A method for constructing an in-situ sulfur active layer of a noble metal nanostructure SERS substrate and products and applications thereof
Patent Information
- Application Number
- CN202611072212.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-20
- Publication Date
- 2026-10-23
AI Technical Summary
硫醇自组装依赖有机分子并可能在复杂基质中失效；液相硫化易产生团聚、残留和非均匀沉积；部分气相硫源储存和工艺安全性不足
（1）与传统方法相比，本发明采用含硫卤化物作为气相硫源，在低温条件下即可原位生成硫活性层，工艺简单、设备要求低，并能适用于不耐高温的柔性基材或已封装器件。所得硫活性层厚度可通过调控气体种类、浓度、湿度、温度与处理时间实现可控，为构建高灵敏、高稳定性SERS基底以用于重金属离子检测、有毒气体识别等应用，提供了一种通用的表面功能化方法。
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Figure CN122959697A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of surface-enhanced Raman spectroscopy (SERS) substrate preparation and surface functionalization technology, and particularly relates to a method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate, its products, and applications. Background Technology
[0002] Surface-enhanced Raman spectroscopy (SERS) significantly enhances the Raman signal of analyte molecules through the localized surface plasmon resonance effect on the surface of noble metal nanostructures, and is widely used in environmental monitoring, biomedical analysis, and security protection. To endow SERS substrates with the ability to recognize or react to specific analytes, functionalized layers, such as organic ligand layers, inorganic shell layers, or composite layers, are usually constructed on the surface of noble metal nanostructures.
[0003] In practical detection, relying solely on the electromagnetic enhancement of noble metal nanostructures is often insufficient for the selective identification of specific analytes. Therefore, it is usually necessary to introduce functionalized interfaces onto the surface of noble metal nanostructures. For the detection of heavy metal ions, sulfur and its related species have a strong affinity for many heavy metal ions, forming metal sulfides or metal-sulfur coordination structures, which exhibit characteristic vibrational peaks in the low-wavenumber Raman region. By constructing an ultrathin sulfur-active layer on the surface of noble metal nanostructures, a specific reaction interface for heavy metal ions can be provided, thereby enabling the SERS identification of multiple heavy metals on a single substrate.
[0004] Existing methods for functionalizing the surface of metal nanostructures with sulfur mainly include thiol self-assembly, liquid-phase sulfidation, and other gas-phase sulfidation methods. Thiol self-assembly depends on organic molecules and may fail in complex matrices; liquid-phase sulfidation is prone to agglomeration, residues, and non-uniform deposition; and some gas-phase sulfur sources have insufficient storage and process safety. Summary of the Invention
[0005] To overcome the shortcomings of the prior art, this invention provides a method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate, along with its products and applications. This invention uses sulfur-containing halides as a gaseous sulfur source, enabling in-situ generation of the sulfur active layer under low-temperature conditions. The process is simple, requires minimal equipment, and is applicable to flexible substrates or encapsulated devices that are not heat-resistant.
[0006] To achieve one of the above objectives, the present invention adopts the following technical solution: A method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate, the specific steps of which are as follows: S1. Prepare a SERS substrate with a noble metal nanostructure layer; S2. Place the SERS substrate in the sample placement area at the bottom of the openable closed or semi-closed reaction chamber. S3. Introduce one or more sulfur-containing halide gas precursors into the reaction chamber and control the humidity in the reaction chamber or introduce water vapor. S4. Treat at 20-80 ℃ for 10 min-24 h (preferably at 25-60 ℃ for 30-120 min) to allow the sulfur-containing halide gas precursor to be adsorbed, decomposed or reacted on the surface of the noble metal nanostructure layer, and to form a sulfur active layer in situ on the noble metal nanostructure layer. S5. Replace the reaction chamber with an inert gas, and then remove the SERS substrate and perform purging, drying or low-temperature annealing to obtain an SERS substrate with a sulfur active layer on its surface.
[0007] Preferably, the sulfur-containing halide gas precursor is one or more of thionyl chloride / thionyl chloride (SOCl2), thionyl chloride (SO2Cl2), disulfide dichloride (S2Cl2), and thionyl bromide (SOBr2); when the sulfur-containing halide gas precursor is thionyl chloride, the thionyl chloride is carried into the reaction chamber by nitrogen or argon gas, the concentration of thionyl chloride is 50-200 ppm, and the gas flow rate is 100-500 sccm.
[0008] Preferably, the noble metal nanostructure layer is a gold nanocone array structure or a silica microsphere template sputtering structure; the silica microsphere template sputtering structure consists of a base substrate, silica microspheres arranged on the surface of the supporting substrate, and a gold layer covering the exposed surface of the silica microspheres or the gap region between adjacent silica microspheres.
[0009] Preferably, the noble metal nanostructure layer is one or more of the following: gold nanoislands, gold nanoparticle arrays, gold nanoporous membranes, silver nanostructures, and gold-silver alloy nanostructures.
[0010] Preferably, the relative humidity inside the reaction chamber is 10%-95%; the inert gas replacement time is 5-30 min; and the drying or low-temperature annealing treatment is carried out at 40-150 ℃ for 10-60 min.
[0011] Preferably, in step S4, the thickness of the sulfur active layer is 0.5-30 nm, more preferably 1-20 nm; the sulfur active layer is one or more of elemental sulfur, polysulfide species, sulfur oxides and metal-sulfur bond structures.
[0012] To achieve the second objective mentioned above, the present invention provides a product obtained by a method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate. The product consists of a supporting substrate, a noble metal nanostructure layer, and a sulfur active layer formed in-situ on the surface of the noble metal nanostructure layer.
[0013] To achieve the third objective mentioned above, the present invention provides an application of the product, namely, the application of the product in heavy metal ion detection, auxiliary screening for heavy metal poisoning, detection of sulfur- or halogen-containing reactive gases, environmental safety monitoring, or chemical sensing.
[0014] Preferably, the specific steps for applying the product to the detection of heavy metal ions are as follows: the product is brought into contact with a sample containing heavy metal ions, so that the heavy metal ions adsorb, coordinate or react with the sulfur active layer to form metal-sulfur related interface species, and surface-enhanced Raman spectroscopy signals are collected for qualitative or quantitative analysis. The heavy metal ion is Hg 2+ Pb 2+ Cu 2+ Cd 2+ Ag + As 3+ One or more of the following, the sample being one or more of blood, serum, plasma, urine, water, food extract, and food diluent.
[0015] Preferably, the specific steps for applying this product to the detection of sulfur- or halogen-containing reactive gases are as follows: exposing the product to the gas environment to be tested, causing the gas to be tested or its reaction / decomposition products to be adsorbed or reacted on the surface of the sulfur active layer, and collecting surface-enhanced Raman spectral signals for identification. The gas to be tested is one or more of SOCl2, SO2Cl2, S2Cl2, and SOBr2.
[0016] The advantages of this invention are: (1) Compared with traditional methods, this invention uses sulfur-containing halides as a gaseous sulfur source, which can generate a sulfur active layer in situ under low temperature conditions. The process is simple, the equipment requirements are low, and it can be applied to flexible substrates or encapsulated devices that are not resistant to high temperatures. The thickness of the obtained sulfur active layer can be controlled by adjusting the gas type, concentration, humidity, temperature and processing time. This provides a general surface functionalization method for constructing highly sensitive and stable SERS substrates for applications such as heavy metal ion detection and toxic gas identification.
[0017] (2) The sulfur-containing halide gas precursor used in this invention can decompose into sulfur and sulfur oxide intermediates on the metal surface and deposit them on the surface in the presence of trace amounts of water. Experiments show that the bare metal SERS substrate exhibits typical sulfur-related signals after treatment with SOCl2 atmosphere, proving that sulfur-containing halide gas can be used as a novel gas-phase sulfur source for low-temperature in-situ construction of sulfur active layers. Based on this, the phenomenon of forming a sulfur coating layer on gold nanostructures by SOCl2 gas-phase treatment in this invention can be extended to a general low-temperature gas-phase functionalization method applicable to noble metal nanostructure SERS substrates.
[0018] (3) The method of this invention can construct a sulfur active layer within the range of 20–80 °C, avoiding the high-temperature process required for the sublimation of elemental sulfur, and is applicable to thermosensitive flexible substrates and some devices. The process only requires a closed or semi-closed container under normal pressure, a gas precursor, and simple temperature control equipment, without the need for a vacuum system or high-temperature furnace, and is easy to connect in series with existing noble metal SERS substrate preparation processes. By adjusting parameters such as the type of sulfur-containing halide, gas concentration, processing time, and humidity, the sulfur layer thickness can be controlled within the range of 1–20 nm, taking into account both the maintenance of SERS "hot spots" and the enhancement of chemical activity.
[0019] (4) This method is applicable to noble metal nanostructures on various supporting substrates such as planar silicon wafers, glass sheets, quartz sheets, flexible polymers, and ceramics, and has strong adaptability to substrate types. The obtained sulfur active layer SERS substrate can be used as a heavy metal ion capture interface, a toxic gas adsorption interface, etc., expanding its application potential in environmental monitoring, biomedicine and safety protection, and forming a general surface functionalization platform. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the method flow of the present invention.
[0021] Figure 2 This is a schematic diagram showing the changes in surface structure of different types of noble metal nanostructure substrates before and after treatment according to the present invention.
[0022] Figure 3 This is a schematic diagram of the device for constructing an in-situ sulfur active layer on a surface-enhanced Raman substrate based on a sulfur-containing halide gas precursor, according to the present invention.
[0023] Figure 4-6 This is a schematic diagram of the characterization of Embodiment 2 of the present invention.
[0024] Figure 7 This is a schematic diagram representing Embodiment 3 of the present invention.
[0025] Figure 8 The images show Raman spectroscopy results before and after the in-situ construction of a sulfur-active layer on the surface of a noble metal nanostructure in Example 1 of this invention.
[0026] Figure 9 This is a schematic diagram of the application of the sulfur active layer surface-enhanced Raman substrate constructed in Example 4 of the present invention and its Raman spectrum.
[0027] Figure 10 This is a schematic diagram of the application of the sulfur active layer surface-enhanced Raman substrate constructed in Example 5 of the present invention and its Raman spectrum.
[0028] Figure 11 This is the X-ray photoelectron spectrum of Embodiment 1 of the present invention.
[0029] Figure 12This is an electron microscope image of Embodiment 1 of the present invention.
[0030] The meanings of the symbols in the diagram are as follows: 1-Openable sealed reaction chamber, 2-Top cover, 3-Sealing ring, 4-Sulfur halide gas inlet, 5-Humidity control inlet, 6-Gas phase reaction zone, 7-Sample placement zone, 8-SERS substrate with noble metal nanostructure layer. Detailed Implementation
[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0032] like Figure 1 As shown, a method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate includes the following steps: S1. Prepare a SERS substrate with a noble metal nanostructure layer; S2. Place the SERS substrate in the sample placement area at the bottom of the openable reaction chamber; S3. Introduce one or more sulfur-containing halide gas precursors into the reaction chamber and control the humidity in the reaction chamber or introduce water vapor to promote gas decomposition. S4. Under the condition of temperature 20-80 °C, the precursor is decomposed or reacted on the substrate surface, and a sulfur active layer with a thickness of 1-20 nm is deposited on the outer surface of the noble metal nanostructure. S5. Replace the reaction chamber with an inert gas, and then remove the SERS substrate and perform purging, drying or low-temperature annealing to obtain an SERS substrate with a sulfur active layer on its surface.
[0033] like Figure 3 As shown, the reaction chamber includes an openable and sealable reaction chamber 1, a top cover 2, a sealing ring 3, a sulfur halide gas inlet 4, a humidity control inlet 5, a gas phase reaction zone 6, an exhaust port or pressure balance port, and a sample placement area 7 located at the bottom of the chamber. The sample placement area 7 can simultaneously place multiple SERS substrates 8 with noble metal nanostructure layers to achieve simultaneous gas phase processing of multiple substrates. Figure 3 The diagram illustrates the diffusion and transport process of the precursor gas within the reaction chamber.
[0034] Figure 2This diagram illustrates the changes in surface structure of different types of noble metal nanostructure substrates before and after treatment, including Type A Au nanocone array substrates and Type B SiO2 microsphere template Au substrates. The diagram compares the original structures of the two types of substrates before treatment and the state of the sulfur active layer formed on their surfaces after treatment.
[0035] Example 1
[0036] SOCl2 vapor-treated gold nanocone array substrate
[0037] S1. Provide a gold nanocone array SERS substrate, the substrate comprising a regular or quasi-regular gold nanocone array on a supporting substrate and its surface.
[0038] S2. Lay multiple gold nanocone array substrates flat on the sample area at the bottom of the openable sealed reaction chamber.
[0039] S3. Nitrogen gas is used to carry SOCl2 gas into the reaction chamber, and the SOCl2 concentration is controlled at 100 ppm and the flow rate is 100 sccm.
[0040] S4. Simultaneously control humidity or introduce H2O(g) and treat at 25 °C for 120 min.
[0041] S5. After the treatment is completed, an inert gas is introduced for 10 min to replace the inert gas. After taking it out, it is dried / annealed at 50 °C in an inert atmosphere for 10 min to obtain the gold nanocone sulfur active layer SERS substrate.
[0042] The obtained gold nanocone sulfur active layer SERS substrate was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and low wavenumber Raman spectroscopy.
[0043] The obtained gold nanocone sulfur active layer substrate was characterized by X-ray photoelectron spectroscopy, scanning electron microscopy and low wavenumber Raman spectroscopy.
[0044] like Figure 11 As shown, the treated substrate exhibits a significant sulfur signal in the S 2p binding energy region. Peak separation results show the presence of SS and Au-S related components, indicating that gas-phase treatment with sulfur-containing halides can form sulfur-related active species on the surface of gold nanocones.
[0045] like Figure 12 As shown, the gold nanocone array still maintains a regular or quasi-regular arrangement after vapor phase treatment, and no obvious collapse, fusion or large-scale aggregation was observed, indicating that low-temperature vapor phase treatment did not significantly damage the original nanostructure.
[0046] like Figure 8As shown, compared with the uncoated substrate, the sulfur-coated substrate exhibits three distinct sulfur-related characteristic peaks in the low wavenumber region, further demonstrating that a sulfur-active layer that can be recognized by SERS is formed on the surface of the gold nanocone.
[0047] Example 2
[0048] SOCl2 vapor-treated SiO2 microsphere template gold sputtering substrate
[0049] S1. Provide a SiO2 microsphere template for gold sputtering: SiO2 microspheres are arranged on the surface of the support substrate, and a gold layer is deposited on the exposed surface of the SiO2 microspheres and / or in the inter-microsphere region.
[0050] S2. Lay multiple substrates directly on the sample area at the bottom of the reaction chamber.
[0051] S3. Introduce SOCl2 gaseous precursor and control H2O(g) or humidity.
[0052] S4. Treat at 30 °C for 120 min to allow sulfur-containing species to deposit on the outermost surface of the gold layer.
[0053] S5. Inert gas is introduced for replacement and the substrate is dried at low temperature to obtain a SiO2 microsphere template with a gold-sulfur active layer SERS substrate.
[0054] In this embodiment, SiO2 microspheres form the core, and the gold layer is distributed along the exposed curved surface of the microspheres and the gaps between adjacent microspheres. The sulfur active layer is mainly located on the outer surface of the gold layer, rather than using the bare SiO2 core as the main functional interface. This structure corresponds to... Figure 2 The B-type structure in the text.
[0055] like Figure 4-6 As shown, the SiO2 microsphere template sputtered with gold after vapor phase treatment still maintains a continuous array and spherical outline, indicating that the treatment process did not significantly damage the SiO2 microsphere template and its outer gold structure. Figure 4 The cross-sectional morphology of the substrate is shown. Figure 5 The transmission electron microscope morphology of a single structural unit is shown. Figure 6 The surface morphology of the array is shown.
[0056] Example 3
[0057] Sulfur active layer thickness regulation
[0058] Using a SiO2 microsphere template sputtered onto a gold substrate, the thickness of the sulfur active layer was controlled by varying the SOCl2 concentration, processing time, humidity, and temperature. The optimal experimental matrix included: SOCl2 concentration of 100 ppm; processing times of 30, 60, and 120 min; and a temperature of 30°C and humidity of 70%. The sulfur layer thickness was confirmed using TEM, XPS depth profiling, or equivalent characterization methods.
[0059] like Figure 7 As shown, under representative treatment conditions, a continuous or quasi-continuous surface layer of approximately 3 nm forms on the outer side of the gold layer. The dashed line in the figure indicates the interface between the gold layer and the outer surface layer. The thickness of samples obtained at different treatment times can be determined using the same method, thereby establishing the correspondence between treatment parameters and the thickness of the sulfur active layer.
[0060] Example 4
[0061] Heavy metal ion detection
[0062] The sulfur-active layer SERS substrate prepared in Example 1 was then mixed with Hg-containing... 2+ Pb 2+ Cu 2+ Cd 2+ The sample, which is serum, comes into contact with heavy metal ions. The heavy metal ions coordinate, adsorb, or react with the sulfur active layer to form M... - S interactions, metal sulfides, or interface species are identified, and then SERS is used to acquire signals in low wavenumber or characteristic ranges for quantitative analysis.
[0063] like Figure 9 As shown, the heavy metal ions to be measured are first captured or transformed into metal-sulfur related species on the surface of the sulfur active layer, and then their Raman signals are acquired using the electromagnetic enhancement effect of the noble metal nanostructure. The characteristic peak positions, peak intensities, or peak shapes corresponding to different heavy metal ions differ, which can be used for target ion identification; the signal changes of the same ion at different concentrations can be used for quantitative analysis.
[0064] Example 5
[0065] Detection of sulfur-containing reactive gases
[0066] The sulfur-active layer SERS substrate prepared in Example 2 was exposed to an SOCl2 gas environment, causing the gas or its decomposition / reaction products to be adsorbed on the substrate surface or generate an interfacial response, and then the characteristic signal was output through SERS.
[0067] like Figure 10As shown, when the gas to be tested comes into contact with the sulfur active layer and the surface of noble metals, it causes changes in the composition of surface species, bonding state or local structure, which are manifested as the appearance, disappearance, shift or intensity change of Raman peaks, and the gas to be tested is identified accordingly.
[0068] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate, characterized in that, The specific steps are as follows: S1. Provide a SERS substrate with a noble metal nanostructure layer; S2. Place the SERS substrate in the sample placement area at the bottom of the openable reaction chamber; S3. Introduce one or more sulfur-containing halide gas precursors into the reaction chamber and control the humidity in the reaction chamber or introduce water vapor. S4. Treat at 20-80 ℃ for 10 min-24 h to allow the sulfur-containing halide gas precursor to be adsorbed on the surface of the noble metal nanostructure layer and then decomposed or reacted, and a sulfur active layer is formed in situ on the noble metal nanostructure layer. S5. Replace the reaction chamber with an inert gas, and then remove the SERS substrate and perform purging, drying or low-temperature annealing to obtain an SERS substrate with a sulfur active layer on its surface.
2. The method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate according to claim 1, characterized in that: The sulfur-containing halide gas precursor is one or more of thionyl chloride, thioyl chloride, disulfide dichloride, and thioyl bromide; when the sulfur-containing halide gas precursor is thionyl chloride, the thionyl chloride is carried into the reaction chamber by nitrogen or argon gas, the concentration of thionyl chloride is 50-200 ppm, and the gas flow rate is 100-500 sccm.
3. The method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate according to claim 1, characterized in that: The noble metal nanostructure layer is a gold nanocone array structure or a silica microsphere template gold sputtering structure; the silica microsphere template gold sputtering structure consists of a base substrate, silica microspheres arranged on the surface of the supporting substrate, and a gold layer covering the exposed surface of the silica microspheres or the gap region between adjacent silica microspheres.
4. The method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate according to claim 1, characterized in that: The noble metal nanostructure layer is one or more of the following: gold nanoislands, gold nanoparticle arrays, gold nanoporous membranes, silver nanostructures, and gold-silver alloy nanostructures.
5. The method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate according to claim 1, characterized in that: The relative humidity inside the reaction chamber is 10%-95%; the inert gas replacement time is 5-30 min; the drying or low-temperature annealing treatment is carried out at 40-150 ℃ for 10-60 min.
6. The method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate according to claim 1, characterized in that: In step S4, the thickness of the sulfur active layer is 0.5-30 nm; the sulfur active layer is one or more of elemental sulfur, polysulfide species, sulfur oxides and metal-sulfur bond structures.
7. A product obtained by the method for constructing an in-situ sulfur active layer on a noble metal nanostructure SERS substrate as described in any one of claims 1-6, characterized in that: The product consists of a supporting substrate, a noble metal nanostructure layer, and a sulfur active layer formed in situ on the surface of the noble metal nanostructure layer.
8. An application of the product as described in claim 7, characterized in that: The product will be applied in heavy metal ion detection, auxiliary screening for heavy metal poisoning, detection of sulfur- or halogen-containing reactive gases, environmental safety monitoring, or chemical sensing.
9. The application of the product according to claim 8, characterized in that, The specific steps for applying this product to the detection of heavy metal ions are as follows: the product is brought into contact with a sample containing heavy metal ions, so that the heavy metal ions adsorb, coordinate or react with the sulfur active layer to form metal-sulfur related interface species, and surface-enhanced Raman spectroscopy signals are collected for qualitative or quantitative analysis. The heavy metal ion is Hg. 2+ Pb 2+ Cu 2+ Cd 2+ Ag + As 3+ One or more of the following, wherein the sample is one or more of blood, serum, plasma, urine, water, food extract, and food diluent.
10. The application of the product according to claim 8, characterized in that, The specific steps for applying this product to the detection of sulfur- or halogen-containing reactive gases are as follows: the product is exposed to the gas environment to be tested, so that the gas to be tested or its reaction / decomposition products are adsorbed or reacted on the surface of the sulfur active layer, and surface-enhanced Raman spectroscopy signals are collected for identification. The gas to be tested is one or more of SOCl2, SO2Cl2, S2Cl2, and SOBr2.