InP / Ti3C2Tx composite photocatalyst as well as preparation method and application thereof

Abstract

The invention provides an InP / Ti3C2Tx composite photocatalyst as well as a preparation method and application thereof, and relates to the technical field of photocatalytic materials. According to the InP / Ti3C2Tx composite photocatalyst, InP and single-layer Ti3C2Tx are used as raw materials, the InP and the single-layer Ti3C2Tx are mixed with deionized water, and then the mixture is subjected to ultrasonic treatment, cooling and washing to obtain the InP / Ti3C2Tx composite photocatalyst. The mass ratio of the InP to the single-layer Ti < 3 > C < 2 > T < x > is (1-7): 1, the ultrasonic treatment temperature is room temperature, the ultrasonic treatment time is 10 minutes, and the ultrasonic treatment frequency is 20 kHZ. The InP quantum dots are loaded on the surface of the single-layer Ti3C2Tx through an in-situ anchoring technology, the Schottky junction type composite photocatalyst is constructed, and the composite catalyst can be used for efficiently preparing H2O2 through photocatalysis under the irradiation of visible light under the condition of no sacrificial agent. The InP / Ti3C2Tx composite photocatalyst has the advantages of being simple in preparation process, high in catalytic activity and the like, the application range of InP quantum dots in the field of photocatalysis is expanded, a new solution is provided for the technology for preparing H2O2 through sacrificial agent-free photocatalysis, and the InP / Ti3C2Tx composite photocatalyst has important significance in promoting development of a clean energy technology.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic materials, and in particular to an InP / Ti3C2T x Composite photocatalyst, preparation method and application thereof. Background Art

[0002] Hydrogen peroxide (H2O2) has the unique advantage of being a clean energy carrier, decomposing into water and oxygen, making it an environmentally friendly option for a variety of applications, including bleaching, green chemical synthesis, and wastewater treatment. Photocatalytic synthesis of H2O2 (via the reaction of O2 and H2O) is an economical, clean, and green method with broad potential applications.

[0003] However, most of the photocatalysts reported so far require sacrificial agents (such as ethanol or methanol) to quench the photogenerated holes (h + ) and promote the reduction of O2 to H2O2. This requirement not only increases the cost of H2O2 production but also hinders the development of photocatalytic technology. Therefore, the development of novel, environmentally friendly, and sacrificial agent-free H2O2 production methods is crucial.

[0004] Quantum dots (QDs), zero-dimensional nanomaterials with sizes in the range of a few nanometers, have attracted widespread attention in the field of photocatalysis due to their unique quantum size effect and excellent optoelectronic properties. However, due to the limited efficiency of photogenerated charge separation, their performance still fails to meet the requirements of practical applications. Therefore, the development of novel composite systems to improve charge separation efficiency and catalytic stability is crucial.

[0005] Indium phosphide (InP) quantum dots, as non-toxic and environmentally friendly III-V semiconductor materials, are ideal candidates for direct conversion of solar energy into chemical fuels. Although InP quantum dots have been extensively studied in the fields of photoelectrodes and solar cells, their photocatalytic properties have limited their application in the photocatalytic production of H2O2 without sacrificial agents.

[0006] MXene is a new type of two-dimensional material with a layered graphene-like structure, composed of transition metal carbides, nitrides or carbonitrides, with the molecular formula Mn +1 XnT x This type of material is obtained by selectively etching the ternary MAX phase (Mn +1 AXn), where n = 1, 2 or 3, M represents an early transition metal such as Sc, Ti, Zr, V, X represents carbon and / or nitrogen, T x represents surface functional groups (such as -O, -OH and / or -F).

[0007] Among the many MXene materials, Ti3C2T xTi3C2T has attracted much attention due to its excellent metallic conductivity and rich surface functional groups. x The suitable Fermi level and high work function make it an ideal material for forming Schottky junction with semiconductors, which can effectively promote the separation of photogenerated carriers. x As a co-catalyst, it can significantly enhance the photocatalytic H2O2 production activity of CdS.

[0008] Therefore, how to convert Ti3C2T x By stably compounding with InP quantum dots, a photocatalyst is obtained that can efficiently photocatalytically prepare H2O2 without sacrificial agents, which is of great significance for the green production of H2O2. Summary of the Invention

[0009] In view of this, the present invention provides an InP / Ti3C2T x Composite photocatalyst and its preparation method and application. The present invention uses in-situ anchoring technology to load InP quantum dots on a single layer of Ti3C2T x Surface, constructed Schottky junction InP / Ti3C2T x The composite photocatalyst can efficiently photocatalytically prepare H2O2 without sacrificial agents under visible light irradiation, and has excellent photocatalytic activity and good stability, and has good application prospects and industrial value.

[0010] The first aspect of the present invention provides an InP / Ti3C2T x The preparation method of the composite photocatalyst specifically comprises the following steps: Preparation of InP and single-layer Ti3C2T x Then, the two were mixed with deionized water, ultrasonically treated, cooled, and washed to obtain InP / Ti3C2T x Composite photocatalyst.

[0011] Preferably, the InP is synthesized by a hot injection method, and the specific steps are as follows: indium chloride (InCl3) is mixed with oleylamine, and then heated in a nitrogen atmosphere for heat treatment, and then heated and injected with a phosphorus source precursor for reaction. After the reaction is completed, the product is purified and dried to obtain InP; the ratio of InCl3, oleylamine, and phosphorus source precursor is (0.55-0.60) g:(8-12) mL:(0.4-0.6) mL, more preferably 0.55 g:10 mL:0.5 mL, and the phosphorus source precursor is tris(dimethylamino)phosphine; the heating treatment temperature is 120°C, and the heating treatment time is 60 min; the temperature after heating is 180°C; the reaction temperature is 180°C, and the reaction time is 30 min; the cooling is natural cooling; the product purification method is ethanol purification, the drying temperature is 60°C, and the drying time is 8-12 h.

[0012] Preferably, the single layer Ti3C2T x The Ti3AlC2 solid powder was acid-etched to obtain multilayer Ti3C2T x , multilayer Ti3C2T x The monolayer Ti3C2T was obtained by washing with pure water until neutral and freeze-drying, followed by ultrasonic stripping and centrifugation. The supernatant was collected and dried. x ; The acid etching method is as follows: Ti3AlC2 solid powder is mixed with acid solution at a mass volume ratio of 1 g:10 mL, stirred at 300-500 rpm at 40 ° C for 36 h, and centrifuged to obtain multilayer Ti3C2T x Precipitation; the acid solution was prepared as follows: in 10 mL of 9 mol L -1 Dissolve 1 g of NaF in HCl solution to obtain an acid solution; The ultrasonic peeling is carried out at room temperature and in an N2 atmosphere. The ultrasonic peeling time is 2 h and the ultrasonic peeling frequency is 20 kHz. The drying temperature is 60° C. and the drying time is 8-12 h.

[0013] Preferably, the InP and single-layer Ti3C2T x The mass ratio of is (1-7):1, the ultrasonic treatment temperature is room temperature, the ultrasonic treatment time is 10 min, and the ultrasonic treatment frequency is 20 kHz.

[0014] The second aspect of the present invention is to provide an InP / Ti3C2T prepared according to the above method. x Composite photocatalyst.

[0015] The third aspect of the present invention is to provide an InP / Ti3C2Tx Application of composite photocatalyst in photocatalytic preparation of H2O2, the InP / Ti3C2T x The composite photocatalyst is InP / Ti3C2T x Composite photocatalyst.

[0016] Preferably, the InP / Ti3C2T x The application method of the composite photocatalyst is as follows: InP / Ti3C2T x The composite photocatalyst was dispersed in pure water. After ultrasonic dispersion, the mixture was purged with oxygen in the dark until it reached oxygen saturation. Then, the suspension was irradiated with a 300 W xenon lamp (λ>420 nm) to obtain H2O2.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects: The present invention uses in-situ anchoring technology to load InP quantum dots on a single layer of Ti3C2T x Surface, constructed Schottky junction InP / Ti3C2T x Composite photocatalyst. Ti3C2T x The introduction of InP significantly improved the photocatalytic efficiency and enhanced the selectivity of O2 two-electron reduction to H2O2.

[0018] InP / Ti3C2T of the present invention x The composite catalyst exhibited excellent catalytic performance in actual water, with an H2O2 synthesis efficiency of 4.21 mmol g in industrial wastewater. -1 h -1 The H2O2 synthesis efficiency in tap water is 14.68 mmol g -1 h -1 .

[0019] The sacrificial agent-free photocatalytic H2O2 preparation system based on InP quantum dots in the present invention not only expands the application scope of InP quantum dots in the field of photocatalysis, but also provides a new technical path for the development of photocatalytic technology, which is of great significance to promoting the development of clean energy technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 InP, Ti3C2T x and 5InP / Ti3C2T x XRD spectrum of the composite catalyst; Figure 2 Ti3C2T x, InP quantum dots and InP / Ti3C2T x HRTEM and SAED characterization of the composite catalyst; (a) and (b) are Ti3C2T x HRTEM image of Ti3C2T; (c) x SAED image; (d) is HRTEM image of InP, (e) and (f) are 5InP / Ti3C2T x HRTEM image of the composite catalyst; Figure 3 Ti3C2T x , InP and 5InP / Ti3C2T x Schematic diagram of the yield of H2O2 produced by photocatalysis; Figure 4 5InP / Ti3C2T x Schematic diagram of the yield of H2O2 produced by the composite catalyst in industrial wastewater and tap water after photocatalysis for 1 h; Figure 5 5InP / Ti3C2T under H2O2, simulated sunlight and H2O2 / simulated sunlight conditions x COD removal rate (COD concentration = 120 mg / L, coking water 50 mL + H2O2 2 mL). DETAILED DESCRIPTION

[0022] The present invention provides an InP / Ti3C2T x The composite photocatalyst and its preparation method and application can be achieved by those skilled in the art by referring to the content of this article and appropriately improving the process parameters. It should be pointed out in particular that all similar replacements and modifications are obvious to those skilled in the art and they all fall within the scope of protection of the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0023] The technical solutions in the implementation cases of this application will be described clearly and completely below. Obviously, the embodiments described are only some of the embodiments of this application, not all of them. Based on the embodiments in this application, other embodiments obtained by ordinary technicians in this field without making creative work are all within the scope of invention protection. In the following examples, all raw materials are commercially available.

[0024] Unless otherwise specified, all experiments were repeated three times. Analysis of variance (ANOVA) and Duncan's multiple comparison analysis were performed using SPSS 21.0. The results are expressed as mean ± SD, and P < 0.05 indicated a significant difference.

[0025] Example 1: InP / Ti3C2T x The preparation method of the composite photocatalyst comprises the following steps: (1) Synthesis of indium phosphide quantum dots using hot injection Mix 0.55 g of InCl3 with 10 mL of oleylamine, heat the mixture to 120°C in a nitrogen atmosphere and hold for 60 min. Then heat the system to 180°C, inject 0.5 mL of tri(dimethylamino)phosphine, hold the system at 180°C for 30 min, and then naturally cool to room temperature. Add 50-80 mL of ethanol, let it stand for 30 min, and then centrifuge at 10,000 rpm. Dry the product at 60°C for 12 h to obtain InP. (2) Synthesis of single-layer Ti3C2T by etching Ti3AlC2 solid powder x At room temperature, 1 g of Ti3AlC2 solid powder was added into 10 mL of HCl (9 mol L) containing 1 g of NaF. -1 ) and stirred at 40 °C and 500 rpm for 36 h. The suspension was centrifuged to obtain multilayer Ti3C2T x The precipitate was washed with pure water until the pH of the system was 7 to complete the purification of the precipitate, and then the purified multilayer Ti3C2T x The precipitate was freeze-dried at -80 °C for 24 h, and the dried multilayer Ti3C2T x The suspension was added into 200 mL of deionized water and ultrasonicated at 20 kHz for 2 h at room temperature under N2 atmosphere. The suspension was then centrifuged at 3500 rpm for 15 min to remove the unpeeled residue. The supernatant was collected and dried into powder to obtain a single-layer Ti3C2T x ; (3) The InP prepared in step (1) and the single-layer Ti3C2T prepared in step (2) are x Composite photocatalysts with different ratios (1:1, 3:1, 5:1, and 7:1) were prepared by adding them into deionized water. InP was solidified on Ti3C2T by ultrasonic treatment at room temperature and 20 kHz for 10 min. x The surface of the material after ultrasonic treatment was taken out and cooled to room temperature, washed with pure water three times, and dried at 60 ° C for 12 h to obtain InP / Ti3C2T x Composite photocatalyst.

[0026] The InP / Ti3C2T x Composite photocatalyst based on InP and Ti3C2T x The ratios are different, respectively recorded as InP / Ti3C2T x、3InP / Ti3C2T x 、5InP / Ti3C2T x 、7InP / Ti3C2T x , corresponding to InP and Ti3C2T x Technical solutions with mass ratios of 1:1, 3:1, 5:1, and 7:1.

[0027] The InP, Ti3C2T x and 5InP / Ti3C2T x (Due to InP and Ti3C2T x The product performance is best when the mass ratio is 5:1, so it is used for characterization) The XRD spectrum of the composite catalyst is as follows Figure 1 As shown, transmission electron microscopy Figure 2 shown.

[0028] Depend on Figure 1 It can be seen that the (002) peak of Ti3AlC2 MAX shifts from 9.54° to 6.14° after etching, indicating that the Al element is removed and the multilayer Ti3C2T x MXene formation. Compared with Ti3AlC2, Ti3C2T x Most of the peaks of are weak and broad, which can be attributed to its thin lamellar structure.

[0029] The diffraction peaks detected at 26.2°, 30.5°, 43.5°, and 51.5° correspond to the (111), (200), (220), and (311) planes, respectively, which are in good agreement with the characteristic peaks of three-phase InP (JCPDS 32-0452). The absence of additional impurity peaks and high crystallinity confirm the successful preparation of InP. x The XRD spectrum of the composite catalyst shows that InP and Ti3C2T x The corresponding peaks indicate that InP / Ti3C2T x The composite catalyst was successfully constructed.

[0030] Depend on Figure 2 It can be seen that Ti3C2T x , InP and InP / Ti3C2T x The appearance of. Figure 2 (a, b) shows Ti3C2T x The morphology is a layered structure of parallel stacked nanosheets. Figure 2 b, Ti3C2T x The lattice spacing of the (002) plane is 1.43 nm. x There are obvious bright spots in the SAED pattern, proving that the crystal structure of the product is highly ordered ( Figure 2c). Figure 2 As shown in Figure d, the InP prepared by the present invention consists of spherical nanoparticles with a lattice spacing of 0.33 nm, which is attributed to the (111) crystal plane. x TEM images of the composite catalysts are shown in Figure 2. Figure 2 (e,f) show that in 5InP / Ti3C2T x HRTEM images of the composite catalyst ( Figure 2 Two different lattice spacing patterns can be observed in Figure e), with interplanar spacings of 1.43 nm and 0.33 nm, respectively, which is consistent with the Ti3C2T x It is consistent with the (002) and (111) planes of InP. Figure 2 f It can be seen that there is a heterojunction interface between the two materials in the composite system. These results show that in 5InP / Ti3C2T x In the composite catalyst, InP and Ti3C2T x There is a close coupling relationship between them, which can act as an electron to Ti3C2T x "Highways" of surface transfer.

[0031] Test Example 1 20 mg of different composite photocatalysts were dispersed in 50 mL of pure water and ultrasonicated at room temperature and 20 kHz for 20 min. The mixture was then purged with oxygen in the dark until it reached oxygen saturation. The suspension was then irradiated with a 300 W xenon lamp (λ>420 nm). The samples were collected at a specific time (60 min) and centrifuged. The results are shown in Figure 2. Figure 3 shown.

[0032] Depend on Figure 3 It can be seen that without adding sacrificial agents, different types of InP / Ti3C2T x All photocatalysts can catalyze the production of H2O2, among which 5InP / Ti3C2T x The maximum yield reached 21.31 mmol g -1 h -1 , which is 112 times that of pure InP.

[0033] Test Example 2 Testing 5InP / Ti3C2T in tap water and industrial wastewater x The efficiency is the same as that of test example 1, and the illumination time is 1h. The results are as follows Figure 4 shown.

[0034] Depend on Figure 4It can be seen that although the synthesis efficiency of H2O2 decreased in the complex system, the synthesis efficiency of H2O2 in industrial wastewater (wastewater from the phosphogypsum slag field of Yunnan Phosphate Group Co., Ltd., with excessive phosphorus content) and tap water was 4.21 mmol g -1 h -1 and 14.68 mmol g -1 h -1 It can be seen that the InP / Ti3C2T x The composite catalyst provides a new green method for producing H2O2.

[0035] Test Example 3 To study the effect of photocatalytic generation of H2O2, the synthesized H2O2 was used to degrade the chemical oxygen demand (COD) in coking wastewater (taken from a coking plant in Qujing, Yunnan) as follows: 20 mg 5InP / Ti3C2T x The composite photocatalyst was dispersed in 50 mL of coking wastewater and ultrasonicated at room temperature and 20 kHz for 20 min. The mixture was then purged with oxygen in the dark until it reached oxygen saturation. The suspension was then irradiated with a 300 W xenon lamp (λ>420 nm). The samples were collected at a specific time (60 min) and centrifuged. The results are shown in Figure 2. Figure 5 shown.

[0036] Depend on Figure 5 It can be seen that after irradiation with simulated sunlight, the photodegradation efficiency of COD reached about 45%, and the COD concentration increased from 120 mg / L to −1 Down to 67 mg L −1 , far below the emission standards of the coking industry.

[0037] In summary, the InP / Ti3C2T x The composite photocatalyst can efficiently photocatalytically produce H2O2 in pure water without sacrificial agent. x The composite catalyst has a large specific surface area, providing abundant active sites for photocatalytic reactions. The composite catalyst of the present invention exhibits a significantly enhanced photocatalytic H2O2 yield, which can reach up to 21.31 mmolg -1 h -1 , which is 112 times that of pure InP quantum dots. In addition, when the photocatalyst of the present invention is used in the treatment of coking wastewater, it can still stably catalyze the production of H2O2, thereby reducing the chemical oxygen demand (COD) of the coking wastewater, opening up new avenues for practical applications in the fields of environmental remediation and clean energy.

Claims

1. InP / Ti3C2T x The preparation method of the composite photocatalyst is characterized in that: The following steps are involved: Preparation of InP and single-layer Ti3C2T x Then, the two were mixed with deionized water, ultrasonically treated, cooled, and washed to obtain InP / Ti3C2T x Composite photocatalyst; The InP and single-layer Ti3C2T x The mass ratio of is (1-7):1, the ultrasonic treatment temperature is room temperature, the ultrasonic treatment time is 10 min, and the ultrasonic treatment frequency is 20 kHz.

2. The preparation method according to claim 1, characterized in that The InP is synthesized by hot injection method.

3. The preparation method according to claim 2, characterized in that The preparation method of InP is as follows: indium chloride and oleylamine are mixed, and then gradually heated in a nitrogen atmosphere for heating treatment, and then heated and quickly injected with a phosphorus source precursor for reaction, and after the reaction is completed, the product is purified and dried to obtain InP.

4. The preparation method according to claim 3, characterized in that The ratio of InCl3, oleylamine, and phosphorus source precursor is (0.55-0.60) g:(8-12) mL:(0.4-0.6) mL, the heating treatment temperature is 120°C, and the heating treatment time is 60 min; the temperature after heating is 180°C; the reaction temperature is 180°C, and the reaction time is 30 min.

5. The preparation method according to claim 1, characterized in that The Ti3C2T x Prepared by chemical etching.

6. The preparation method according to claim 5, characterized in that The Ti3C2T x The preparation method is as follows: Ti3AlC2 solid powder is acid-etched to obtain multilayer Ti3C2T x , multilayer Ti3C2T x The supernatant was collected and dried to obtain Ti3C2T.

7. The preparation method according to claim 6, characterized in that The acid etching method is as follows: Ti3AlC2 solid powder is mixed with acid solution at a mass volume ratio of 1 g:10 mL, stirred at 40 ° C for 36 h, and centrifuged to obtain multilayer Ti3C2T x ultrasonic stripping was carried out at room temperature and in a N2 atmosphere, the ultrasonic stripping time was 2 h, and the ultrasonic stripping frequency was 20 kHz.

8. InP / Ti3C2T x A composite photocatalyst, characterized in that Prepared by the method according to any one of claims 1 to 7.

9. InP / Ti3C2T x The application of the composite photocatalyst in the photocatalytic preparation of H2O2 is characterized in that: The InP / Ti3C2T x The composite photocatalyst is InP / Ti3C2T prepared by any method of claims 1-7 x Composite photocatalyst or InP / Ti3C2T as claimed in claim 8 x Composite photocatalyst.

10. The use according to claim 9, characterized in that The InP / Ti3C2T x The application method of composite photocatalyst is as follows: InP / Ti3C2T x The composite photocatalyst was dispersed in pure water. After ultrasonic dispersion, the mixture was purged with oxygen in the dark until it reached oxygen saturation. Then, the suspension was irradiated with a 300 W xenon lamp at λ>420 nm to obtain H2O2.

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