Application of atomically dispersed dual-active-site Pt-Cu / TiO2 catalysts in propane oxidation catalysis

Abstract

The application discloses an application of an atomic dispersion double-active-site Pt-Cu / TiO2 catalyst in propane oxidation catalysis and belongs to the fields of environmental protection catalytic materials and atmospheric pollution treatment. The catalyst takes TiO2 as a carrier, takes Pt and Cu as double-loaded catalytic active components, the loading amount of the active component Cu is 0.1-1wt% of the mass of the TiO2 carrier, the loading amount of Pt is 0.02-0.06wt% of the sum of the mass of Cu and TiO2, and Pt-O-Cu double active sites are formed on the surface of the catalyst. The catalyst has excellent propane catalytic oxidation performance and sulfur resistance.

Description

Technical Field

[0001] This invention relates to the application of a highly active, sulfur-resistant, atomically dispersed dual-active-site Pt-Cu / TiO2 catalyst in propane oxidation catalysis, belonging to the fields of environmentally friendly catalytic materials and air pollution control. Background Technology

[0002] Propane (C3H8), a common fuel, is the main component of liquefied petroleum gas (LPG). Propane is generally produced by the catalytic and thermal cracking of crude oil in oil refineries. Atmospheric propane mainly originates from stationary sources such as refineries and oil fields in the petrochemical industry, as well as mobile sources such as vehicle exhaust emissions. Propane is a short-chain alkane volatile organic compound, and due to its stable molecular structure, it is considered one of the most difficult VOCs to eliminate.

[0003] Catalytic purification is one of the most effective technologies for controlling gaseous pollutants at their source, and catalysts are the core of achieving efficient catalytic purification. However, under actual operating conditions, the temperature of exhaust gases varies greatly and their composition is complex, containing impurities such as SO2 and H2O. This places stringent requirements on the catalyst's activity temperature window, thermal stability, and sulfur resistance. Therefore, designing and developing stable and efficient environmental remediation catalysts is a key challenge for scientists. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a highly active, sulfur-resistant, atomically dispersed dual-active-site Pt-Cu / TiO2 catalyst for propane oxidation catalysis.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The application of an atomically dispersed dual-active-site Pt-Cu / TiO2 catalyst in propane oxidation catalysis, wherein the catalyst uses TiO2 as a support and Pt and Cu as dual-loaded catalytic active components. The loading of Cu active component is 0.1-1 wt% of the mass of TiO2 support, and the loading of Pt is 0.02-0.06 wt% of the sum of the masses of Cu and TiO2. Pt-O-Cu dual active sites are formed on the surface of the catalyst.

[0007] Furthermore, the catalyst is obtained according to the following preparation method:

[0008] Using tetrabutyl titanate as a titanium precursor and poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) as a template agent, TiO2 catalyst support was prepared by sol-gel method.

[0009] Using copper nitrate as a precursor for Cu, Cu was loaded onto the catalyst support TiO2 via an impregnation method to obtain a single-atom Cu / TiO2 precursor; oxygen vacancies were constructed on the surface of the single-atom Cu / TiO2 precursor using NaBH4 to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

[0010] Using chloroplatinic acid as a precursor for Pt, Pt was loaded onto a single-atom Cu / TiO2 catalyst rich in oxygen vacancies via an impregnation method to obtain a diatomic Pt-Cu / TiO2 catalyst.

[0011] Furthermore, the catalyst support TiO2 is prepared via the sol-gel method, including:

[0012] A transparent solution is formed by stirring poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol), tetrahydrofuran, acetic acid and concentrated hydrochloric acid. Tetrabutyl titanate is then quickly added and stirring is continued until a golden yellow solution is formed.

[0013] The golden yellow solution was kept at a warm temperature and dried to obtain a hydrogel. The hydrogel was dried to obtain a white precipitate. The white precipitate was calcined in air to obtain a TiO2 support.

[0014] The ratio of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol), tetrahydrofuran, acetic acid, concentrated hydrochloric acid and tetrabutyl titanate is 1.6g-4.8g: 30-90mL: 2.4-7.2mL: 1.5-4.5mL: 0.01-0.03mol.

[0015] The temperature for heat preservation and drying of the golden yellow solution is 45℃-65℃, and the drying time is 24-72h.

[0016] The drying temperature for the hydrogel is 80-100℃, and the drying time is 15-25 hours.

[0017] The white precipitate is calcined in air at a temperature of 400-500℃ for 3-5 hours, with a heating rate of 1-5℃ / min.

[0018] Furthermore, in the step of preparing the single-atom Cu / TiO2 precursor, the amount of copper nitrate added is such that the copper loading is 0.1~1 wt% of the TiO2 support mass.

[0019] Furthermore, in the step of constructing oxygen vacancies on the surface of a single-atom Cu / TiO2 precursor using NaBH4, the mass ratio of NaBH4 to the single-atom Cu / TiO2 precursor is 0.18915-0.56745:1.

[0020] Furthermore, the preparation steps of the oxygen-vacancy-rich single-atom Cu / TiO2 catalyst specifically include:

[0021] TiO2 was uniformly dispersed in deionized water to prepare a TiO2 suspension;

[0022] Copper nitrate was dissolved in deionized water and added to a TiO2 suspension. The mixture was stirred until homogeneous to obtain a single-atom Cu / TiO2 precursor.

[0023] A single-atom Cu / TiO2 precursor was impregnated in a NaBH4 solution and stirred thoroughly to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

[0024] More specifically, copper nitrate aqueous solution is added to TiO2 suspension and stirred for 1-3 hours; then dried in an oven at 70-90℃ for 8-24 hours to obtain single-atom Cu / TiO2 precursor;

[0025] The single-atom Cu / TiO2 precursor was impregnated in NaBH4 solution and stirred thoroughly for 15-35 min. It was then washed 3-5 times with deionized water and anhydrous ethanol and dried in an oven at 70-90℃ for 8-24 h to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

[0026] Furthermore, in the step of preparing the diatomic Pt-Cu / TiO2 catalyst by impregnation, the amount of chloroplatinic acid added is 0.02-0.06 wt% of the mass of the oxygen-vacancy-rich single-atom Cu / TiO2 catalyst, so that the Pt loading is 0.02-0.06 wt%.

[0027] Furthermore, the preparation steps of the diatomic Pt-Cu / TiO2 catalyst specifically include:

[0028] A single-atom Cu / TiO2 catalyst rich in oxygen vacancies was dispersed in deionized water to obtain solution A;

[0029] Dissolve chloroplatinic acid in deionized water to obtain solution B;

[0030] Solution B was added dropwise to solution A, and the pH of the solution was adjusted to 8-10 using ammonia. After magnetic stirring, the solution was dried and calcined to obtain a diatomic Pt-Cu / TiO2 catalyst.

[0031] Among them, after adjusting the pH of the solution to 8-10 with ammonia water, the solution is magnetically stirred for 1-3 hours;

[0032] After stirring, place in an oven at 70-90℃ and dry for 8-24 hours;

[0033] After drying, the product is placed in a muffle furnace and calcined at 400-500℃ for 3-5 hours to obtain the Pt-Cu / TiO2 catalyst.

[0034] Furthermore, the Pt-Cu / TiO2 catalyst exhibits resistance to sulfur poisoning in propane oxidation catalysis.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The catalyst prepared in this invention can efficiently catalyze the oxidation of gaseous pollutants such as propane. Compared with existing technologies, this catalyst system first synthesizes TiO2 via a solution gelation method, then loads Cu onto TiO2, ensuring uniform dispersion of Cu species and their occupation of Ti vacancies on the TiO2 crystal surface. Before loading atomically dispersed Pt, surface oxygen vacancies are constructed on the Cu / TiO2 sample surface through NaBH4 reduction. The Cu occupying Ti vacancies causes TiO2 crystal distortion, and the Cu-O bond between Cu and adjacent surface lattice oxygen is unstable. After NaBH4 reduction, the Cu-O bond breaks, forming oxygen vacancies. The oxygen vacancies constructed near Cu sites can serve as anchoring sites for Pt, and the oxygen vacancy-induced electron donor enhancement strategy improves the stability of atomically dispersed Pt.

[0037] By adjusting the pH of the solution with ammonia, the electronegativity of the Cu / TiO2 surface is controlled, thereby anchoring the atomically dispersed Cu-Pt dual active sites. The hybrid structure between the single-atom Cu occupying Ti vacancies on the Cu / TiO2 surface and the TiO2 support, as well as the charge transfer effect, gives the single-atom Cu sites a strong •OH affinity. The bonding between the abundant negatively charged •OH in the solution and the Cu sites maximizes the binding of ionic Pt. n+ The proximity of the catalyst to Cu promotes the formation of Pt-O-Cu dual sites, enhancing its propane catalytic oxidation activity and sulfur resistance. Furthermore, this catalyst is environmentally friendly, has a simple preparation process, low cost, and high cost-effectiveness. It also possesses high mechanical strength, effectively reducing the operating costs of air pollution control. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the structure of the catalyst prepared in Example 1 of the present invention;

[0039] Figure 2 This is a comparison of the catalytic activity of Pt-Cu / TiO2 prepared in Example 1 of this invention for propane oxidation as a function of temperature;

[0040] Figure 3 This is a catalytic stability test diagram of Pt-Cu / TiO2 prepared in Example 1 of the present invention;

[0041] Figure 4 This is a sulfur resistance test diagram of Pt-Cu / TiO2 prepared in Example 1 of the present invention;

[0042] Figure 5This is a comparison graph showing the change in the catalytic activity of Pt-Cu / TiO2 for propane oxidation as a function of temperature in Example 2 of the present invention.

[0043] Figure 6 This is a catalytic stability test diagram of Pt-Cu / TiO2 prepared in Example 2 of the present invention;

[0044] Figure 7 This is a sulfur resistance test diagram of Pt-Cu / TiO2 prepared in Example 2 of the present invention;

[0045] Figure 8 This is a comparison of the catalytic activity of Pt-Cu / TiO2 prepared in Example 3 of the present invention for propane oxidation as a function of temperature;

[0046] Figure 9 This is a catalytic stability test diagram of Pt-Cu / TiO2 prepared in Example 3 of the present invention;

[0047] Figure 10 This is a sulfur resistance test diagram of Pt-Cu / TiO2 prepared in Example 3 of the present invention;

[0048] Figure 11 This is a comparison graph showing the change in the catalytic activity of Pt-Cu / TiO2 for propane oxidation as a function of temperature in Comparative Example 1 of this invention;

[0049] Figure 12 This is a sulfur resistance test diagram of Pt-Cu / TiO2 in Comparative Example 1 of the present invention;

[0050] Figure 13 This is a comparison graph showing the change in the catalytic activity of Pt-Cu / TiO2 for propane oxidation as a function of temperature in Comparative Example 2 of this invention;

[0051] Figure 14 This is a sulfur resistance test diagram of Pt-Cu / TiO2 in Comparative Example 2 of the present invention;

[0052] Figure 15 This is a comparison graph showing the change in the catalytic activity of Cu / TiO2 for propane oxidation as a function of temperature in Comparative Example 3 of this invention;

[0053] Figure 16 This is a sulfur resistance test diagram of Cu / TiO2 in Comparative Example 3 of the present invention;

[0054] Figure 17 This is a comparison graph showing the change in the catalytic activity of Pt / TiO2 for propane oxidation as a function of temperature in Comparative Example 4 of this invention;

[0055] Figure 18 This is a sulfur resistance test diagram of Pt / TiO2 in Comparative Example 4 of the present invention. Detailed Implementation

[0056] The present invention will be further described below with reference to specific embodiments. These embodiments are only used to more clearly illustrate the technical solutions of the present invention and should not be construed as limiting the scope of protection of the present invention.

[0057] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. Example 1

[0058] (1) Preparation of catalyst support TiO2

[0059] TiO2 was prepared by the sol-gel method: 1.6 g of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (P123) and 30 mL of tetrahydrofuran were added to a beaker, followed by the addition of 2.4 mL of acetic acid and 1.5 mL of concentrated hydrochloric acid. After the mixture was stirred to form a transparent solution, 3.4 g of tetrabutyl titanate (0.01 mol) was quickly added, and stirring continued until a golden-yellow solution was formed.

[0060] A beaker was placed in a forced-air drying oven at 45°C for 24 hours to obtain a slightly yellowish white TiO2 hydrogel. The hydrogel was dried at 80°C for 15 hours to obtain a white TiO2 precipitate. Then, the obtained white TiO2 precipitate was calcined in air at 400°C for 3 hours (heating rate: 1°C / min) to obtain TiO2.

[0061] (2) Preparation of single-atom Cu / TiO2:

[0062] A single-atom Cu / TiO2 catalyst with a Cu loading of 0.1 wt% (mass ratio of copper to TiO2 of 0.1:100) was prepared by impregnation method.

[0063] Take 1g of TiO2 obtained in step (1) and uniformly disperse it in 30mL of deionized water to obtain a TiO2 suspension. Weigh 0.003775g of copper nitrate trihydrate and dissolve it in 10mL of deionized water. Add the copper nitrate aqueous solution to the TiO2 suspension and stir for 1h. Place it in an oven at 70℃ and dry for 8h.

[0064] Weigh 1 g of the obtained product and 0.18915 g of NaBH4 and dissolve them in 50 mL of deionized water, stirring thoroughly for 15 min. After removal, wash three times with deionized water and anhydrous ethanol, and finally dry in a 70 °C oven for 8 h to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

[0065] (3) Preparation of diatomic Pt-Cu / TiO2 catalyst

[0066] 1 g of Cu / TiO2 catalyst was dispersed in 30 mL of deionized water and labeled as solution A; 0.000531 g of chloroplatinic acid (Pt to Cu / TiO2 mass ratio 0.02:100) was weighed and dissolved in 10 mL of deionized water and labeled as solution B.

[0067] Solution B was added dropwise to solution A, and the pH of the solution was adjusted to 8 using ammonia. The mixture was then magnetically stirred for 1 hour. After drying in an oven at 70°C for 8 hours, the solution was calcined in a muffle furnace at 400°C for 3 hours to obtain the Pt-Cu / TiO2 catalyst.

[0068] The structure of the catalyst prepared in Example 1 is as follows: Figure 1 As shown.

[0069] (4) Catalytic activity test

[0070] The catalytic oxidation of propane (to carbon dioxide and water) was carried out in a fixed-bed reactor operating at atmospheric pressure. A catalyst (100 mg; 60 mesh) was inserted into the center of a 500 mm long quartz tube with an inner diameter of 10 mm, and quartz wool was inserted into both ends of the catalyst. The feed gas contained 500 ppm propane, and the equilibrium gas mixture was 40 vol% O2 and 10 vol% C3H8 and N2 (weight hourly space velocity (WHSV = 60000 mL⋅h)). -1 ⋅g −1 A gas chromatograph equipped with a flame ionization detector (FID) is used for online analysis of propane and reaction product concentrations.

[0071] Figure 2 This is a comparison graph showing the change in catalytic activity of Pt-Cu / TiO2 for propane oxidation with temperature in Example 1 of the present invention. It can be seen that the propane removal efficiency reaches 100% at 270℃.

[0072] Figure 3 This is a catalytic stability test chart of the Pt-Cu / TiO2 prepared in Example 1 of this invention. It can be seen that the catalyst, after 48 hours of use (T...), exhibits good catalytic stability. 90 The stability remains at around 90%.

[0073] (5) Sulfur resistance test

[0074] Sulfur resistance testing was conducted in a fixed-bed reactor operating at atmospheric pressure. A catalyst (100 mg; 60 mesh) was inserted into the center of a 500 mm long quartz tube with an inner diameter of 10 mm, and quartz wool was inserted into both ends of the catalyst. The feed gas contained 500 ppm propane and 500 ppm SO2; the equilibrium gas mixture was 30 vol% O2, 10 vol% SO2, 10 vol% C3H8, and N2 (weight hourly space velocity (WHSV = 60000 mL⋅h)). -1⋅g −1 A gas chromatograph equipped with a flame ionization detector (FID) is used for online analysis of propane and reaction product concentrations.

[0075] Figure 4 The sulfur resistance test diagram of Pt-Cu / TiO2 prepared in Example 1 of this invention shows that when SO2 was introduced during the propane catalytic oxidation test, the propane conversion rate did not change significantly. Example 2

[0076] (1) Preparation of catalyst support TiO2

[0077] TiO2 was prepared by the sol-gel method: 3g of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) and 60mL of tetrahydrofuran were added to a beaker, followed by the addition of 4.8mL of acetic acid and 3mL of concentrated hydrochloric acid. After stirring the mixture to form a transparent solution, 6.8g of tetrabutyl titanate (0.02mol) was quickly added, and stirring continued until a golden-yellow solution was formed.

[0078] A beaker was placed in a forced-air drying oven at 55℃ for 48 hours to obtain a slightly yellowish white TiO2 hydrogel. The hydrogel was dried at 90℃ for 20 hours to obtain a white TiO2 precipitate. Then, the obtained white TiO2 precipitate was calcined in air at 450℃ for 3 hours (heating rate: 3℃ / min) to obtain TiO2.

[0079] (2) Preparation of single-atom Cu / TiO2:

[0080] A single-atom Cu / TiO2 catalyst with a Cu loading of 0.5 wt% (mass ratio of copper to TiO2 of 0.5:100) was prepared by impregnation method.

[0081] Take 1g of TiO2 obtained in step 1 and uniformly disperse it in 30mL of deionized water to prepare a TiO2 suspension. Weigh 0.018875g of copper nitrate trihydrate and dissolve it in 10mL of deionized water. Add the copper nitrate aqueous solution to the TiO2 suspension and stir for 2 hours. Place it in an oven at 80℃ and dry for 16 hours.

[0082] Take 1g of the product obtained above and dissolve 0.3873g of NaBH4 in 50mL of deionized water and stir for 25min. After taking it out, wash it 4 times with deionized water and anhydrous ethanol, and finally dry it in an oven at 80℃ for 16h to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

[0083] (3) Preparation of diatomic Pt-Cu / TiO2 catalyst

[0084] Take 1g of Cu / TiO2 catalyst and disperse it in 30mL of deionized water, and record it as solution A; weigh 0.00106g of chloroplatinic acid (mass ratio of Pt to Cu / TiO2 0.04:100), dissolve it in 10mL of deionized water, and record it as solution B;

[0085] Solution B was added dropwise to solution A, and the pH of the solution was adjusted to 9 using ammonia. The mixture was then magnetically stirred for 2 hours. After drying in an oven at 80°C for 15 hours, the solution was calcined in a muffle furnace at 450°C for 4 hours to obtain the Pt-Cu / TiO2 catalyst.

[0086] (4) Catalytic activity test

[0087] The propane oxidation catalytic reaction was carried out in a fixed-bed reactor operating at atmospheric pressure. A catalyst (100 mg; 70 mesh) was inserted into the center of a 500 mm long quartz tube with an inner diameter of 10 mm, and quartz wool was inserted into both ends of the catalyst. The feed gas contained 500 ppm propane, and the equilibrium gas mixture was 40 vol% O2 and 10 vol% C3H8 and N2. The weight hourly space velocity (WHSV) was 60000 mL⋅h⁻¹. -1 ⋅g −1 A gas chromatograph equipped with a flame ionization detector (FID) is used for online analysis of propane and reaction product concentrations.

[0088] Figure 5 This is a comparison graph showing the change in catalytic activity of Pt-Cu / TiO2 for propane oxidation with temperature in Example 2 of the present invention. It can be seen that the propane removal efficiency reaches 100% at 270℃.

[0089] Figure 6 This is a catalytic stability test chart of the Pt-Cu / TiO2 prepared in Example 2 of this invention. It can be seen that the catalyst, after 48 hours of use, exhibits good catalytic stability. 90 The stability remains at 90%.

[0090] (5) Sulfur resistance test

[0091] Sulfur resistance testing was conducted in a fixed-bed reactor operating at atmospheric pressure. A catalyst (100 mg; 70 mesh) was inserted into the center of a 500 mm long quartz tube with an inner diameter of 10 mm, and quartz wool was inserted into both ends of the catalyst. The feed gas contained 500 ppm propane and 500 ppm SO2; the equilibrium gas mixture was 30 vol% O2, 10 vol% SO2, 10 vol% C3H8, and N2 (weight hourly space velocity (WHSV = 60000 mL⋅h)). -1 ⋅g −1 A gas chromatograph equipped with a flame ionization detector (FID) is used for online analysis of propane and reaction product concentrations.

[0092] Figure 7 The image shows the sulfur resistance test results of Pt-Cu / TiO2 prepared in Example 2 of this invention. When SO2 was introduced into the catalyst during the propane catalytic oxidation test, the propane conversion rate did not change significantly. Example 3

[0093] (1) Preparation of catalyst support TiO2

[0094] TiO2 was prepared by the sol-gel method: 4.8 g of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) and 90 mL of tetrahydrofuran were added to a beaker, followed by the addition of 7.2 mL of acetic acid and 4.5 mL of concentrated hydrochloric acid. After the mixture was stirred to form a transparent solution, 10.2 g of tetrabutyl titanate (0.03 mol) was quickly added, and stirring continued until a golden-yellow solution was formed.

[0095] The beaker was placed in a forced-air drying oven at 65℃ for 72 hours to obtain a slightly yellowish TiO2 hydrogel. The hydrogel was dried at 100℃ for 25 hours to obtain a white TiO2 precipitate. Then, the obtained white TiO2 precipitate was calcined in air at 500℃ for 5 hours (heating rate: 5℃ / min) to obtain TiO2.

[0096] (2) Preparation of single-atom Cu / TiO2:

[0097] A single-atom Cu / TiO2 catalyst with a Cu loading of 1 wt% (mass ratio of copper to TiO2 is 1:100) was prepared by impregnation method.

[0098] Take 1g of TiO2 obtained in step (1) and uniformly disperse it in 30mL of deionized water to obtain a TiO2 suspension. Weigh 0.03775g of copper nitrate trihydrate and dissolve it in 10mL of deionized water. Add the copper nitrate aqueous solution to the TiO2 suspension and stir for 3h. Place it in an oven at 90℃ and dry for 24h.

[0099] 1 g of the obtained product and 0.56745 g of NaBH4 were dissolved in 50 mL of deionized water and stirred thoroughly for 35 min. After removal, the product was washed 5 times with deionized water and anhydrous ethanol, and finally dried in an oven at 90 °C for 24 h to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

[0100] (3) Preparation of diatomic Pt-Cu / TiO2 catalyst

[0101] Take 1g of Cu / TiO2 catalyst and disperse it in 30mL of deionized water, and record it as solution A; weigh 0.00159g of chloroplatinic acid (mass ratio of Pt to Cu / TiO2 0.06:100), dissolve it in 10mL of deionized water, and record it as solution B;

[0102] Solution B was added dropwise to solution A, and the pH of the solution was adjusted to 10 using ammonia. The mixture was then magnetically stirred for 3 hours. After drying in an oven at 90°C for 24 hours, the solution was calcined in a muffle furnace at 500°C for 5 hours to obtain the Pt-Cu / TiO2 catalyst.

[0103] (4) Catalytic activity test

[0104] The propane oxidation catalytic reaction was carried out in a fixed-bed reactor operating at atmospheric pressure. A catalyst (100 mg; 80 mesh) was inserted into the center of a 500 mm long quartz tube with an inner diameter of 10 mm, and quartz wool was inserted into both ends of the catalyst. The feed gas contained 500 ppm propane, and the equilibrium gas mixture was 40 vol% O2 and 10 vol% C3H8 and N2 (weight hourly space velocity (WHSV = 60000 mL⋅h)). -1 ⋅g −1 A gas chromatograph equipped with a flame ionization detector (FID) is used for online analysis of propane and reaction product concentrations.

[0105] Figure 8 This is a comparison graph showing the change in catalytic activity of Pt-Cu / TiO2 for propane oxidation with temperature in Example 3 of the present invention. It can be seen that the Pu-Cu / TiO2 catalyst achieves 100% propane removal efficiency at 270℃.

[0106] Figure 9 This is a catalytic stability test chart of the Pt-Cu / TiO2 prepared in Example 3 of this invention. It can be seen that the catalyst, after 48 hours of use (T...),... 90 Stability remains at 90%.

[0107] (6) Sulfur resistance test

[0108] Sulfur resistance testing was conducted in a fixed-bed reactor operating at atmospheric pressure. A catalyst (100 mg; 80 mesh) was inserted into the center of a 500 mm long quartz tube with an inner diameter of 10 mm, and quartz wool was inserted into both ends of the catalyst. The feed gas contained 500 ppm propane and 500 ppm SO2; the equilibrium gas mixture was 30 vol% O2, 10 vol% SO2, 10 vol% C3H8, and N2 (weight hourly space velocity (WHSV = 60000 mL⋅h)). -1 ⋅g −1 A gas chromatograph equipped with a flame ionization detector (FID) is used for online analysis of propane and reaction product concentrations.

[0109] Figure 10 This is a sulfur resistance test diagram of the Pt-Cu / TiO2 prepared in Example 3 of this invention. When SO2 was introduced into the catalyst during the propane catalytic oxidation test, the propane conversion rate showed no significant change.

[0110] Comparative Example 1:

[0111] The catalyst preparation steps were the same as in Example 1. However, unlike Example 1, NaBH4 reduction was not used in the Cu / TiO2 preparation process.

[0112] Figure 11 This is a comparison graph showing the change in catalytic activity of Pt-Cu / TiO2 for propane oxidation as a function of temperature in Comparative Example 1 of this invention. The test conditions and methods are the same as in Example 1. It can be seen that the propane conversion rate reaches 90% at T=261℃.

[0113] Figure 12 This is a sulfur resistance test diagram of Pt-Cu / TiO2 in Comparative Example 1 of this invention. SO2 was introduced into the catalyst during the propane catalytic oxidation test, and the test conditions and methods were the same as in Example 1. It can be seen that the propane conversion rate decreased significantly.

[0114] Comparative Example 2:

[0115] The catalyst was prepared in the same way as in Example 1. However, unlike Example 1, ammonia was not used to adjust the pH when impregnating Pt on Cu / TiO2.

[0116] Figure 13 This is a comparison graph showing the change in catalytic activity of Pt-Cu / TiO2 for propane oxidation as a function of temperature in Comparative Example 2 of this invention. The test conditions and methods were the same as in Example 1. At T=269℃, the propane conversion rate reached 90%.

[0117] Figure 14 This is a sulfur resistance test diagram of Pt-Cu / TiO2 in Comparative Example 2 of this invention. SO2 was introduced into the catalyst during the propane catalytic oxidation test, and the test conditions and methods were the same as in Example 1. It can be seen that the propane conversion rate decreased significantly.

[0118] Comparative Example 3:

[0119] The preparation of single-atom Cu / TiO2 was consistent with the preparation method of Cu / TiO2 in Example 1. A single-atom Cu / TiO2 catalyst with a Cu loading of 0.1 wt% was prepared by impregnation.

[0120] Take 1g of TiO2 obtained in Example 1 and uniformly disperse it in deionized water to prepare a TiO2 suspension. Weigh 0.003775g of copper nitrate trihydrate and dissolve it in 10mL of deionized water. Add the copper nitrate aqueous solution to the TiO2 suspension and stir for 1h. Place it in an oven at 70℃ and dry for 8h.

[0121] Weigh 1 g of the obtained product and 0.18915 g of NaBH4 and dissolve them in 50 mL of deionized water. Stir thoroughly for 15 min. Wash three times with deionized water and anhydrous ethanol, and finally dry in an oven at 70 °C for 8 h to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

[0122] Figure 15 This is a comparison graph showing the change in catalytic activity of Cu / TiO2 for propane oxidation as a function of temperature in Comparative Example 3 of this invention. The test conditions and methods were the same as in Example 1. At T=310℃, the propane conversion rate reached 90%.

[0123] Figure 16 This is a sulfur resistance test diagram of Cu / TiO2 in Comparative Example 3 of the present invention. SO2 was introduced into the catalyst during the propane catalytic oxidation test, and the test conditions and methods were the same as in Example 1. It can be seen that the propane conversion rate decreased significantly.

[0124] Comparative Example 4:

[0125] The preparation of single-atom Pt / TiO2, the preparation method of the support, and the loading amount of Pt are the same as in Example 1.

[0126] A catalyst with 0.02 wt% Pt loading and single-atom Pt / TiO2 was prepared by impregnation method:

[0127] 1 g of TiO2 prepared in Example 1 was uniformly dispersed in 30 mL of deionized water to obtain a TiO2 suspension, denoted as solution A. 0.000531 g of chloroplatinic acid was weighed and dissolved in 10 mL of deionized water (Pt to TiO2 mass ratio of 0.02:100), denoted as solution B. Solution B was added dropwise to solution A, and the pH of the solution was adjusted to 8 using ammonia. The solution was magnetically stirred for 1 h and then dried in an oven at 70 °C for 8 h. Finally, the solution was calcined in a muffle furnace at 400 °C for 3 h to obtain a single-atom Pt / TiO2 catalyst.

[0128] Figure 17 This is a comparison graph showing the change in catalytic activity of Pt / TiO2 for propane oxidation as a function of temperature in Comparative Example 4 of this invention. The test conditions and methods were the same as in Example 1. At T=290℃, the propane conversion rate reached 90%.

[0129] Figure 18 This is a sulfur resistance test diagram of Pt / TiO2 in Comparative Example 4 of this invention. SO2 was introduced into the catalyst during the propane catalytic oxidation test, and the test conditions and methods were the same as in Example 1. It can be seen that the propane conversion rate decreased significantly.

[0130] Actual results show that, compared with Comparative Examples 1-4, the Pt-Cu / TiO2 catalysts prepared in Examples 1, 2 and 3 exhibited excellent propane catalytic oxidation performance and sulfur resistance.

[0131] The present invention has been disclosed above with reference to preferred embodiments, but it is not intended to limit the present invention. All technical solutions obtained by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the present invention.

Claims

1. The application of an atomically dispersed dual-active-site Pt-Cu / TiO2 catalyst in propane oxidation catalysis, characterized in that, The catalyst uses TiO2 as a support and Pt and Cu as dual-loaded catalytic active components. The Cu loading is 0.1-1 wt% of the mass of the TiO2 support, and the Pt loading is 0.02-0.06 wt% of the sum of the masses of Cu and TiO2. Pt-O-Cu dual active sites are formed on the surface of the catalyst. The catalyst is obtained according to the following preparation method: Using tetrabutyl titanate as a titanium precursor and poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) as a template agent, TiO2 catalyst support was prepared by sol-gel method. Using copper nitrate as a precursor for Cu, Cu was loaded onto the catalyst support TiO2 via an impregnation method to obtain a single-atom Cu / TiO2 precursor; oxygen vacancies were constructed on the surface of the single-atom Cu / TiO2 precursor using NaBH4 to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies. Using chloroplatinic acid as a precursor for Pt, Pt was loaded onto a single-atom Cu / TiO2 catalyst rich in oxygen vacancies via an impregnation method to obtain a diatomic Pt-Cu / TiO2 catalyst. The preparation steps of the diatomic Pt-Cu / TiO2 catalyst specifically include: A single-atom Cu / TiO2 catalyst rich in oxygen vacancies was dispersed in deionized water to obtain solution A; Dissolve chloroplatinic acid in deionized water to obtain solution B; Solution B was added dropwise to solution A, and the pH of the solution was adjusted to 8-10 using ammonia. After magnetic stirring, the solution was dried and calcined to obtain a diatomic Pt-Cu / TiO2 catalyst.

2. The application according to claim 1, characterized in that, The preparation of TiO2 catalyst support by sol-gel method includes: A transparent solution is formed by stirring poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol), tetrahydrofuran, acetic acid and concentrated hydrochloric acid. Tetrabutyl titanate is then quickly added and stirring is continued until a golden yellow solution is formed. The golden yellow solution was kept at a warm temperature and dried to obtain a hydrogel. The hydrogel was dried to obtain a white precipitate. The white precipitate was calcined in air to obtain a TiO2 support.

3. The application according to claim 1, characterized in that, The ratio of poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol), tetrahydrofuran, acetic acid, concentrated hydrochloric acid and tetrabutyl titanate is 1.6g-4.8g : 30-90mL : 2.4-7.2mL : 1.5-4.5mL : 0.01-0.03mol.

4. The application according to claim 1, characterized in that, In the step of preparing the single-atom Cu / TiO2 precursor, the amount of copper nitrate added is such that the copper loading is 0.1~1 wt% of the TiO2 support mass.

5. The application according to claim 1, characterized in that, In the step of constructing oxygen vacancies on the surface of a single-atom Cu / TiO2 precursor using NaBH4, the mass ratio of NaBH4 to the single-atom Cu / TiO2 precursor is 0.18915-0.56745:

1.

6. The application according to claim 1, characterized in that, In the step of preparing the diatomic Pt-Cu / TiO2 catalyst by impregnation, the amount of chloroplatinic acid added is 0.02-0.06 wt% of the mass of the oxygen-vacancy-rich single-atom Cu / TiO2 catalyst, so that the Pt loading is 0.02-0.06 wt%.

7. The application according to claim 1, characterized in that, The preparation steps of oxygen-vacancy-rich single-atom Cu / TiO2 catalysts specifically include: TiO2 was uniformly dispersed in deionized water to prepare a TiO2 suspension; Copper nitrate was dissolved in deionized water and added to a TiO2 suspension. The mixture was stirred until homogeneous to obtain a single-atom Cu / TiO2 precursor. A single-atom Cu / TiO2 precursor was impregnated in a NaBH4 solution and stirred thoroughly to obtain a single-atom Cu / TiO2 catalyst rich in oxygen vacancies.

8. The application according to claim 1, characterized in that, The catalyst exhibits resistance to sulfur poisoning in propane oxidation catalysis.

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