Ti3C2 (at) AgNPs (at) BiOI compound as well as preparation method and application thereof

Abstract

The invention discloses a Ti3C2 (at) AgNPs (at) BiOI compound as well as a preparation method and application thereof, titanium nitride is taken as a matrix, silver nitrate (AgNO3) is taken as an Ag source, and the titanium nitride and silver nanoparticle compound (Ti3C2 (at) AgNPs) is synthesized by a hydrothermal method. And synthesizing the Ti3C2 (at) AgNPs serving as a matrix, a Bi source and an I source to obtain the Ti3C2 (at) AgNPs (at) BiOI compound. Wherein Ti3C2 serves as a reducing agent to reduce Ag < + > into silver nanoparticles (AgNPs), introduction of an additional reducing agent is avoided, and Ti3C2-AgNPs can promote effective separation of BiOI electrons and holes on the premise that the Ti3C2-AgNPs have the advantages of visible light absorption or band gap reduction, so that the photocatalytic activity of BiOI is improved. Meanwhile, the problems of high radiation coincidence rate of photo-induced electron-hole pairs and low photocatalytic efficiency of the material are solved.

Description

Technical Field

[0001] This invention relates to the field of photocatalyst preparation technology, and more specifically, to a Ti3C2@AgNPs@BiOI composite, its preparation method, and its application. Background Technology

[0002] Traditional wastewater treatment technologies, such as physical and biological methods, offer some relief but also have significant limitations. Physical methods, such as adsorption, coagulation-sedimentation, and ultrafiltration, often merely transfer pollutants from one medium to another, potentially leading to new pollution problems. Furthermore, these methods are frequently costly, limiting their application. Biological treatment is more efficient, affordable, and less toxic than physical methods, but it faces challenges such as long treatment cycles, specific conditions, and susceptibility to microbial populations, making its application relatively cumbersome. Therefore, traditional water treatment methods are insufficient for treating dye wastewater, necessitating the development of a new, efficient, and environmentally friendly water treatment technology.

[0003] Currently, photocatalysis, as an emerging advanced oxidation technology, has attracted widespread attention due to its advantages such as low cost, simple required conditions, and the ability to degrade pollutants into non-toxic and harmless substances. It is expected to become one of the most promising technologies for the efficient treatment of organic wastewater. Compared with traditional treatment methods, photocatalysis has many obvious advantages: First, most photocatalysts are non-toxic, harmless, and chemically stable, avoiding secondary pollution that may occur during the degradation process. Furthermore, they can be largely recycled and reused, reducing operating costs and making them environmentally friendly and economical materials. Second, photocatalysts directly use solar energy as an energy source, requiring no additional conditions and operating under natural conditions, thus saving energy and protecting the environment. Third, the catalytic reaction conditions of photocatalysts are mild, allowing for the adsorption and degradation of pollutants under natural conditions, resulting in a wide range of applications. Therefore, improving the catalytic performance of photocatalysts is key to the efficient removal of pollutants.

[0004] For example, CN115337942A discloses a method for preparing and applying Ag-TiO2 / BiOI composite photocatalytic materials. BiOI is grown in situ on Ag-TiO2 material to obtain Ag-TiO2 / BiOI materials. Silver doping of titanium dioxide solves the problem of the narrow light response range of titanium dioxide. Further composite with bismuth iodide makes it less likely for bismuth iodide to generate recombination centers for photogenerated electrons and holes, thus maximizing the advantages of both titanium dioxide and bismuth iodide. Due to the more uniform distribution of BiOI, the composite effect of the two materials is better, causing photogenerated electrons and holes to migrate towards lower potential energy directions, thereby promoting the effective separation of photogenerated carriers. Compared with products obtained by directly compositing Ag-TiO2 and BiOI materials, this composite exhibits better photocatalytic degradation. Although this patent improves the narrow light response range of titanium dioxide through silver doping, the composite material still requires high temperature and long time (hydrothermal temperature of 120℃ and hydrothermal time of 12h) to achieve good catalytic effects, resulting in low efficiency. Summary of the Invention

[0005] The main technical problem to be solved by this invention is to address the shortcomings of existing Ag-TiO2 / BiOI composite photocatalytic materials, such as the need to improve their catalytic efficiency, and to provide a Ti3C2@AgNPs@BiOI composite.

[0006] Another technical problem solved by the present invention is to provide a method for preparing the Ti3C2@AgNPs@BiOI complex.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A method for preparing a Ti3C2@AgNPs@BiOI complex, comprising the following steps: S1. Dissolve Ti3C2 in water, then add AgNO3 solution. After mixing, the concentration ratio of Ti3C2 solution to AgNO3 solution is 1~14:1. Perform hydrothermal reaction at 50~100℃ for 1~6 min to obtain Ti3C2@AgNPs solution. S2. Add Bi source and I source to Ti3C2@AgNPs solution, dissolve and adjust the solution to acidity, heat in oil bath at 50~100℃ for 6~14h, and obtain Ti3C2@AgNPs@BiOI complex after centrifugation and drying.

[0009] Furthermore, the preparation steps of the Ti3C2 solution include: dissolving LiF in hydrochloric acid solution, adding TiAlC2, reacting at 35 °C for 24 h, and obtaining Ti3C2 after centrifugation and drying.

[0010] Furthermore, the concentration ratio of the Ti3C2 solution to the AgNO3 solution is 1:1~10.

[0011] Furthermore, the reaction temperature in S1 is 70℃, and the reaction time is 3 minutes.

[0012] Furthermore, the Bi source includes Bi(NO3)3. One or more of 5H2O, Bi2(SO4)3, and Bi2(CO3)3; the I source includes KI or NaI.

[0013] Furthermore, the addition ratio of Ti3C2@AgNPs to Bi source and I source is 0.01~1:3:1.

[0014] Furthermore, the pH value of the solution described in step S2 is 2.5 to 3.5.

[0015] Furthermore, in step S2, the oil bath temperature is 70°C and the reaction time is 10 hours.

[0016] A Ti3C2@AgNPs@BiOI composite was prepared by the above method, and the Ti3C2@AgNPs@BiOI composite was used as a photocatalyst.

[0017] Compared with existing technologies, the beneficial effects are: This invention uses Ti3C2 as a matrix and AgNO3 as a precursor to prepare a Ti3C2@AgNPs composite via hydrothermal synthesis. Then, using Ti3C2@AgNPs as a support, Bi(NO3)3 is selected... Ti3C2@AgNPs@BiOI complexes were synthesized under oil bath conditions using 5H2O as the Bi source and KI as the I source. The Ti3C2 used in this invention not only possesses reducing properties but also... + Reduced to silver nanoparticles (AgNPs), Ti3C2@AgNPs exhibits advantages in improving visible light absorption or reducing band gap. It can also serve as a co-catalyst material, possessing excellent electron-accepting capabilities, promoting the effective separation and transfer of electrons and holes in BiOI, thereby enhancing BiOI activity. Ag effectively reduces the recombination probability of photogenerated electron-hole pairs, increases the probability of photogenerated charge separation, and inhibits photocorrosion of Ag-based materials. Simultaneously, the intensity of the diffraction peaks of titanium carbide composited with silver nanoparticles significantly decreases, and the interlayer spacing increases, thereby increasing the material's adsorption capacity for pollutants. This allows for better contact between the catalyst and pollutants, while also promoting the transfer of photogenerated charge carriers, improving the catalyst's catalytic performance and thus enhancing its catalytic efficiency for pollutants.

[0018] The Ti3C2@AgNPs@BiOI composite prepared in this invention exhibits a low electron-hole recombination rate under light irradiation, a narrow band gap, a large specific surface area, a certain pore size distribution, and excellent adsorption capacity. When the MO concentration is 50 mg / L... -1 The optimal dosage of the Ti3C2@AgNPs@BiOI composite was 10 mg. After 50 min of light irradiation, the MO degradation rate reached 80%. The Ti3C2@AgNPs@BiOI composite material exhibited a broad visible light absorption capacity and excellent photocatalytic effect. Attached Figure Description

[0019] Figure 1 These are scanning electron microscope (SEM) images: A is the SEM image of Ti3C2, B is the SEM image of Ti3C2@AgNPs, and C and D are the SEM images of the Ti3C2@AgNPs@BiOI complex. Figure 2 This is an X-ray energy chromatogram. A represents I, B represents Bi, C represents Ti, D represents C, E represents O, F represents Ag, and G represents the Ti3C2@AgNPs@BiOI complex. Figure 3 The image shows the XRD patterns of the complexes Ti3C2@AgNPs@BiOI and Ti3C2. Figure 4 The photocurrent it diagrams are of the composites Ti3C2@AgNPs@BiOI and Ti3C2@AgNPs and Ti3C2. Figure 5 The images show the EIS spectra of the complexes Ti3C2@AgNPs@BiOI and Ti3C2@AgNPs and Ti3C2. Figure 6 The image shows the CV curves of the complexes Ti3C2@AgNPs@BiOI and Ti3C2. Figure 7 The degradation rate of MO by the Ti3C2@AgNPs@BiOI complex synthesized at different hydrothermal reaction times in Example 2: 1 min (a), 2 min (b), 3 min (c), 4 min (d), 5 min (e) and 6 min (f); Figure 8 The degradation rate of MO by the Ti3C2@AgNPs@BiOI complex synthesized with different hydrothermal reactant ratios in Example 2: 1:1 (a), 5:1 (b), 8:1 (c), 10:1 (d), 12:1 (e) and 14:1 (f); Figure 9The degradation rate of MO by the Ti3C2@AgNPs@BiOI complex synthesized at different hydrothermal reaction temperatures in Example 2: 50 ℃ (a), 60 ℃ (b), 70 ℃ (c), 80 ℃ (d), 90 ℃ (e) and 100 ℃ (f); Figure 10 The different oil bath reaction times in Example 3 are: 6 h (a), 8 h (b), 10 h (c), 12 h (d) and The degradation rate of MO by the Ti3C2@AgNPs@BiOI complex synthesized at 14 h (e); Figure 11 The degradation rate of MO by the Ti3C2@AgNPs@BiOI complex synthesized in different oil bath reactant ratios in Example 3: 1.0 mL (a), 2.0 mL (b), 2.5 mL (c), 3.0 mL (d) and 4.0 mL (e) is shown. Figure 12 The degradation rate of MO by the Ti3C2@AgNPs@BiOI complex synthesized at different oil bath reaction temperatures in Example 3: 50 ℃ (a), 60 ℃ (b), 70 ℃ (c), 80 ℃ (d), 90 ℃ (e) and 100 ℃ (f); Figure 13 Adsorption capacity of Ti3C2@AgNPs@BiOI complex synthesized under optimal conditions; Figure 14 The degradation rate of MO catalyzed by Ti3C2, Ti3C2@AgNPs and Ti3C2@AgNPs@BiOI complex under visible light irradiation; Figure 15 The graph shows the degradation performance of the Ti3C2@AgNPs@BiOI complex on RhB and MB. a represents the photodegradation rate of MB, and b represents the degradation rate of RhB.

[0020] Detailed implementation method.

[0021] The following examples further explain and illustrate the invention, but the specific examples do not limit the invention in any way.

[0022] Example 1 This embodiment provides a method for preparing a Ti3C2@AgNPs@BiOI composite, the preparation steps of which include: Preparation of S1.Ti3C2; Weigh 1.5 g LiF, add 14.89 mL concentrated HCl and 3.86 mL H2O to dissolve by sonication, then add 0.1 g TiAlC2 while stirring, and stir at 35 ℃ for 24 h. Centrifuge the solid-liquid mixture, wash with ultrapure water and anhydrous ethanol until neutral, and freeze-dry to obtain a gray-black Ti3C2 powder with catalytic properties.

[0023] Preparation of S2.Ti3C2@AgNPs complex; Weigh 20 mg of Ti3C2 and dissolve it in 2 mL of H2O by sonication. Weigh 0.0119 g of AgNO3 and dissolve it in water to prepare 6 mmol / L AgNO3. Take 1 mL of the sonicated Ti3C2 solution and add 9 mL of AgNO3 solution. Stir and heat in a 70 ℃ water bath for 3 min to obtain a Ti3C2@AgNPs composite solution with silver nanoparticles.

[0024] Preparation of S3.Ti3C2@AgNPs@BiOI complex; Mix 2.5 mL of 0.1 mg / mL Ti3C2@AgNPs, 25 mL of ethylene glycol, and 22.5 mL of H2O thoroughly. Then add 2.4 g of Bi(NO3)3. The solution was dissolved by sonication with 5H2O and 0.8 g KI, and the pH was adjusted to 3 using nitric acid and NaOH solution. The solution was heated in an oil bath at 70℃ for 10 h to obtain an orange suspension. After centrifugation and drying, an orange solid was obtained, which is the Ti3C2@AgNPs@BiOI complex.

[0025] (1) Scanning electron microscopy (SEM) characterization; The morphological characteristics of three materials, Ti3C2, Ti3C2@AgNPs, and Ti3C2@AgNPs@BiOI, were characterized using scanning electron microscopy (SEM). Figure 1 As shown in Figure A, Ti3C2 exhibits a blocky structure with a smooth surface. In Figure B, Ti3C2@AgNPs shows spherical particles on its surface compared to Ti3C2, increasing the specific surface area of ​​the material. In Figures C and D, the microstructure of the Ti3C2@AgNPs@BiOI composite shows a distinct lamellar structure, indicating that BiOI has successfully grown on the surface of Ti3C2@AgNPs, further increasing the specific surface area of ​​the composite material.

[0026] (2) X-ray energy dispersive spectroscopy (EDS) characterization; The elemental composition and relative content of the Ti3C2@AgNPs@BiOI complex were determined by energy-dispersive X-ray spectroscopy (EDS), such as... Figure 2As shown in the AF image, the EDS image of the Ti3C2@AgNPs@BiOI composite indicates that the prepared composite is mainly composed of C, O, Ti, Bi, Ag, and I, and BiOI has been successfully grown on Ti3C2@AgNPs. The G image, showing the overall elemental distribution, clearly illustrates the mass distribution of each element in the Ti3C2@AgNPs@BiOI composite, with Bi and I having the largest proportions, further indicating a good composite effect.

[0027] (3) X-ray diffraction (XRD) characterization; X-ray diffraction (XRD) was used to study and analyze Ti3C2@AgNPs@BiOI and Ti3C2 materials. Figure 3 As shown, XRD characterization of the crystal structures of the Ti3C2@AgNPs@BiOI composite and Ti3C2 revealed distinctly different diffraction patterns, indicating a significant change in the matrix's crystal structure during the composite process. According to PDF#78-1217, the diffraction peak at 38.7 ° belongs to the (111) plane, and the diffraction peak at 44.9 ° belongs to the (200) plane, suggesting that the synthesized Ti3C2 possesses a hexagonal layered structure. The addition of BiOI affected the presentation of the characteristic peaks of Ti3C2 in the synthesized composite Ti3C2@AgNPs@BiOI. The diffraction peaks at 29.6 °, 31.7 °, 45.4 ° and 55.1 ° correspond to the (102), (110), (200) and (212) crystal planes of the tetrahedral phase BiOI (PDF#10-0445), respectively. The figure shows the characteristic peaks of anions. Apart from these, there are no obvious impurity diffraction peaks, which indicates that the sample of Ti3C2@AgNPs@BiOI composite was successfully synthesized.

[0028] (3) Characterization of photoelectrochemical properties; Further investigation was conducted on the photoelectrochemical properties of the Ti3C2@AgNPs@BiOI complex. The it curves, EIS curves, and CV curves of the Ti3C2@AgNPs@BiOI complex, Ti3C2@AgNPs, and Ti3C2 were obtained.

[0029] like Figure 4 As shown, the Ti3C2@AgNPs@BiOI composite, Ti3C2@AgNPs, and Ti3C2 demonstrate that the mesoporous lamellar structure is beneficial for effective charge separation. like Figure 5As shown, the arc radius of the Ti3C2@AgNPs@BiOI composite electrode is significantly smaller than that of the other two materials, indicating that the Ti3C2@AgNPs@BiOI composite electrode has lower impedance. This suggests that the Ti3C2@AgNPs@BiOI composite can exhibit more efficient charge transfer.

[0030] like Figure 6 As shown, the symmetrical trend of the curves indicates that the reaction occurring on the electrode surface is reversible and that the electrode material has high activity. Among them, the Ti3C2@AgNPs@BiOI composite has the highest peak intensity, indicating that the reaction of this composite material on the electrode surface generates the largest current and the material has the lowest resistance, which is conducive to the generation of photocurrent. Compared with Ti3C2, it has better optical properties.

[0031] Example 2 This embodiment is based on the preparation method in Example 1, and optimizes the hydrothermal reaction conditions and reactant ratios in step S2: (1) Based on Example 1, the hydrothermal reaction time was set to 1 min, 2 min, 3 min, 4 min, 5 min, and 6 min respectively, according to... Figure 7 As shown, the catalytic effect increases with increasing hydrothermal time from 1 to 3 minutes, but decreases after 4 minutes, indicating that the optimal reaction time is 3 minutes.

[0032] (2) Under optimal hydrothermal time conditions, the ratios of Ti3C2 solution to AgNO3 solution were set to 1:1, 5:1, 8:1, 10:1, 12:1, and 14:1, respectively. Figure 8 As shown, the Ti3C2@AgNPs@BiOI complex prepared by synthesizing Ti3C2@AgNPs with a synthesis ratio of 10:1 exhibits the best catalytic effect.

[0033] (3) Under the optimal hydrothermal time and reactant ratio conditions, the hydrothermal temperatures were set to 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃ and 100 ℃ respectively, such as Figure 9 As shown, when the hydrothermal reaction temperature is set to 70 °C, the Ti3C2@AgNPs@BiOI composite material prepared by the synthesized Ti3C2@AgNPs composite exhibits the best photodegradation effect on MO.

[0034] Example 3 This embodiment is based on the preparation method in Example 1. Under the optimal conditions in step S2, the oil bath reaction conditions and the amount of Ti3C2@AgNPs added in S3 are further optimized: (1) Set the oil bath time to 6 h, 8 h, 10 h, 12 h and 14 h respectively, such as Figure 10As shown, the catalytic effect increases with increasing oil bath time from 6 to 10 hours, but decreases after 12 hours. Therefore, the optimal oil bath reaction time is 10 hours.

[0035] (2) Under the optimal oil bath time conditions, the addition amounts were set to 1.0 mL, 2.0 mL, 2.5 mL, 3.0 mL, and 4.0 mL, respectively. Figure 11 As shown, the Ti3C2@AgNPs@BiOI complex exhibits the best catalytic effect when 2.5 mL of Ti3C2@AgNPs solution is added.

[0036] (3) Under the optimal oil bath time and Ti3C2@AgNPs addition conditions, the oil bath temperature was set to 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃ and 100 ℃ respectively, as follows: Figure 12 As shown, the synthesized Ti3C2@AgNPs@BiOI complex exhibits the best catalytic effect when the oil bath reaction temperature is set to 70 ℃.

[0037] Example 4 In this embodiment, the Ti3C2@AgNPs@BiOI complex prepared under optimal conditions was used as the experimental object, and MO solutions of different concentrations were used as adsorbates to study the adsorption performance and photocatalytic performance of the Ti3C2@AgNPs@BiOI complex.

[0038] (1) 0.01 g of the Ti3C2@AgNPs@BiOI complex was mixed with 10 mL of MO solutions of different concentrations. The mixture was stirred for 40 min under no-light conditions. Every 5 min, 0.4 mL of the reaction suspension in the reactor was taken to measure the absorbance. Finally, the concentration of the MO solution was determined by measuring the absorbance at approximately 465 nm using a UV spectrophotometer. Figure 13 As shown, when the MO concentration is 50~90 mg L... -1 At that time, the Ti3C2@AgNPs@BiOI complex reached saturated adsorption equilibrium after 5 min.

[0039] (2) Mix 0.01 g Ti3C2@AgNPs@BiOI complex with 10 mL of 50 mg L -1The MO solution was mixed and irradiated continuously for 50 min under constant stirring conditions using a 50 W halogen tungsten lamp. During this period, a sample was taken from the reactor every 5 min for a total of four times, then every 10 min for a total of three times. Each sample was 0.4 mL, and its absorbance at approximately 465 nm was measured, corresponding to the characteristic absorption peak of MO. Finally, by analyzing these absorbance data and referring to a pre-plotted MO standard curve, the concentration of MO in the reaction system could be accurately calculated. According to the formula: Degradation rate = [(C0-C t ) / C0] 100% The degradation rate of MO solution at each time period was calculated. Here, C0 represents the initial MO concentration (mg / L). -1 ), C t This represents the concentration of MO (mg / L) after photocatalytic time t (min). -1 ).

[0040] like Figure 14 As shown, after 30 minutes of light irradiation, the photodegradation rate of the Ti3C2@AgNPs@BiOI composite reached 83%, while the degradation rate of Ti3C2@AgNPs with only silver nanoparticles was only 46%, and the degradation rate of pure Ti3C2 was only 30%. Clearly, the introduction of BiOI can improve the catalytic performance of titanium carbide-based catalysts, because [Bi2O2]... 2+ The staggered arrangement of graphite layers and I reduces the recombination of excited electrons and holes. By composite BiOI onto the composite material, the radiative recombination rate of photogenerated electron-hole pairs is reduced, thus effectively improving the catalytic performance.

[0041] Example 5 This embodiment further utilizes the degradation performance of the Ti3C2@AgNPs@BiOI complex on other pollutants such as RhB and MB, for example... Figure 15 As shown, the Ti3C2@AgNPs@BiOI composite is also effective in the photodegradation of MB and RhB. The degradation rates for RhB and MB were 30% and 76%, respectively, indicating that the Ti3C2@AgNPs@BiOI composite also exhibits photocatalytic activity in the degradation of other organic pollutants.

[0042] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a Ti3C2@AgNPs@BiOI composite, characterized in that, The preparation steps include: S1. Dissolve Ti3C2 in water, then add AgNO3 solution. After mixing, the concentration ratio of Ti3C2 solution to AgNO3 solution is 1~14:

1. Perform hydrothermal reaction at 50~100℃ for 1~6 min to obtain Ti3C2@AgNPs solution. S3. Add Bi source and I source to Ti3C2@AgNPs solution, dissolve and adjust the solution to acidity, heat in oil bath at 50~100℃ for 6~14h, and obtain Ti3C2@AgNPs@BiOI complex after centrifugation and drying.

2. The method for preparing the Ti3C2@AgNPs@BiOI composite according to claim 1, characterized in that, The preparation steps of the Ti3C2 solution include: dissolving LiF in hydrochloric acid solution, adding TiAlC2, reacting at 35°C for 24 hours, and obtaining Ti3C2 after centrifugation and drying.

3. The method for preparing the Ti3C2@AgNPs@BiOI composite according to claim 1, characterized in that, The concentration ratio of the Ti3C2 solution to the AgNO3 solution is 1:1~10.

4. The method for preparing the Ti3C2@AgNPs@BiOI composite according to claim 1, characterized in that, The reaction temperature in S1 is 70℃, and the reaction time is 3 minutes.

5. The method for preparing the Ti3C2@AgNPs@BiOI composite according to claim 1, characterized in that, The Bi source includes Bi(NO3)3. One or more of 5H2O, Bi2(SO4)3, and Bi2(CO3)3; the I source includes KI or NaI.

6. The method for preparing the Ti3C2@AgNPs@BiOI composite according to claim 1, characterized in that, The addition ratio of Ti3C2@AgNPs to Bi and I sources is 0.01 to 1:3:

1.

7. The method for preparing the Ti3C2@AgNPs@BiOI composite according to claim 1, characterized in that, The pH value of the solution described in step S2 is 2.5~3.

5.

8. The method for preparing the Ti3C2@AgNPs@BiOI composite according to claim 1, characterized in that, In step S2, the oil bath temperature is 70℃ and the reaction time is 10h.

9. A Ti3C2@AgNPs@BiOI composite, characterized in that, It is prepared by the method described in any one of claims 1 to 8.

10. The application of the Ti3C2@AgNPs@BiOI composite according to claim 9, characterized in that, The Ti3C2@AgNPs@BiOI composite is used as a photocatalyst.

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