Method for implementing atomic-scale regulation on platinum sites on TiO2 nanotubes and applying platinum sites to light-driven methane dry reforming

Abstract

The invention discloses a method for implementing atomic-scale regulation and control on platinum sites on TiO2 nanotubes and applying the platinum sites to light-driven methane dry reforming, provides a preparation method of a light-driven methane dry reforming catalytic material, and relates to implementation of atomic-scale precise regulation and control on the platinum sites on the TiO2 nanotubes. Therefore, two greenhouse gases, namely CO2 and CH4, are converted into synthesis gases (H2 and CO) under relatively mild conditions, and raw materials are provided for Fischer-Tropsch synthesis or preparation of chemicals with higher value. The preparation method comprises the following steps: by taking tubular sodium titanate obtained by alkalizing anatase as a substrate and tetraammineplatinum dichloride as a platinum source, carrying out ion exchange on positively charged platinum ammonia ions and substrate sodium ions by virtue of an electrostatic adsorption method, so that the platinum ammonia ions are embedded into the substrate; by controlling the calcination temperature and duration under different atmospheres, sodium titanate is promoted to be converted into TiO2, redundant ligands are effectively removed, and meanwhile precise regulation and control from Pt single atoms to Pt sub-nanocluster sites are achieved. The electronic metal-carrier interaction between the Pt site and the carrier induces local charge rearrangement, promotes directional adsorption and activation of CO2 and CH4 molecules at active sites, and shows excellent methane dry reforming activity and stability under xenon lamp simulated illumination and focused natural sunlight.

Description

Technical Field

[0001] The invention relates to an atomic-level Pt site-modified TiO2 nanotube material for light-driven methane dry reforming, belonging to the field of nanomaterials and light-driven catalytic technology. Background Art

[0002] The conversion of two greenhouse gases, CH4 and CO2, into synthesis gas (CO and H2) is called methane dry reforming reaction. The synthesis gas can be further used for the synthesis of acetic acid and dimethyl ether, hydroformylation of olefins, and Fischer-Tropsch synthesis. If the production of 6 billion tons of hydrogen per year is switched from steam reforming to methane dry reforming, 0.5 billion tons of carbon dioxide emissions can be reduced. Therefore, DRM reaction has important social and economic value in reducing carbon dioxide, utilizing carbon resources of methane, and providing chemical raw materials. However, the complex DRM process involving the activation of CH and C=O usually requires high energy input of high-temperature thermal catalysis (>973 K). This traditional heat-driven DRM is prone to carbon deposition, sintering of active components, and consumption of a large amount of fossil fuels. Light-driven DRM reaction provides a mild and sustainable solution to reduce the reaction temperature and alleviate catalyst sintering. To date, many light-driven DRM catalysts based on precious metal modification have been reported in this field. However, the size control of precious metal components and their structure-activity mechanism with the carrier are still unclear, and the catalytic activity and stability still need to be improved. The unbalanced product ratio and high cost of materials have hindered the development of light-driven DRM towards industrial applications.

[0003] Based on the above research background, the present invention uses cheap and readily available TiO2 as raw material, undergoes hydrothermal alkalization treatment, and uses electrostatic adsorption and spatial confinement strategies to modify atomic-level Pt sites. By controlling the electronic metal-carrier interaction, the platinum species on the surface of TiO2 nanotubes are regulated from Pt single atoms to Pt sub-nanoclusters, greatly improving the atomic utilization of precious metals. Compared with unmodified TiO2 materials, the loading of atomic-level Pt sites greatly improves the material's absorption of visible light and significantly promotes the separation and migration of photogenerated charges. The synergistic effect between Pt single atoms and Pt sub-nanoclusters induces local charge rearrangement and promotes the directional adsorption and activation of CH4 and CO2 molecules on active sites. Under xenon lamp simulated illumination and focused natural sunlight, the material exhibits excellent methane dry reforming activity and stability, with the ratio of H2 and CO products close to 1:1, achieving efficient and balanced conversion of CH4-CO2 under relatively mild conditions. Summary of the invention

[0004] The present invention uses layered sodium titanate nanotubes obtained by hydrothermal alkalization treatment as a substrate, and exchanges positively charged platinum complexes with substrate sodium ions through electrostatic adsorption, thereby embedding them into the sodium titanate interlayer; by controlling the calcination temperature and duration under different atmospheres, the sodium titanate is transformed into TiO2, and the excess ligands are effectively removed, while achieving precise regulation of the Pt single atom to Pt sub-nano cluster sites.

[0005] The method for preparing layered sodium titanate nanotubes by hydrothermal alkalization of the present invention is as follows: 2 g of nano-anatase is fully mixed with a sodium hydroxide aqueous solution (10 M, 60 mL), and magnetically stirred at room temperature for 60 min; the mixture is transferred to a 100 mL polytetrafluoroethylene liner, and encapsulated in a stainless steel hydrothermal synthesis reactor, which is fixed in a homogeneous stirring reaction device, and stirred and reacted continuously at 130° C. for 3 days; after the reaction is completed and cooled to room temperature, a white solid is separated from a liquid by a vacuum filtration method, and the white solid is repeatedly washed with ultrapure water under the monitoring of a high-precision pH detector until the pH value on the solid surface is 8.5; the solid is vacuum dried in a 70° C. oven for 12 h and then ground into powder to obtain alkalized layered sodium titanate nanotubes.

[0006] The method for preparing sodium titanate adsorbed with platinum-ammonia ligands by an ion exchange method disclosed by the present invention is as follows: the sodium titanate nanotubes prepared in the first step are dispersed in a dilute hydrochloric acid aqueous solution (0.1 M), ultrasonically treated for 30 min, placed at room temperature and stirred for 30 min, and a pre-prepared tetraammine dichloroplatinum aqueous solution (compared to the mass of sodium titanate, the theoretical mass of Pt accounts for 1%) is added dropwise; the mixture is further stirred at room temperature for 10 h, washed twice with ultrapure water, and vacuum dried in an oven at 70°C for 12 h to obtain sodium titanate adsorbed with platinum-ammonia ligands (Pt-Na x H 2-x Ti3O7).

[0007] The method for preparing atomic-level Pt site-loaded TiO2 according to the spatial confinement strategy of the present invention is as follows: 0.2 gPt-Na x H 2-x Ti3O7 was placed in a porcelain ark and calcined at 400°C for 1 h in an air atmosphere in a muffle furnace to obtain Pt single atom-modified TiO2 nanotubes (Pt1-Air / TNT). Pt1-Air / TNT was further placed in a tubular furnace with high-purity argon and calcined at 400°C for an additional 1 h to obtain Pt single atom and Pt sub-nano cluster-modified TiO2 nanotubes (Pt n -AirAr / TNT); 0.2 g Pt-Na x H 2-xTi3O7 was directly placed in high-purity argon and calcined at 400℃ for 1 h to obtain Pt sub-nanoclusters (Pt n -Ar1 / TNT); Pt n -Ar1 / TNT was placed in a high-purity argon environment and the calcination time was extended to 8 h to obtain a TiO2 nanotube material modified with larger Pt nanoclusters (Pt n -Ar8 / TNT).

[0008] The advantages of the present invention are embodied in 1. By using the ion adsorption method and spatial confinement strategy, the platinum species on TiO2 nanotubes were regulated from Pt single atoms to Pt sub-nanoclusters (~1 nm), which greatly improved the atomic utilization of precious metals and provided sufficient active sites for the bimolecular reaction system, solving the problem of balancing the number of active sites and atomic utilization in multi-molecular reactions in precious metal catalytic systems.

[0009] 2. Compared with unmodified TiO2, the absorption of visible light by TiO2 nanotube materials modified with atomic-level Pt sites is greatly enhanced, and the separation efficiency of photogenerated electrons and holes is significantly improved, which solves the problem of low visible light utilization of TiO2 materials.

[0010] 3. The electronic interaction between Pt single atoms, Pt sub-nanoclusters and carriers induces charge rearrangement at different Pt sites, promoting the directional adsorption and activation of CO2 and CH4 molecules at single atom sites and sub-nano cluster sites, respectively, solving the problem of the difficult balanced adsorption of two inert gas molecules, CO2 and CH4.

[0011] 4. Under xenon lamp simulated light and concentrated natural sunlight, atomic-level Pt site-modified TiO2 nanotubes exhibited excellent methane dry reforming activity and stability, breaking the thermodynamic limit and demonstrating the feasibility of the invention in low-cost solar catalytic applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 a is a schematic diagram of the preparation of all examples and comparative examples, in which the adsorption forms of layered sodium titanate nanotubes and platinum ammine complexes are marked in detail. By adopting different calcination conditions, four different Pt site-loaded TiO2 nanotubes (Pt / TNT) of I-IV are achieved. Figure 1 be is the spherical aberration corrected high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) images of Example 3, Comparative Example 1 and Comparative Example 2. The sample of Comparative Example 1 shows a clear nanotube structure ( Figure 1 b), in the enlarged Figure 1In c, isolated Pt single atom bright spots can be observed, which are embedded in the lattice of the TiO2 carrier and form coordination with the surrounding oxygen atoms. In Example 3, Pt single atom bright spots and Pt sub-nano clusters ( Figure 1 d) From the enlarged image in the upper right corner, it can be clearly observed that most of the Pt atoms are still embedded in the TiO2 lattice, thus forming a strong electronic interaction with the carrier, limiting the further agglomeration of Pt and maintaining the stability of the structure. Figure 1 e is the HAADF-STEM image of the sample in comparative example 2. It can be seen that the Pt atoms are irregularly aggregated into sub-nano clusters, and no isolated Pt single atom bright spots are observed, indicating that the Pt on this sample grows outward from the carrier. This growth arrangement mode is not structurally stable due to the lack of restraint from the surrounding carrier, and the Pt atoms are prone to further aggregate to form larger Pt nanoclusters.

[0013] Figure 2 a is the X-ray photoelectron spectra (XPS) of Pt 4f orbitals of samples in Example 3, Comparative Example 1 and Comparative Example 2. It can be seen that Pt 4+ The strength of Pt1-Air / TNT, Pt n -AirAr / TNT, Pt n -Ar1 / TNT to Pt n -Ar8 / TNT in decreasing order, while Pt 2+ The intensity of increases accordingly. The Pt single atom sample shows the highest chemical valence state due to its complete coordination with oxygen atoms, and the clusters with Pt-Pt bonds show a lower chemical valence state due to the weakened interaction with oxygen atoms. Figure 2 b is the X-ray absorption near-edge structure spectra (XANES) of the Pt L3 edge of the samples of Example 3, Comparative Example 1 and Comparative Example 2. From the edge front, the Pt of all samples is in an oxidized state, and its average valence decreases with the increase of Pt size, which is consistent with the XPS results. From the white line peak, the white line peak intensity of Pt1-Air / TNT is stronger, indicating that its inner orbital has a stronger electronic transition to the Pt 5d orbital. Figure 2 c Comparison of the infrared test results of CO adsorption of samples in Example 3, Comparative Example 1 and Comparative Example 2. 2105 and 2083 cm -1 The adsorption peak of represents the linear adsorption of CO by Pt single atom, and the σ electron supply of the adsorbate to the metal is dominant; with the formation of clusters, the peak position moves to the low band, at which time the π feedback is dominant, that is, the d orbital electrons of Pt will flow into the π antibonding orbital of CO. In addition, at 1800 cm -1A broad bulge peak can also be observed near the band, representing the bridge adsorption of CO by Pt clusters. This result confirms the distribution of Pt sites in different samples and also shows that Pt sub-nanoclusters are more suitable as activation sites for CO2 to adsorb CO products than Pt single atoms. Figure 2 d is the UV-visible diffuse reflectance absorption diagram of pure TNT and Pt-modified TNT samples. The results show that Pt modification significantly improves the absorption of visible light by TiO2 materials.

[0014] Figure 3 ad are the DRM activity test results of this material under xenon lamp simulated light. Compared with pure TNT, Pt modification significantly improves the methane dry reforming activity ( Figure 3 a). Among them, the sample of Example 3 (Pt n -AirAr / TNT) showed the closest H2 / CO product ratio to 1:1 and maintained an excellent stability of >95% during a 20-h illumination test. Figure 3 cd explored the contributions of photothermal and photoelectric effects to the DRM system. Figure 3 c shows that light irradiation significantly enhances the reaction activity in the range of 300–550 °C, breaking the limitations of traditional thermal catalysis. Figure 3 dShow Pt n The DRM activity of -AirAr / TNT samples showed a positive correlation with light intensity and H2 / CO, indicating that light plays a dominant role in this system. Figure 3 ef is the DRM activity test result of this material under outdoor natural sunlight. In the 40-minute continuous sunlight test, Pt n -AirAr / TNT showed up to 205 mmol g cat -1 h -1 The syngas generation rate fully demonstrates the feasibility of the invention in low-cost solar catalytic applications.

[0015] Figure 4 These are the characterization results of the photogenerated charge separation capabilities of the samples of Example 3, Comparative Example 1 and Comparative Example 2. Figure 4 ad are the transient photocurrent, electrochemical impedance, fluorescence emission, and time-resolved fluorescence lifetime diagrams of pure TNT and Pt / TNT samples, respectively. The stronger photocurrent response indicates that the Pt-modified sample can promote the separation of photogenerated charges; the lower electrochemical impedance means that Pt modification reduces the electron transfer barrier of TiO2 materials, which helps to improve the mobility of photogenerated carriers; the lower fluorescence intensity means that the photogenerated electrons and holes of the Pt / TNT sample are not easy to recombine; the longer fluorescence lifetime of the Pt / TNT sample indicates that its photogenerated carriers have a longer lifetime. These results show that the Pt-modified sample can significantly promote the separation and migration of photogenerated charges, thereby improving the photocatalytic DRM performance.

[0016] Figure 5 a is Pt n Theoretical calculation model of -AirAr / TNT and its isosurface electron localization function. The two Pt sites farther from the interface show stronger electron localization ability (darker areas represent higher electron density), which is beneficial to the adsorption and activation of CO2. Millikan charge analysis shows that the charge exchange at the interface between the Pt site and TiO2 is stronger, and the acidity of the Pt single atom site is higher (+0.82), which is beneficial to the adsorption of CH4. Figure 5 b Simulation of excited state photogenerated electrons and holes in Pt n -AirAr / TNT model. The results show that the photogenerated electrons are preferentially localized in the region far from the interface. 3 Pt and 4 Pt sites, and strong charge exchange with the interface 1 Pt and 2 The Pt sites show low electron / hole ratios of 0.18 and 0.24, respectively. This indicates 3 Pt and 4 Pt sites help activate CO2 molecules, while 1 Pt and 2 The Pt site is conducive to the adsorption and activation of CH4, which is consistent with the analysis of the ground state electron localization function. Based on the above analysis, Figure 5 c proposed the reaction mechanism of the present invention: CO2 and CH4 molecules are adsorbed on Pt n -Pt sub-nano clusters and Pt single atom sites of the AirAr / TNT sample. Under light irradiation, photogenerated electrons migrate to the Pt sub-nano cluster sites to activate CO2 molecules, while photogenerated holes flow to Pt single atoms to promote the breakage of CH bonds of methane. n -The significant electronic metal-support interaction of the AirAr / TNT sample enhances the activation and adsorption of reactants and intermediates. The appropriate spatial distance and arrangement between the active sites of CH4 and CO2 promote efficient intermediate coupling and minimize the occurrence of side reactions, thereby achieving efficient and balanced generation of H2 and CO.

[0017] The above experimental results prove that the atomic-level Pt site-modified TiO2 nanotubes we synthesized have excellent light-driven methane dry reforming performance and stability.

[0018] Although the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Specific implementation plan

[0019] The present invention will be described in more detail below through specific embodiments, but the protection scope of the present invention is not limited to these embodiments.

[0020] Example 1 Synthesis of Layered Sodium Titanate Nanotubes 2 g of nano-anatase was mixed with 10 M sodium hydroxide aqueous solution and stirred for 60 min, and the mixture was transferred to a 100 mL polytetrafluoroethylene liner and encapsulated in a stainless steel hydrothermal synthesis reactor, which was fixed in a homogeneous stirring reaction equipment and continuously stirred at 130°C for 72 h; after the reaction was completed and cooled to room temperature, the white solid was separated from the liquid by vacuum filtration, and the white solid was repeatedly washed with ultrapure water under the monitoring of a high-precision pH detector until the pH value on the solid surface was 8.5; the above solid was vacuum dried in an oven at 70°C and then ground into powder to obtain alkalized layered sodium titanate nanotubes.

[0021] Example 2 Synthesis of Sodium Titanate Adsorbed by Platinum-Ammine Ligand Sodium titanate nanotubes were dispersed in a 0.1 M dilute hydrochloric acid aqueous solution, and after ultrasonic treatment for 30 min, they were placed at room temperature and stirred for 30 min, and a pre-prepared tetraammine dichloroplatinum aqueous solution (the theoretical mass of Pt is 1% compared to the mass of sodium titanate) was added dropwise; the mixture was further stirred at room temperature for 10 h, washed twice with ultrapure water, and dried in a 70 ° C oven under vacuum for 12 h to obtain sodium titanate adsorbed with platinum ammonia ligands (Pt-Na x H 2-x Ti3O7).

[0022] Example 3 Synthesis of TiO2 Nanotubes Co-modified with Pt Single Atoms and Pt Sub-nanoclusters Put 0.2 g Pt-Na x H 2-x Ti3O7 was placed in a porcelain ark and calcined at 400℃ for 1h in an air atmosphere in a muffle furnace. It was then placed in a tube furnace with high-purity argon and calcined at 400℃ for another 1h to obtain TiO2 nanotubes (Pt n -AirAr / TNT).

[0023] Comparative Example 1 Synthesis of Pt Single Atom-Decorated TiO2 Nanotubes Put 0.2 g Pt-Na x H 2-x Ti3O7 was placed in a porcelain ark and calcined at 400°C in an air atmosphere in a muffle furnace for 1 h to obtain Pt single atom-modified TiO2 nanotubes (Pt1-Air / TNT).

[0024] Comparative Example 2 Synthesis of outward-aligned Pt nanoclusters loaded with TiO2 nanotubes Put 0.2 g Pt-Na x H 2-x Ti3O7 was directly placed in high-purity argon and calcined at 400℃ for 1 h to obtain Pt sub-nanoclusters (Pt n -Ar1 / TNT); Pt n -Ar1 / TNT was placed in a high-purity argon environment and the calcination time was extended to 8 h to obtain a TiO2 nanotube material modified with larger Pt nanoclusters (Pt n -Ar8 / TNT).

[0025] Experiments and data The activity investigation method of photocatalytic methane dry reforming provided by the present invention is as follows: Laboratory xenon lamp simulated light activity investigation method: 20 mg of catalyst was placed in a flow-type photothermal catalytic reaction device (PLR-PTSR II) at 30 mL min -1 A mixed gas of CH4: CO2: Ar (volume ratio of 5:5:10) was introduced into the reaction device at a flow rate of 1.5 %. The adsorption saturation was maintained for 30 min under dark conditions, and then the activity test was carried out under simulated light of a 300 W xenon lamp. The photothermal reaction temperature during illumination was kept constant at 300°C by the temperature control component, and the pressure was kept constant at 0.15 MPa. The outlet of the reaction device was connected to a gas chromatograph, and the reaction products were detected in automatic injection mode. A flame ionization detector was used for the detection of CO, and a thermal conductivity detector was used for the detection of H2.

[0026] Outdoor focused natural sunlight activity test method: 20 mg of catalyst was placed at 100 cm 3 In a homemade quartz reactor, the -1 A mixed gas of CH4: CO2: Ar (volume ratio of 5:5:10) was introduced into the reactor from the inlet at a flow rate of 100 ℃. The adsorption saturation was maintained for 30 min under dark conditions, and then the quartz reactor was placed in the center of an outdoor plastic reflective concentrator to conduct an activity test under natural sunlight. Every 10 minutes, a gas bag was used to collect the gas product at the reactor outlet, and the product was extracted with a gas sampling needle and injected into a gas chromatograph. A flame ionization detector was used for the detection of CO, and a thermal conductivity detector was used for the detection of H2.

Claims

1. A method for atomic-level regulation of platinum sites on TiO2 nanotubes and application in light-driven methane dry reforming, characterized in that First, the layered sodium titanate nanotubes are obtained by alkalizing nano-anatase by hydrothermal method, and then ion exchange is carried out with cationic complexes containing platinum under weak acidic conditions. The coordination environment and aggregation degree of Pt atoms on the TiO2 carrier are regulated by changing the calcination atmosphere and duration, and finally TiO2 nanotube materials with different Pt coordination forms are obtained. The prepared material has excellent light absorption ability, shows efficient adsorption and activation ability for CH4 and CO2, and exhibits excellent methane dry reforming performance under simulated light source and natural sunlight light source; the preparation of the atomic-level Pt site-modified TiO2 nanotube material specifically includes the following steps: Step 1: Fully mix 2 g of nano-anatase with a pre-prepared sodium hydroxide aqueous solution (10 M, 60 mL), and stir magnetically at room temperature for 60 min; transfer the mixture to a 100 mL polytetrafluoroethylene liner, and encapsulate it in a stainless steel hydrothermal synthesis reactor, fix it in a homogeneous stirring reaction device, and stir the reaction continuously at 130°C for 3 days; after the reaction is completed and cooled to room temperature, separate the white solid from the liquid by vacuum filtration, and repeatedly wash the white solid with ultrapure water under the monitoring of a high-precision pH detector until the pH value on the solid surface is 8.5; the above solid is vacuum dried in a 70°C oven for 12 hours and then ground into powder to obtain alkalized layered sodium titanate nanotubes; Step 2: The sodium titanate nanotubes prepared in the first step were dispersed in a dilute hydrochloric acid aqueous solution (0.1 M), and after ultrasonic treatment for 30 min, they were placed at room temperature and stirred for 30 min, and a pre-prepared tetraammine dichloroplatinum aqueous solution (the theoretical mass of Pt is 1% compared to the mass of sodium titanate) was added dropwise; the mixture was further stirred at room temperature for 10 h, washed twice with ultrapure water, and dried in a 70 ° C oven under vacuum for 12 h to obtain sodium titanate adsorbed with platinum ammonia ligands (Pt-Na x H 2-x Ti3O7); Step 3: 0.2 g Pt-Na x H 2-x Ti3O7 was placed in a porcelain ark and calcined at 400℃ in an air atmosphere in a muffle furnace for 1 h to obtain Pt single atom-modified TiO2 nanotubes (Pt1-Air / TNT), in which the Pt atoms were embedded in the TiO2 lattice and coordinated with the surrounding oxygen atoms; Pt1-Air / TNT was further placed in a tubular furnace with high-purity argon gas and calcined at 400℃ for an additional 1 h to obtain TiO2 nanotubes modified with Pt single atoms and Pt sub-nanoclusters (Pt n -AirAr / TNT), in which most of the Pt atoms are still embedded in the TiO2 lattice; 0.2 g Pt-Na x H 2-x Ti3O7 was directly placed in high-purity argon and calcined at 400℃ for 1 h to obtain Pt sub-nanoclusters (Pt n -Ar1 / TNT); Pt n -Ar1 / TNT was placed in a high-purity argon environment and the calcination time was extended to 8 h to obtain a TiO2 nanotube material modified with larger Pt nanoclusters (Pt n -Ar8 / TNT).

2. The method for preparing the atomic-level Pt site-modified TiO2 nanotube material according to claim 1, characterized in that: The homogeneous stirring reaction equipment used in the first step can ensure continuous stirring of the mixture in the stainless steel hydrothermal synthesis reactor while heating the reactor, so that the nano-anatase is fully alkalized, thereby forming a tubular nanomaterial with a high specific surface area.

3. The method for preparing the atomic-level Pt site-modified TiO2 nanotube material according to claim 1, characterized in that: The high-precision pH detector used in the first step can accurately monitor the pH on the solid surface, thereby accurately controlling the washing time to obtain a solid product with a constant pH of 8.5, ensuring the consistency of the alkalinity degree of each batch of samples.

4. The method for preparing the atomic-level Pt site-modified TiO2 nanotube material according to claim 1, characterized in that: The platinum source in the second step must be a positively charged platinum metal complex, the purpose of which is to use an electrostatic adsorption strategy to allow the platinum-ammonia ligand to be adsorbed between the layers of sodium titanate and to undergo ion exchange with sodium ions.

5. The method for preparing the atomic-level Pt site-modified TiO2 nanotube material according to claim 1, characterized in that: The third step requires strict control of the calcination temperature at 400°C, the purpose of which is to transform the sodium titanate nanotubes into anatase phase TiO2 nanotubes and remove excess impurity ligands at high temperature.

6. The method for preparing the atomic-level Pt site-modified TiO2 nanotube material according to claim 1, characterized in that: The third step requires strict control of the calcination atmosphere and calcination time. The purpose is to control the growth and coordination environment of different Pt sites by controlling the electronic metal-support interaction between Pt and TiO2 support. x H 2-x Ti3O7 was used to obtain Pt1-Air / TNT, which was attributed to the oxygen-rich environment providing sufficient oxygen atoms for Pt, forming Pt-O coordination in the TiO2 lattice, and preventing Pt from agglomerating. Pt1-Air / TNT was further calcined in high-purity argon to obtain Pt n -AirAr / TNT, the surface oxygen atoms are easily released with the inert gas flow, some Pt ​​atoms agglomerate to form sub-nano clusters, and some Pt ​​atoms are still embedded in the TiO2 lattice, forming a TiO2 structure modified by Pt single atoms and Pt sub-nano clusters; x H 2-x Ti3O7 was directly calcined in high-purity argon for 1 h to obtain Pt n -Ar1 / TNT, in which the process of titanate conversion to TiO2 will lead to the consumption of a large number of its own oxygen atoms, and the lack of oxygen atoms will effectively anchor Pt atoms, so that Pt grows outward from the surface of the TiO2 carrier to form outward arranged Pt sub-nanoclusters; this Pt sub-nanoclusters are not stable enough, so extending the calcination time in argon to 8 h will lead to further aggregation of Pt, forming larger-sized Pt nanoclusters loaded with TiO2 (Pt n -Ar8 / TNT).

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