MXene (at) rGO optical fiber probe as well as preparation method and application thereof

Abstract

The invention provides an MXene (at) rGO optical fiber probe as well as a preparation method and application thereof. According to the invention, the advantages of MXene and rGO are combined, and the MXene (at) rGO heterostructure material is synthesized on the surface of the optical fiber sensing probe. The sensitivity of the prepared MXene (at) rGO optical fiber probe reaches 4312.72 nm / RIU, and is improved by 99.92% compared with the sensitivity 2157.23 nm / RIU of the MXene (at) rGO optical fiber probe which is only sprayed with a gold film, and is far higher than the sensitivity improvement value of MXene to a sensor; the problem that the sensitivity of the sensor is reduced due to rGO is solved, and the effect of greatly improving the sensitivity of the optical fiber probe through combined utilization of Mxene and rGO materials is achieved. According to the MXene (at) rGO optical fiber probe prepared by the invention, the sensitivity of the optical fiber is greatly improved, and a high-sensitivity sensing material and an improvement thought are provided for further development of an optical fiber sensor.

Description

Technical Field

[0001] The present invention relates to the technical field of optical fiber sensitive materials, and in particular to a MXene@rGO optical fiber probe and a preparation method and application thereof. Background Art

[0002] Fiber optic chemical and biological sensors have the advantages of flexible mechanical properties, small size, high sensitivity, and portability. They have received more and more attention and have been extended to multiple scenarios, such as biomedical testing, electrochemical reaction process monitoring, and environmental water quality analysis. In the actual detection process, most of the analytes or markers exist in trace or even trace levels in the environment, which requires the sensor to have extremely high sensitivity and selectivity during application. However, the sensitivity of fiber optic sensing is far from meeting the needs of trace marker detection by simply spraying gold film on the surface of the optical fiber or combining gold nanoparticles. Therefore, it is particularly important to develop new fiber optic sensitive materials or adopt new fiber optic structures to improve the signal transmission and molecular / ion recognition capabilities of sensitive materials on the sensor surface.

[0003] Two-dimensional (2D) transition metal carbides, nitrides or carbonitrides (MXenes) have become an emerging family of layered nanomaterials and have been intensively studied in multidisciplinary applications. Their large specific surface area, excellent mechanical strength, ideal biocompatibility, tunable electronic and optical properties, active performance properties and abundant surface functional groups make 2D MXenes a multifunctional nanosensor with biosensing potential.

[0004] Previous studies have shown that the sensitivity of MXene-enhanced SPR fiber sensors can be increased by up to 30%, but this is still a long way from achieving the detection capability of trace markers. It is imperative to develop a new generation of fiber-optic sensitive materials with higher sensitivity and stronger signal transmission capabilities.

[0005] As the "king of black gold new materials" in the 21st century, graphene is a hexagonal honeycomb two-dimensional material formed by sp2 hybridization. It has a zero-gap Dirac cone electronic band structure and is one of the materials with the highest conductivity, the lowest optical loss, and the highest mechanical strength. It is also one of the materials widely studied in the field of optical fiber sensing in recent years. However, pure rGO (reduced graphene oxide) lacks surface hydrophilic functional groups and cannot produce good infiltration with the markers in the solution to be tested, which will reduce the sensitivity of the sensor by 5-8%, so it is rarely used directly as a sensitive material for optical fiber probes.

[0006] Based on the limited detection capability of the current MXene-enhanced SPR fiber optic sensor and the fact that rGO directly used as the sensitive material of the fiber optic probe results in a 5-8% decrease in the sensitivity of the sensor, it is necessary to improve this. Summary of the invention

[0007] The present invention aims to provide a MXene@rGO optical fiber probe and a preparation method and application thereof, so as to solve the problem that the sensitivity of existing optical fiber sensors cannot realize trace marker detection.

[0008] In order to achieve the above object, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing a MXene@rGO optical fiber probe, comprising the following steps:

[0010] Preparing Au film on the surface of optical fiber;

[0011] The optical fiber with Au film on the surface is immersed in cysteamine hydrochloride ethanol solution, and after the immersion is completed, it is washed with water and ethanol in sequence to obtain a positively charged optical fiber;

[0012] The modified optical fiber is immersed in a MXene dispersion to obtain an Au-MXene optical fiber probe;

[0013] The Au-MXene optical fiber probe was immersed in the rGO dispersion to obtain the MXene@rGO optical fiber probe.

[0014] Preferably, the concentration of the cysteamine hydrochloride ethanol solution is 3.0 to 10.0 mg / mL.

[0015] Preferably, in the step of immersing the optical fiber having the Au film on the surface in the cysteamine hydrochloride ethanol solution, the immersion time is 12 to 24 hours.

[0016] Preferably, the method for preparing the MXene dispersion comprises: 3 C 2 T x Add to deionized water to obtain a MXene dispersion;

[0017] The concentration of the MXene dispersion is 1.0 to 3.0 mg / mL.

[0018] Preferably, in the step of immersing the modified optical fiber in the MXene dispersion, the immersion time is 0.5 to 3.0 hours.

[0019] Preferably, the method for preparing the rGO dispersion comprises: adding rGO powder to a hydrochloric acid solution to obtain the rGO dispersion;

[0020] The concentration of the hydrochloric acid solution is 1.0-2.0M;

[0021] The concentration of the rGO dispersion is 1.0-2.0 mg / mL.

[0022] Preferably, in the step of immersing the Au-MXene optical fiber probe in the rGO dispersion, the immersion time is 1.0 to 3.0 hours.

[0023] Preferably, the Au film is prepared on the surface of the optical fiber by magnetron sputtering;

[0024] The thickness of the Au film is 50-55 nm.

[0025] In a second aspect, the present invention also provides a MXene@rGO optical fiber probe, which is prepared using the preparation method.

[0026] In a third aspect, the present invention also provides a MXene@rGO optical fiber probe prepared by the preparation method or the use of the MXene@rGO optical fiber probe in detecting markers.

[0027] The MXene@rGO optical fiber probe of the present invention and its preparation method and application have the following beneficial effects compared with the prior art:

[0028] 1. The present invention combines the advantages of MXene and rGO and proposes a method for synthesizing a MXene@rGO heterostructure material on the surface of an optical fiber sensing probe. In subsequent tests, the plasma resonance sensor exhibited extremely high sensitivity. Specifically, the preparation method of the MXene@rGO optical fiber probe of the present invention comprises the following steps: immersing the modified optical fiber in a MXene dispersion, and adsorbing a large amount of MXene on the surface of the optical fiber coated with an Au film by electrostatic adsorption to form an intermediate Au-MXene optical fiber probe; then immersing the Au-MXene optical fiber probe in an rGO dispersion, and through nucleophilic substitution and dehydration condensation reactions, rGO and the MXene on the surface of the optical fiber are combined by Ti-OC heterogeneous bonding to form a MXene@rGO two-dimensional heterostructure material, and attached to the surface of the optical fiber probe, to obtain the final product Au-MXene@rGO optical fiber probe; subsequent spectral tests found that the sensitivity of the optical fiber probe reached 4312.72nm / RIU, which is 99.92% higher than the sensitivity of 2157.23nm / RIU of only spraying gold film, which is much higher than the sensitivity improvement value of Mxene to the sensor; the present invention overcomes the problem that rGO will cause the sensitivity of the sensor to decrease, and realizes the effect of greatly improving the sensitivity of the optical fiber probe by combining Mxene and rGO materials. The MXene@rGO optical fiber probe prepared by the present invention has a significant improvement in the sensitivity of the optical fiber, which will provide highly sensitive sensing materials and improvement ideas for the further development of optical fiber sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 This is a physical picture of an optical fiber after an Au film is sputtered on the surface of the optical fiber according to the method in Example 1;

[0031] Figure 2 The surface microscopic image (SEM) of the optical fiber after the Au film is sputtered on the surface of the optical fiber according to the method in Example 1;

[0032] Figure 3 This is a scanning electron microscope (SEM) image of the MXene@rGO optical fiber probe finally prepared according to the method in Example 1;

[0033] Figure 4 Schematic diagram of the crystal structure of the MXene@rGO heterostructure material in Example 1;

[0034] Figure 5 The spectral test curves of the MXene@rGO optical fiber probe in Example 3 and the Au film optical fiber probe in Comparative Example 1 testing glycerol aqueous solutions of different concentrations;

[0035] Figure 6 This is a linear graph of the drift amount and the refractive index of the glycerol aqueous solution obtained by testing the MXene@rGO optical fiber probe in Example 3 and the Au film optical fiber probe in Comparative Example 1. DETAILED DESCRIPTION

[0036] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] The order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0038] The present invention provides a method for preparing a MXene@rGO optical fiber probe, comprising the following steps:

[0039] S1, preparing Au film on the surface of optical fiber;

[0040] S2, soaking the optical fiber with Au film on the surface in cysteamine hydrochloride ethanol solution, and after soaking, washing with water and ethanol in sequence to obtain a positively charged optical fiber;

[0041] S3, immersing the modified optical fiber in a MXene dispersion to obtain an Au-MXene optical fiber probe;

[0042] S4. Immerse the Au-MXene optical fiber probe in the rGO dispersion to obtain a MXene@rGO optical fiber probe.

[0043] The present invention combines the advantageous properties of MXene and rGO and proposes a method for synthesizing a MXene@rGO heterostructure material on the surface of an optical fiber sensing probe; in subsequent tests, the plasma resonance sensor exhibited extremely high sensitivity. Specifically, the preparation method of the MXene@rGO optical fiber probe of the present invention comprises the following steps: immersing the modified optical fiber in a MXene dispersion, and adsorbing a large amount of MXene on the surface of the optical fiber coated with an Au film by electrostatic adsorption to form an intermediate Au-MXene optical fiber probe; then immersing the Au-MXene optical fiber probe in an rGO dispersion, and through nucleophilic substitution and dehydration condensation reactions, rGO and the MXene on the surface of the optical fiber are combined by Ti-OC heterogeneous bonding to form a MXene@rGO two-dimensional heterostructure material, and attached to the surface of the optical fiber probe, to obtain the final product Au-MXene@rGO optical fiber probe; subsequent spectral tests found that the sensitivity of the optical fiber probe reached 4312.72nm / RIU, which is 99.92% higher than the sensitivity of 2157.23nm / RIU of only spraying gold film, which is much higher than the sensitivity improvement value of Mxene to the sensor; the present invention overcomes the problem that rGO will cause the sensitivity of the sensor to decrease, and realizes the effect of greatly improving the sensitivity of the optical fiber probe by combining Mxene and rGO materials. The MXene@rGO optical fiber probe prepared by the present invention has a significant improvement in the sensitivity of the optical fiber, which will provide highly sensitive sensing materials and improvement ideas for the further development of optical fiber sensors.

[0044] In some embodiments, cysteamine hydrochloride (C 2 H 8 The concentration of ClNS) ethanol solution is 3.0~10.0mg / mL.

[0045] Specifically, cysteamine hydrochloride (C 2 H 8 The preparation method of cysteamine hydrochloride (C 1NS) ethanol solution is as follows: weigh 100 mg of cysteamine hydrochloride (C 2 H 8 ClNS) is added into 10-30 mL of ethanol to prepare a cysteamine hydrochloride ethanol solution with a concentration of 3.0-10.0 mg / mL.

[0046] In some embodiments, an optical fiber having an Au film on its surface is immersed in a cysteamine hydrochloride ethanol solution for 12 to 24 hours. After the immersion is completed, the optical fiber is taken out and rinsed with deionized water and ethanol. In this step, the cysteamine hydrochloride dissolved in ethanol will ionize and decompose into positively charged groups carrying amino groups. The S in the positively charged groups will combine with the Au film to form an Au-S bond, thereby firmly fixing the amino groups on the surface of the optical fiber and making the surface of the optical fiber appear positively charged.

[0047] In some embodiments, a method for preparing a MXene dispersion comprises: 3 C 2 T x Add to water to obtain a MXene dispersion;

[0048] In some embodiments, the concentration of the MXene dispersion is 1.0 to 3.0 mg / mL.

[0049] Specifically, Ti 3 C 2 T x The conventional method is used for preparation, and the specific preparation method is as follows:

[0050] 7.5 mL of 37% hydrochloric acid solution (density 1.17 g / mL) was diluted in 2.5 mL of deionized water, and 0.5 g of LiF was added and stirred for 10 min to obtain a mixed solution; then 0.5 g of Ti was added to the mixed solution. 3 AlC 2 The precursor was placed in a 35°C water bath with magnetic stirring and etched for 24 h; the deionized water was centrifuged several times until the pH value of the solution reached neutral conditions to obtain an accordion-shaped multilayer Ti 3 C 2 T x The above solution was then ultrasonicated for 60 min under an argon atmosphere and centrifuged to obtain an ultra-thin few-layer Ti 3 C 2 T x .

[0051] Due to the present invention Ti 3 C 2 T x , prepared by HCl+LiF etching method, so the obtained Ti 3 C 2 T x The surface contains a large number of -O, -F and -OH functional groups, thus showing negative charge; while the modified optical fiber surface is positively charged. When the positively charged optical fiber probe is in contact with the negatively charged MXene, the MXene will be tightly adsorbed on the optical fiber surface due to electrostatic adsorption.

[0052] In some embodiments, 30 to 90 mg of Ti 3 C 2 T x Add 30 mL of deionized water to obtain a 1.0-3.0 mg / mL MXene dispersion.

[0053] In some embodiments, in the step of immersing the modified optical fiber in a MXene dispersion, the immersion time is 0.5 to 3.0 hours. The modified optical fiber is immersed in a 0.5-3.0 mg / mL MXene dispersion for 0.5-3.0 hours, and then rinsed with ethanol to obtain an intermediate Au-MXene optical fiber probe with MXene attached to the surface.

[0054] In some embodiments, a method for preparing a rGO dispersion includes: adding rGO powder to a hydrochloric acid solution to obtain a rGO dispersion;

[0055] The concentration of hydrochloric acid solution is 1.0-2.0M;

[0056] The concentration of rGO dispersion is 1.0-2.0 mg / mL.

[0057] In some embodiments, in the step of immersing the Au-MXene optical fiber probe in the rGO dispersion, the immersion time is 1.0 to 3.0 hours.

[0058] In some embodiments, the Au-MXene fiber probe is immersed in a rGO dispersion having a concentration of 1.0-2.0 mg / mL for 1.0-3.0 h, taken out, rinsed with ethanol, and dried to obtain an Au-MXene@rGO fiber probe with a MXene@rGO two-dimensional heterostructure material attached to the surface.

[0059] In some embodiments, the preparation process of the rGO dispersion is as follows: 30 to 60 mg of rGO powder is weighed and poured into 30 mL of 1.0 to 2.0 M hydrochloric acid solution to obtain 1.0 to 2.0 mg / mL of rGO dispersion. In this process, the rGO dispersed in the hydrochloric acid will undergo H2O2 reaction in the solution due to the presence of a certain amount of carboxyl groups (-COOH) and hydroxyl groups (-OH) on the surface. + Nucleophilic substitution reaction to form -C=OH + Functional groups and -C-OH 2 + Functional groups; As the reaction continues, the Ti-O - Will attack -C=OH + and -C-OH 2 + The functional group C produces dehydration condensation to lead to H 2 O is removed from the rGO surface, so that MXene and rGO are combined through Ti-OC bonds to form a MXene@rGO heterostructure.

[0060] In some embodiments, the Au film is prepared on the surface of the optical fiber by magnetron sputtering.

[0061] In some embodiments, the Au film has a thickness of 50-55 nm.

[0062] In some embodiments, an optical fiber with a diameter of 600 mm is taken, and the thickness of the optical fiber can also be adjusted according to actual needs, and the optical fiber is cut into 8-10 cm long optical fiber segments, and both ends of the optical fiber are polished to a mirror state with a polishing machine;

[0063] Then peel off the outer layer, the length of which is 1.0 to 1.5 cm;

[0064] The optical fiber was then immersed in acetone for 3 h to completely remove the residual cladding residue on the core surface;

[0065] After rinsing with ethanol and drying, the optical fiber was placed vertically in a magnetron sputtering chamber, the sputtering power was controlled to 14 W, and a gold film with a thickness of 50 to 55 nm was sprayed on the circumferential surface of the fiber core.

[0066] Based on the same inventive concept, the present invention also provides a MXene@rGO optical fiber probe, which is prepared by the above-mentioned preparation method.

[0067] Based on the same inventive concept, the present invention also provides a MXene@rGO optical fiber probe prepared by the above preparation method or the application of the above MXene@rGO optical fiber probe in detecting disease markers or environmental pollutants.

[0068] Specifically, the MXene@rGO optical fiber probe of the present invention demonstrates its application potential by taking the detection of glycerol as an example.

[0069] The following further illustrates the MXene@rGO optical fiber probe of the present application and its preparation method and application with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0070] In the following examples, rGO powder was purchased from MacLean Reagent, specifically H992598 high temperature reduced graphene industrial grade powder, item number H992598-100 mg.

[0071] In the following embodiments, Ti 3 C 2 T x The preparation method is:

[0072] 7.5 mL of 37% hydrochloric acid solution (density 1.17 g / mL) was diluted in 2.5 mL of deionized water, and 0.5 g of LiF was added and stirred for 10 min to obtain a mixed solution; then 0.5 g of Ti was added to the mixed solution. 3 AlC2 , magnetic stirring, placed in a 35°C water bath, etched for 24 h; deionized water centrifuged several times until the pH value of the solution reached neutral conditions to obtain accordion-shaped multilayer Ti 3 C 2 T x The above solution was ultrasonicated for 60 min under an argon atmosphere and centrifuged to obtain Ti 3 C 2 T x .

[0073] Example 1

[0074] The present invention provides a method for preparing a MXene@rGO optical fiber probe, comprising the following steps:

[0075] S1. Take an optical fiber with a diameter of 600 mm, cut it into 8 cm long segments, and polish both ends of the optical fiber to a mirror state with a polishing machine; then strip off the outer cladding, the stripping length is 1.5 cm; then soak the optical fiber in acetone and keep it for 3 hours to completely remove the residual cladding residue on the core surface; rinse with ethanol and dry it, then place the optical fiber vertically in a magnetron sputtering chamber, control the sputtering power to 14 W, and spray-plate a 50 nm thick Au film on the circumference of the core;

[0076] S2, immersing the optical fiber with Au film on the surface in cysteamine hydrochloride ethanol solution for 18 hours, and washing with deionized water and ethanol in turn to obtain positively charged optical fiber; cysteamine hydrochloride (C 2 H 8 The concentration of cysteamine hydrochloride (C 2 H 8 The preparation method of cysteamine hydrochloride (C 1NS) ethanol solution is as follows: weigh 100 mg of cysteamine hydrochloride (C 2 H 8 ClNS) is added to 20 mL of ethanol to prepare a 2.0 mg / mL cysteamine hydrochloride ethanol solution;

[0077] S3, immerse the modified optical fiber in MXene dispersion for 1.0 h, rinse with ethanol after immersion to obtain Au-MXene optical fiber probe; the concentration of MXene dispersion is 3.0 mg / mL, and the preparation method of MXene dispersion is as follows: 90 mg of Ti 3 C 2 T x Add 30 mL of deionized water to obtain a 3.0 mg / mL MXene dispersion;

[0078] S4. Immerse the Au-MXene fiber probe in the rGO dispersion for 3.0 h. After immersion, rinse with ethanol and dry to obtain a MXene@rGO fiber probe. The concentration of the rGO dispersion is 1.0 mg / mL. The preparation process of the rGO dispersion is as follows: weigh 30 mg of rGO powder and pour it into 30 mL of 1.0 M hydrochloric acid solution to obtain a 1.0 mg / mL rGO dispersion.

[0079] Example 2

[0080] The present invention provides a method for preparing a MXene@rGO optical fiber probe, comprising the following steps:

[0081] S1. Take an optical fiber with a diameter of 600 mm, cut it into 8 cm long segments, and polish both ends of the optical fiber to a mirror state with a polishing machine; then strip off the outer cladding, the stripping length is 1.5 cm; then soak the optical fiber in acetone and keep it for 3 hours to completely remove the residual cladding residue on the core surface; rinse with ethanol and dry it, then place the optical fiber vertically in a magnetron sputtering chamber, control the sputtering power to 14 W, and spray-plate a 50 nm thick Au film on the circumference of the core;

[0082] S2, immersing the optical fiber with Au film on the surface in cysteamine hydrochloride ethanol solution for 24.0 hours, and then washing with deionized water and ethanol in turn to obtain positively charged optical fiber; cysteamine hydrochloride (C 2 H 8 The concentration of cysteamine hydrochloride (C 2 H 8 The preparation method of cysteamine hydrochloride (C 1NS) ethanol solution is as follows: weigh 100 mg of cysteamine hydrochloride (C 2 H 8 ClNS) was added to 33.33 mL of ethanol to prepare a 3.0 mg / mL cysteamine hydrochloride ethanol solution;

[0083] S3, immerse the modified optical fiber in MXene dispersion for 3.0 hours, and rinse with ethanol after immersion to obtain Au-MXene optical fiber probe; the concentration of MXene dispersion is 1.0 mg / mL, and the preparation method of MXene dispersion is as follows: 30 mg of Ti 3 C 2 T x Add 30 mL of deionized water to obtain a 1.0 mg / mL MXene dispersion;

[0084] S4. Immerse the Au-MXene fiber probe in the rGO dispersion for 2.0 h. After immersion, rinse with ethanol and dry to obtain a MXene@rGO fiber probe. The concentration of the rGO dispersion is 2.0 mg / mL. The preparation process of the rGO dispersion is as follows: weigh 60 mg of rGO powder and pour it into 30 mL of 1.0 M hydrochloric acid solution to obtain a 2.0 mg / mL rGO dispersion.

[0085] Example 3

[0086] The present invention provides a method for preparing a MXene@rGO optical fiber probe, comprising the following steps:

[0087] S1. Take an optical fiber with a diameter of 600 mm, cut it into 8 cm long segments, and polish both ends of the optical fiber to a mirror state with a polishing machine; then strip off the outer cladding, the stripping length is 1.5 cm; then soak the optical fiber in acetone and keep it for 3 hours to completely remove the residual cladding residue on the core surface; rinse with ethanol and dry it, then place the optical fiber vertically in a magnetron sputtering chamber, control the sputtering power to 14 W, and spray-plate a 50 nm thick Au film on the circumference of the core;

[0088] S2, immersing the optical fiber with Au film on the surface in cysteamine hydrochloride ethanol solution for 12.0 hours, and then washing with deionized water and ethanol in turn to obtain positively charged optical fiber; cysteamine hydrochloride (C 2 H 8 The concentration of cysteamine hydrochloride (C 2 H 8 The preparation method of cysteamine hydrochloride (C 1NS) ethanol solution is as follows: weigh 100 mg of cysteamine hydrochloride (C 2 H 8 ClNS) is added to 10 mL of ethanol to prepare a 10.0 mg / mL cysteamine hydrochloride ethanol solution;

[0089] S3, immerse the modified optical fiber in MXene dispersion for 2.0 h, rinse with ethanol after immersion to obtain Au-MXene optical fiber probe; the concentration of MXene dispersion is 2.0 mg / mL, and the preparation method of MXene dispersion is as follows: 60 mg of Ti 3 C 2 T x Add 30 mL of deionized water to obtain a 2.0 mg / mL MXene dispersion;

[0090] S4. Immerse the Au-MXene fiber probe in the rGO dispersion for 2.0 h. After immersion, rinse with ethanol and dry to obtain a MXene@rGO fiber probe. The concentration of the rGO dispersion is 1.5 mg / mL. The preparation process of the rGO dispersion is as follows: weigh 45 mg of rGO powder and pour it into 30 mL of 1.0 M hydrochloric acid solution to obtain a 1.5 mg / mL rGO dispersion.

[0091] Comparative Example 1

[0092] This comparative example provides a method for preparing an Au film optical fiber probe, comprising the following steps:

[0093] S1. Take an optical fiber with a diameter of 600 mm, cut it into 8 cm long segments, and polish both ends of the optical fiber to a mirror state with a polishing machine; then peel off the outer cladding, the stripping length is 1.5 cm; then soak the optical fiber in acetone and keep it for 3 hours to completely remove the residual cladding residue on the surface of the core; rinse with ethanol and dry it, then place the optical fiber vertically in a magnetron sputtering chamber, control the sputtering power to 14 W, and spray a 50 nm thick Au film on the circumference of the core to obtain an Au film optical fiber probe.

[0094] Comparative Example 2

[0095] This comparative example provides a method for preparing an Au-rGO optical fiber probe, comprising the following steps:

[0096] S1. Take an optical fiber with a diameter of 600 mm, cut it into 8 cm long segments, and polish both ends of the optical fiber to a mirror state with a polishing machine; then strip off the outer cladding, the stripping length is 1.5 cm; then soak the optical fiber in acetone and keep it for 3 hours to completely remove the residual cladding residue on the core surface; rinse with ethanol and dry it, then place the optical fiber vertically in a magnetron sputtering chamber, control the sputtering power to 14 W, and spray-plate a 50 nm thick Au film on the circumference of the core;

[0097] S2, immersing the optical fiber with Au film on the surface in cysteamine hydrochloride ethanol solution for 12.0 hours, and then washing with deionized water and ethanol in turn to obtain positively charged optical fiber; cysteamine hydrochloride (C 2 H 8 The preparation method of cysteamine hydrochloride (C 1NS) ethanol solution is as follows: weigh 100 mg of cysteamine hydrochloride (C 2 H 8 ClNS) is added to 10 mL of ethanol to prepare a 10.0 mg / mL cysteamine hydrochloride ethanol solution;

[0098] S3. Immerse the positively charged Au film optical fiber in S2 in rGO dispersion for 2.0 h. Rinse with ethanol and dry in air to obtain an Au-rGO optical fiber probe. The concentration of the rGO dispersion is 1.5 mg / mL. The preparation process of the rGO dispersion is as follows: weigh 45 mg of rGO powder and pour it into 30 mL of 1.0 M hydrochloric acid solution to obtain a 1.5 mg / mL rGO dispersion.

[0099] Comparative Example 3

[0100] This comparative example provides a method for preparing an Au-MXene optical fiber probe, comprising the following steps:

[0101] S1. Take an optical fiber with a diameter of 600 mm, cut it into 8 cm long segments, and polish both ends of the optical fiber to a mirror state with a polishing machine; then strip off the outer cladding, the stripping length is 1.5 cm; then soak the optical fiber in acetone and keep it for 3 hours to completely remove the residual cladding residue on the core surface; rinse with ethanol and dry it, then place the optical fiber vertically in a magnetron sputtering chamber, control the sputtering power to 14 W, and spray-plate a 50 nm thick Au film on the circumference of the core;

[0102] S2, immersing the optical fiber with Au film on the surface in cysteamine hydrochloride ethanol solution for 12.0 hours, and then washing with deionized water and ethanol in turn to obtain positively charged optical fiber; cysteamine hydrochloride (C 2 H 8 The concentration of cysteamine hydrochloride (C 2 H 8 The preparation method of cysteamine hydrochloride (C 1NS) ethanol solution is as follows: weigh 100 mg of cysteamine hydrochloride (C 2 H 8 ClNS) is added to 10 mL of ethanol to prepare a 10.0 mg / mL cysteamine hydrochloride ethanol solution;

[0103] S3, immerse the modified optical fiber in MXene dispersion for 2.0 h, rinse with ethanol after immersion to obtain Au-MXene optical fiber probe; the concentration of MXene dispersion is 2.0 mg / mL, and the preparation method of MXene dispersion is as follows: 60 mg of Ti 3 C 2 T x Add 30 mL of deionized water to obtain a 2.0 mg / mL MXene dispersion.

[0104] Performance Characterization

[0105] Figure 1This is a real picture of the optical fiber after the Au film is sputtered on the surface of the optical fiber according to the method in Example 1.

[0106] The surface microscopic image (SEM) of the optical fiber after sputtering the Au film on the optical fiber surface according to the method in Example 1 is as follows: Figure 2 shown.

[0107] The scanning electron microscope (SEM) image of the MXene@rGO optical fiber probe finally prepared according to the method in Example 1 is as follows: Figure 3 shown.

[0108] from Figure 2 It can be seen from the figure that after the Au film is sputtered on the optical fiber surface, the optical fiber surface is smooth and only tiny Au nanoparticles can be observed; Figure 3 It can be seen that the surface of the MXene@rGO optical fiber probe has been completely wrapped due to the formation of heterogeneous structural materials, presenting a relatively rough state.

[0109] The MXene@rGO optical fiber probe prepared in Example 1 was further studied and observed, and its crystal structure and charge distribution were as follows: Figure 4 shown.

[0110] Figure 4 The red atoms are oxygen atoms, the blue atoms are titanium atoms, the brown atoms are carbon atoms, the yellow area is the charge depletion area, the cyan area is the charge accumulation area, and the coordinates a, b, and c are the x, y, and z axes respectively. Figure 4 It can be clearly seen that after the heterostructure is formed, the charge on rGO is significantly transferred to MXene. At the same time, the charge accumulated in MXene is further transferred to the Au film because Ti 3 C 2 T x The work function of MXene@rGO is about 3.8-5.0eV, which is smaller than the work function of Au (5.1eV). The charge will spontaneously transfer from the low work function side to the high work function side. This phenomenon will greatly increase the charge concentration on the surface of the Au film, and under the influence of the evanescent wave, a more significant surface plasmon resonance will be generated, and the electromagnetic field intensity on the surface of the optical fiber will also be greater. Therefore, the MXene@rGO optical fiber probe can detect analytes with lower concentrations and higher sensitivity.

[0111] The sensitivity tests were performed on the MXene@rGO optical fiber probes prepared in Examples 1 to 3 and the Au film optical fiber probes, Au-rGO optical fiber probes, and Au-MXene optical fiber probes prepared in Comparative Examples 1 to 3, and the results are shown in Table 1. During the test, the optical fiber probes in Comparative Examples 1 to 3 were tested three times in parallel, and the MXene@rGO optical fiber probes prepared in Examples 1 to 3 were tested once.

[0112] The specific test method is as follows: connect the optical fiber probes prepared by different methods to the Y-type optical fiber port between the light source and the spectrometer, and after the incident light is introduced, detect the glycerol aqueous solution with volume concentrations of 0%, 5%, 10%, 15%, 20%, and 25% in turn to obtain the spectral curve; the refractive indexes of the glycerol aqueous solution with volume concentrations of 0%, 5%, 10%, 15%, 20%, and 25% are 1.3312, 1.3421, 1.3461, 1.3544, 1.3611, and 1.3686, respectively. ; Among them, as the volume concentration of the glycerol aqueous solution increases, the drift amount of the absorption peak of the absorption spectrum increases (the drift amount is calculated relative to the glycerol aqueous solution with a volume concentration of 0%), and the drift amount is used as the vertical coordinate, and the refractive index of the glycerol aqueous solution with different volume concentrations is used as the horizontal coordinate to obtain a linear relationship between the drift amount and the refractive index of the glycerol aqueous solution, and the slope of the straight line is the sensitivity; when testing the glycerol aqueous solution of the to-be-tested concentration in practice, the drift amount of the absorption peak of the absorption spectrum is measured first, and then the concentration of the to-be-tested glycerol aqueous solution can be obtained based on the linear relationship.

[0113] Table 1 - Sensitivity test results of different fiber optic probes

[0114]

[0115] It can be seen from Table 1 that the sensitivity improvement of the MXene@rGO optical fiber probe prepared in the present invention is much higher than the sensitivity improvement of the Au-rGO optical fiber probe and the Au-MXene optical fiber probe relative to the Au film optical fiber probe in Comparative Examples 2 to 3.

[0116] The sensitivity of the MXene@rGO optical fiber probe in Example 3 and the Au film optical fiber probe in Comparative Example 1 were tested according to the same test method as above. Specifically, the detection volume concentrations of 0%, 5%, 10%, 15%, 20%, and 25% glycerol aqueous solution were respectively obtained. The spectral curves are as follows: Figure 5 shown. Figure 5 The dotted line and the solid line are the spectral curves of the Au film fiber probe in Comparative Example 1 and the MXene@rGO fiber probe in Example 3, as well as the glycerol aqueous solution when the detection volume concentrations are 0% (dark blue), 5% (light blue), 10% (green), 15% (yellow), 20% (orange), and 25% (red), respectively.

[0117] from Figure 5 It can be seen that the spectral drift of the Au film optical fiber probe in Comparative Example 1 is only 80.02 nm, while the drift of the MXene@rGO optical fiber probe in Example 3 reaches 152.04 nm.

[0118] The sensitivity of the MXene@rGO optical fiber probe in Example 3 and the Au film optical fiber probe in Comparative Example 1 were tested respectively according to the same test method as above, and a linear graph of the drift amount and the refractive index of the glycerol aqueous solution was obtained, as shown in FIG. Figure 6 shown. Figure 6 In the figure, Au represents the Au film optical fiber probe in Comparative Example 1, and MXene@rGO represents the MXene@rGO optical fiber probe in Example 3. Figure 5 The vertical axis represents the drift of the absorption peak of the absorption spectrum (Wavelength shift), and the horizontal axis represents the refractive index (RIU) of the glycerol aqueous solution.

[0119] from Figure 6 It can be seen that the sensitivity of the Au film optical fiber probe in Comparative Example 1 is 2157.23nm / RIU, while the sensitivity of the MXene@rGO optical fiber probe in Example 3 is 4312.72nm / RIU. From this comparison, it is found that the sensitivity of the MXene@rGO optical fiber probe of the present invention has been greatly improved, which is about twice that of the Au optical fiber probe. This higher sensitivity can be more suitable for the detection and analysis of trace or even trace markers.

[0120] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a MXene@rGO optical fiber probe, characterized in that: The following steps are involved: Preparing Au film on the surface of optical fiber; The optical fiber with Au film on the surface is immersed in cysteamine hydrochloride ethanol solution, and after the immersion is completed, it is washed with water and ethanol in sequence to obtain a positively charged optical fiber; The modified optical fiber is immersed in a MXene dispersion to obtain an Au-MXene optical fiber probe; The Au-MXene optical fiber probe was immersed in the rGO dispersion to obtain the MXene@rGO optical fiber probe.

2. The method for preparing the MXene@rGO optical fiber probe according to claim 1, characterized in that: The concentration of the cysteamine hydrochloride ethanol solution is 3.0-10.0 mg / mL.

3. The method for preparing the MXene@rGO optical fiber probe according to claim 1, characterized in that: The step of immersing the optical fiber having the Au film on the surface in a cysteamine hydrochloride ethanol solution for 12 to 24 hours.

4. The method for preparing the MXene@rGO optical fiber probe according to claim 1, characterized in that: The preparation method of the MXene dispersion comprises: x Add to deionized water to obtain a MXene dispersion; The concentration of the MXene dispersion is 1.0 to 3.0 mg / mL.

5. The method for preparing the MXene@rGO optical fiber probe according to claim 1, characterized in that: The modified optical fiber is immersed in a MXene dispersion for a period of 0.5 to 3.0 hours.

6. The method for preparing the MXene@rGO optical fiber probe according to claim 1, characterized in that: The method for preparing the rGO dispersion comprises: adding rGO powder into a hydrochloric acid solution to obtain the rGO dispersion; The concentration of the hydrochloric acid solution is 1.0-2.0M; The concentration of the rGO dispersion is 1.0-2.0 mg / mL.

7. The method for preparing the MXene@rGO optical fiber probe according to claim 1, characterized in that: The Au-MXene optical fiber probe is immersed in the rGO dispersion for a period of 1.0 to 3.0 hours.

8. The method for preparing the MXene@rGO optical fiber probe according to claim 1, characterized in that: The Au film was prepared on the optical fiber surface by magnetron sputtering; The thickness of the Au film is 50-55 nm.

9. A MXene@rGO optical fiber probe, characterized in that: The preparation method is as described in any one of claims 1 to 8.

10. Use of a MXene@rGO optical fiber probe prepared by the preparation method according to any one of claims 1 to 8 or the MXene@rGO optical fiber probe according to claim 9 in detecting environmental pollution markers.

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