Red phosphorus / montmorillonite photoresponsive composite material, and preparation method and application thereof

Abstract

The present application relates to the technical field of photocatalyst, and particularly relates to a red phosphorus / montmorillonite light response composite material, a preparation method and application thereof. The preparation method is as follows: red phosphorus is removed and ultrasonically peeled to obtain flaky red phosphorus, and the flaky red phosphorus is stirred with montmorillonite in a first solvent, separated, and vacuum dried to obtain the red phosphorus / montmorillonite light response composite material. In the present application, the layered structure of the montmorillonite can provide a stable support framework for the red phosphorus, effectively inhibiting the recombination of photo-generated carriers of the red phosphorus, and the combination of the montmorillonite and the red phosphorus through the formation of P-O-Si chemical bonds can enhance the separation and transmission efficiency of the photo-generated carriers, improve the photocatalytic activity, and improve the photocatalytic removal of pollutants and antibacterial performance of the composite material, and the cyclic stability is good. At the same time, the montmorillonite can also enrich pollutants and bacteria in the surrounding environment by virtue of its strong adsorption capacity, so that the pollutants and bacteria are more easily contacted with the composite material, thereby improving the efficiency of the photocatalytic reaction.

Description

Technical Field

[0001] This invention relates to the field of photocatalyst technology, and in particular to a red phosphorus / montmorillonite photoresponsive composite material, its preparation method, and its application. Background Technology

[0002] Semiconductor photocatalysis technology has been developed as an alternative to water purification due to its advantages such as strong disinfection capabilities, energy saving, environmental friendliness, no toxic byproducts, and self-purification. When semiconductor materials are stimulated by light, they can generate electron-hole pairs, which can further generate reactive oxygen species (ROS) in the presence of oxygen. This has been proven to be effective and feasible in the photodegradation of organic pollutants and the inactivation of bacteria.

[0003] Traditional photocatalysts such as titanium dioxide (TiO) and zinc oxide (ZnO) can only be activated by the ultraviolet portion of the solar spectrum, which accounts for only 4% of the total spectrum, resulting in unsatisfactory photocatalytic efficiency. Therefore, researchers are dedicated to developing novel photocatalysts that can be activated by visible light. Red phosphorus (RP) is a low-cost, chemically stable, and biocompatible visible light semiconductor material; however, the rapid recombination of its photogenerated carriers limits its further utilization. Summary of the Invention

[0004] The purpose of this invention is to address the aforementioned shortcomings of the prior art by proposing a red phosphorus / montmorillonite photoresponsive composite material, its preparation method, and its application.

[0005] The first objective of this invention is to provide a method for preparing a red phosphorus / montmorillonite photoresponsive composite material, wherein red phosphorus is purified and ultrasonically exfoliated to obtain flake red phosphorus, and the flake red phosphorus and montmorillonite are stirred in a first solvent, separated, and vacuum dried to obtain the red phosphorus / montmorillonite photoresponsive composite material.

[0006] Furthermore, the mass ratio of flaky red phosphorus to montmorillonite is 0.1-0.9:1.

[0007] Furthermore, the montmorillonite is ground.

[0008] Furthermore, the montmorillonite is placed in a ball mill jar and ground thoroughly for 2-5 hours.

[0009] Furthermore, the first solvent is one or more of N-methylpyrrolidone, water, or ethanol; the stirring time is 1-4 hours.

[0010] Further, the specific operation for removing impurities is as follows: red phosphorus is ultrasonically dispersed in water to obtain a red phosphorus suspension, which is then subjected to a hydrothermal reaction, naturally cooled, washed, centrifuged, and vacuum dried; the concentration of the red phosphorus suspension is 0.08 g / mL, the hydrothermal reaction temperature is 180-200℃, and then it is vacuum dried at 65℃ for 12-24 h.

[0011] Furthermore, the specific operation of ultrasonic stripping is as follows: the impurity-removed red phosphorus is ultrasonically dispersed in a second solvent, then washed with ethanol, centrifuged, and vacuum dried; the second solvent is one or more of N-methylpyrrolidone, water, or ethanol.

[0012] Furthermore, the mass-to-volume ratio of the purified red phosphorus to the second solvent is 1:1 g / L; the ultrasonic power is 800W, and the time is 2-4 hours.

[0013] Furthermore, the centrifugation speed is 8000-12000 rpm for 5-20 min, followed by vacuum drying at 60-70℃ for 12-24 h.

[0014] A second objective of this invention is to provide a red phosphorus / montmorillonite photoresponsive composite material prepared using the above-described preparation method.

[0015] A third objective of this invention is to provide an application of the red phosphorus / montmorillonite photoresponsive composite material as described above as a photocatalyst for photocatalytic degradation of Orange II and antibacterial activity at wavelengths of 420-780 nm.

[0016] In the responsive composite material prepared in this invention, montmorillonite is a clay mineral with a special layered structure and a large specific surface area, exhibiting excellent ion exchange and adsorption properties. The layered structure of montmorillonite provides a stable supporting framework for red phosphorus, effectively inhibiting the recombination of photogenerated charge carriers. Furthermore, the bonding between montmorillonite and red phosphorus through the formation of PO-Si chemical bonds enhances the separation and transport efficiency of photogenerated charge carriers. The construction of the composite material overcomes the drawback of rapid recombination of photogenerated electrons and holes in red phosphorus, improving photocatalytic activity and enhancing the photocatalytic removal of pollutants and antibacterial performance. Simultaneously, montmorillonite, with its strong adsorption capacity, can enrich pollutants and bacteria in the surrounding environment, making it easier for pollutants and bacteria to contact the red phosphorus photocatalyst, thereby improving the efficiency of the photocatalytic reaction.

[0017] The responsive composite material prepared by this invention exhibits good cyclic stability.

[0018] The preparation methods of this invention all use common chemical reagents, which are widely available, inexpensive and readily available; the reaction equipment is simple, the reaction conditions are mild, and only a hydrothermal process is carried out, resulting in a low synthesis temperature and simple preparation steps; Attached Figure Description

[0019] Figure 1 The figures show the photocatalytic removal performance of Orange II by the products of Examples 1-2 and Comparative Examples 1-3 of this invention.

[0020] Figure 2 The products of Example 1 and Comparative Examples 1 and 2 of this invention exhibit visible light photocatalytic antibacterial properties.

[0021] Figure 3 These are X-ray diffraction patterns of the products of Examples 1-2 and Comparative Examples 1-3 of the present invention;

[0022] Figure 4 These are the X-ray photoelectron spectra of the products of Examples 1-2 and Comparative Example 1 of this invention;

[0023] Figure 5 These are the Fourier transform infrared spectra of the products of Examples 1-2 and Comparative Examples 1-3 of this invention;

[0024] Figure 6 These are the transient fluorescence spectra of the products from Examples 1-2 and Comparative Example 1 of this invention;

[0025] Figure 7 These are scanning electron microscope (SEM) images and EDX mapping images of the products of Embodiment 2 and Comparative Example 1 of the present invention;

[0026] Figure 8 XRD patterns of the product prepared in Example 2 before and after five cycles of degradation of Orange 2;

[0027] Figure 9 The degradation rate of the product prepared in Example 2 after 5 cycles of degradation of Orange 2 is shown in the graph. Detailed Implementation

[0028] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0029] It should be noted that, unless otherwise specified, the experimental methods described in the following implementation plan are all conventional methods, and the reagents and materials described are all commercially available unless otherwise specified.

[0030] Example 1:

[0031] This embodiment prepares a red phosphorus / montmorillonite photoresponsive composite material. The specific preparation steps are as follows:

[0032] (1) Add 5g of red phosphorus to 65mL of deionized water, sonicate for 30min, transfer to a reaction vessel, heat at 200℃ for 24h, cool to room temperature, wash with deionized water, centrifuge, and vacuum dry to obtain product A.

[0033] (2) Add 0.22g of product A to 220mL of NMP, sonicate at 800W for 4h, centrifuge at 12000rpm for 20min, and then vacuum dry at 65℃ for 24h to obtain product B;

[0034] (3) The mass ratio of B to the directly purchased montmorillonite is 0.1-0.9, the stirring time is 1h, and then the mixture is vacuum dried at 65℃ for 24h to obtain the red phosphorus / montmorillonite photoresponsive composite material, labeled as RP / MMT;

[0035] Example 2:

[0036] This embodiment prepares a red phosphorus / montmorillonite photoresponsive composite material. The specific preparation steps are as follows:

[0037] (1) Add 5g of red phosphorus to 65mL of deionized water, sonicate for 30min, transfer to a reaction vessel, heat at 200℃ for 24h, cool to room temperature, wash with deionized water, centrifuge, and vacuum dry to obtain product A.

[0038] (2) Add 0.22g of product A to 220mL of NMP and sonicate at 800W for 4h; centrifuge at 12000rpm for 20min and then vacuum dry at 65℃ for 24h to obtain product B;

[0039] (3) Place montmorillonite in a ball mill jar and grind it thoroughly for 4 hours to obtain product C.

[0040] (4) The mass ratio of B and C is 0.9. They are dispersed in an ethanol solution and stirred for 1 hour. Then they are vacuum dried at 65°C for 24 hours to obtain the red phosphorus / montmorillonite photoresponsive composite material, labeled as RP / eMMT.

[0041] Comparative Example 1: Red Phosphorus Catalyst

[0042] Add 5g of red phosphorus to 65mL of deionized water, sonicate for 30min, then transfer to a reaction vessel and react at 200℃ for 24h. Cool to room temperature, wash with deionized water, centrifuge, and vacuum dry to obtain product A. Add 0.22g of product A to 220mL of NMP, sonicate at 800W for 4h, centrifuge at 12000rpm for 20min, and then vacuum dry at 65℃ for 24h, labeling as RP.

[0043] Comparative Example 2: Montmorillonite

[0044] Montmorillonite purchased directly is marked as MMT.

[0045] Comparative Example 3: Modified Montmorillonite

[0046] Place the purchased montmorillonite in a ball mill jar and grind for 4 hours. Mark it as eMMT.

[0047] Experiments demonstrate that the photocatalytic removal performance of the red phosphorus / montmorillonite photoresponsive composite material prepared in Example 2 of this invention, as well as the red phosphorus catalyst (RP) obtained in Comparative Example 1 and the modified montmorillonite (eMMT) in Comparative Example 3, was evaluated. The photocatalytic antibacterial performance of the red phosphorus / montmorillonite photoresponsive composite material prepared in Example 1 of this invention, as well as the red phosphorus catalyst (RP) obtained in Comparative Example 1 and the montmorillonite (MMT) in Comparative Example 2, was also evaluated.

[0048] The specific operating steps are as follows:

[0049] Figure 1 The figures show the performance of photocatalytic removal of Orange II in Examples 1, 2, and Comparative Examples 1-3 of the present invention. It can be seen that Example 2 of the present invention exhibits the best performance in photocatalytic removal of Orange II.

[0050] Figure 2 The figures show the photocatalytic antibacterial performance of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention. It can be seen that the photocatalytic antibacterial performance of Example 1 is higher than that of Comparative Examples 1 and 2.

[0051] Figure 3 The X-ray diffraction patterns of Examples 1-2, Comparative Examples 1, 2 and 3 of the present invention are shown. Compared with single red phosphorus and single montmorillonite, it can be seen that Examples 1-2 of the present invention all contain two substances, red phosphorus and montmorillonite, and no other impurities.

[0052] Figure 4 The X-ray photoelectron spectra of Examples 2, 1, 2 and 3 of this invention are shown. In the O1s spectrum of single red phosphorus, the peaks of POP and P=O bonds are the main ones. In contrast, the characteristic peaks of Si-O in PO-Si bonds appear in the O1s spectra of RP / MMT and RP / eMMT, which confirms that chemical bonding occurs after montmorillonite is combined with red phosphorus. This bonding has an important impact on the performance of the composite material.

[0053] Figure 5 The Fourier transform infrared spectra of Examples 1-2, Comparative Examples 1, 2, and 3 of this invention are shown. RP / MMT and RP / eMMT exhibit characteristic absorption peaks different from those of single red phosphorus and single montmorillonite. Around 1100 cm⁻¹, the red phosphorus curve shows a distinct POP absorption peak; however, in the RP / MMT and RP / eMMT curves, this POP absorption peak gradually disappears. Simultaneously, the absorption peak of the PO bond gradually strengthens and gradually blue-shifts (towards increasing wavenumber). This phenomenon indicates that with the recombination of montmorillonite and red phosphorus, especially in RP / eMMT, the formed PO-Si bond becomes increasingly stable.

[0054] Figure 6The transient fluorescence spectra of Examples 1-2 and Comparative Example 1 of this invention are shown. Transient fluorescence spectroscopy is an effective means of studying carrier transfer and separation in semiconductor catalysts. The fluorescence intensity of RP decays relatively quickly, with an average lifetime of only 13.6 ns for photogenerated carriers, indicating that carrier recombination is rapid in pure red phosphorus, making separation relatively difficult. The fluorescence lifetime of the red phosphorus / montmorillonite composite material is lower than that of pure red phosphorus, indicating that the PO-Si bond provides a more efficient transport channel for photogenerated electrons, enabling them to rapidly transfer from the red phosphorus surface to the montmorillonite, effectively suppressing the recombination of photogenerated electrons and holes, and thus significantly improving the photocatalytic removal of Orange II and antibacterial performance of red phosphorus.

[0055] Figure 7 These are transmission electron microscope (TEM) images and EDX mapping images of Embodiment 2 and Comparative Example 1 of the present invention. The layered montmorillonite and lamellar red phosphorus have been successfully composited and are uniformly distributed in the composite material. The distribution of elements such as Si, Al, O, and P can be clearly observed in the elemental EDX mapping image after composite formation.

[0056] Figure 8 The XRD patterns of the product prepared in Example 2 before and after five cycles of degradation of Orange 2 are shown. The overall shape and trend of the curves before and after the reaction are similar, and there are no impurity peaks, indicating that the material has good cycle stability.

[0057] Figure 9 The figure shows the degradation rate of Orange 2 after 5 cycles of degradation of the product prepared in Example 2. As can be seen from the figure, the degradation rate of Orange 2 after 5 cycles of degradation remains at a relatively high level, indicating that the material has good cycle stability.

[0058] This invention utilizes multiple characterization methods such as XRD, SEM, TEM, and XPS to characterize the crystal structure, morphology, and light absorption performance of red phosphorus, demonstrating that red phosphorus forms chemical bonds with montmorillonite to form a composite material. This is of great significance in overcoming the drawback of rapid recombination of photogenerated electrons and photogenerated vacancies in red phosphorus. The formation of the heterojunction overcomes the drawback of rapid recombination of photogenerated electrons and photogenerated holes in red phosphorus, thereby improving photocatalytic activity.

[0059] In summary, this invention provides a red phosphorus / montmorillonite photoresponsive composite material, its preparation method, and its applications. Montmorillonite accelerates the transport process of photogenerated carriers in red phosphorus, effectively separating photogenerated electrons and holes, thus enhancing the photocatalytic removal of Orange II and antibacterial properties of red phosphorus. The red phosphorus / montmorillonite photoresponsive composite material provided by this invention exhibits excellent photocatalytic performance, and its preparation method is simple, mild, and low-cost, enabling large-scale production.

[0060] For any points not covered above, existing technologies shall apply.

[0061] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the direction of the invention or exceeding the scope defined by the appended claims. Those skilled in the art should understand that any modifications, equivalent substitutions, improvements, etc., made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a red phosphorus / montmorillonite photoresponsive composite material, characterized by comprising the following steps: The red phosphorus is purified, ultrasonically exfoliated to obtain flaky red phosphorus, the flaky red phosphorus is stirred with the montmorillonite in a first solvent, separated, and vacuum dried to obtain the red phosphorus / montmorillonite photoresponsive composite material; ​ The mass ratio of the flaky red phosphorus to the montmorillonite is 0.1-0.9:1; The montmorillonite is placed in a ball mill jar and fully ground for 2-5 h; The vacuum drying is performed at 60-70℃ for 12-24 h; The first solvent is ethanol.

2. The production method according to claim 1, characterized by: The stirring time is 1-4 h; The specific operation of the purification is that the red phosphorus is ultrasonically dispersed in water to obtain a red phosphorus suspension, the red phosphorus suspension is subjected to a hydrothermal reaction, naturally cooled, washed, centrifuged, and vacuum dried; the concentration of the red phosphorus suspension is 0.08 g / mL, the hydrothermal reaction temperature is 180-200℃, and then vacuum drying is performed at 65℃ for 12-24 h.

3. The production method according to claim 1, wherein: The specific operation of the ultrasonic exfoliation is that the purified red phosphorus is ultrasonically dispersed in a second solvent, then washed with ethanol, centrifuged, and vacuum dried; the second solvent is one or more of N-methyl pyrrolidone, water, or ethanol.

4. The production method according to claim 3, characterized by: The mass-volume ratio of the purified red phosphorus to the second solvent is 1:1 g / L; the ultrasonic power is 800 W, and the time is 2-4 h.

5. The production method according to any one of claims 1 to 4, characterized by: The centrifugation speed is 8000-12000 rpm, and the time is 5-20 min.

6. A red phosphorus / montmorillonite photoresponsive composite material prepared by the preparation method of any one of claims 1-5.

7. Use of the red phosphorus / montmorillonite photoresponsive composite material according to claim 6 as a photocatalyst, characterized by: Used for photocatalytic degradation of orange II and antibacterial under 420-780 nm wavelength.

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