.

[0073] Exemplarily, the present invention provides a method for using the above-mentioned TiO2-supported bimetallic catalyst, comprising the following steps:

[0074] The above-mentioned TiO2-supported bimetallic catalyst is mixed with a mixture of carbonate, bicarbonate or hydroxide aqueous solution and CO2 gas, and then hydrogen is introduced under a protective gas atmosphere to carry out a hydrogenation reaction.

[0075] Wherein, the carbonate is selected from any one or more of sodium carbonate, potassium carbonate or ammonium carbonate; the bicarbonate is selected from any one or more of sodium bicarbonate, potassium bicarbonate or ammonium bicarbonate; the hydroxide in the hydroxide aqueous solution is selected from any one or more of sodium hydroxide, potassium hydroxide or ammonium hydroxide; the protective gas is argon and / or helium; the hydrogen is pure hydrogen or a mixed gas containing hydrogen.

[0076] In the present invention, the pressure of the hydrogenation reaction is 1-5 MPa, preferably 2-4 MPa; the temperature is 100-500° C., preferably 200-400° C.; and the time is 1-5 h, preferably 2-4 h.

[0077] In some specific embodiments of the present invention, it is preferred to dissolve the TiO2-supported bimetallic catalyst with carbonate, bicarbonate or CO2 gas and hydroxide in water and add them to a high-pressure reactor, introduce protective gas to evacuate the gas in the reactor, then introduce hydrogen, close the reactor, set the reaction temperature and time, and cool to room temperature after the reaction is completed. Open the reactor to take out the product, centrifuge and filter it, wash and dry the separated solid catalyst for reuse, and analyze the separated liquid product.

[0078] The centrifugal speed is 6000-12000 rpm, preferably 8000-10000 rpm, the time is 2-10 min, preferably 3-8 min, and the drying temperature is 60-80°C, preferably 65-75°C.

[0079] Specifically, when the non-precious metal salt used to prepare the TiO2-loaded bimetallic catalyst is nickel salt and the precious metal salt is platinum salt, the obtained is a TiO2-based catalyst loaded with single nickel atoms and platinum particles. The catalyst can use sodium carbonate as a reaction substrate under the conditions of a reaction temperature of 200°C and 2 MPa hydrogen (containing 0.1 vt% CO), tolerate CO poisoning, and produce sodium formate with high activity and selectivity greater than 99%, with no performance degradation after 6 cycles.

[0080] Compared with other metal-supported catalysts of the same type in the prior art, the TiO2-supported bimetallic catalyst provided by the present invention makes the non-precious metal single atoms and the precious metal particles uniformly dispersed on the TiO2 carrier through electrostatic adsorption and chemical blessing, which is not easy to aggregate and has high reaction activity. Due to the special and stable coordination environment and the synergistic effect between the supported non-precious metal single atoms and the precious metal particles, the catalyst has the advantages of high activity, good selectivity, strong stability, etc. In the selective hydrogenation catalytic reaction, the TiO2-supported bimetallic catalyst provided by the present invention has excellent catalytic performance.

[0081] In summary, the TiO2-supported bimetallic catalyst provided by the present invention not only has high activity, high selectivity and high stability, but also has a simple preparation method and low preparation cost, and can exhibit excellent catalytic performance in selective hydrogenation reactions.

[0082] In order to further illustrate the present invention, the following examples are provided for detailed description. The experimental raw materials used in the following examples of the present invention are all common commercially available products.

[0083] Example 1

[0084] A TiO2-based catalyst loaded with nickel single atoms and platinum particles is prepared by the following steps:

[0085] S1: Mix 25 mL of 99 wt% Ti(OBu)4 and 3 mL of 40 wt% HF, place in a 180°C autoclave for 24 h, cool to room temperature, centrifuge at 10,000 rpm for 5 min, and then wash the product with 1 M NaOH solution to remove fluoride ions. Finally, wash with water, alcohol, and dry at 70°C to obtain a product, which is recorded as TiO2-{001} and set aside.

[0086] S2: 100 mg TiO2-{001} was dispersed in 25 mL aqueous solution, 100 μL ammonia water, 1.10 mg nickel chloride and 1.09 mg chloroplatinic acid hexahydrate were added, and then stirred at room temperature for 24 h at a speed of 500 r / min; dried at 100 °C, and finally calcined at 350 °C in a tube furnace for 3 h in a 10 vt% hydrogen-argon mixed atmosphere (H2:Ar=10:90, volume ratio (vt%)) at a heating rate of 2 °C / min, and then cooled to room temperature to obtain a TiO2-based product loaded with nickel single atoms and platinum particles, denoted as Ni SAs -Pt NPs / TiO2-{001}.

[0087] Specifically, during the implementation of Example 1 of the present invention, detection was performed to obtain the following detection results:

[0088] (1) X-ray diffraction was used to characterize the TiO2-based catalyst loaded with nickel atoms and platinum particles, and the following results were obtained: Figure 1 The X-ray diffraction pattern shown. Figure 1 It can be seen that the TiO2-based catalyst loaded with nickel single atoms and platinum particles prepared in Example 1 of the present invention has no obvious metal diffraction peaks, confirming that it is in the state of nickel single atoms and platinum nanoparticles (the particles are too small and no crystal diffraction peaks appear).

[0089] (2) A spherical aberration-corrected transmission electron microscope was used to observe the TiO2-based catalyst loaded with nickel atoms and platinum particles, and the following results were obtained: Figure 2 Transmission electron microscope photo shown. Figure 2 It can be seen that the TiO2-based catalyst loaded with nickel atoms and platinum particles prepared in Example 1 of the present invention has nickel atoms (circled points) and platinum particles (highlighted area in the center) uniformly dispersed on the TiO2 carrier, and the average particle size of the platinum particles is about 2 nm.

[0090] (3) The TiO2-based catalyst loaded with single nickel atoms and platinum particles was used as a catalyst for the hydrogenation reaction of sodium carbonate and its performance was tested. The specific process is as follows: In the hydrogen hydrogenation process, 1 mmol of sodium carbonate, 20 mg of the TiO2-based catalyst loaded with single nickel atoms and platinum particles prepared in Example 1 of the present invention, and 6 mL of water were added to a high-pressure reactor, and nitrogen was introduced to 1 MPa. This operation was performed three times in succession to empty the gas in the reactor. Hydrogen was then introduced to 2 MPa (0.1 vt% CO), the reactor was closed, the reaction temperature (200°C) and time (2 h) were set, and the reaction was cooled to room temperature after the reaction was completed. The reactor was opened to take out the product, and it was separated by centrifugation and filtration. The separated solid catalyst was washed and dried, and the reaction was repeated 6 times. The separated liquid product was sent to liquid chromatography and nuclear magnetic resonance spectrometer for analysis (such as Figure 3 As shown), we can get Figure 4 The product performance diagram shown in the figure, where yield = product formate molar amount / (precious metal salt molar amount × reaction time). Figure 4 It can be seen that the TiO2-based catalyst loaded with nickel single atoms and platinum particles prepared in Example 1 of the present invention has a strong sodium carbonate hydrogenation performance. Under the conditions of reaction temperature of 200°C and hydrogen pressure of 2 MPa (0.1 vt.% CO), with sodium carbonate as the reaction substrate, it can withstand CO poisoning to produce sodium formate with high activity and selectivity greater than 99%, and there is no attenuation after 6 cycles.

[0091] Example 2

[0092] Compared with Example 1, the difference is that 20 mL of Ti(OBu)4 with a concentration of 99 wt% is mixed with 2 mL of HF with a concentration of 40 wt%, and the other parameters and steps are consistent with Example 1. The prepared material is a TiO2-based catalyst loaded with nickel single atoms and platinum particles.

[0093] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0094] Example 3

[0095] Compared with Example 1, the difference is that a high pressure reaction at 160° C. is used, and the other parameters and steps are consistent with Example 1. The prepared material is a TiO2-based catalyst loaded with nickel single atoms and platinum particles.

[0096] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0097] Example 4

[0098] Compared with Example 1, the difference is that the centrifugal speed is 8000 rpm and the time is 7 min. The other parameters and steps are consistent with Example 1. The prepared material is a TiO2-based catalyst loaded with nickel single atoms and platinum particles.

[0099] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0100] Example 5

[0101] Compared with Example 1, the difference is that 0.5 M NaOH is used to wash the centrifuged product, and the other parameters and steps are consistent with Example 1. The prepared material is a TiO2-based catalyst loaded with nickel single atoms and platinum particles.

[0102] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0103] Example 6

[0104] Compared with Example 1, the difference is that 50 μL of ammonia water is used to adjust the pH value of the solution, and the other parameters and steps are consistent with Example 1. The prepared material is a catalyst loaded with nickel single atoms and platinum particles.

[0105] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0106] Example 7

[0107] Compared with Example 1, the difference is that 1.10 mg of cobalt chloride is used as the non-precious metal salt, and the other parameters and steps are consistent with Example 1. The prepared material is a TiO2-based catalyst loaded with cobalt single atoms and platinum particles.

[0108] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0109] Example 8

[0110] Compared with Example 1, the difference is that 1.87 mg of potassium chloropalladate is used as the noble metal salt, and the prepared material is a TiO2-based catalyst loaded with nickel atoms and palladium particles.

[0111] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0112] Example 9

[0113] Compared with Example 1, the difference is that 40 mL of water is used to disperse TiO2-{001}, and the other parameters and steps are consistent with Example 1. The prepared material is a catalyst loaded with nickel single atoms and platinum particles.

[0114] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0115] Example 10

[0116] Compared with Example 1, the difference is that the rotation speed is changed to 1000 r / min and stirring is performed for 12 hours, and the other parameters and steps are consistent with Example 1. The prepared material is a loaded nickel single atom and platinum particle catalyst.

[0117] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0118] Embodiment 11

[0119] Compared with Example 1, the difference is that the drying temperature is set to 120° C. after stirring and centrifuging, and the other parameters and steps are consistent with Example 1. The prepared material is a loaded nickel single atom and platinum particle catalyst.

[0120] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0121] Example 12

[0122] Compared with Example 1, the difference is that a 10 vt% hydrogen-helium mixed atmosphere is used as the calcination reducing atmosphere, and the other parameters and steps are consistent with Example 1. The prepared material is a supported nickel single atom and platinum particle catalyst.

[0123] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0124] Example 13

[0125] Compared with Example 1, the difference is that the calcination reduction temperature is 450°C for 2 h, and the other parameters and steps are consistent with Example 1. The prepared material is a supported nickel single atom and platinum particle catalyst.

[0126] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0127] Embodiment 14

[0128] The specific reaction process and detection method are the same as those in Example 1, except that the reaction substrate sodium carbonate is replaced by sodium bicarbonate.

[0129] After testing, the sodium bicarbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0130] Embodiment 15

[0131] The specific reaction process and detection method are the same as those in Example 1, except that the reaction substrate sodium carbonate is replaced by potassium carbonate.

[0132] According to tests, potassium carbonate hydrogenation reaction has high activity and selectivity greater than 99%.

[0133] Example 16

[0134] The specific reaction process and detection method are the same as those in Example 1, except that the reaction substrate sodium carbonate is replaced by ammonium carbonate.

[0135] After testing, the ammonium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0136] Embodiment 17

[0137] Compared with Example 1, the difference is that 1.06 mg of copper chloride is used as the non-precious metal salt, and the other parameters and steps are consistent with Example 1. The prepared material is a TiO2-based catalyst loaded with copper single atoms and platinum particles.

[0138] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0139] Embodiment 18

[0140] Compared with Example 1, the difference is that 1.45 mg of ferric chloride is used as the non-precious metal salt, and the other parameters and steps are consistent with Example 1. The prepared material is a TiO2-based catalyst loaded with iron single atoms and platinum particles.

[0141] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0142] Embodiment 19

[0143] Compared with Example 1, the difference is that 1.03 mg of ruthenium chloride is used as the noble metal salt, and the prepared material is a TiO2-based catalyst loaded with nickel atoms and ruthenium particles.

[0144] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0145] Embodiment 20

[0146] Compared with Example 1, the difference is that 1.02 mg of rhodium chloride is used as the noble metal salt, and the prepared material is a TiO2-based catalyst loaded with nickel atoms and rhodium particles.

[0147] The reaction performance test is the same as that in Example 1. The sodium carbonate hydrogenation reaction has high activity and a selectivity of more than 99%.

[0148] Comparative Example 1

[0149] Compared with Example 1, the difference is that only 1.10 mg of nickel chloride is used as the non-precious metal salt, and no precious metal salt is added. The remaining steps and parameters refer to Example 1, and the prepared material is a TiO2-based catalyst loaded with nickel single atoms.

[0150] The detection method was the same as in Example 1, and it was found that the catalytic activity was 20% of that in Example 1, and the sodium carbonate hydrogenation selectivity was greater than 99%.

[0151] Comparative Example 2

[0152] Compared with Example 1, the difference is that only 1.06 mg of copper chloride is used as the non-precious metal salt, and no precious metal salt is added. The remaining steps and parameters refer to Example 1, and the prepared material is a TiO2-based catalyst loaded with copper single atoms.

[0153] The detection method was the same as in Example 1, and it was found that the catalytic activity was 18% of that in Example 1, and the sodium carbonate hydrogenation selectivity was greater than 99%.

[0154] Comparative Example 3

[0155] Compared with Example 1, the difference is that only 1.45 mg of ferric chloride is used as a non-precious metal salt, and no precious metal salt is added. The remaining steps and parameters refer to Example 1, and the prepared material is a TiO2-based catalyst loaded with single iron atoms.

[0156] The detection method was the same as in Example 1, and it was found that the catalytic activity was 23% of that in Example 1, and the sodium carbonate hydrogenation selectivity was greater than 99%.

[0157] Comparative Example 4

[0158] Compared with Example 1, the difference is that only 1.87 mg of potassium chloropalladate is used as the noble metal salt, and no non-noble metal salt is added. The remaining steps and parameters refer to Example 1, and the prepared material is a TiO2-based catalyst loaded with palladium particles.

[0159] The detection method was the same as in Example 1, and it was found that the catalytic activity was 25% of that in Example 1, and the sodium carbonate hydrogenation selectivity was greater than 99%.

[0160] Comparative Example 5

[0161] Compared with Example 1, the difference is that only 1.03 mg of ruthenium chloride is used as the noble metal salt, no non-noble metal salt is added, and the remaining steps and parameters are referred to Example 1. The prepared material is a TiO2-based catalyst loaded with ruthenium particles.

[0162] The detection method was the same as in Example 1, and it was found that the catalytic activity was 24% of that in Example 1, and the sodium carbonate hydrogenation selectivity was greater than 99%.

[0163] Comparative Example 6

[0164] Compared with Example 1, the difference is that only 1.02 mg of rhodium chloride is used as the noble metal salt, no non-noble metal salt is added, and the remaining steps and parameters refer to Example 1. The prepared material is a TiO2-based catalyst loaded with rhodium particles.

[0165] The detection method was the same as in Example 1, and it was found that the catalytic activity was 27% of that in Example 1, and the sodium carbonate hydrogenation selectivity was greater than 99%.

[0166] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A TiO2-supported bimetallic catalyst, characterized in that: It includes a TiO2 carrier and non-noble metal single atoms and noble metal particles loaded on the TiO2 carrier; Taking the mass of the TiO2 carrier as 100%, the loading amounts of the non-precious metal single atoms and the precious metal particles are both 0.1-1 wt%.

2. The TiO2-supported bimetallic catalyst according to claim 1, characterized in that: The non-noble metal in the non-noble metal single atom is selected from any one or more of nickel, cobalt, copper or iron; The precious metal in the precious metal particles is selected from any one or more of platinum, ruthenium, rhodium or palladium.

3. The TiO2-supported bimetallic catalyst according to claim 1 or 2, characterized in that: The noble metal particles are spherical, and the average particle size of the noble metal particles is 1.5-2.5 nm.

4. A method for preparing a TiO2-supported bimetallic catalyst as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: The TiO2 carrier, noble metal salt, non-noble metal salt, alkaline substance and solvent are mixed, dried and calcined to obtain a TiO2-supported bimetallic catalyst.

5. The preparation method according to claim 4, characterized in that: The non-precious metal salt is selected from any one or more of nickel salt, copper salt, cobalt salt or iron salt; The noble metal salt is selected from any one or more of platinum salt, ruthenium salt, rhodium salt or palladium salt; The alkaline substance is selected from aqueous ammonia; The solvent is selected from water; The ratio of the TiO2 carrier, the noble metal salt, the non-noble metal salt, the alkaline substance and the solvent is 100 mg: (0.1~1) mg: (0.1~1) mg: (20~200) μL: (25~50) mL.

6. The preparation method according to claim 4 or 5, characterized in that: The mixing time is 10 to 24 hours, and the mixing is carried out under stirring conditions at a stirring rate of 500 to 1000 r / min; The drying temperature is 80-120°C; The calcination is carried out in a reducing atmosphere, and the reducing atmosphere is selected from a hydrogen-argon mixed gas and / or a hydrogen-nitrogen mixed gas; The calcination temperature is 300-450° C. and the calcination time is 2-6 h.

7. Use of the TiO2-supported bimetallic catalyst according to any one of claims 1 to 3 or the TiO2-supported bimetallic catalyst prepared according to the preparation method according to any one of claims 4 to 6 in a hydrogenation reaction of a mixture of an aqueous carbonate, bicarbonate or hydroxide solution and CO2 gas.

8. A method for using a TiO2-supported bimetallic catalyst, characterized in that: The following steps are involved: The TiO2-loaded bimetallic catalyst according to any one of claims 1 to 3 or the TiO2-loaded bimetallic catalyst prepared by the preparation method according to any one of claims 4 to 6 is mixed with a mixture of an aqueous carbonate, bicarbonate or hydroxide solution and CO2 gas, and then hydrogen is introduced under a protective gas atmosphere to carry out a hydrogenation reaction.

9. The method of use according to claim 8, characterized in that: The carbonate is selected from any one or more of sodium carbonate, potassium carbonate or ammonium carbonate; The bicarbonate is selected from any one or more of sodium bicarbonate, potassium bicarbonate or ammonium bicarbonate; The hydroxide in the aqueous hydroxide solution is selected from any one or more of sodium hydroxide, potassium hydroxide or ammonium hydroxide; The protective gas is argon and / or helium; The hydrogen is pure hydrogen or a mixed gas containing hydrogen.

10. The method of use according to claim 8 or 9, characterized in that: The hydrogenation reaction is carried out under a pressure of 1-5 MPa, a temperature of 100-500°C and a time of 1-5 h.

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