A rod-shaped N-TiO2 / Sv-ZIS photocatalyst and its preparation method

Abstract

The application discloses a rod-shaped N-TiO2 / Sv-ZIS photocatalyst and a preparation method thereof, and the method comprises the following steps: in the first step, taking a titanium mesh as a substrate, acetylacetone and titanium acid tetraisopropyl ester as raw materials, and adopting tetraacetate diamine disodium to prepare conical TiO2 by means of a hydrothermal method; in the second step, the titanium mesh loaded with TiO2 is put into a mixed solution of triethylamine, H2SO4, ethanol and water, and is ultrasonically treated for 30 minutes, and then is transferred to a reaction kettle to carry out a hydrothermal reaction, and after the hydrothermal reaction is completed, conical N-TiO2 is prepared by high-temperature annealing in a muffle furnace; in the third step, N-TiO2, ZnCl2, InCl3.4H2O and thioacetamide are used as raw materials to prepare a composite material N-TiO2 / Sv-ZIS by means of a solvothermal method. The rod-shaped N-TiO2 / Sv-ZIS photocatalyst prepared by the method can improve the photocatalytic efficiency.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a rod-shaped N-TiO2 / Sv-ZIS photocatalyst and its preparation method. Background Technology

[0002] Photoelectrocatalytic water splitting for hydrogen production refers to the conversion of water into hydrogen and oxygen using solar energy and electricity. It is a very promising approach to producing clean and renewable hydrogen. Therefore, developing novel photocatalysts for water splitting and exploring the mechanism of action of photocatalytic water splitting is a fundamental research area with great potential.

[0003] Titanium dioxide (TiO2) has attracted attention due to its high photoreactivity, good chemical stability, low cost, and non-toxicity. However, its wide band gap, poor response in the visible light region, and high recombination probability of photogenerated electron-hole pairs, coupled with its small nanoparticle size, make it prone to aggregation during synthesis. This reduces the efficiency of TiO2 photocatalysts and affects their photocatalytic performance in practical applications such as organic matter degradation and hydrogen evolution. Therefore, enhancing the photoactivity of TiO2 through morphology control, doping, and defect engineering, especially by constructing heterojunctions with other types of semiconductors, is an effective method to improve photocatalytic activity. Summary of the Invention

[0004] The purpose of this invention is to provide a rod-shaped N-TiO2 / Sv-ZIS photocatalyst and its preparation method, wherein the prepared rod-shaped N-TiO2 / Sv-ZIS photocatalyst can improve photocatalytic efficiency.

[0005] In one aspect of the present invention, a method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst is provided. According to an embodiment of the present invention, the method includes the following steps:

[0006] (1) Preparation of cone-shaped N-TiO2

[0007] Titanium mesh loaded with conical TiO2 was placed in a mixed solution of triethylamine, ethanol, sulfuric acid and deionized water, and then transferred to a reaction vessel. After hydrothermal reaction, it was washed and calcined to obtain conical N-TiO2.

[0008] (2) Preparation of rod-shaped N-TiO2 / Sv-ZIS

[0009] A titanium mesh loaded with conical N-TiO2 was placed in a homogeneous solution of ZnCl2, InCl3·4H2O and thioacetamide, then transferred to a reaction vessel. After solvothermal reaction, the mesh was washed and vacuum dried to obtain the rod-shaped N-TiO2 / Sv-ZIS photocatalyst.

[0010] In addition, the method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst according to the above embodiments of the present invention may also have the following additional technical features:

[0011] In some embodiments of the present invention, step (1) involves the following steps: firstly, a titanium mesh with an area of ​​2 x 3 cm is used. 2 A clean titanium mesh with a thickness of 0.27 mm and a mesh size of 100 was used as the substrate. A mixed solution of acetylacetone and tetraisopropyl titanate was added dropwise to a 0.5 mol / L Na2EDTA aqueous solution, wherein the volume ratio of tetraisopropyl titanate, acetylacetone and Na2EDTA aqueous solution was 3:20:180. After stirring at room temperature for 20-30 minutes until homogeneous, the mixture was transferred together with the clean titanium mesh to a reactor for hydrothermal reaction. After the hydrothermal reaction was completed, the mixture was washed with anhydrous ethanol and deionized water, and then vacuum dried to obtain a titanium mesh loaded with conical TiO2.

[0012] In some embodiments of the present invention, the hydrothermal reaction of the titanium mesh is carried out in an oven at a temperature of 180-200°C for 5-7 hours, and the drying temperature is 40-60°C for 2-3 hours.

[0013] In some embodiments of the present invention, in step (1), a titanium mesh loaded with conical TiO2 is placed in a mixed solution of triethylamine, 0.5 mol / L sulfuric acid, ethanol and deionized water and ultrasonically mixed for 20-30 minutes. The ultrasonic machine operates at a frequency of 60-90 kHz and a power of 50-150 W. The ultrasonic temperature is room temperature. The volume ratio of triethylamine, 0.5 mol / L sulfuric acid, ethanol and deionized water is 12:1:200:100. After ultrasonication, the titanium mesh and the mixed solution are transferred together to a reaction vessel for hydrothermal reaction.

[0014] In some embodiments of the present invention, in step (1), the hydrothermal reaction is carried out in an oven at a temperature of 110-120°C for 10-12 hours. After the hydrothermal reaction is completed, the product is washed with anhydrous ethanol and deionized water. After washing, the product is placed in a muffle furnace for high-temperature calcination and annealing at a temperature of 400-500°C for 2-4 hours to obtain nitrogen-doped conical TiO2, denoted as N-TiO2.

[0015] In some embodiments of the present invention, in step (2), ZnCl2, InCl3·4H2O, and thioacetamide (TAA) are dissolved in 30 ml of ethylene glycol solution, wherein the molar ratio of ZnCl2, InCl3·4H2O, and thioacetamide (TAA) is 1:2:16.

[0016] In some embodiments of the present invention, the solvothermal reaction in step (2) is carried out in an oven, the solvothermal reaction temperature is 140-180℃, and the solvothermal reaction holding time is 18-24h;

[0017] In some embodiments of the present invention, after the solvothermal reaction in step (2) is completed, the product is washed with anhydrous ethanol and deionized water, and then vacuum dried at a temperature of 40-60°C for 10-12 hours.

[0018] In another aspect of the present invention, a rod-shaped N-TiO2 / Sv-ZIS photocatalyst prepared according to the preparation method of the rod-shaped N-TiO2 / Sv-ZIS photocatalyst is provided.

[0019] In another aspect of the invention, the rod-shaped N-TiO2 / Sv-ZIS photocatalyst is proposed for photoelectrocatalytic water splitting to produce hydrogen under simulated light conditions with a certain bias voltage. The specific operation is as follows: Photoelectrocatalytic water splitting hydrogen evolution tests are conducted using a Labsolar 6A all-glass automated online trace gas analysis system, a GC9790Π gas chromatograph, and an electrochemical workstation (CHI 660E). The entire hydrogen evolution test is carried out in a matching three-electrode glass reactor (platinum electrode as the counter electrode and saturated Ag / AgCl electrode as the reference electrode), with 80-90 mL of 0.5 M Na2SO4 solution as the electrolyte. The electrochemical workstation is in it mode, the test time is set to 250-360 min, and a constant bias voltage of 0.5-0.8 V is applied. Simultaneously, a 300 W xenon lamp (PLS-SXE300) is used to simulate sunlight, and the hydrogen evolution amount is tested over 5 hours.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] (1) This invention prepares a Z-shaped rod N-TiO2 / Sv-ZIS photocatalyst using a pre-preparation and post-assembly method. Under light excitation, when TiO2 and ZIS come into contact, electrons in ZIS spontaneously diffuse into TiO2, forming an electron depletion layer and an accumulation layer, creating a built-in electric field. The establishment of this electric field promotes the separation of photogenerated electrons and holes. The CB position of ZIS is -0.41 eV, which is more negative than the potential of H+ / H2, so its excited electrons can combine with protons H+ in water and reduce them to H2. The VB position of TiO2 is 2.39 eV, which is more positive than the potential of H2O / ·OH, so it leaves holes (h + It simultaneously oxidizes H2O in the system to produce ·OH, which in turn produces O2, thus realizing the photoelectrocatalytic decomposition of water.

[0022] (2) TiO2 and ZnIn2S4 are two n-type semiconductors with matching band structures, which can generate superoxide radicals with reducing ability and hydroxyl radicals with oxidizing ability. Moreover, the combination of the two can construct an S-type heterostructure, thereby improving the hydrogen production capacity of the photocatalyst.

[0023] (3) The constructed Z-type heterojunction promotes the diffusion and migration of photogenerated carriers. Under simulated sunlight conditions, a bias voltage is applied simultaneously to generate clean energy hydrogen. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the preparation process of the rod-shaped N-TiO2 / Sv-ZIS photocatalyst in this embodiment of the invention.

[0025] Figure 2 The XRD patterns of N-TiO2 / Sv-ZIS-0.025 (i.e., N-TZ-0.025 in the figure), N-TiO2, TiO2, and Sv-ZIS in Example 1 of the present invention are shown.

[0026] Figure 3 The UV-Vis spectra of N-TiO2 / Sv-ZIS-0.025, N-TiO2, TiO2, and Sv-ZIS in Example 1 of this invention are shown.

[0027] Figure 4 The images are SEM images of TiO2(a), N-TiO2(b), N-TiO2 / Sv-ZIS(c) and ZIS(d) in Example 1 of the present invention.

[0028] Figure 5 XPS spectra of N-TiO2 / Sv-ZIS(a), Ti 2p(b), N 1s(c), O 1s(d), Zn2p(e), In 3d(f), and S2p(g) in Example 1 of this invention;

[0029] Figure 6 In the middle, the left figure is the Tauc-Plot spectrum of N-TiO2 in Example 1 of the present invention, and the right figure is the Tauc-Plot spectrum of Sv-ZIS photocatalyst in the example of the present invention;

[0030] Figure 7 In the middle, the left figure is the MS spectrum of N-TiO2 in Example 1 of the present invention, and the right figure is the MS spectrum of Sv-ZIS photocatalyst in the example of the present invention;

[0031] Figure 8The it spectrum of TiO2, N-TiO2, N-TiO2 / Sv-ZIS-0.025, N-TiO2 / Sv-ZIS-0.01, N-TiO2 / Sv-ZIS-0.05, and N-TiO2 / Sv-ZIS-0.1 in Example 1 of this invention;

[0032] Figure 9 The EIS spectra of N-TiO2 / Sv-ZIS-0.025, N-TiO2, and TiO2 in Example 1 of this invention are shown.

[0033] Figure 10 The hydrogen evolution spectra of TiO2, N-TiO2, N-TiO2 / Sv-ZIS-0.025, N-TiO2 / Sv-ZIS-0.01, N-TiO2 / Sv-ZIS-0.05, and N-TiO2 / Sv-ZIS-0.1 in Example 1 of this invention are shown.

[0034] Figure 11 The left figure shows the EPR spectrum of hydroxyl radicals of N-TiO2 / Sv-ZIS-0.025, N-TiO2, and Sv-ZIS after 6 minutes of illumination in Example 1 of the present invention. The right figure shows the EPR spectrum of superoxide radicals of N-TiO2 / Sv-ZIS-0.025, N-TiO2, and Sv-ZIS after 6 minutes of illumination in Example 1 of the present invention.

[0035] Figure 12 This is a mechanistic diagram of the rod-shaped N-TiO2 / Sv-ZIS photocatalyst in Example 1 of the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1

[0038] like Figure 1 As shown, a method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst includes the following steps:

[0039] (1) Preparation of conical TiO2

[0040] 0.3 mL of tetraisopropyl titanate (TTIP) and 2 mL of acetylacetone were added dropwise to 18 mL of aqueous solution containing 0.56 g of Na₂EDTA (disodium ethylenediaminetetraacetate). After stirring for 20 minutes, the mixture, along with a clean titanium mesh (3 cm x 2 cm), was transferred to a reaction vessel. The reaction was carried out hydrothermally at 200 °C for 7 hours. After the reaction vessel cooled naturally to room temperature, the sample was removed and washed repeatedly with ethanol and deionized water. It was then dried at 60 °C for 3 hours. The sample was collected to obtain a titanium mesh loaded with TiO₂.

[0041] (2) Preparation of cone-shaped N-TiO2

[0042] The titanium mesh loaded with TiO2 was placed in a mixed solution containing 1.2 mL triethylamine, 0.1 mL 1 M H2SO4, 20 mL ethanol, and 10 mL deionized water and sonicated for 30 minutes (ultrasound machine operating frequency 90 kHz, power 150 W, room temperature sonication). Then it was transferred to a reaction vessel and hydrothermally reacted in an oven at 120 °C for 12 h. After the reaction vessel cooled naturally to room temperature, the sample was washed several times with ethanol and deionized water and then calcined in a muffle furnace at an initial temperature of 30 °C and a heating rate of 5 °C / min. After calcination at 450 °C for 2 h, the titanium mesh loaded with N-TiO2 was obtained.

[0043] (3) Preparation of rod-shaped N-TiO2 / Sv-ZIS

[0044] Two portions of the above solution were prepared simultaneously: 0.025 mmol ZnCl2, 0.05 mmol InCl3·4H2O, and 0.4 mmol thioacetamide (TAA) were added to 30 mL of ethylene glycol solution. After stirring for 30 minutes, one portion was directly transferred to a reaction vessel and reacted solvothermally at 180 °C for 24 h in an oven. After the reaction vessel cooled naturally to room temperature, the sample was collected, washed repeatedly with ethanol and deionized water, and then vacuum dried overnight at 60 °C to obtain the Sv-ZIS photocatalyst. The other portion, along with the N-TiO2-supported titanium mesh synthesized in the previous step, was transferred to a reaction vessel and reacted solvothermally at 180 °C for 24 h in an oven. After the reaction vessel cooled naturally to room temperature, the sample was washed repeatedly with ethanol and deionized water, and then vacuum dried overnight at 60 °C. The collected sample yielded a rod-shaped N-TiO2 / Sv-ZIS photocatalyst, named N-TiO2 / Sv-ZIS-0.025.

[0045] Similarly, N-TiO2 / Sv-ZIS composite photocatalysts with different concentrations of Sv-ZIS were also prepared, as shown below.

[0046] The preparation method of N-TiO2 / Sv-ZIS-0.1 differs from that of N-TiO2 / Sv-ZIS-0.025 in that 0.1 mmol ZnCl2, 0.2 mmol InCl3·4H2O, and 1.6 mmol thioacetamide are added.

[0047] The preparation method of N-TiO2 / Sv-ZIS-0.05 differs from that of N-TiO2 / Sv-ZIS-0.025 in that 0.05 mmol ZnCl2, 0.1 mmol InCl3·4H2O, and 0.8 mmol thioacetamide are added.

[0048] The preparation method of N-TiO2 / Sv-ZIS-0.001 differs from that of N-TiO2 / Sv-ZIS-0.025 in that 0.001 mmol ZnCl2, 0.002 mmol InCl3·4H2O, and 0.016 mmol thioacetamide are added.

[0049] Example 2

[0050] A method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst includes the following steps:

[0051] (1) Preparation of conical TiO2

[0052] 0.3 mL of tetraisopropyl titanate and 2 mL of acetylacetone were added dropwise to 18 mL of aqueous solution containing 0.56 g of Na₂EDTA. After stirring for 20 minutes, the mixture, along with a clean titanium mesh (3 cm x 2 cm), was transferred to a reaction vessel. The reaction was carried out hydrothermally at 200 °C for 5 hours. After the reaction vessel cooled naturally to room temperature, the sample was removed and washed repeatedly with ethanol and deionized water. It was then dried at 60 °C for 3 hours. The sample was collected to obtain a titanium mesh loaded with TiO₂.

[0053] (2) Preparation of cone-shaped N-TiO2

[0054] The titanium mesh loaded with TiO2 was placed in a mixed solution containing 2.4 mL triethylamine, 0.1 mL 1 M H2SO4, 20 mL ethanol, and 10 mL deionized water and sonicated for 30 minutes (ultrasound machine operating frequency 90 kHz, power 150 W, room temperature sonication). Then it was transferred to a reaction vessel and hydrothermally reacted in an oven at 120 °C for 12 h. After the reaction vessel cooled naturally to room temperature, the sample was washed several times with ethanol and deionized water and then calcined in a muffle furnace at an initial temperature of 30 °C and a heating rate of 5 °C / min. After calcination at 450 °C for 2 h, the titanium mesh loaded with N-TiO2 was obtained.

[0055] (3) Preparation of rod-shaped N-TiO2 / Sv-ZIS

[0056] 0.025 mmol ZnCl2, 0.05 mmol InCl3·4H2O, and 0.4 mmol TAA were added to 30 mL of ethylene glycol solution and stirred for 30 minutes. The mixture was then transferred to a reaction vessel along with the N-TiO2 synthesized in the previous step. The reaction was carried out hydrothermally at 140 °C for 24 h. After the reaction vessel cooled to room temperature, the sample was washed several times with ethanol and deionized water and then vacuum dried overnight at 60 °C. The sample was collected, and different concentrations of Sv-ZIS were synthesized by changing the mass of the three raw materials, with a concentration ratio of 1:2.5:5:10. Therefore, the sample was named N-TiO2 / Sv-ZIS-0.025-2.

[0057] The following tests were all performed on the sample from Example 1.

[0058] (1) XRD analysis

[0059] The crystal forms of TiO2, N-TiO2, ZIS, and N-TiO2 / Sv-ZIS-0.025 composites were analyzed by XRD, such as... Figure 2 As shown, for TiO2, the diffraction peaks at 21.4°, 36.1°, 54.3°, and 76.4° correspond to the (110), (101), (211), and (320) crystal planes, respectively. For N-TiO2, the characteristic peaks of TiO2 and N-TiO2 are the same, all corresponding to the rutile phase (PDF#21-1276), indicating that N doping did not change the crystal structure of TiO2. For ZIS, the diffraction peaks at 21.5°, 27.6°, and 47.4° correspond to the (006), (102), and (111) crystal planes, respectively. In addition, the XRD pattern of the N-TiO2 / Sv-ZIS-0.025 composite material only shows the diffraction peaks of TiO2, and no ZIS diffraction peaks were found, which may be due to the low loading of ZIS in the N-TiO2 / Sv-ZIS-0.025 composite material.

[0060] (2) UV-Vis analysis

[0061] Stronger light absorption capacity corresponds to better photocatalytic performance. Generally, a wider spectral response range corresponds to stronger photocatalytic performance. The light absorption range of the prepared photocatalyst was studied using UV-Vis absorption spectroscopy, such as... Figure 3 As shown, compared with N-TiO2, the light absorption intensity of the N-TiO2 / Sv-ZIS composite material is reduced, while the light absorption range remains unchanged. This is due to the insufficient amount of ZIS in the composite.

[0062] (3) SEM analysis

[0063] Figure 4SEM images of TiO2, N-TiO2, ZIS and N-TiO2 / Sv-ZIS composites, from Figure 4 (a) It can be seen that smooth-surfaced cone-shaped TiO2 was successfully synthesized, and the TiO2 nanocones were uniformly and densely distributed on the titanium mesh, forming a 3D structure with a large specific surface area. Figure 4 As can be seen in (b), N-TiO2 remains a smooth cone shape, indicating that N doping did not change the morphology of TiO2. Figure 4 (c) is a SEM image of N-TiO2 / Sv-ZIS. It can be seen that after ZIS is combined, the conical N-TiO2 is transformed into rod-shaped N-TiO2, and at the same time, the petal-shaped ZnIn2S4 nanosheets uniformly and densely wrap the TiO2 nanorods. Figure 4 (d) is a ZIS SEM image, which shows that many irregular nanosheets are stacked into dense nanospheres during the solvothermal process.

[0064] (4) XPS Analysis

[0065] XPS was used to further investigate the elemental composition and chemical composition of the prepared N-TiO2 / Sv-ZIS sample, such as... Figure 5 As shown in (a), N, Ti, O, Zn, In, and S elements are clearly visible in the total spectrum of the N-TiO2 / Sv-ZIS composite material, proving the successful preparation of the N-TiO2 / Sv-ZIS composite material. Figure 5 (b) In the Ti 2p spectrum, Ti 2p 3 / 2 and Ti 2p 1 / 2 are located at 459.1 eV and 464.7 eV, respectively. Figure 5 (b) In the O 1s spectrum, the characteristic peak at 530.3 eV corresponds to Ti-O; the characteristic peak at 531.9 eV corresponds to OH. Figure 5 In the (d)N 1s spectrum, the characteristic peak at 401.4 eV can be attributed to N adsorbed by molecules on the surface of the TiO2 nanocone array, while the characteristic peak at 399.9 eV may be due to interstitial nitrogen atoms in the Ti-ON lattice structure of titanium dioxide. Figure 5 (e) The characteristic peak at 1022.3 eV in the Zn 2p spectrum corresponds to Zn 2p³ / 2; the characteristic peak at 1045.3 eV corresponds to Zn 2p¹ / ². Figure 5 (f) The characteristic peak at 445.1 e V in the In 3d spectrum is In 3d 5 / 2; the characteristic peak at 452.6 e V corresponds to In 3d 3 / 2. Figure 5 (g) The characteristic peak at 161.3 e V in the S2p spectrum is S2p3 / 2; the characteristic peak at 163.2 e V corresponds to S2p1 / 2.

[0066] (5) Tauc Plot curve analysis

[0067] For semiconductor materials, they possess a certain band gap (Eg), which can be derived from ultraviolet-visible diffuse reflectance testing and the formula (ahv)² = K(hv - Eg). From... Figure 6 As shown, the band gap of N-TiO2 is 2.73 eV, and the band gap of ZIS is 2.54 eV.

[0068] (5) Mott-Schottky analysis

[0069] The Mott-Schottky test can determine the type and flat band potential of a semiconductor, and the conduction band position of N-TiO2 and ZIS can be calculated by combining the Tauc-Plot curves. Figure 7 It can be seen that the tangent slopes of the MS curves for both N-TiO2 and ZIS are positive, indicating that both N-TiO2 and ZIS are n-type semiconductors. For n-type semiconductors, the flat band potential is 0.1 eV higher than the conduction band potential. Therefore, the conduction band potential of N-TiO2 can be calculated to be -0.34 eV, and that of ZIS to be -0.41 eV. This, combined with the Tauc-Plot curves and the formula Eg = E... VB -E CB The valence band of N-TiO2 can be calculated to be 2.39 eV, and the valence band of ZIS is 2.13 eV.

[0070] (5) IT analysis

[0071] Photocurrent reflects the separation properties of photogenerated electrons and holes; the larger the photocurrent, the higher the separation efficiency of photogenerated electron-hole pairs. For example... Figure 8 As shown, compared with pure TiO2, N-doped TiO2 exhibits a significantly enhanced photocurrent, which facilitates effective charge separation / transfer. The N-TiO2 / Sv-ZIS-0.025 exhibits the largest photocurrent, indicating the successful construction of a heterojunction structure. This effectively promotes the separation efficiency of photogenerated electron-hole pairs and enhances photocatalytic activity.

[0072] (6) EIS Analysis

[0073] A smaller radius of impedance spectrum arc indicates better separation of photogenerated electron-hole pairs, resulting in better photocatalytic performance. EIS test results are as follows: Figure 9 As shown, the radius of the N-TiO2 / Sv-ZIS composite material is clearly smaller than that of TiO2, indicating a lower interfacial transport resistance, which is beneficial for the transport and transfer of photogenerated electrons. This demonstrates that the N-TiO2 / Sv-ZIS composite material facilitates effective charge separation / transfer, thereby improving photocatalytic activity.

[0074] (7) Hydrogen evolution analysis

[0075] The photoelectrochemical activity of different samples in water splitting and hydrogen evolution was evaluated under visible light (λ>420nm) irradiation, using 0.5M NaSO4 solution as the electrolyte and a sample with an area of ​​2.5 x 1 cm². 2 Using a Ti mesh as the working electrode and applying a constant bias voltage of 0.6V, the catalyst was subjected to photoelectrocatalytic water splitting tests. The hydrogen evolution test results are as follows: Figure 10 As shown, all tested samples exhibited H2 evolution activity. Furthermore, with increasing Sv-ZIS loading, the hydrogen evolution rate of N-TiO2 / Sv-ZIS continuously increased compared to N-TiO2. Specifically, N-TZ-0.025 achieved a hydrogen production rate of 297.5 mmol / g within 6 hours. The significant improvement in the photoelectrocatalytic hydrogen production performance of N-TiO2 / Sv-ZIS is attributed to the formation of the Z-shaped structure and the accelerated separation of photogenerated carriers induced by S vacancies as electron traps. Under applied bias, photoelectrocatalysis showed improved photoelectric conversion efficiency and reduced recombination rate of photogenerated carriers compared to photocatalytic water splitting.

[0076] (8) EPR analysis

[0077] Figure 11 EPR images of N-TiO2, Sv-ZIS, and the N-TiO2 / Sv-ZIS-0.025 composite material are shown. After 6 minutes of illumination, the DMPO-·OH signal of TiO2 / ZnIn2S4-Sv is significantly stronger than that of N-TiO2, while the DMPO-·OH signal of ZnIn2S4 is relatively weaker. This is mainly because the oxidation potential of photogenerated holes in the valence band of N-TiO2 (2.39V) is more positive than that in the valence band of ZnIn2S4, suggesting that photogenerated holes mainly reside in the valence band of N-TiO2. The DMPO-·OH signal of N-TiO2 / ZnIn2S4-Sv is also shown. - The signal is significantly stronger than that of N-TiO2 and Sv-ZnIn2S4, with the signal of N-TiO2 being relatively weak. This is mainly due to the suitable conduction band potential of ZnIn2S4, thus DMPO-·O2 - The signal is relatively strong, indicating that photogenerated electrons mainly accumulate in the conduction band of ZnIn2S4. These results are in good agreement with the Z-scheme mechanism.

[0078] (8) Z-type mechanism analysis

[0079] By constructing Z-shaped heterojunctions, the separation efficiency of photogenerated carriers can be improved, greatly enhancing the photocatalytic performance of the photocatalyst. The Z-mechanism is as follows: Figure 12As shown, under visible light irradiation, valence band electrons of both N-TiO2 and Sv-ZIS transition to their respective conduction bands. Due to band bending and the built-in electric field at the interface, photogenerated electrons in the N-TiO2 conduction band spontaneously transfer to the Sv-ZIS valence band and recombine with holes in the Sv-ZIS valence band. Simultaneously, photogenerated holes in the N-TiO2 valence band and photogenerated electrons in the Sv-ZnIn2S4 conduction band remain unchanged, participating in the photocatalytic redox reaction. Combined with EPR analysis, in the photoelectrochemical water splitting and hydrogen evolution test, the working electrode was a Z-type N-TiO2 / ZnIn2S4-Sv-0.025 heterojunction photoanode, and the cathode was a Pt electrode, with a bias voltage of 0.6V applied. Because S... v -ZIS has a CB of -0.845 eV and can generate O2. - Active free radicals, TAs has a VB of 2.75 eV, and can generate ·OH active free radicals. Simultaneously, photogenerated electrons from the conduction band of Sv-ZnIn2S4 are transferred to the Pt electrode, reacting with H+. + Combine to generate H2.

[0080] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst, characterized in that, Includes the following steps: (1) Preparation of conical N-TiO2 Titanium mesh loaded with conical TiO2 was placed in a mixed solution of triethylamine, ethanol, sulfuric acid and deionized water, and then transferred to a reaction vessel. After hydrothermal reaction, it was washed and calcined to obtain conical N-TiO2. (2) Preparation of rod-shaped N-TiO2 / Sv-ZIS A titanium mesh loaded with conical N-TiO2 was placed in a homogeneous mixed solution of ZnCl2, InCl3·4H2O, thioacetamide, and ethylene glycol. The solution was then transferred to a reaction vessel, subjected to solvothermal reaction, washed, and vacuum dried to obtain the rod-shaped N-TiO2 / Sv-ZIS photocatalyst. The ZnCl2 content was 0.025 mmol, and the InCl3 content was... . 4H₂O is 0.05 mmol, thioacetamide is 0.4 mmol, and ethylene glycol is 30 ml, or ZnCl₂ is 0.1 mmol and InCl₃ is 0.1 ml. . 4H₂O is 0.2 mmol, thioacetamide is 1.6 mmol, and ethylene glycol is 30 ml, or ZnCl₂ is 0.05 mmol and InCl₃ is 0.2 mmol. . 4H2O is 0.1 mmol, thioacetamide is 0.8 mmol, and ethylene glycol is 30 ml.

2. The method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst according to claim 1, characterized in that: In step (1), the preparation method of the titanium mesh loaded with conical TiO2 includes the following steps: firstly, using a titanium mesh with an area of ​​2x3 cm... 2 A clean titanium mesh with a thickness of 0.27 mm and a mesh size of 100 was used as the substrate. A mixed solution of acetylacetone and tetraisopropyl titanate was added dropwise to a 0.5 mol / L Na2EDTA aqueous solution, wherein the volume ratio of tetraisopropyl titanate, acetylacetone and Na2EDTA aqueous solution was 3:20:

180. After stirring at room temperature for 20-30 minutes until homogeneous, the mixture was transferred together with the clean titanium mesh to a reactor for hydrothermal reaction. After the hydrothermal reaction was completed, the mixture was washed with anhydrous ethanol and deionized water, and then vacuum dried to obtain a titanium mesh loaded with conical TiO2.

3. The method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst according to claim 2, characterized in that: The hydrothermal reaction of the titanium mesh is carried out in an oven at a temperature of 180-200℃ for 5-7 hours, followed by drying at a temperature of 40-60℃ for 2-3 hours.

4. The method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst according to claim 1, characterized in that: In step (1), the titanium mesh loaded with conical TiO2 is placed in a mixed solution of triethylamine, 0.5 mol / L sulfuric acid, ethanol and deionized water and ultrasonically mixed for 20-30 minutes. The ultrasonic machine operates at a frequency of 60-90 kHz and a power of 50-150 W. The ultrasonic temperature is room temperature. The volume ratio of triethylamine, 0.5 mol / L sulfuric acid, ethanol and deionized water is 12:1:200:

100. After ultrasonication, the titanium mesh and the mixed solution are transferred together to a reaction vessel for hydrothermal reaction.

5. The method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst according to claim 1, characterized in that: In step (1), the hydrothermal reaction is carried out in an oven at a temperature of 110-120°C for 10-12 hours. After the hydrothermal reaction is completed, the product is washed with anhydrous ethanol and deionized water. After washing, the product is placed in a muffle furnace for high-temperature calcination and annealing at a temperature of 400-500°C for 2-4 hours to obtain nitrogen-doped conical TiO2, denoted as N-TiO2.

6. The method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst according to claim 1, characterized in that: In step (2), the solvothermal reaction is carried out in an oven at a temperature of 140-180°C and a holding time of 18-24 hours.

7. The method for preparing a rod-shaped N-TiO2 / Sv-ZIS photocatalyst according to claim 1, characterized in that: In step (2), after the solvothermal reaction is completed, the mixture is washed with anhydrous ethanol and deionized water, and then vacuum dried at a temperature of 40-60°C for 10-12 hours.

8. A rod-shaped N-TiO2 / Sv-ZIS photocatalyst prepared by the method according to any one of claims 1-7.

9. The rod-shaped N-TiO2 / Sv-ZIS photocatalyst of claim 8 is used for photoelectrocatalytic water splitting to produce hydrogen under simulated light conditions with a bias voltage applied simultaneously.

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