Platinum-doped defective titanium dioxide catalyst and preparation method and application thereof

Abstract

The present invention discloses a platinum-doped defective titanium dioxide catalyst, a preparation method thereof and an application thereof. The preparation method of the platinum-doped defective titanium dioxide catalyst comprises: mixing defective titanium dioxide and water evenly to obtain an aqueous solution of defective titanium dioxide; dropping an aqueous solution of chloroplatinic acid into the aqueous solution of defective titanium dioxide under stirring conditions; centrifuging; drying the precipitate obtained by centrifugation; and then calcining at 300-400 °C for 3-5 h to obtain the platinum-doped defective titanium dioxide catalyst. The platinum-doped defective titanium dioxide catalyst of the present invention has more titanium vacancies and more adsorption sites, which is beneficial to the adsorption and activation of H2 and NO molecules, and still maintains a high removal efficiency of nitrogen oxides at low temperatures.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium dioxide catalysts, and specifically relates to a platinum-doped defective titanium dioxide catalyst and a preparation method and application thereof. Background Art

[0002] As people's understanding of sustainable development strategies continues to deepen, air pollution and its prevention and control measures have attracted widespread attention from countries around the world. x ) is mainly derived from emissions from fixed and mobile sources. As one of the main pollutants in the atmosphere, it causes acid rain, photochemical smog, greenhouse gases and PM 2.5 It will damage the ecological environment and seriously affect human health. For this reason, countries around the world have strictly regulated NO x Emission standards in the atmosphere, so how to effectively remove NO in the atmosphere x , has always been a problem that scientists have been committed to solving and have invested a lot of research.

[0003] Currently eliminating NO x There are many methods to reduce NO, and catalytic reduction technology is one of the most widely used methods. This technology refers to the reaction of NO with a reducing agent to convert it into harmless N in the presence of a catalyst. 2 process, achieving NO x The common reducing agents are NH 3 , HC, CO and H 2 etc. Due to NH 3 As a reducing agent, it is highly corrosive and can damage pipelines and equipment, and excessive hydrocarbons and CO also pose a problem of secondary pollution to the environment. Therefore, H2, which is easy to obtain and non-toxic, is used. 2 Replace NH 3 and hydrocarbons for NO x The reduction of H has attracted worldwide attention. Studies have shown that the NO bond in the NO molecule is extremely stable and not easy to break directly, so more research focuses on H 2 The mechanism of the catalytic reaction of NO reduction was investigated. The results showed that the catalytic reaction was catalyzed by H 2 The cleavage of the HH bond begins, and the active H species formed by the cleavage of the HH bond promote the efficient reduction of NO molecules to N 2 In addition, most of the current catalysts are affected by the complex exhaust gas components under actual working conditions. Improving the resistance of the catalyst to other toxic gases is the key to solving the problem of NO in the air. x Therefore, a heterogeneous catalyst is designed to promote H 2 The adsorption and activation of NO on the catalyst surface are particularly important to improve the catalytic performance under complex working conditions. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention aims to provide a platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ).

[0005] Another object of the present invention is to provide a platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ), wherein tetrabutyl titanate, glycerol and anhydrous ethanol are first added by a solvent thermal method, and then calcined. During the removal of organic carbon components, Ti atoms on the catalyst surface are also partially taken away, thereby preparing a nano-sheet defective titanium dioxide (d-TiO 2 ), and then chloroplatinic acid was used as the platinum source to achieve the reaction with defective titanium dioxide (d-TiO 2 ) to obtain a platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ).

[0006] Another object of the present invention is to provide the above-mentioned platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) in the removal of nitrogen oxides.

[0007] The purpose of the present invention is achieved through the following technical solutions.

[0008] A platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ), platinum is uniformly dispersed on the surface of defective titanium dioxide, wherein the defective titanium dioxide has Ti vacancies.

[0009] In the above technical solution, the defective titanium dioxide is a flaky nanostructure.

[0010] A platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) comprises: uniformly mixing defective titanium dioxide and water to obtain an aqueous solution of defective titanium dioxide, dripping an aqueous solution of chloroplatinic acid into the aqueous solution of defective titanium dioxide under stirring conditions, centrifuging, drying the precipitate obtained by centrifugation, and then calcining at 300-400° C. for 3-5 hours to obtain a platinum-doped defective titanium dioxide catalyst.

[0011] In the above technical solution, the ratio of defective titanium dioxide in the defective titanium dioxide aqueous solution to platinum in the chloroplatinic acid aqueous solution is 100:(0.1-1.0) in terms of mass fractions.

[0012] In the above technical solution, the concentration of defective titanium dioxide in the defective titanium dioxide aqueous solution is 4 to 10 mg / mL, and the concentration of platinum in the chloroplatinic acid aqueous solution is 1.3 to 1.5 mg / mL.

[0013] In the above technical solution, the method for uniformly mixing defective titanium dioxide and water is: mixing defective titanium dioxide and water, first ultrasonicating for 0.5 to 1.5 hours, and then stirring for 0.5 to 1.5 hours.

[0014] In the above technical solution, the drying temperature is 60 to 80° C., and the drying time is 20 to 40 hours.

[0015] In the above technical solution, the temperature is increased from room temperature to 1-3℃min. -1 The temperature is raised to 300-400° C. at a heating rate and then kept at this temperature for 3-5 hours.

[0016] In the above technical solution, the defective titanium dioxide (d-TiO 2 ) is:

[0017] 1) dissolving glycerol in anhydrous ethanol, and adding tetrabutyl titanate dropwise under stirring to obtain solution A, wherein the ratio of glycerol, anhydrous ethanol and tetrabutyl titanate is (9-11):30:1 by volume;

[0018] 2) The solution A is kept at 170-190°C for 20-30h, cooled naturally to room temperature (20-25°C), centrifuged, the precipitate obtained by centrifugation is washed, dried, and calcined at 450-550°C for 3-5h to obtain defective titanium dioxide (d-TiO 2 ).

[0019] In the step 2), the washing is carried out successively with distilled water and anhydrous ethanol.

[0020] In the step 2), the drying temperature is 60 to 80° C., and the drying time is 20 to 40 hours.

[0021] In the step 2), the temperature is 1 to 3 ° C min -1 The temperature is raised to 450-550°C at a heating rate and then calcined at 450-550°C for 3-5h.

[0022] A platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) in the removal of nitrogen oxides.

[0023] In the above technical solution, the defective titanium dioxide catalyst doped with platinum (Pt / d-TiO 2 ) is used to catalyze hydrogen and nitrogen oxides to produce water.

[0024] The technical solution of the present invention has the following beneficial effects:

[0025] 1. Compared with the conventional platinum-doped titanium dioxide catalyst, the defective platinum-doped titanium dioxide catalyst (Pt / d-TiO 2 ) has more titanium vacancies and more adsorption sites, which is beneficial to H 2 and adsorption and activation of NO molecules.

[0026] 2. The platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) can still maintain a high nitrogen oxide removal efficiency at low temperatures (100-200°C).

[0027] 3. The platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) has stability and the ability to resist the influence of impurity gas components under complex working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The defective titanium dioxide catalyst (Pt / d-TiO 2 ), the defective titanium dioxide (d-TiO 2 ) and the platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2 ) conversion rate of nitrogen oxides at 50-200°C;

[0029] Figure 2 The defective titanium dioxide catalyst (Pt / d-TiO 2 )’s EPR spectrum;

[0030] Figure 3 XRD, where (a) is the defective titanium dioxide (d-TiO 2 ), (b) is the XRD of the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 )’s XRD;

[0031] Figure 4 (a) is the defective titanium dioxide (d-TiO 2 ), (b) and (c) are HRTEM images of the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 )’s HRTEM and HAADF-STEM images;

[0032] Figure 5The defective titanium dioxide catalyst (Pt / d-TiO 2 )’s EDS diagram;

[0033] Figure 6 The defective titanium dioxide catalyst (Pt / d-TiO 2 ), the defective titanium dioxide (d-TiO 2 ) and the platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2 ) thermal stability at 125°C;

[0034] Figure 7 The defective titanium dioxide catalyst (Pt / d-TiO 2 ) and the platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2 ) conversion of nitrogen oxides after introduction of oxygen, water vapor and carbon monoxide atmosphere at 125°C and 175°C;

[0035] Figure 8 The defective titanium dioxide catalyst (Pt / d-TiO 2 ) high-resolution XPS spectra of Pt 4f (a), O 1s (b) and Ti 2p (c);

[0036] Fig. 9 The defective titanium dioxide catalyst (Pt / d-TiO 2 ) and the conventional titanium dioxide catalyst (Pt / n-TiO 2 ) 2 -TPD spectrum;

[0037] Fig.10 The defective titanium dioxide catalyst (Pt / d-TiO 2 ) and the conventional titanium dioxide catalyst (Pt / n-TiO 2 )’s NO-TPD spectrum. DETAILED DESCRIPTION

[0038] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0039] The purity and purchasing manufacturers of the drugs involved in the following examples are as follows:

[0040]

[0041] The purity and manufacturers of the gases involved in the following examples are as follows:

[0042]

[0043] The models and manufacturers of the instruments involved in the following embodiments are as follows:

[0044]

[0045]

[0046] Comparative Example 1

[0047] A defective titanium dioxide (d-TiO 2 ), the method for preparing defective titanium dioxide is:

[0048] 1) dissolving glycerol in anhydrous ethanol, and adding tetrabutyl titanate dropwise under stirring to obtain solution A, wherein the ratio of glycerol, anhydrous ethanol and tetrabutyl titanate is 10:30:1 by volume;

[0049] 2) Transfer solution A to a polytetrafluoroethylene-lined container, place it in an electric constant temperature blast drying oven at 180°C for 24 hours, cool it naturally to room temperature (20-25°C), centrifuge it at 9000 rpm in a desktop high-speed centrifuge, wash the precipitate obtained by centrifugation, dry it in an electric constant temperature blast drying oven at 80°C for 24 hours, and place it in a muffle furnace at 2°C min -1 The temperature was raised to 500 °C at a heating rate and then calcined at 500 °C for 4 h to obtain defective titanium dioxide (d-TiO 2 ), wherein the washing is carried out successively with distilled water and anhydrous ethanol, the number of washings with distilled water is 5 times, and the number of washings with anhydrous ethanol is 5 times.

[0050] Embodiments 1 to 4

[0051] A platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) comprises: mixing defective titanium dioxide and distilled water, placing the mixture in an ultrasonic cleaner for ultrasonication for 0.5 h, and then vigorously stirring the mixture in a magnetic stirrer for 0.5 h to obtain an aqueous solution of defective titanium dioxide, and under the condition of vigorous stirring, dripping an aqueous solution of chloroplatinic acid into the aqueous solution of defective titanium dioxide to obtain a suspension, centrifuging the mixture, placing the precipitate obtained by centrifugation in an electric constant temperature blast drying oven at 80° C. and drying the mixture for 24 h, and placing the mixture in a muffle furnace at a temperature of 1° C. min from room temperature. -1The temperature was raised to 300° C. at a heating rate of 100° C. and then kept at 300° C. for 4 hours to obtain a platinum-doped defective titanium dioxide catalyst, wherein the method for preparing defective titanium dioxide is the same as that in Comparative Example 1, and the ratio of defective titanium dioxide in the defective titanium dioxide aqueous solution to platinum in the chloroplatinic acid aqueous solution is shown in Table 1, the concentration of defective titanium dioxide in the defective titanium dioxide aqueous solution is 4 mg / mL, and the concentration of platinum in the chloroplatinic acid aqueous solution is 1.5 mg / mL.

[0052] Table 1

[0053]

[0054]

[0055] Comparative Example 2

[0056] A platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2 ), comprising the following steps:

[0057] 1) adding tetrabutyl titanate dropwise to anhydrous ethanol under stirring to obtain a solution B, wherein the ratio of anhydrous ethanol to tetrabutyl titanate is 30:1 by volume;

[0058] 2) Transfer solution B to a polytetrafluoroethylene-lined container, then place it in an electric constant temperature blast drying oven and heat it at 180°C for 24 hours, and cool it naturally to room temperature of 20-25°C;

[0059] 3) centrifuging the sample obtained in step 2) at 9000 rpm in a desktop high-speed centrifuge, and washing the precipitate with anhydrous ethanol and distilled water, washing with anhydrous ethanol 5 times and washing with distilled water 5 times;

[0060] 4) The precipitate obtained in step 3) was placed in an electric constant temperature forced air drying oven at 80°C for 24 hours, and then placed in a muffle furnace at 2°C min -1 The temperature was raised to 500 °C at a heating rate and calcined at 500 °C for 4 h. The calcined material was collected as a common titanium dioxide catalyst (n-TiO 2 );

[0061] 5) 200 mg of ordinary titanium dioxide catalyst (n-TiO 2 ) was dissolved in 50 mL of distilled water, placed in an ultrasonic cleaner for ultrasonic treatment for 0.5 h, and then vigorously stirred in a magnetic stirrer for 0.5 h. During the vigorous stirring, an aqueous solution of chloroplatinic acid was added dropwise to obtain a suspension, which was centrifuged. The precipitate obtained by centrifugation was placed in an electric constant temperature blast drying oven at 80 ° C for 24 h, and placed in a muffle furnace at 1 ° C min -1The heating rate was increased to 300 °C and calcined at 300 °C for 4 h to obtain a platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2 ), wherein, by mass fraction, the mass ratio of the ordinary titanium dioxide catalyst to the platinum in the chloroplatinic acid aqueous solution is 100:0.3, and the concentration of platinum in the chloroplatinic acid aqueous solution is 1.5 mg / mL.

[0062] Nitrogen oxide conversion rate test method: The platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ), the defective titanium dioxide (d-TiO 2 ) and the platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2 ) as a powdered catalyst, the powdered catalyst is granulated into 40-60 meshes as a sample, 0.1 g of the sample is loaded into a quartz tube, and the quartz tube is placed in a heatable fixed bed reactor, a reaction gas is introduced into the fixed bed reactor so that the reaction gas passes through the powdered catalyst and reacts, and the tail gas discharged from the fixed bed reactor is detected by a flue gas analyzer to obtain the nitrogen oxide conversion rate of the powdered catalyst, wherein the reaction gas is a mixture of nitrogen monoxide, hydrogen and balance gas, the concentration of nitrogen monoxide in the reaction gas is 1000 ppm, the concentration of hydrogen in the reaction gas is 1000 ppm, the balance gas is Ar, the total flow rate of the reaction gas is 100 mL / min, and the reaction space velocity (GHSV) is controlled to be 60,000 mL g -1 h -1 , the catalytic reaction temperature is 50~200℃.

[0063] like Figure 1 As shown, when the mass ratio of defective titanium dioxide in the defective titanium dioxide aqueous solution to platinum in the chloroplatinic acid aqueous solution is 100:0.3 (Example 2), at a temperature of 100°C, the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) has a denitration efficiency of more than 90%. Compared with Comparative Example 1, the introduction of platinum greatly promotes the conversion of nitrogen oxides. At the same time, in the entire temperature range, Example 2 shows a better catalytic performance than Comparative Example 2, proving that the presence of defects promotes the catalytic process and improves the catalytic efficiency.

[0064] Electron paramagnetic resonance (EPR) was used to detect the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) microstructure, the results show that when the g value is 1.998, the characteristic peak of unpaired electrons captured by titanium vacancies appears, which indicates that the defective titanium dioxide catalyst (Pt / d-TiO 2) The surface contains a large number of titanium vacancies, which provide sufficient sites for the adsorption and activation of gas molecules and promote the catalytic reaction of gas molecules.

[0065] like Figure 3 The XRD results show that the defective titanium dioxide (d-TiO 2 ) have different exposed crystal faces, and (101), (004), (200), (204), (215) and (224) crystal faces are detected respectively. When a considerable amount of Pt species is loaded, the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) did not change significantly, which indicates that the Pt species are evenly dispersed on the catalyst surface, which can maximize the atomic utilization and promote the adsorption and activation of gas molecules.

[0066] Figure 4 The HRTEM image of (a) shows that the defective titanium dioxide (d-TiO 2 ) shows a flake-like nanostructure, and the average size of the nanosheets is about 20 nm. Figure 4 The HRTEM image of (b) shows that the defective titanium dioxide catalyst (Pt / d-TiO 2 ) shows a flaky nanostructure similar to that of Comparative Example 1, confirming that the introduction of platinum species does not change the microstructure of defective titanium dioxide. Figure 4 (c) HAADF-STEM further analyzed the Pt-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ), and individual platinum bright spots can be clearly observed in the image without obvious aggregation, confirming the uniform dispersion of platinum species.

[0067] like Figure 5 As shown in Example 2, the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) and Figure 4 The results are consistent, confirming that the Pt species are uniformly dispersed on the surface of defective TiO2.

[0068] like Figure 6 As shown, the defective titanium dioxide catalyst (Pt / d-TiO 2 ), the defective titanium dioxide (d-TiO 2 ) and the platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2) was tested for thermal stability, i.e., the reaction gas was introduced into the fixed bed reactor for 50 h according to the aforementioned nitrogen oxide conversion rate test method. The results showed that the defective titanium dioxide catalyst (Pt / d-TiO 2 ) After a performance test of up to 50 hours, the catalytic activity did not decrease significantly, proving that the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) has good stability.

[0069] In actual working conditions, H 2 The process of reducing NO is often affected by other competitive components (oxygen, water vapor, carbon monoxide, etc.). The interfering gas components will compete with the reactive gas components for adsorption on the catalyst surface, resulting in a decrease in the nitrogen oxide conversion rate. Based on this, the reactive gas in the aforementioned nitrogen oxide conversion rate test method is adjusted to "the reactive gas is a mixture of nitric oxide, hydrogen, interfering gas and balance gas, the interfering gas is oxygen, water vapor or carbon monoxide, when the interfering gas is oxygen ( Figure 7 O 2 ), the concentration of interfering gas in the reaction gas is 5% (volume percentage); when the interfering gas is water vapor ( Figure 7 H 2 O), the concentration of interfering gas in the reaction gas is 100ppm; when the interfering gas is carbon monoxide ( Figure 7 CO in the reaction gas), the concentration of the interfering gas in the reaction gas is 200 ppm. ", Test Example 2 prepared the obtained platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) and the platinum-doped conventional titanium dioxide catalyst (Pt / n-TiO 2 ) at 125°C and 175°C. The results show that the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) still retains a fairly high catalytic activity in the three competitive atmospheres and has strong resistance to O 2 , H 2 O and CO, and can adapt to complex working environments.

[0070] like Figure 8 As shown, the high-resolution Pt 4f spectrum can be divided into two characteristic peaks, corresponding to 75.1eV and 71.9eV respectively. The high-resolution O1s spectrum is deconvoluted into two characteristic peaks, the peaks at 530.5eV and 529.2eV are attributed to oxygen vacancies and lattice oxygen respectively; the high-resolution Ti 1s spectrum is deconvoluted into two characteristic peaks, at 463.5eV and 457.7eV respectively. According to the XPS scanning spectrum, the presence of Pt, O and Ti spectral signals confirms that the defective titanium dioxide catalyst (Pt / d-TiO2 ) was successfully synthesized.

[0071] like Fig. 9 As shown, the quantitative H 2 The adsorption amount of H 2 The platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) is 10 μmol g -1 , higher than H 2 In the conventional titanium dioxide catalyst (Pt / n-TiO 2 ) surface adsorption (7 μmol g -1 ). At the same time, H 2 In the case of Pt / d-TiO 2 The desorption peaks on the catalyst are located at 69°C and 160°C, which are lower than those of the conventional platinum-doped titanium dioxide catalyst (Pt / n-TiO 2 These results show that the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) promotes H 2 Adsorption and activation of molecules on catalyst surfaces.

[0072] like Fig.10 As shown, the defective titanium dioxide catalyst (Pt / d-TiO 2 ) and the conventional titanium dioxide catalyst (Pt / n-TiO 2 ) was used for NO-TPD measurement. In the conventional titanium dioxide catalyst (Pt / n-TiO 2 ) is located at 88°C, and the desorption peak of NO by chemical adsorption is located at 214°C. In contrast, NO is not significantly desorbed from the defective titanium dioxide catalyst (Pt / d-TiO 2 ) has a lower physical desorption peak temperature (201°C). It is also worth noting that the quantitative analysis of NO on the defective titanium dioxide catalyst (Pt / d-TiO 2 ) and the conventional titanium dioxide catalyst (Pt / n-TiO 2 ) on the physical adsorption and chemical adsorption content (Example 2: physical adsorption 980μmol g -1 and chemical adsorption 1158 μmol g -1 , Comparative Example 2: Physical adsorption 335 μmol g -1and chemical adsorption 402 μmol g -1 ), indicating that the platinum-doped defective titanium dioxide catalyst (Pt / d-TiO 2 ) greatly promoted the adsorption and activation of NO.

[0073] The present invention is described above by way of example. It should be noted that, without departing from the core of the present invention, any simple deformation, modification or other equivalent replacement that can be made by those skilled in the art without inventive effort falls within the protection scope of the present invention.

Claims

1. A method for preparing a platinum-doped defective titanium dioxide catalyst, It is characterized in that The platinum-doped defective titanium dioxide catalyst is platinum uniformly dispersed on the surface of the defective titanium dioxide, wherein the defective titanium dioxide has Ti vacancies; The preparation method of the platinum-doped defective titanium dioxide catalyst comprises: uniformly mixing defective titanium dioxide and water to obtain a defective titanium dioxide aqueous solution, dripping a chloroplatinic acid aqueous solution into the defective titanium dioxide aqueous solution under stirring conditions, centrifuging, drying the precipitate obtained by centrifugation, and then calcining at 300-400° C. for 3-5 hours to obtain a platinum-doped defective titanium dioxide catalyst, wherein the ratio of defective titanium dioxide in the defective titanium dioxide aqueous solution to platinum in the chloroplatinic acid aqueous solution is 100:0.3 by mass; The method for obtaining the defective titanium dioxide is: 1) dissolving glycerol in anhydrous ethanol, and adding tetrabutyl titanate dropwise under stirring to obtain solution A, wherein the ratio of glycerol, anhydrous ethanol and tetrabutyl titanate is (9-11):30:1 by volume; 2) The solution A is kept at 170-190° C. for 20-30 hours, cooled naturally to room temperature (20-25° C.), centrifuged, the precipitate obtained by centrifugation is washed, dried, and calcined at 450-550° C. for 3-5 hours to obtain defective titanium dioxide.

2. The preparation method according to claim 1, It is characterized in that The defective titanium dioxide is a sheet-like nanostructure.

3. The preparation method according to claim 1, It is characterized in that In the step 2), the temperature is 1 to 3 °C / min. -1 The temperature is raised to 450-550°C at a heating rate and then calcined at 450-550°C for 3-5h.

4. The preparation method according to claim 1, It is characterized in that The concentration of defective titanium dioxide in the defective titanium dioxide aqueous solution is 4-10 mg / mL.

5. The preparation method according to claim 1, It is characterized in that The concentration of platinum in the chloroplatinic acid aqueous solution is 1.3-1.5 mg / mL.

6. The preparation method according to claim 1, It is characterized in that The method for uniformly mixing defective titanium dioxide and water is as follows: the defective titanium dioxide and water are mixed, firstly ultrasonicated for 0.5 to 1.5 hours, and then stirred for 0.5 to 1.5 hours.

7. The preparation method according to claim 1, It is characterized in that The drying temperature is 60-80° C., and the drying time is 20-40 hours.

8. The preparation method according to claim 1, It is characterized in that From room temperature to 1~3℃·min -1 The temperature is raised to 300-400° C. at a heating rate and then kept at this temperature for 3-5 hours.

9. The preparation method according to claim 1, It is characterized in that In the step 2), the washing is carried out successively with distilled water and anhydrous ethanol.

10. The preparation method according to claim 1, It is characterized in that In the step 2), the drying temperature is 60-80° C., and the drying time is 20-40 hours.

11. The platinum-doped defective titanium dioxide catalyst obtained by the preparation method according to any one of claims 1 to 10.

12. Use of the platinum-doped defective titanium dioxide catalyst as claimed in claim 11 in removing nitrogen oxides.

13. The use according to claim 12, It is characterized in that Platinum-doped defective titanium dioxide catalysts are used to catalyze the production of water from hydrogen and nitrogen oxides.

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