An ultrafine MoO2 nanowire bundle with surface-enhanced Raman effect, its preparation method and application
The preparation of ultrafine MoO2 nanowires by the sol-gel method solves the problems of high cost and instability of noble metal nanomaterials, and realizes a low-cost and highly stable surface-enhanced Raman spectroscopy detection substrate, which is suitable for detecting low concentrations of toxic and harmful substances.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINESE ACAD OF INSPECTION & QUARANTINE
- Filing Date
- 2023-10-11
- Publication Date
- 2026-05-26
AI Technical Summary
In existing surface-enhanced Raman spectroscopy techniques, noble metal nanomaterials are expensive and unstable, which limits their large-scale detection applications.
Ultrafine MoO2 nanowires were prepared using the sol-gel method. A hexagonal channel template was formed by reacting P123, water, n-butanol, concentrated hydrochloric acid, and TEOS, followed by hydrofluoric acid treatment. The template was then mixed with ammonium molybdate, calcined, and removed to obtain MoO2 nanowires with surface-enhanced Raman effect.
The prepared ultrafine MoO2 nanowire bundles have controllable diameter, regular morphology, good repeatability and stability, and exhibit strong localized surface plasmon resonance and surface-enhanced Raman spectroscopy effects, making them suitable for detecting low concentrations of toxic and harmful substances.
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Figure CN117550640B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of nanomaterial synthesis, and in particular to an ultrafine MoO2 nanowire bundle with surface-enhanced Raman effect, its preparation method and application. Background Technology
[0002] As an important analytical technique, surface-enhanced Raman spectroscopy (SERS) boasts high sensitivity, short detection time, and ease of on-site detection. It holds immense promise for applications in trace chemical substance determination, biological tissue imaging, product authenticity verification, and catalytic reaction monitoring, making it a leading research area internationally. Although SERS technology has developed rapidly in recent years, several challenges still hinder its large-scale application. Firstly, the most common Raman-enhancing substrates are currently made from precious metals such as gold and silver nanomaterials. However, the high cost and complex preparation of gold substrates lead to high usage costs in large-scale detection activities. Secondly, while silver is only about one percent the price of gold, it is easily oxidized by air and reacts readily with sulfur compounds, quickly losing its Raman enhancement effect and reducing its practicality. Therefore, developing low-cost and highly stable SERS substrate materials is imperative.
[0003] There are few reports on the preparation of ultrafine MoO2 nanowires. This invention aims to develop a new type of nano-MoO2 material. Summary of the Invention
[0004] To address the problems existing in the prior art, this invention provides an ultrafine MoO2 nanowire bundle with surface-enhanced Raman effect, its preparation method, and its application.
[0005] Specifically, the present invention provides the following technical solutions:
[0006] A method for preparing ultrafine MoO2 nanowire bundles with surface-enhanced Raman effect includes the following steps:
[0007] 1) A sol-gel reaction was carried out using P123, water, n-butanol, concentrated hydrochloric acid, and TEOS as raw materials. The reaction product was then heated and aged, followed by washing, filtration, drying, and calcination to obtain a template with hexagonal channels. The mass ratio of P123, water, n-butanol, concentrated hydrochloric acid, and TEOS was 1:35-38:0.5-1.5:1.5-2.5:1.7-2.7. The aging temperature was 60-140℃.
[0008] 2) Dissolve ammonium molybdate in water, then mix it with the template obtained in step 1), stir, let stand, dry for the first time, calcine under a hydrogen-containing inert atmosphere, remove the template with hydrofluoric acid, wash, and dry for the second time to obtain ultrafine MoO2 nanowires.
[0009] Preferably, in step 1), the sol-gel reaction involves stirring P123, water, n-butanol, and concentrated hydrochloric acid at 28–45°C until completely dissolved, then adding TEOS, and continuing to stir the reaction at 28–45°C for a period of time (preferably 24 hours).
[0010] Preferably, in step 1), the aging time is 24 to 72 hours.
[0011] Preferably, in step 1), the filtration process involves first washing the filter with deionized water 3 to 4 times, and then washing the filter with ethanol 1 to 2 times.
[0012] Preferably, in step 1), the drying is carried out in a forced-air drying oven at 60-80°C for 18-24 hours.
[0013] Preferably, in step 1), the calcination is carried out in a muffle furnace at 500-600°C for 2-4 hours, with a heating rate of 0.5-3°C / min.
[0014] Preferably, in step 2), the mass ratio of ammonium molybdate, water, and template is 0.5–0.8:4–20:1.
[0015] Preferably, in step 2), the stirring time is 1-2 hours (room temperature), and the standing time is 18-24 hours.
[0016] Preferably, in step 2), the temperature of the first drying is 60-80°C and the time is 2-24 hours.
[0017] Preferably, in step 2), the roasting is carried out in a tube furnace at 450-550°C for 4-6 hours, with a heating rate of 1-3°C / min.
[0018] Preferably, in step 2), the concentration of hydrofluoric acid is 3-5%, and the mass ratio of hydrofluoric acid to template is 50-70:1.
[0019] Preferably, in step 2), the washing process involves washing the sample with deionized water until it becomes neutral.
[0020] Preferably, in step 2), the temperature of the second drying is 60-80°C, and the drying time is 18-24 hours.
[0021] Another objective of this invention is to protect the ultrafine MoO2 nanowires prepared by the preparation method described herein.
[0022] The final objective of this invention is to protect the application of the ultrafine MoO2 nanowires described herein in the preparation of surface-enhanced Raman spectroscopy detection substrates.
[0023] The concentrated hydrochloric acid described in this invention contains approximately 36-37% hydrochloric acid by mass.
[0024] The present invention has the following beneficial effects:
[0025] The method for preparing ultrafine MoO2 nanowire bundles provided by this invention is highly controllable. The resulting ultrafine nanowire bundles have a diameter of about 5 nm, regular and controllable morphology, good repeatability and stability, and strong localized surface plasmon resonance effect and outstanding surface-enhanced Raman spectroscopy effect. They can be directly used to prepare surface-enhanced Raman spectroscopy detection substrates, which is of great significance for the detection of toxic and harmful substances in consumer products. Attached Figure Description
[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0027] Figure 1 The XRD pattern of the ultrafine MoO2 nanowire bundle prepared in Example 1 of this invention;
[0028] Figure 2 This is a SEM image of the ultrafine MoO2 nanowire bundle prepared in Example 1 of this invention;
[0029] Figure 3 TEM image of the ultrafine MoO2 nanowire bundle prepared in Example 1 of this invention;
[0030] Figure 4 This is an HRTEM image of the ultrafine MoO2 nanowire bundle prepared in Example 1 of the present invention;
[0031] Figure 5 The ultrafine MoO2 nanowire bundles prepared in Example 1 of this invention have a concentration of 10 -9 The surface-enhanced Raman spectrum of M's R6G; where the horizontal axis represents the Raman shift, in cm. -1 The vertical axis represents the Raman light intensity (Counts).
[0032] Figure 6 The XRD pattern of the ultrafine MoO2 nanowire bundle prepared in Example 2 of this invention;
[0033] Figure 7 This is a SEM image of the ultrafine MoO2 nanowire bundle prepared in Example 2 of the present invention;
[0034] Figure 8 This is a TEM image of the ultrafine MoO2 nanowire bundle prepared in Example 2 of the present invention;
[0035] Figure 9 The image shows an HRTEM image of the ultrafine MoO2 nanowire bundle prepared in Example 2 of this invention.
[0036] Figure 10 The ultrafine MoO2 nanowire bundles prepared in Example 2 of this invention have a concentration of 10 -9 Surface-enhanced Raman spectra of M for R6G;
[0037] Figure 11 The XRD pattern of the ultrafine MoO2 nanowire bundle prepared in Example 3 of this invention;
[0038] Figure 12 This is a SEM image of the ultrafine MoO2 nanowire bundle prepared in Example 3 of the present invention;
[0039] Figure 13 This is a TEM image of the ultrafine MoO2 nanowire bundle prepared in Example 3 of the present invention;
[0040] Figure 14 Here is an HRTEM image of the ultrafine MoO2 nanowire bundle prepared in Example 3 of this invention;
[0041] Figure 15 The ultrafine MoO2 nanowire bundles prepared in Example 3 of this invention have a concentration of 10. -8 Surface-enhanced Raman spectroscopy of malachite green in M;
[0042] Figure 16 The XRD pattern of the ultrafine MoO2 nanowire bundle prepared in Example 4 of this invention;
[0043] Figure 17 This is a SEM image of the ultrafine MoO2 nanowire bundle prepared in Example 4 of the present invention;
[0044] Figure 18 This is a TEM image of the ultrafine MoO2 nanowire bundle prepared in Example 4 of the present invention;
[0045] Figure 19 This is an HRTEM image of the ultrafine MoO2 nanowire bundle prepared in Example 4 of the present invention;
[0046] Figure 20 The ultrafine MoO2 nanowire bundles prepared in Example 4 of this invention have a concentration of 10. -8 Surface-enhanced Raman spectroscopy of malachite green in M;
[0047] Figure 21The XRD pattern of the ultrafine MoO2 nanowire bundle prepared in Example 5 of this invention;
[0048] Figure 22 This is a SEM image of the ultrafine MoO2 nanowire bundle prepared in Example 5 of the present invention;
[0049] Figure 23 This is a TEM image of the ultrafine MoO2 nanowire bundle prepared in Example 5 of the present invention;
[0050] Figure 24 This is an HRTEM image of the ultrafine MoO2 nanowire bundle prepared in Example 5 of the present invention;
[0051] Figure 25 The ultrafine MoO2 nanowire bundles prepared in Example 5 of this invention have a concentration of 10. -9 Surface-enhanced Raman spectra of M for R6G;
[0052] Figure 26 HRTEM image of the nano-MoO2 particles prepared for Comparative Example 1. Detailed Implementation
[0053] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in the art, or in accordance with the product manual.
[0054] In this invention, all instruments and other equipment whose manufacturers are not specified are conventional products that can be purchased through legitimate channels. Unless otherwise specified, all methods described are conventional methods, and all raw materials are commercially available. Where specific techniques or conditions are not specified in the embodiments, they should be performed in accordance with the techniques or conditions described in the literature in this field, or according to the product instructions.
[0055] Example 1
[0056] This embodiment provides a method for preparing ultrafine MoO2 nanowire bundles:
[0057] 1) P123 (9g), deionized water (325.5g), n-butanol (9g), and concentrated hydrochloric acid (17.7g) were mixed and magnetically stirred at 300 rpm at 31℃ until P123 was completely dissolved. TEOS (19.35g) was added, and stirring continued for 24 hours at constant temperature and speed. The mixture was then transferred to a forced-air drying oven and aged at 100℃ for 24 hours. The resulting powder was washed and filtered, washed three times with deionized water and twice with ethanol, and then dried in a forced-air drying oven at 60℃ for 24 hours. The dried sample was calcined in a muffle furnace at 550℃ for 3 hours at a heating rate of 1℃ / min to obtain the template.
[0058] 2) Dissolve 0.3245 g of ammonium molybdate tetrahydrate in 2 mL of deionized water, add 0.5 g of the template prepared in step 1), stir at room temperature for 1 h, then let stand for 24 h, and then transfer to a forced-air drying oven to dry at 60 °C for 24 h. Calcine the dried sample in a tube furnace under a 10% H2, 90% Ar atmosphere at 500 °C for 5 h, with a heating rate of 2 °C / min. Add 30 mL of 4% HF to the calcined sample, stir for 3 h, centrifuge with deionized water until the sample is neutral, and then dry in a forced-air drying oven at 60 °C for 24 h to obtain the final sample.
[0059] The final sample obtained was subjected to XRD ( Figure 1 SEM Figure 2 ), TEM Figure 3 ) and HRTEM Figure 4 Characterization revealed that the final product was an ultrafine MoO2 nanowire bundle, which was used as a SERS substrate. Figure 5 The detection concentration of R6G can be as low as 10. -9 M.
[0060] Example 2
[0061] This embodiment provides a method for preparing ultrafine MoO2 nanowire bundles:
[0062] 1) P123 (9g), deionized water (315g), n-butanol (4.5g), and concentrated hydrochloric acid (13.5g) were mixed and magnetically stirred at 300 rpm at 28℃ until P123 was completely dissolved. TEOS (15.3g) was added, and stirring continued for 24 hours at constant temperature and speed. The mixture was then transferred to a forced-air drying oven and aged at 60℃ for 72 hours. The resulting powder was washed and filtered, washed four times with deionized water and once with ethanol, and then dried at 65℃ for 22 hours. The dried sample was calcined in a muffle furnace at 500℃ for 4 hours at a heating rate of 0.5℃ / min to obtain the template.
[0063] 2) Dissolve 0.25 g of ammonium molybdate tetrahydrate in 4 mL of deionized water, add 0.5 g of the template prepared in step 1), stir at room temperature for 2 h, then let stand for 18 h, and then transfer to a forced-air drying oven to dry at 70 °C for 12 h. Calcine the dried sample in a tube furnace under a 10% H2, 90% Ar atmosphere at 450 °C for 6 h, with a heating rate of 1 °C / min. Add 3% HF (35 mL) to the calcined sample, stir for 3 h, centrifuge with deionized water until the sample is neutral, and then dry at 70 °C for 20 h in a forced-air drying oven to obtain the final sample.
[0064] The final sample obtained was subjected to XRD ( Figure 6 SEM Figure 7 ), TEM Figure 8 ) and HRTEM Figure 9 Characterization revealed that the final product was an ultrafine MoO2 nanowire bundle, which was used as a SERS substrate. Figure 10 The detection concentration of R6G can be as low as 10. -9 M.
[0065] Example 3
[0066] This embodiment provides a method for preparing ultrafine MoO2 nanowire bundles:
[0067] 1) P123 (9g), deionized water (324g), n-butanol (7.5g), and concentrated hydrochloric acid (16.5g) were mixed and magnetically stirred at 300 rpm at 35℃ until P123 was completely dissolved. TEOS (18.3g) was added, and stirring continued for 24 hours at constant temperature and speed. The mixture was then transferred to a forced-air drying oven and aged at 80℃ for 48 hours. The resulting powder was washed and filtered, washed three times with deionized water and twice with ethanol, and then dried at 70℃ for 20 hours. The dried sample was calcined in a muffle furnace at 600℃ for 2 hours at a heating rate of 2℃ / min to obtain the template.
[0068] 2) Dissolve 0.3 g of ammonium molybdate tetrahydrate in 5 mL of deionized water, add 0.5 g of the template prepared in step 1), stir at room temperature for 1 h, then let stand for 20 h, and then transfer to a forced-air drying oven to dry at 80 °C for 2 h. Calcine the dried sample in a tube furnace under a 10% H2, 90% Ar atmosphere at 550 °C for 4 h, with a heating rate of 3 °C / min. Add 25 mL of 5% HF to the calcined sample, stir for 3 h, centrifuge with deionized water until the sample is neutral, and then dry at 80 °C for 18 h in a forced-air drying oven to obtain the final sample.
[0069] The final sample obtained was subjected to XRD ( Figure 11 SEM Figure 12 ), TEM Figure 13 ) and HRTEM Figure 14 Characterization revealed that the final product was an ultrafine MoO2 nanowire bundle, which was used as a SERS substrate. Figure 15 The minimum detection concentration of malachite green can reach 10. -8 M.
[0070] Example 4
[0071] This embodiment provides a method for preparing ultrafine MoO2 nanowire bundles:
[0072] 1) P123 (9g), deionized water (333g), n-butanol (10.5g), and concentrated hydrochloric acid (19.5g) were mixed and magnetically stirred at 300 rpm at 40℃ until P123 was completely dissolved. TEOS (21.3g) was added, and stirring continued for 24 hours at constant temperature and speed. The mixture was then transferred to a forced-air drying oven and aged at 120℃ for 36 hours. The resulting powder was washed and filtered, washed four times with deionized water and once with ethanol, and then dried in a forced-air drying oven at 75℃ for 19 hours. The dried sample was calcined in a muffle furnace at 550℃ for 3 hours at a heating rate of 3℃ / min to obtain the template.
[0073] 2) Dissolve 0.35 g of ammonium molybdate tetrahydrate in 8 mL of deionized water, add 0.5 g of the template prepared in step 1), stir at room temperature for 2 h, then let stand for 22 h, and then transfer to a forced-air drying oven to dry at 70 °C for 16 h. Calcine the dried sample in a tube furnace under a 10% H2, 90% Ar atmosphere at 500 °C for 5 h, with a heating rate of 2 °C / min. Add 30 mL of 4% HF to the calcined sample, stir for 3 h, centrifuge with deionized water until the sample is neutral, and then dry at 70 °C for 22 h in a forced-air drying oven to obtain the final sample.
[0074] The final sample obtained was subjected to XRD ( Figure 16 SEM Figure 17 ), TEM Figure 18 ) and HRTEM Figure 19 Characterization revealed that the final product was an ultrafine MoO2 nanowire bundle, which was used as a SERS substrate. Figure 20 The minimum detection concentration of malachite green can reach 10. -8 M.
[0075] Example 5
[0076] This embodiment provides a method for preparing ultrafine MoO2 nanowire bundles:
[0077] 1) P123 (9g), deionized water (342g), n-butanol (13.5g), and concentrated hydrochloric acid (22.5g) were mixed and magnetically stirred at 300r / min at 45℃ until P123 was completely dissolved. TEOS (24.3g) was added, and stirring continued for 24h at constant temperature and speed. The mixture was then transferred to a forced-air drying oven and aged at 140℃ for 28h. The resulting powder was washed and filtered, washed three times with deionized water and twice with ethanol, and then dried in a forced-air drying oven at 80℃ for 18h. The dried sample was calcined in a muffle furnace at 600℃ for 2h at a heating rate of 1.5℃ / min to obtain the template.
[0078] 2) Dissolve 0.4 g of ammonium molybdate tetrahydrate in 10 mL of deionized water, add 0.5 g of the template prepared in step 1), stir at room temperature for 1 h, then let stand for 24 h, and then transfer to a forced-air drying oven to dry at 60 °C for 20 h. Calcine the dried sample in a tube furnace under a 10% H2, 90% Ar atmosphere at 550 °C for 4 h, with a heating rate of 2 °C / min. Add 3% HF (35 mL) to the calcined sample, stir for 3 h, centrifuge with deionized water until the sample is neutral, and then dry at 60 °C for 20 h in a forced-air drying oven to obtain the final sample.
[0079] The final sample obtained was subjected to XRD ( Figure 21 SEM Figure 22 ), TEM Figure 23 ) and HRTEM Figure 24 Characterization revealed that the final product was an ultrafine MoO2 nanowire bundle, which was used as a SERS substrate. Figure 25 The detection concentration of R6G can be as low as 10. -9 M.
[0080] Comparative Example 1
[0081] The difference between this comparative example and Example 1 is that ammonium molybdate tetrahydrate, the reaction raw material in step 2), is replaced with phosphomolybdic acid. As a result, under the same experimental conditions, it was impossible to generate ultrafine MoO2 nanowire bundles (such as...). Figure 26 ).
[0082] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.
Claims
1. A method for preparing ultrafine MoO2 nanowire bundles with surface-enhanced Raman effect, characterized in that, Includes the following steps: 1) A sol-gel reaction was carried out using P123, water, n-butanol, concentrated hydrochloric acid, and TEOS as raw materials. The reaction product was then heated and aged, followed by washing, filtration, drying, and calcination to obtain a template with hexagonal channels. The mass ratio of P123, water, n-butanol, concentrated hydrochloric acid, and TEOS was 1:35~38:0.5~1.5:1.5~2.5:1.7~2.
7. The aging temperature was 60~140℃. 2) Dissolve ammonium molybdate in water, then mix it with the template obtained in step 1), stir, let stand, dry for the first time, calcine under a hydrogen-containing inert atmosphere, remove the template with hydrofluoric acid, wash, and dry for the second time to obtain ultrafine MoO2 nanowires with surface-enhanced Raman effect. In step 2), the mass ratio of ammonium molybdate, water, and template is 0.5~0.8:4~20:1; The ultrafine MoO2 nanowire bundles prepared by the method have a diameter of approximately 5 nm.
2. The preparation method according to claim 1, characterized in that, In step 1), the sol-gel reaction involves stirring P123, water, n-butanol, and concentrated hydrochloric acid at 28-45°C until completely dissolved, then adding TEOS, and continuing to stir the reaction for a period of time.
3. The preparation method according to claim 2, characterized in that, In step 1), the aging time is 24~72h.
4. The preparation method according to claim 3, characterized in that, In step 1), the filtration process involves first washing the filter with deionized water 3-4 times, and then washing the filter with ethanol 1-2 times. And / or, in step 1), the drying is carried out in a forced-air drying oven at 60~80℃ for 18~24h; And / or, in step 1), the calcination is carried out in a muffle furnace at 500~600℃ for 2~4h, with a heating rate of 0.5~3℃ / min.
5. The preparation method according to claim 1, characterized in that, In step 2), the stirring time is 1-2 hours and the settling time is 18-24 hours; And / or, in step 2), the temperature of the first drying is 60~80℃, and the time is 2~24h; And / or, in step 2), the calcination is carried out in a tube furnace at 450-550℃ for 4-6 hours, with a heating rate of 1-3℃ / min.
6. The preparation method according to claim 5, characterized in that, In step 2), the concentration of hydrofluoric acid is 3-5%, and the mass ratio of hydrofluoric acid to template is 50-70:
1.
7. The preparation method according to claim 6, characterized in that, In step 2), the cleaning process involves washing the sample with deionized water until it becomes neutral. And / or, in step 2), the temperature of the second drying is 60~80℃, and the drying time is 18~24h.
8. The preparation method according to any one of claims 1 to 7 yields an ultrafine MoO2 nanowire bundle with surface-enhanced Raman effect, wherein the ultrafine MoO2 nanowire bundle has a diameter of approximately 5 nm.
9. The application of the preparation method according to any one of claims 1 to 7 to prepare ultrafine MoO2 nanowires with surface-enhanced Raman effect, or the ultrafine MoO2 nanowires with surface-enhanced Raman effect according to claim 8, in the preparation of a surface-enhanced Raman spectroscopy detection substrate.