Nanogold paper and preparation method and application thereof

Abstract

The application provides a kind of nano gold paper and its preparation method and application, the nano gold paper includes carrier and several gold nanoparticles loaded on the carrier, the several gold nanoparticles are uniformly dispersed, and the carrier is cellulose paper containing hydroxyl.In situ growth of gold nanoparticles on cellulose paper containing hydroxyl, the stability of gold nanoparticles is enhanced, the cost of carrier is reduced, and the preparation step of supported nanomaterial is simplified.The nano gold paper of the application can be used as a simple and effective catalyst, and can also be used as a SERS sensor to detect pH and hydrogen peroxide concentration.The in situ preparation method of the nano gold paper provided by the application does not need complex pretreatment of the carrier material, is easy to operate, low in cost, and can be widely used in various catalysis and detection.

Description

Technical Field

[0001] This invention belongs to the field of gold nanomaterial preparation, and specifically relates to a nano-gold paper, its preparation method and application. Background Technology

[0002] Gold nanomaterials, due to their high specific surface area and unique surface electronic properties, have broad application prospects in energy and environmental catalysis, sensing and detection, and biomedicine, and have become a long-term research hotspot. However, free noble metal nanoparticles are prone to aggregation due to their small particle size and high surface energy, leading to reduced catalytic activity. Furthermore, nanoscale catalysts are difficult to separate, recover, and reuse from the reaction system. Therefore, gold nanomaterials are supported on polymers, mesoporous silica, metal oxides, and other supports to improve the dispersibility, stability, and reusability of the materials. These supports can immobilize nanoparticles through electrostatic adsorption, spatial confinement, and coordination of surface functionalized groups. However, the pretreatment and preparation steps of these supports are usually complex and costly. Therefore, developing simple, effective, low-cost, and reusable supported gold nanomaterials can promote their large-scale production and application. Summary of the Invention

[0003] This invention provides a nano-gold paper, its preparation method, and its applications to solve the aforementioned technical problems. The method is simple and easy to implement, not only meeting the requirements for low-cost, large-scale preparation, but also functioning as a solid catalyst and sensor.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A nano-gold paper, comprising a carrier and a plurality of gold nanoparticles loaded on the carrier, wherein the carrier is cellulose paper containing hydroxyl groups.

[0006] Preferably, each cellulose paper containing hydroxyl groups has a size of (10-20) mm × (10-20) mm, and its shape is not limited, but it is preferably square. It is understood that up to 20 cellulose papers can be added at a time to ensure that the gold nanoparticles are uniformly dispersed on the carrier and to achieve good application results.

[0007] The method for preparing the aforementioned nano-gold paper includes the following steps:

[0008] Step 1: Soak the cellulose paper in a chloroauric acid aqueous solution for t1; then soak it in a NaBH4 aqueous solution for t2; rinse with ultrapure water and dry to obtain nano gold seed paper.

[0009] Step 2: Add dichloroauric acid aqueous solution to an aqueous solution containing hexadecyltrimethylammonium bromide, sonicate, and then add ascorbic acid. After the solution changes from yellow to colorless, immediately add the nano-gold seed paper to soak for t3. Then take it out, wash and dry it to obtain nano-gold paper.

[0010] Preferably, the concentration of the first chloroauric acid aqueous solution is 5 mmol / L to 80 mmol / L, more preferably 10 mmol / L to 50 mmol / L, and even more preferably 10 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, or 50 mmol / L.

[0011] Preferably, t1 is 2 min to 5 min, and more preferably 2 min.

[0012] Preferably, the concentration of the NaBH4 aqueous solution is 10 mmol / L to 50 mmol / L, more preferably 10 mmol / L, 20 mmol / L, 30 mmol / L, 40 mmol / L, or 50 mmol / L.

[0013] Preferably, t2 is 8 to 12 minutes, more preferably 10 minutes.

[0014] Preferably, the concentration ratio of the NaBH4 aqueous solution to the first chloroauric acid aqueous solution is 1:1.

[0015] Preferably, the concentration of hexadecyltrimethylammonium bromide is 0.1–0.3 mol / L, more preferably 0.2 mol / L.

[0016] Preferably, the concentration of the second chloroauric acid aqueous solution is 0.2 to 0.8 mmol / L, more preferably 0.5 mmol / L.

[0017] Preferably, the concentration of ascorbic acid is 2-8 mmol / L, more preferably 5 mmol / L.

[0018] Preferably, the ultrasound time is 5 to 10 minutes, more preferably 6 minutes.

[0019] Preferably, t3 is 15 to 25 minutes, more preferably 20 minutes.

[0020] Preferably, the cleaning in step two involves rinsing with deionized water 6 to 8 times, more preferably 8 times.

[0021] Preferably, the drying in step two is vacuum drying, with a drying temperature of 30-90°C and a drying time of 1-3 hours (h), more preferably, the drying temperature is 60°C and the drying time is 2 hours.

[0022] The application of the aforementioned nano-gold paper in catalysis and detection.

[0023] The catalysis is the catalytic reduction of p-nitrophenol and the degradation of rhodamine B.

[0024] Preferably, in the application of the catalyst for p-nitrophenol, the concentration of p-nitrophenol (4-NP) is 0.01-0.1 mmol / L, preferably 0.07 mmol / L; the reducing agent is NaBH4, with a concentration of 0.01-0.1 mol / L, preferably 0.021 mol / L; and the catalyst is gold nanopaper, preferably gold nanopaper prepared by growth with 40 mmol / L chloroauric acid.

[0025] Preferably, in the application of catalytic degradation of Rhodamine B, the concentration of Rhodamine B used is 0.01-0.1 mmol / L, preferably 0.04 mmol / L; the reducing agent is NaBH4, with a concentration of 0.001-0.1 mol / L, preferably 0.01 mol / L; and the catalyst is gold nanopaper, preferably gold nanopaper prepared by growth of 10 mmol / L chloroauric acid.

[0026] The detections were performed on the pH of the SERS detection solution and the concentration of hydrogen peroxide.

[0027] Preferably, in the application of pH detection, the detection method used is surface-enhanced Raman (SERS) detection, and the sensor used is a nano-gold paper SERS sensor modified with 4-mercaptobenzoic acid (4-MBA).

[0028] Preferably, the gold nanopaper is gold nanopaper prepared by growth with 40 mmol / L chloroauric acid;

[0029] Preferably, the 4-MBA is modified onto the gold nanosheet by immersing 10 pieces of gold nanosheet in 20 mL of 4-MBA ethanol solution, then removing, washing and drying.

[0030] Preferably, the concentration of the 4-MBA ethanol solution is 0.05–0.15 mmol / L, more preferably 0.1 mmol / L;

[0031] Preferably, the soaking time is 2-4 hours, more preferably 3 hours;

[0032] Preferably, the cleaning conditions are ultrasonic washing in ethanol solution 2 to 3 times, preferably 3 times, with each ultrasonic washing lasting 2 to 4 minutes, preferably 3 minutes;

[0033] Preferably, the drying is vacuum drying, with a drying temperature of 30-40°C and a drying time of 20-30 minutes; more preferably, the drying temperature is 37°C and the drying time is 30 minutes, thus obtaining a nano-gold paper sensor for pH detection.

[0034] Preferably, in the application of detecting hydrogen peroxide concentration, the detection method used is surface-enhanced Raman spectroscopy (SERS), and the sensor used is a nano-gold paper SERS sensor modified with m-mercaptophenylboronic acid (3-MPBA).

[0035] Preferably, the gold nanopaper is gold nanopaper prepared by growth with 40 mmol / L chloroauric acid;

[0036] Preferably, the 3-MPBA is modified onto the gold nanosheet by the following method: 10 pieces of gold nanosheet are immersed in 10 mL of 3-MPBA ethanol solution, then removed, washed and dried;

[0037] Preferably, the concentration of the 3-MPBA ethanol solution is 1.0–1.5 mmol / L, more preferably 1.4 mmol / L;

[0038] Preferably, the soaking time is 2-4 hours, more preferably 3 hours;

[0039] Preferably, the cleaning conditions are ultrasonic washing in ethanol solution 2 to 3 times, preferably 3 times, with each ultrasonic washing lasting 2 to 3 minutes, preferably 3 minutes;

[0040] Preferably, the drying is vacuum drying, with a drying temperature of 30-40°C and a drying time of 20-30 minutes, and more preferably a drying temperature of 37°C and a drying time of 30 minutes, thus obtaining a nano-gold paper SERS sensor for hydrogen peroxide concentration detection.

[0041] The principle of this invention is as follows: the in-situ preparation method of the nano-gold paper of this invention is the seed growth method, which involves first preparing nano-gold seed paper in situ, and then growing it into nano-gold paper.

[0042] Compared with existing technologies, the advantages of this invention are as follows: In-situ growth of gold nanoparticles on hydroxyl-containing cellulose paper enhances the stability of the gold nanoparticles, reduces the cost of the support, and simplifies the preparation steps of supported nanomaterials. The gold nanopaper of this invention can serve as a simple and effective catalyst, as well as a SERS sensor for detecting pH and hydrogen peroxide concentration. The in-situ preparation method of gold nanopaper provided by this invention does not require complex pretreatment of the support material, is highly operable, low-cost, and can be widely applied in various catalysis and detection applications. Attached Figure Description

[0043] Figure 1 The images shown are (a) physical image, (b) ultraviolet-visible spectrophotometric absorption spectrum, and (c) scanning electron microscope (SEM) image of the nano-gold seed paper-1 involved in Example 1 of the present invention;

[0044] Figure 2The images shown are (a), (b), and (c) of the nano-gold seed paper-2 described in Example 2 of this invention.

[0045] Figure 3 The images shown are (a), (b), and (c) of the nano-gold seed paper-3 described in Example 3 of this invention.

[0046] Figure 4 The images shown are (a), (b), and (c) of the nano-gold seed paper-4 described in Example 4 of this invention.

[0047] Figure 5 The images shown are (a), (b), and (c) of the nano-gold seed paper-5 described in Example 5 of this invention.

[0048] Figure 6 The images (a) and (b) show the physical image of the gold nanopaper (N-AuP-1-5) prepared using nitrocellulose paper as a carrier, as described in Comparative Example 1 of this invention.

[0049] Figure 7 The images (a) and (b) show the physical image of the gold nanopaper (Ac-AuP-1-5) prepared using fiber paper containing carboxylic acid groups as a substrate, as described in Comparative Example 2 of this invention.

[0050] Figure 8 The results of the UV-Vis spectrum changes over time and the kinetic analysis results of the reduction of p-nitrophenol by nano-gold paper-1 (AuP-1), 2 (AuP-2), 3 (AuP-3), 4 (AuP-4) and 5 (AuP-5) involved in Example 6 of the present invention are shown in Example (ae) and Example (f).

[0051] Figure 9 The results of UV-Vis light spectrum changes over time and kinetic analysis results of the reduction of Rhodamine B by nano-gold paper-1 (AuP-1), 2 (AuP-2), 3 (AuP-3), 4 (AuP-4) and 5 (AuP-5) involved in Example 7 of the present invention are shown in the following figures (af) and (g).

[0052] Figure 10 The images show the Raman peak intensity (a) and fitting curve (b) of the solution at different pH values ​​after the nano-gold paper-4 involved in Example 8 of this invention was modified with 4-MBA as a SERS substrate.

[0053] Figure 11The images show the Raman peak intensity diagram (a) and fitting curve (b) of H2O2 solutions of different concentrations after the nano-gold paper-4 involved in Example 9 of this invention was modified with 3-MPBA as a SERS substrate. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0055] The present invention provides a nano-gold paper, which includes a carrier and a plurality of gold nanoparticles loaded on the carrier, wherein the carrier is cellulose paper containing hydroxyl groups.

[0056] The present invention also provides a method for preparing the nano-gold paper, comprising the following steps:

[0057] Cellulose paper was soaked in a chloroauric acid aqueous solution for t1 and then removed; it was then soaked in a NaBH4 aqueous solution for t2 and then removed; the paper was rinsed with ultrapure water and dried to obtain nano-gold seed paper.

[0058] Add dichloroauric acid aqueous solution to an aqueous solution containing hexadecyltrimethylammonium bromide, sonicate, and then add ascorbic acid. After the solution changes from yellow to colorless, immediately add the nano-gold seed paper to soak for t3. Then take it out, wash and dry it to obtain nano-gold paper.

[0059] This invention first prepares nano-gold seed paper in situ, and then grows it into nano-gold paper.

[0060] In the following examples, the concentration of the first chloroauric acid aqueous solution was 10, 20, 30, 40, and 50 mmol / L, and the prepared gold nanopapers were named gold nanopaper-1, 2, 3, 4, and 5, respectively. The gold nanopapers prepared by further growth of these nanopapers were named gold nanopaper-1, 2, 3, 4, and 5, respectively.

[0061] The application of the described gold nanopaper is in catalytic detection. The catalytic application involves gold nanopaper-4 catalyzing the reduction of 4-NP and the degradation of Rhodamine B; the detection application involves gold nanopaper-4 acting as a SERS substrate to modify Raman signal molecules for detecting the pH and hydrogen peroxide concentration of the solution. The gold nanopapers in the following examples were prepared under conditions of different concentrations of chloroauric acid seed precursor solutions, and gold nanopaper-4 was applied to the fields of catalysis and detection, but is not limited to the concentration of the chloroauric acid seed precursor solution, the type of gold nanopaper used, or the type of catalysis, detection target, and detection method.

[0062] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0063] Example 1

[0064] This embodiment provides an in-situ preparation method for nano-gold paper, wherein the nano-gold paper is prepared by reducing nano-gold seed paper with 10 mmol / L chloroauric acid and then further growing it in situ.

[0065] The specific preparation method of the nano-gold paper-1 is as follows:

[0066] 1) Preparation of nano-gold seed paper-1: 20 sheets of 10mm×10mm cellulose paper were added to 5mL of 10mmol / L chloroauric acid aqueous solution and soaked for 2min. The cellulose paper changed from white to yellow. Then, it was placed in 10mL of 10mmol / L NaBH4 aqueous solution and soaked for 10min. The cellulose paper changed from yellow to light red. Finally, it was rinsed twice with ultrapure water and excess water was absorbed with filter paper.

[0067] 2) Preparation of nano-gold paper-1: Add 1.8 mL of 0.5 mmol / L second HAuCl4 solution to a solution containing 9.0 mL of 0.2 mol / L CTAB and sonicate for 6 min. Then add 1.0 mL of 0.5 mmol / L ascorbic acid solution. After the solution changes from yellow to colorless, immediately add the above-mentioned nano-gold seed paper and soak for 20 min. Then take it out and rinse it 8 times with deionized water. Dry it in a vacuum drying oven at 60℃ for 2 h to obtain the final product.

[0068] 3) Results Analysis: See attached document. Figure 1 As shown, the gold nanopaper-1 exhibits the red color of colloidal gold with an absorption wavelength of 530 nm. The SEM image shows that gold nanoparticles are loaded onto the fibers of cellulose paper, indicating that the gold nanopaper-1 was successfully prepared.

[0069] Example 2

[0070] This embodiment provides an in-situ preparation method for nano-gold paper, wherein the nano-gold paper is prepared by reducing nano-gold seed paper with 20 mmol / L chloroauric acid and then further growing it in situ.

[0071] The specific preparation method of the nano-gold paper-2 is as follows:

[0072] 1) Preparation of nano-gold seed paper for nano-gold paper-2: 20 sheets of 10mm×10mm cellulose paper were added to 5mL of 20mmol / L chloroauric acid aqueous solution and soaked for 2min. The cellulose paper changed from white to yellow. Then, it was placed in 10mL of 20mmol / L NaBH4 aqueous solution and soaked for 10min. The cellulose paper changed from yellow to light red. Finally, it was rinsed twice with ultrapure water and excess water was absorbed with filter paper.

[0073] 2) Preparation of nano-gold paper-2: Add 1.8 mL of 0.5 mmol / L second HAuCl4 solution to a solution containing 9.0 mL of 0.2 mol / L CTAB and sonicate for 6 min. Then add 1.0 mL of 0.5 mmol / L ascorbic acid solution. After the solution changes from yellow to colorless, immediately add the above-mentioned nano-gold seed paper and soak for 20 min. Then take it out and rinse it 8 times with deionized water. Dry it in a vacuum drying oven at 60℃ for 2 h to obtain the final product.

[0074] 3) Results Analysis: See attached document. Figure 2 As shown, the gold nanopaper-2 exhibits the red color of colloidal gold, with an absorption wavelength of 524 nm. The SEM image shows that gold nanoparticles are loaded onto the fibers of cellulose paper, indicating that the gold nanopaper-2 was successfully prepared.

[0075] Example 3

[0076] This embodiment provides an in-situ preparation method for nano-gold paper, wherein the nano-gold paper is prepared by reducing nano-gold seed paper with 30 mmol / L chloroauric acid and then further growing it in situ.

[0077] The specific preparation method of the nano-gold paper-3 is as follows:

[0078] 1) Preparation of nano-gold seed paper for nano-gold paper-3: 20 sheets of 10mm×10mm cellulose paper were added to 5mL of 30mmol / L chloroauric acid aqueous solution and soaked for 2min. The cellulose paper changed from white to yellow. Then, it was placed in 10mL of 30mmol / L NaBH4 aqueous solution and soaked for 10min. The cellulose paper changed from yellow to light red. Finally, it was rinsed twice with ultrapure water and excess water was absorbed with filter paper.

[0079] 2) Preparation of nano-gold paper-3: Add 1.8 mL of 0.5 mmol / L second HAuCl4 solution to a solution containing 9.0 mL of 0.2 mol / L CTAB and sonicate for 6 min. Then add 1.0 mL of 0.5 mmol / L ascorbic acid solution. After the solution changes from yellow to colorless, immediately add the above-mentioned nano-gold seed paper and soak for 20 min. Then take it out and rinse it 8 times with deionized water. Dry it in a vacuum drying oven at 60℃ for 2 h to obtain the final product.

[0080] 3) Results Analysis: See attached document. Figure 3 As shown, the gold nanopaper-3 exhibits the red color of colloidal gold, with an absorption wavelength of 525 nm. The SEM image shows that gold nanoparticles are loaded onto the fibers of cellulose paper, indicating that the gold nanopaper-3 was successfully prepared.

[0081] Example 4

[0082] This embodiment provides an in-situ preparation method for nano-gold paper, wherein the nano-gold paper is prepared by reducing nano-gold seed paper with 40 mmol / L chloroauric acid and then further growing it in situ.

[0083] The specific preparation method of the nano-gold paper-4 is as follows:

[0084] 1) Preparation of nano-gold seed paper for nano-gold paper-4: 20 sheets of 10mm×10mm cellulose paper were added to 5mL of 40mmol / L chloroauric acid aqueous solution and soaked for 2min. The cellulose paper changed from white to yellow. Then, it was placed in 10mL of 40mmol / L NaBH4 aqueous solution and soaked for 10min. The cellulose paper changed from yellow to light red. Finally, it was rinsed twice with ultrapure water and excess water was absorbed with filter paper.

[0085] 2) Preparation of nano-gold paper-4: Add 1.8 mL of 0.5 mmol / L second HAuCl4 solution to a solution containing 9.0 mL of 0.2 mol / L CTAB and sonicate for 6 min. Then add 1.0 mL of 0.5 mmol / L ascorbic acid solution. After the solution changes from yellow to colorless, immediately add the above-mentioned nano-gold seed paper and soak for 20 min. Then take it out and rinse it 8 times with deionized water. Dry it in a vacuum drying oven at 60℃ for 2 h to obtain the final product.

[0086] 3) Results Analysis: See attached document. Figure 4 As shown, the gold nanopaper-4 exhibits the red color of colloidal gold with an absorption wavelength of 526 nm. The SEM image shows that gold nanoparticles are loaded onto the fibers of cellulose paper, indicating that the gold nanopaper-4 was successfully prepared.

[0087] Example 5

[0088] This embodiment provides an in-situ preparation method for nano-gold paper, wherein the nano-gold paper is prepared by reducing nano-gold seed paper with 50 mmol / L chloroauric acid and then further growing it in situ.

[0089] The specific preparation method of the nano-gold paper-5 is as follows:

[0090] 1) Preparation of nano-gold seed paper for nano-gold paper-5: 20 sheets of 10mm×10mm cellulose paper were added to 5mL of 50mmol / L chloroauric acid aqueous solution and soaked for 2min. The cellulose paper changed from white to yellow. Then, it was placed in 10mL of 50mmol / L NaBH4 aqueous solution and soaked for 10min. The cellulose paper changed from yellow to light red. Finally, it was rinsed twice with ultrapure water and excess water was absorbed with filter paper.

[0091] 2) Preparation of nano-gold paper-5: Add 1.8 mL of 0.5 mmol / L second HAuCl4 solution to a solution containing 9.0 mL of 0.2 mol / L CTAB and sonicate for 6 min. Then add 1.0 mL of 0.5 mmol / L ascorbic acid solution. After the solution changes from yellow to colorless, immediately add the above-mentioned nano-gold seed paper and soak for 20 min. Then take it out and rinse it 8 times with deionized water. Dry it in a vacuum drying oven at 60℃ for 2 h to obtain the final product.

[0092] 3) Results Analysis: See attached document. Figure 5 As shown, the gold nanopaper-5 exhibits the red color of colloidal gold with an absorption wavelength of 529 nm. The SEM image shows that gold nanoparticles are loaded onto the fibers of cellulose paper, indicating that the gold nanopaper-5 was successfully prepared.

[0093] Comparative Example 1

[0094] This comparative example provides a method for preparing nano-gold paper using nitrocellulose paper as a carrier.

[0095] The nitro-functionalized nano-gold paper (N-AuP) consists of N-AuP-1, N-AuP-2, N-AuP-3, N-AuP-4, and N-AuP-5. The preparation steps are the same as those for AuP-1, AuP-2, AuP-3, AuP-4, and AuP-5 in Examples 1-5, except that the cellulose paper used is nitro-functionalized cellulose paper.

[0096] Results analysis: see attached. Figure 6As shown, N-AuP-1, N-AuP-2, N-AuP-3, N-AuP-4, and N-AuP-5 exhibit the red color of colloidal gold, with an absorption wavelength of approximately 533 nm (±1 nm). However, the gold particles are unevenly distributed on the cellulose paper, and the effect is not as ideal as that of hydroxyl-functionalized cellulose paper.

[0097] Comparative Example 2

[0098] This comparative example provides a method for preparing nano-gold paper using carboxycellulose paper as a carrier.

[0099] The carboxylated nano-gold paper (Ac-AuP) is Ac-AuP-1, Ac-AuP-2, Ac-AuP-3, Ac-AuP-4, and Ac-AuP-5. The preparation steps are the same as those for AuP-1, AuP-2, AuP-3, AuP-4, and AuP-5 in Examples 1-5, except that the cellulose paper used is carboxylated functionalized cellulose paper.

[0100] Results analysis: see attached. Figure 7 As shown, Ac-AuP-1, Ac-AuP-2, Ac-AuP-3, Ac-AuP-4, and Ac-AuP-5 exhibit a purplish-red color of colloidal gold, with an absorption wavelength of approximately 549 nm (±1 nm). However, the gold particles are unevenly distributed on the cellulose paper, and the effect is not as ideal as that of hydroxyl-functionalized cellulose paper.

[0101] Example 6

[0102] This embodiment provides a catalytic application method for nano-gold paper, wherein nano-gold paper-1,-2,-3,-4, and-5 are used as solid catalysts to catalyze the reduction of p-nitrophenol.

[0103] The specific preparation method of the nano-gold paper-1, 2, 3, 4, 5 catalysts for the reduction of p-nitrophenol is as follows:

[0104] 1) Preparation of reaction solution: Take 1.5 mL of 0.07 mmol / L p-nitrophenol (4-NP) aqueous solution and 1.5 mL of 0.021 mol / L freshly prepared sodium borohydride aqueous solution and add them simultaneously to a 3 mL quartz cuvette to prepare the solution.

[0105] 2) Monitoring the catalytic reaction: Nano gold paper-1, 2, 3, 4, and 5 were added to cuvettes as solid catalysts, and the UV-Vis absorption spectrum of the solution was detected every 20 min, and the kinetic constants were calculated;

[0106] 3) Results Analysis: See attached document. Figure 8As shown, when nano-gold paper-1, 2, 3, 4, and 5 are used as catalysts, the absorption peak of 4-NP at 400 nm decreases with time, while the absorption peak at 315 nm increases with time, indicating that the nano-paper has a catalytic effect on p-nitrophenol; their reaction constants are 0.0160, 0.0244, 0.0243, 0.0446, and 0.0161, respectively, indicating that nano-gold paper-4 has the best catalytic performance.

[0107] Example 7

[0108] This embodiment provides a catalytic application method for nano-gold paper, wherein the nano-gold paper is used as a solid catalyst for the catalytic reduction of Rhodamine B (RhB). The applications of the nano-gold paper -1, -2, -3, -4, and -5 in the catalytic reduction of RhB are as follows:

[0109] 1) Preparation of reaction solution: Take 2.5 mL of 0.04 mmol / L RhB aqueous solution and 0.5 mL of 0.01 mol / L freshly prepared sodium borohydride aqueous solution and add them simultaneously to a 3 mL quartz cuvette to obtain the solution;

[0110] 2) Monitoring the catalytic reaction: Nano gold paper-1, -2, -3, -4, and -5 were added to cuvettes as solid catalysts, and the UV-Vis absorption spectrum of the solution was detected every 8 minutes, and the kinetic constants were calculated.

[0111] 3) Results Analysis: See attached document. Figure 9 As shown, when nano-gold paper-1, 2, 3, 4, and 5 are used as catalysts, the absorption peak of RhB at 550 nm decreases with time, indicating that the nano-paper has the effect of catalyzing the reduction of RhB; their reaction constants are 0.143, 0.076, 0.098, 0.098, and 0.055, respectively, indicating that nano-gold paper-1 has the best catalytic performance.

[0112] Example 8

[0113] This embodiment provides a detection application method for nano-gold paper, wherein nano-gold paper-4 is used as a SERS substrate to modify 4-MBA Raman reporter molecules to detect the pH of the solution.

[0114] The specific method for applying the 4-MBA modified gold nanopaper-4 solution to pH measurement is as follows:

[0115] 1) Modification of 4-MBA on nano-gold paper-4: 10 nano-gold paper-4 sheets were immersed in 20 mL of 0.1 mmol / L 4-MBA ethanol solution for 3 h, then removed, ultrasonically washed 3 times, and dried in a vacuum drying oven at 37 °C for 30 min to obtain the product;

[0116] 2) pH detection of the solution: 40 μL of the test liquid was dropped onto 4-MBA modified gold nanopaper-4, dried at 37℃ for 1 hour and then Raman detection was performed.

[0117] 3) Results Analysis: See attached document. Figure 10 As shown, the results indicate that the Raman signal intensity of 4-MBA exhibits a good linear response to pH within the solution pH range of 3–11 (R0). 2 =0.99), which proves that the pH of the solution was detected using nano-gold paper-4 as a SERS substrate.

[0118] Example 9

[0119] This embodiment provides a detection application method for nano-gold paper, wherein nano-gold paper-4 is used as a SERS substrate modified with 3-MPBA Raman reporter molecule to detect the concentration of H2O2 in solution.

[0120] The specific method for using the 3-MPBA-modified gold nanopaper-4 to detect the H2O2 concentration in the solution is as follows:

[0121] 1) Modification of 3-MPBA on nano-gold paper-4: 10 nano-gold paper-4 sheets were immersed in 10 mL of 1.3 mmol / L 3-MPBA ethanol solution for 3 h, then removed, ultrasonically washed 3 times, and dried in a vacuum drying oven at 37 °C for 30 min to obtain the product;

[0122] 2) H2O2 concentration detection in solution: 40 μL of the test liquid was dropped onto 3-MPBA modified nano gold paper-4 and dried at 37℃ for 1 hour before Raman detection.

[0123] 3) Results Analysis: such as Figure 11 As shown, the results indicate that the Raman signal intensity of 3-MPBA exhibits a good linear response to H2O2 concentration in the range of 10 μmol / L–10 mmol / L (R0). 2 =0.98), and its detection limit is 8 μmol / L.

[0124] The above results demonstrate the in-situ preparation method of the nano-gold paper designed and constructed in this invention and its applications. The nano-gold paper of this invention possesses catalytic and detection functions, meeting the requirements of simple, large-scale preparation and exhibiting direct detection performance. The prepared nano-gold paper can be directly used for the reduction of 4-nitrophenol and rhodamine B, and can also be modified with 4-MBA and 3-MPBA to detect the pH and hydrogen peroxide concentration of the test solution, respectively. Furthermore, it is of great significance for exploring new, simple, and effective metal nanocatalyst supports, promoting the practical application of nanocatalysts, and using simple and low-cost high-performance SERS substrates.

[0125] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations; therefore, any obvious variations or modifications derived therefrom remain within the scope of protection of this invention.

Claims

1. A method for preparing nano-gold paper, characterized in that, Includes the following steps: Cellulose paper was soaked in a chloroauric acid aqueous solution for t1 and then removed; it was then soaked in a NaBH4 aqueous solution for t2 and then removed; the paper was rinsed with ultrapure water and dried to obtain nano-gold seed paper. A solution of hexadecyltrimethylammonium bromide containing chloroauric acid was added, followed by sonication and then ascorbic acid. Once the solution changed from yellow to colorless, the nano-gold seed paper was immediately added and soaked for t3. The paper was then removed, washed, and dried to obtain the nano-gold paper. The concentration of the first chloroauric acid solution was 5 mmol / L–80 mmol / L, t1 was 2–5 min, the concentration of the NaBH4 solution was 10 mmol / L–50 mmol / L, t2 was 8–12 min, the concentration ratio of the NaBH4 solution to the first chloroauric acid solution was 1:1, the concentration of the hexadecyltrimethylammonium bromide solution was 0.1–0.3 mol / L, the concentration of the second chloroauric acid solution was 0.2–0.8 mmol / L, the concentration of ascorbic acid was 2–8 mmol / L, the sonication time was 5–10 min, and t3 was 15–25 min.

2. A nano-gold paper prepared by the preparation method according to claim 1, characterized in that, The nano-gold paper includes a carrier and a plurality of gold nanoparticles loaded on the carrier. The plurality of gold nanoparticles are uniformly dispersed, and the carrier is cellulose paper containing hydroxyl groups.

3. The nano-gold paper as described in claim 2, characterized in that, The cellulose paper containing hydroxyl groups has a size of (10~20) mm × (10~20) mm.

4. The application of the nano-gold paper as described in claim 2 in catalysis and detection.

5. The application as described in claim 4, characterized in that, The catalysis is the catalytic reduction of p-nitrophenol and the degradation of rhodamine B.

6. The application as described in claim 4, characterized in that, The detections were performed on the pH of the SERS detection solution and the concentration of hydrogen peroxide.

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