SERS sensor and preparation method and application thereof

Abstract

The invention discloses an SERS (Surface Enhanced Raman Scattering) sensor as well as a preparation method and application thereof, and relates to the technical field of compound detection, the SERS sensor comprises gold nanoparticles, an MXenes material and bacterial cellulose hydrogel; the gold nanoparticles are loaded on the MXenes material to form a composite nano material; the composite nano material is dispersed and fixed in the bacterial cellulose hydrogel; according to the application, the gold nanoparticles are loaded on the MXenes material, and meanwhile, the MXenes material (Mxene / Au NPs) loaded with the gold nanoparticles is dispersed and fixed in the bacterial cellulose hydrogel, so that a good dispersion and support environment is provided for the Mxene / Au NPs, agglomeration of nano ions is effectively avoided, the SERS sensor is endowed with good aerosol performance, and the SERS sensor has good application prospects. The full contact of a target detection object and the SERS sensor is facilitated, and the detection sensitivity is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compound detection, in particular to a SERS sensor and a preparation method and application thereof. BACKGROUND

[0002] Benzaldehyde, as a common volatile organic compound, widely exists in industrial waste gas, automobile exhaust and gas released by indoor decoration materials. It has a stimulating odor and can cause damage to the respiratory system and nervous system of the human body. Long-term exposure can cause more serious health problems, and even has the risk of causing cancer. The current detection methods of benzaldehyde mainly include spectrophotometry, chromatography and the like. Usually, a higher concentration of benzaldehyde is needed to produce a detectable signal, and it is easily affected by other coexisting substances and environmental factors. Therefore, the existing technology still needs to be improved. SUMMARY

[0003] The main purpose of the present application is to provide a SERS sensor and a preparation method and application thereof, aiming at solving the problems of insufficient sensitivity and weak anti-interference ability of the existing benzaldehyde detection method.

[0004] To achieve the above-mentioned purpose, the SERS sensor provided by the present application comprises gold nanoparticles, MXenes material and bacterial cellulose hydrogel. The gold nanoparticles are loaded on the MXenes material to form a composite nanomaterial. The composite nanomaterial is dispersed and fixed in the bacterial cellulose hydrogel.

[0005] Preferably, the number of layers of the MXenes material is 5-10 layers.

[0006] Preferably, the SERS sensor comprises 4-aminophenylthiophenol, which is anchored on the gold nanoparticles.

[0007] The present application also provides a preparation method of a SERS sensor, comprising: loading gold nanoparticles on MXenes material to form a composite nanomaterial; mixing the composite nanomaterial with bacterial cellulose hydrogel and performing freezing treatment, and then freeze-drying to obtain the SERS sensor; wherein the number of layers of the MXenes is 5-10 layers.

[0008] Preferably, the method for loading gold nanoparticles on MXenes material comprises: mixing MXenes aqueous solution, HAuCl4 and ethanol and performing ultraviolet irradiation to obtain the composite nanomaterial.

[0009] Preferably, the mass fraction ratio of the MXenes, the HAuCl4 and the ethanol is 10:1:1~10:1:4.

[0010] Preferably, the irradiation is performed by using ultraviolet light with a wavelength of 405 nm, a power of 200~400 mW and a time of 1~90 min.

[0011] Preferably, the mass ratio of the composite nanomaterial and the bacterial cellulose hydrogel is 1:1~1:6.

[0012] Preferably, the preparation method of the SERS sensor further comprises: immersing the product after the freezing treatment in 4-aminobenzene sulfide and drying under lightless conditions to obtain the SERS sensor.

[0013] The application also provides a SERS sensor and application of the SERS sensor in detection of benzaldehyde.

[0014] The SERS sensor of the application can realize detection of trace target detection objects based on surface-enhanced Raman scattering by loading gold nanoparticles on MXenes material, and disperses and fixes the MXenes material (Mxenes / Au NPs) loaded with gold nanoparticles in the bacterial cellulose hydrogel, which not only makes full use of the three-dimensional network structure of the bacterial cellulose hydrogel to provide a good dispersion and support environment for the Mxenes / Au NPs, effectively avoids agglomeration of nano-ions, but also endows the SERS sensor with good aerosol performance, which is conducive to full contact of the target detection object with the SERS sensor and further improves the detection sensitivity. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions of the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0016] Figure 1 The transmission electron microscope observation figure provided by the application is as follows: a is MXenes nanosheets in MXenes aqueous solution; b is Mxenes / Au NPs prepared in Example 3; c is bacterial cellulose hydrogel; d is BC / Mxenes / Au NPs prepared in Example 3; Figure 2 The ultraviolet-visible absorption spectrum of the SERS sensor provided by the application is as follows: Figure 3 The SERS sensor prepared by the bacterial cellulose hydrogel of different proportions of BC / Mxenes / Au NPs provided in the application has a SERS characteristic peak intensity distribution diagram of 4-ATP molecules; Figure 4 The SERS spectrum of the SERS sensor provided in the application for adsorbing different concentrations of 4-ATP is shown in the following table: Figure 5 The SERS spectrum of the SERS sensor provided in the application for detecting benzaldehyde is shown in the following table.

[0017] The implementation, functional features and advantages of the application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only some of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0019] It should be noted that if the embodiments of the application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture, and if the certain posture changes, the directional indications also change accordingly.

[0020] In addition, if the embodiments of the application involve descriptions such as “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first” and “second” can explicitly or implicitly include at least one of the features. In addition, “and / or” or “and / or” appearing throughout the text means that the three parallel schemes are included, for example, “A and / or B” includes A scheme, or B scheme, or A and B are satisfied at the same time. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the realization of a person skilled in the art, and when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, and is not within the protection scope claimed by the application.

[0021] Currently, the methods for detecting benzaldehyde mainly include spectrophotometry, chromatography, etc., and usually a high concentration of benzaldehyde is needed to produce a detectable signal. For example, the minimum detection concentration of benzaldehyde by the acetylacetone method is 0.25 mg / L. When detecting complex samples, it is easy to be interfered by other coexisting substances. For example, the electrochemical sensor may be affected by other chemical substances such as alcohols and aldehydes, resulting in inaccurate detection results. In addition, during the detection process, it is easy to be affected by environmental factors (such as temperature, humidity, light, etc.), resulting in unstable detection results. For example, the detection results of the benzaldehyde detection box are easily affected by environmental factors and have poor stability. Finally, chromatography, spectrophotometry, etc. usually need complex sample pretreatment steps and long detection time. For example, professional detection institutions need to sample air on site and then take it back to the laboratory for testing, and at least 2-3 working days are needed to wait for the results.

[0022] To solve the problems of low sensitivity, poor selectivity and weak anti-interference of the existing benzaldehyde detection technology, the present application provides a SERS sensor.

[0023] In an embodiment of the present application, the SERS sensor comprises gold nanoparticles (Au NPs), MXenes material and bacterial cellulose hydrogel, wherein the gold nanoparticles are loaded on the MXenes material to form a composite nanomaterial (MXenes / Au NPs), and the MXenes / Au NPs are dispersed and fixed on the bacterial cellulose hydrogel.

[0024] Firstly, when the target detection object is added dropwise on the SERS sensor, or the SERS sensor is exposed to the target detection object vapor, the target detection object is adsorbed on the surface of the gold nanoparticles and in the gap area between the gold nanoparticles and the MXenes material. When a laser beam of a specific wavelength is used to irradiate the SERS sensor, the target detection object molecules will undergo Raman scattering. Further, the laser irradiation will cause the collective oscillation of free electrons in the gold nanoparticles (surface plasmon resonance). Between adjacent gold nanoparticles and between the gold nanoparticles and the conductive MXenes material, an extremely strong local electromagnetic field will be generated. The Raman scattering signal of the molecules in this strong field will be amplified by millions or even hundreds of millions of times; in addition, charge transfer may occur between the MXenes material and the Au NPs and the molecules to be detected, changing the polarizability of the molecules, thereby producing additional enhancement of the Raman signal (usually several orders of magnitude weaker than electromagnetic enhancement), and thus realizing the identification and detection of extremely small target detection objects.

[0025] Secondly, by dispersing and fixing the Mxenes / Au NPs in the bacterial cellulose hydrogel, the three-dimensional network structure of the bacterial cellulose hydrogel is fully utilized to provide a good dispersion and support environment for the Mxenes / Au NPs, effectively avoiding the agglomeration of nano-ions, and at the same time, endowing the SERS sensor with good aerosol performance, which is conducive to the full contact of the target detection object with the SERS sensor, realizing efficient capture of trace target detection objects, and further improving the detection sensitivity of the SERS sensor.

[0026] In some embodiments, the MXenes material has a layer number of 5-10 layers. The MXenes material refers to a two-dimensional transition metal carbide, nitride or carbonitride.

[0027] The 5-10 layer few-layer MXenes material can provide a large specific surface area and abundant active sites, which is conducive to the loading of Au NPs. At the same time, in the few-layer MXenes material, the electronic migration resistance in the two-dimensional plane is small, and the conductivity is excellent. When Au NPs are loaded thereon, the local surface plasmon resonance (LSPR) of the Au NPs and the high-conductivity substrate of the MXenes will produce strong electromagnetic coupling, so that the electromagnetic field at the target detection object is further enhanced, thereby greatly improving the SERS enhancement factor. Finally, the few-layer MXenes will generate abundant surface end groups (-O, -OH, -F, etc.) in the exfoliation process. These functional groups are not only anchoring sites for loading gold particles, but also have good hydrophilicity, which is conducive to the photochemical reduction reaction in the aqueous phase and the compounding with the bacterial cellulose hydrogel.

[0028] In some embodiments, the SERS sensor comprises 4-aminothiophenol (4-ATP), and the 4-aminothiophenol is anchored on the gold nanoparticles.

[0029] One end of the 4-ATP molecule comprises a sulfur group (-SH), which has a strong affinity with the gold nanoparticles and can form a firm Au-SH covalent bond, so that the 4-ATP is anchored on the gold nanoparticles. On the other hand, the other end of the 4-ATP molecule comprises an amino group (-NH2), which can undergo a characteristic condensation reaction with an aldehyde group (-CHO), and then when the target detection object is benzaldehyde, the aldehyde group in the benzaldehyde reacts with the amino group in the 4-ATP, thereby realizing efficient capture of the benzaldehyde.

[0030] The application also provides a preparation method of the SERS sensor, comprising: S11, loading the gold nanoparticles on the MXenes material to form a composite nanomaterial (MXenes / Au NPs).

[0031] The MXenes material has a layer number of 5-10. For example, the MXenes material has a layer number of 5, 6, 7, 8, 9 or 10. Alternatively, the MXenes material includes at least one of 5-layer MXenes material, 6-layer MXenes material, 7-layer MXenes material, 8-layer MXenes material, 9-layer MXenes material or 10-layer MXenes material.

[0032] In some embodiments, S11 includes: S111, mixing the MXenes aqueous solution, HAuCl4 and ethanol and performing ultraviolet irradiation to obtain the composite nanomaterial.

[0033] The MXenes material serves as a substrate for gold nanoparticles, and the few-layer MXenes material has a large specific surface area, which is conducive to the uniform loading and fixation of metal nanoparticles. HAuCl4 is a precursor of metal nanoparticles. Under ultraviolet irradiation, HAuCl4 is reduced to gold atoms and aggregated into gold nanoparticles, which are loaded on the surface of the MXenes material. Ethanol acts as a sacrificial agent or reducing agent during ultraviolet irradiation, which is used to capture holes or directly provide electrons to facilitate the reduction of HAuCl4 to gold atoms.

[0034] In some embodiments, the mass fraction ratio of the composite nanomaterial MXenes, HAuCl4 and ethanol is 10:1:1-10:1:4. For example, the mass fraction ratio of the composite nanomaterial MXenes, HAuCl4 and ethanol can be 10:1, 1, 10:1, 2, 10:1, 3 or 10:1, 4, etc.

[0035] In some embodiments, the wavelength of the ultraviolet light used for ultraviolet irradiation is 405 nm, and the power of the ultraviolet irradiation is 200-400 mW. For example, the power of the ultraviolet irradiation can be 200 mW, 250 mW, 300 mW, 350 mW or 400 mW, etc., and the time is 1-90 min. For example, the time of ultraviolet irradiation can be 1 min, 5 min, 10 min, 50 min, 80 min or 90 min, etc.

[0036] Through ultraviolet irradiation, HAuCl4 can be reduced to gold atoms, and in-situ photochemical synthesis of gold nanoparticles is realized. By using the aforementioned power and time settings, the size and density of gold nanoparticles can be accurately controlled, and the uniform loading of gold nanoparticles on MXenes can be achieved.

[0037] In some embodiments, S11 further includes: S112, washing the product after ultraviolet irradiation with deionized water for 1-3 times, collecting the precipitate and drying it at 60℃.

[0038] S12, mixing the composite nanomaterial with the bacterial cellulose hydrogel and performing freeze treatment, and then freeze drying to obtain the SERS sensor.

[0039] By mixing the composite nanomaterial with the bacterial cellulose hydrogel, the Mxenes / Au NPs can be dispersed and fixed in the bacterial cellulose hydrogel, the three-dimensional network structure of the bacterial cellulose hydrogel is fully utilized, a good dispersion and support environment is provided for the Mxenes / Au NPs, the agglomeration of the nano-ions is effectively avoided, and the SERS sensor is endowed with good aerosol performance, which is conducive to the full contact of the target detection object with the SERS sensor.

[0040] In some embodiments, the mass ratio of the composite nanomaterial to the bacterial cellulose hydrogel is 1:1-6:1, for example, the mass ratio of the composite nanomaterial to the bacterial cellulose is 1:1, 2:1, 3:1, 4:1, 5:1 or 6:1, etc.

[0041] In some embodiments, the temperature of the freeze treatment is 0- -20℃. For example, the temperature of the freeze treatment is 0℃, -5℃, -10℃, -15℃ or -20℃, etc. The time of the freeze treatment is 10-12 h. For example, the time of the freeze treatment is 10 h, 10.5 h, 11 h, 11.5 h or 12 h, etc. The time of the freeze drying is 44-48 h. For example, the time of the freeze drying is 44 h, 45 h, 46 h, 47 h or 48 h, etc.

[0042] In some embodiments, the preparation method of the SERS sensor further comprises: S13, soaking the product (BC / MXenes / Au NPs) after freeze drying in S12 in 4-aminobenzene sulfide (4-ATP), and drying in the dark to obtain the SERS sensor.

[0043] By soaking the BC / MXenes / Au NPs in 10 -6 M of 4-ATP solution, the surface of the Au NPs is modified by 4-ATP molecules, the surface of the Au NPs is changed into a chemically active surface with specific functional groups (-NH2), which is conducive to the efficient capture of benzaldehyde.

[0044] The application also provides the use of the SERS sensor prepared by the above-mentioned preparation method of the SERS sensor in detecting benzaldehyde.

[0045] In some embodiments, the method for detecting benzaldehyde comprises: S21, using anhydrous ethanol to prepare 10 -4 ~10 -12M benzaldehyde solution; S22, the SERS sensor (BC / Mxenes / Au NPs composite aerosol) is placed in a sealed glass tank and different concentrations of benzaldehyde solution are added. Heating makes benzaldehyde volatilize completely. Confocal probe Raman spectrometer is used to detect and obtain Raman spectrum under room temperature conditions. Among them, the excitation wavelength is 633 nm, the integration time is 5 s, and the laser power is 50 μW.

[0046] S23, the same method as S22 is used to detect and obtain the Raman spectrum of the target detection object (unknown concentration) benzaldehyde solution. According to the Raman spectrum of the known concentration benzaldehyde standard, the concentration of benzaldehyde in the target detection object can be obtained.

[0047] The following is further illustrated by specific examples.

[0048] Comparative example 1 and examples 1-5 Comparative example 1 and examples 1-5 analyze the effect of different ultraviolet irradiation times on the gold nanoparticle loading in the SERS sensor.

[0049] A mixture solution composed of 20 mL of 0.1 mg / mL 5-10 layer Mxenes aqueous solution, 500 μL of 0.05 M HAuCl4, 2 mL of ethanol and 5 mL of deionized water is then irradiated with a 405 nm ultraviolet continuous laser with a power of 300 mW for 0 min, 15 min, 30 min, 45 min, 60 min and 90 min (corresponding to comparative example 1 and examples 1-5). The obtained suspension is centrifuged and washed with deionized water three times. Finally, the precipitate is collected and placed in an oven at 60°C overnight to obtain Mxene / Au NPs composite nanomaterials with different Au loadings.

[0050] The Mxenes / Au NPs powder and the bacterial cellulose hydrogel (1:1) are mixed uniformly with an electric mixer, then poured into a petri dish with a radius of 5 cm and placed in a refrigerator for 12 h. It is transferred to a vacuum freeze dryer for 48 h, and finally, the BC / Mxenes / Au NPs composite aerosol SERS sensor is obtained.

[0051] The MXenes nanosheets in the MXenes aqueous solution in example 3, the MXenes / Au NPs composite nanomaterial after irradiation treatment (45 min), the bacterial cellulose hydrogel and the finally prepared BC / Mxenes / Au NPs composite aerosol SERS sensor are observed by transmission electron microscopy (TEM), and the results are as shown in Figure 1 a, b, c or d. FromFigure 1 It can be seen from FIG. 2b that the gold nanoparticles are uniformly loaded on the MXenes material. Figure 1 It can be seen from FIG. 2d that the MXenes / Au NPs composite nanomaterial is uniformly dispersed and fixed in the bacterial cellulose hydrogel.

[0052] The UV-visible absorption spectra of the SERS sensors prepared in Examples 1-5 and Comparative Example 1 are shown in FIG. 3. Figure 1 It can be seen from FIG. 3 that the amount of gold nanoparticles loaded on the MXenes material can be precisely controlled by controlling the time of UV irradiation. Figure 2

[0053] Comparative Example 2 and Examples 6-11 Comparative Example 2 and Examples 6-11 analyze the effect of different ratios of Mxenes / Au NPs powder and bacterial cellulose hydrogel on the prepared SERS sensor.

[0054] A mixed solution composed of 20 mL of 0.1 mg / mL 5-10 layer Mxenes aqueous solution, 500 μL of 0.05 M HAuCl4, 2 mL of ethanol and 5 mL of deionized water was prepared, and then the mixed solution was irradiated with a 405 nm UV continuous laser with a power of 300 mW for 45 min. The obtained suspension was centrifuged and washed with deionized water for three times. Finally, the precipitate was collected and placed in an oven at 60°C overnight to obtain Mxene / Au NPs composite nanomaterials with different Au loadings.

[0055] Mxenes / Au NPs powder and bacterial cellulose hydrogel were mixed in a ratio of 1:1, 2:1, 3:1, 4:1, 5:1 and 6:1 (corresponding to Examples 6-11, respectively), and Comparative Example 2 was not added with bacterial cellulose hydrogel. The mixture was mixed uniformly with an electric mixer, then poured into a petri dish with a radius of 5 cm and placed in a refrigerator for 12 h. It was transferred to a vacuum freeze dryer for 48 h, and finally the freeze-dried BC / MXenes / Au NPs powder was soaked in 1 mL of 10 -7 BC / Mxenes / Au NPs composite aerosol SERS sensors were obtained by soaking the freeze-dried BC / MXenes / Au NPs powder in 1 mL of 10

[0056] The SERS sensors in Comparative Example 2 and Examples 6-11 were tested for the SERS characteristic peak intensity of 4-ATP molecules using a confocal probe Raman spectrometer, and the results are shown in FIG. 4. Figure 3 It can be seen from FIG. 4 that the SERS characteristic peak intensity of 4-ATP molecules is the highest in Example 6, and the SERS characteristic peak intensity of 4-ATP molecules is the lowest in Comparative Example 2. Figure 3 MA (Mxenes / Au NPs) in FIG. 4 represents Comparative Example 2 without adding bacterial cellulose hydrogel. It can be seen from FIG. 4 that the SERS characteristic peak intensity of 4-ATP molecules is the highest in Example 6, and the SERS characteristic peak intensity of 4-ATP molecules is the lowest in Comparative Example 2. Figure 3 ​As can be seen, the intensity of the SERS characteristic peak for 4-ATP molecules is highest when the ratio of Mxenes / Au NPs powder to bacterial cellulose hydrogel is 5:1. Therefore, the preferred ratio of Mxenes / Au NPs powder to bacterial cellulose hydrogel is 5:1.

[0057] Examples 12-17 Examples 12-17 analyze the effect of SERS sensors with different concentrations of 4-ATP adsorbed on SERS intensity.

[0058] A mixed solution consisting of 20 mL of 0.1 mg / mL 5-10 layer Mxenes aqueous solution, 500 μL of 0.05 M HAuCl4, 2 mL of ethanol, and 5 mL of deionized water was irradiated with a 300 mW 405 nm continuous ultraviolet laser for 45 min. The resulting suspension was centrifuged and washed three times with deionized water. Finally, the precipitate was collected and placed in a 60°C oven overnight to obtain Mxenes / Au NPs composite nanomaterials with different Au loadings.

[0059] Mxenes / Au NPs powder and bacterial cellulose hydrogel were mixed thoroughly with an electric stirrer at a ratio of 5:1, then poured into 5 cm radius petri dishes and frozen for 12 h. The mixture was then transferred to a vacuum freeze dryer and freeze-dried for 48 h. Finally, the freeze-dried BC / MXenes / Au NPs powder was immersed in 1 mL of 10... -6 M, 10 -8 M, 10 -10 M, 10 - 11 M, 10 -12 M, 10 -13 BC / Mxenes / Au NPs composite aerosol SERS sensors were obtained in 4-ATP solutions of M (corresponding to Examples 12-17 respectively).

[0060] The SERS spectra of the SERS sensors prepared in Examples 12-17 were tested using a confocal probe Raman spectrometer, and the results are as follows: Figure 4 As shown, from Figure 4 It can be seen from this that when the 4-ATP concentration is 10... -6 At time M, the SERS characteristic peak intensity is highest; therefore, preferably, the concentration of 4-ATP is 10. -6 M.

[0061] The SERS sensor prepared in Example 12 was used to detect benzaldehyde. The specific steps are as follows: Experimental group: the SERS sensor prepared in Example 12 was placed in a sealed glass tank and 10 μL of benzaldehyde solution was added -10 M benzaldehyde solution, heating to make benzaldehyde volatilize completely; Control group: the control group does not add benzaldehyde solution.

[0062] The confocal probe Raman spectrometer was used to detect and obtain the Raman spectrum under room temperature conditions. The excitation wavelength was 633 nm, the integration time was 5 s, and the laser power was 50 μW. The determination results are shown in Figure 5 It can be seen that the benzaldehyde is detected by the SERS sensor prepared in Example 12, which shows that the SERS sensor prepared in the present application can efficiently and accurately realize the detection of trace benzaldehyde, and also shows that the detection process in the present application is reasonable. Figure 5

[0063] In summary, the SERS sensor prepared in the present application utilizes the three-dimensional network structure of the bacterial cellulose hydrogel by dispersing and fixing Mxenes / Au NPs in the bacterial cellulose hydrogel, effectively avoids the agglomeration of nano-ions, and at the same time endows the SERS sensor with good aerosol performance, which is conducive to the full contact of the target detection material with the SERS sensor; at the same time, by optimizing the ratio of Mxenes / Au NPs and bacterial cellulose hydrogel and the amount of anchored 4-ATP, the accurate detection of trace benzaldehyde is realized.

[0064] The above only describes exemplary embodiments of the present application, and does not limit the patent scope of the present application, and any equivalent structural transformation made by using the contents of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the present application.​

Claims

1. A SERS sensor, characterized in that, Including gold nanoparticles, MXenes materials, and bacterial cellulose hydrogels; The gold nanoparticles are loaded onto the MXenes material to form a composite nanomaterial; The composite nanomaterials are dispersed and immobilized in the bacterial cellulose hydrogel.

2. The SERS sensor as described in claim 1, characterized in that, The MXenes material has 5 to 10 layers.

3. The SERS sensor as described in claim 1, characterized in that, The SERS sensor includes 4-aminothiophenol, which is anchored on the gold nanoparticles.

4. A method for fabricating a SERS sensor, characterized in that, include: Gold nanoparticles were loaded onto MXenes materials to form composite nanomaterials; The SERS sensor was prepared by mixing composite nanomaterials with bacterial cellulose hydrogel and then freezing them, followed by freeze-drying. The number of layers in the MXenes is 5 to 10.

5. The method for fabricating a SERS sensor as described in claim 4, characterized in that, Methods for loading gold nanoparticles onto MXenes materials include: The composite nanomaterial was prepared by mixing MXenes aqueous solution, HAuCl4, and ethanol and then subjecting the mixture to ultraviolet irradiation.

6. The method for fabricating a SERS sensor as described in claim 5, characterized in that, The mass ratio of MXenes, HAuCl4, and ethanol is 10:1:1 to 10:1:

4.

7. The method for fabricating a SERS sensor as described in claim 5, characterized in that, The irradiation was performed using ultraviolet light with a wavelength of 405 nm, a power of 200~400 mW, and a duration of 1~90 min.

8. The method for fabricating a SERS sensor as described in claim 4, characterized in that, The mass ratio of the composite nanomaterial to the bacterial cellulose hydrogel is 1:1 to 1:

6.

9. The method for fabricating a SERS sensor as described in claim 4, characterized in that, The method for preparing the SERS sensor further includes: The frozen product was soaked in 4-aminophenylthiocyanate and dried under dark conditions to obtain a SERS sensor.

10. The application of the SERS sensor according to any one of claims 1 to 3, or the SERS sensor prepared by the preparation method of any one of claims 4 to 9, in the detection of benzaldehyde.

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