Preparation method and application of nickel-selenium compound with inverse opal structure

Abstract

The invention discloses a preparation method and application of a nickel-selenium compound with an inverse opal structure, and belongs to the technical field of material preparation. The method comprises the following steps: assembling a polystyrene nanosphere template on a conductive substrate through a vertical pulling method, filling pores of the template with a nickel-selenium compound precursor through constant potential electrodeposition, removing the template, and carrying out inert atmosphere heat treatment to obtain the three-dimensional ordered macroporous network inverse opal structure nickel-selenium compound. The invention also provides application of the material as a working electrode in non-enzymatic glucose electrochemical detection. The nickel-selenium compound with the inverse opal structure has a highly-ordered and communicated pore channel network, a large number of active sites can be exposed, diffusion mass transfer can be accelerated, and therefore the conductivity and the electrocatalytic activity are improved. Through the synergistic effect of structural design and element composition, the sensitivity, the linear range and the selectivity of glucose detection are further improved, and the application potential of the sensor in a non-enzymatic glucose sensor is highlighted.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation technology, specifically relating to a method for preparing an anti-opal structure nickel selenium compound and its application. Background Technology

[0002] Accurate glucose detection plays a crucial role in clinical medicine (such as diabetes management), the food industry, and bioprocess monitoring. Current mainstream detection methods include optical methods, chromatographic methods, and electrochemical methods, among which electrochemical methods are favored due to their simplicity, rapid response, low cost, and ease of miniaturization.

[0003] The performance of electrochemical glucose sensors hinges on the working electrode material. While traditional enzyme-catalyzed sensors (such as those based on glucose oxidase) offer high selectivity, the enzyme's biological activity is easily affected by environmental factors (temperature, pH), resulting in inherent drawbacks such as poor stability, high cost, and inconvenient storage. Therefore, developing non-enzymatic electrochemical sensors that do not rely on biological enzymes and are based on the catalytic activity of the materials themselves has become an important trend. The performance of such sensors directly depends on the conductivity, catalytic activity, and structural stability of the electrode material.

[0004] Transition metal compounds, especially nickel-based materials (such as nickel hydroxide and nickel oxide), have become star materials for non-enzymatic glucose sensors due to their high catalytic activity, good stability, and low cost in alkaline media for glucose oxidation. However, traditional materials, represented by nickel oxide, still face challenges such as relatively insufficient inherent conductivity, limited exposure of active sites, and low mass transfer efficiency, which restrict further improvements in their detection sensitivity and response speed. In recent years, transition metal selenides (such as NiSe2 and Ni3Se2) have begun to show great application potential due to their superior metallic conductivity and electrochemical activity compared to oxides / hydroxides. Material structural design is another key to overcoming performance bottlenecks. Three-dimensional ordered porous structures, especially inverse opal structures, are considered ideal electrode structures due to their highly interconnected macroporous networks, large specific surface areas, and efficient mass transfer channels. This structure not only exposes more catalytic active sites but also promotes rapid diffusion of reactants / products, thereby significantly improving sensor performance.

[0005] However, there are still insufficient reports on the application of combining highly conductive nickel-selenium compounds with finely controlled inverse opal structures in high-performance glucose electrochemical sensors. Nickel-selenium compounds prepared by conventional methods are mostly dense particles or stacked nanosheets, failing to fully utilize their structural advantages. How to construct structurally complete, homogeneous nickel-selenium compounds with inverse opal structures using a simple and controllable synthetic strategy, and further explore their application potential in glucose detection, is a technical problem that needs to be solved. Summary of the Invention

[0006] The purpose of this invention is to address the limitations of non-enzymatic electrochemical sensors in terms of sensitivity and detection range for glucose under alkaline conditions, and to prepare inverse opal structure nickel selenium compounds and their applications.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a method for preparing a nickel selenium compound having an anti-opal structure, comprising the following steps:

[0009] Step S1: Polystyrene nanospheres were prepared by emulsion polymerization. Specifically, 0.1 g of sodium carbonate as a buffer and 0.2 g of sodium dodecyl sulfate as an emulsifier were dissolved in 300 mL of distilled water to form a mixture. The mixture was purged with nitrogen for 30 minutes, and then stirred vigorously for 30 minutes in a water bath at 60 °C. 30 mL of styrene monomer was added, followed by 15 mL of 0.23 M potassium persulfate solution as an initiator. The initiation temperature was 75 °C and maintained for 20 h to obtain polystyrene nanospheres with a particle size of 200 nm.

[0010] Step S2: A 1×0.5 cm² ITO glass substrate was ultrasonically cleaned sequentially with acetone, ethanol, and deionized water and then dried. The cleaned ITO substrate was then vertically immersed in a polystyrene nanosphere dispersion. Polystyrene nanospheres were self-assembled using a vertical pull-out method to form a uniformly arranged polystyrene nanosphere template film. The polystyrene nanosphere dispersion contained, by mass ratio: 0.3 g polystyrene nanospheres, 0.02 g sodium dodecyl sulfate, and 10 g deionized water. The vertical pull-out process involved slowly removing the substrate at a controlled rate of 0.005 mm / min using a dip-coating apparatus and allowing it to air dry naturally at room temperature to obtain the template film.

[0011] Step S3: A three-electrode system was used for constant potential electrodeposition, with the template film obtained in step S2 as the working electrode, the platinum plate as the counter electrode, and the Ag / AgCl electrode as the reference electrode. The electrolyte contained 5 mM nickel chloride hexahydrate as the nickel source, 10 mM selenium oxide as the selenium source, and a supporting electrolyte. The potential was set to -0.8 V to allow the nickel selenium compound precursor to fill the template pores. The electrodeposition times were 2 min, 5 min, and 8 min.

[0012] The supporting electrolyte is lithium chloride;

[0013] Step S4: Dissolve and remove the above polystyrene nanosphere film with toluene to obtain an inverse opal structure framework with a three-dimensional ordered macroporous network. The processing time is 2-4 h.

[0014] Step S5: Heat-treat the inverse opal skeleton with a three-dimensional ordered macroporous network structure obtained in step S4.

[0015] The heat treatment was carried out in a tube furnace under a high-purity nitrogen atmosphere at a flow rate of 50-100 mL / min. The temperature was increased in stages at a rate of 5 °C / min: from room temperature to 100 °C, 200 °C, and 300 °C, and held at 300 °C for 2 h, followed by natural cooling to room temperature.

[0016] The final product obtained is a nickel-selenium compound with an inverse opal structure, namely IO-Ni3Se4.

[0017] Secondly, the present invention also provides a nickel selenium compound having an inverse opal structure, which is prepared by the above-described method.

[0018] Thirdly, the present invention also provides an electrochemical sensor working electrode comprising the nickel selenium compound having an inverse opal structure.

[0019] Fourthly, the present invention also provides an electrochemical detection method for glucose, comprising the following steps:

[0020] Step S1: Using the working electrode of the electrochemical sensor as the working electrode, evaluate its electrocatalytic oxidation activity for glucose in 0.1 M NaOH electrolyte by cyclic voltammetry.

[0021] Step S2: Determine the optimal working potential for glucose detection to be 0.60 V;

[0022] Step S3: Determine the linear relationship between current response and glucose concentration using the amperometric method, and calculate the sensitivity and linear range;

[0023] Step S4: Evaluate the selectivity of the sensor by introducing common interfering elements.

[0024] This invention provides a nickel-selenium compound with an inverse opal structure, its preparation method, and its applications. This material possesses a three-dimensionally ordered, highly interconnected porous network structure with a large specific surface area, providing abundant catalytic active sites and efficient mass transfer channels. When used as the working electrode material for a non-enzymatic electrochemical glucose sensor, it exhibits high sensitivity, a wide linear range, a low detection limit, excellent selectivity, and good stability, providing a new material platform and technical solution for high-performance glucose detection. Attached Figure Description

[0025] Figure 1 SEM images of the polystyrene film prepared in Example 2;

[0026] Figure 2 SEM images of the materials obtained by electrodeposition in Example 3 after 2 min, 5 min, and 8 min;

[0027] Figure 3 SEM images of IO-Ni3Se4 prepared in Example 3 after final heat treatment;

[0028] Figure 4 XRD patterns of IO-Ni3Se4 prepared in Example 3 before and after final heat treatment;

[0029] Figure 5 CV curve of glucose detection using the IO-Ni3Se4 sensor in Example 4;

[0030] Figure 6 Example 5 shows the current response histogram of IO-Ni3Se4 when 1 mM glucose solution is added to 0.1 M NaOH successively at different applied potentials.

[0031] Figure 7 The constant current response curve of IO-Ni3Se4 when glucose solution is added sequentially under constant stirring at 0.6 V in Example 5;

[0032] Figure 8 Example 5: Current response versus glucose concentration calibration curve;

[0033] Figure 9 Example 5: Bar graph comparing the current density increments of glucose with other interfering species. Detailed Implementation

[0034] The present invention is further illustrated below through examples.

[0035] The present invention will now be described in detail with reference to the accompanying drawings, such as... Figure 1-9 As shown:

[0036] Example 1: Preparation of polystyrene (PS) nanospheres

[0037] The preparation method is as follows:

[0038] PS nanospheres were synthesized via emulsion polymerization. 0.1 g of sodium carbonate and 0.2 g of sodium dodecyl sulfate were dissolved in 300 mL of distilled water, and the mixture was purged with nitrogen for 30 min. Subsequently, the mixture was vigorously stirred at 60 °C for 30 min, and 30 mL of styrene was added to the solution. Then, 15 mL of 0.23 M potassium persulfate (K₂S₂O₈) solution was rapidly added, and the reaction temperature was raised to 75 °C and maintained for 20 h. After the reaction was complete, the system was cooled to room temperature, and the PS nanospheres were separated by centrifugation and washed three times with distilled water. The size of the PS nanospheres was controlled by adjusting the amount of styrene monomer added during polymerization; the preferred amount was 1.4 mL.

[0039] Example 2: Preparation of polystyrene film

[0040] Step S1: First, ultrasonically clean the ITO glass substrate (1×0.5 cm²) with acetone and ethanol for 10 min each, then rinse with deionized water and air dry at room temperature to obtain a clean surface.

[0041] Step S2: 0.3 g of synthesized PS nanospheres were dispersed in 10 g of deionized water, and a 2% (w / w) sodium dodecyl sulfate (SDS) solution was added dropwise. The mixture was sonicated for 30 min to ensure uniform dispersion. The cleaned ITO substrate was vertically immersed in the PS suspension, covering a region of 0.5 × 0.5 cm, and slowly removed using a dip-coating system at a controlled rate of 0.005 mm / min, thereby forming a highly ordered PS nanosphere array. The coated substrate was allowed to air dry at room temperature to stabilize the assembled structure, ultimately obtaining a uniform PS template for subsequent inverse opal structure preparation. The resulting SEM image of the thin film is shown below. Figure 1 As shown.

[0042] Example 3: Preparation of IO-Ni3Se4

[0043] IO-Ni3Se4 was synthesized by electrodeposition, using the PS film from Example 2 as the working electrode. The PS film was immersed in an electrolyte containing 5 mM NiCl2·6H2O, 10 mM SeO2, and 25 mM LiCl. A platinum plate was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. Electrodeposition was performed at a constant potential of -0.8 V (relative to Ag / AgCl), and the electrodeposition times were controlled at 2 min, 5 min, and 8 min to investigate the effect of different deposition times on the material structure. After electrodeposition, the PS template was selectively dissolved and removed using toluene to obtain an inverse opal structure framework with a three-dimensional ordered macroporous network (before heat treatment). The corresponding SEM images are shown below. Figure 2As shown in the figure. Comparison revealed that the sample prepared with a deposition time of 5 min had the most regular structure; therefore, this condition was determined to be the optimal electrodeposition time. The material obtained under these conditions was placed in a nitrogen atmosphere with a gas flow rate of 50-100 mL / min, and heated in stages at a rate of 5 °C / min: from room temperature to 100 °C, 200 °C, and 300 °C sequentially, and held at 300 °C for 2 h to obtain the final product IO-Ni3Se4 with enhanced crystallinity. Its SEM image is shown below. Figure 3 As shown, a complete inverse opal structure is revealed. Meanwhile, Figure 4 The corresponding XRD pattern was shown, and diffraction peaks corresponding to the standard card were observed in the pattern. The intensity of the relevant diffraction peaks was significantly enhanced after heat treatment, which further confirmed that IO-Ni3Se4 was successfully deposited on the ITO substrate and maintained structural integrity. Furthermore, heat treatment under a nitrogen atmosphere further improved its crystallinity.

[0044] Example 4: Electrochemical performance evaluation of IO-Ni3Se4

[0045] The IO-Ni3Se4 prepared in Example 3 was used as the working electrode, forming a three-electrode system with a platinum counter electrode and an Ag / AgCl reference electrode. Its electrocatalytic oxidation activity for glucose was evaluated using cyclic voltammetry (CV) in 0.1 M NaOH electrolyte. Figure 5 As shown, upon addition of 1.0 mM glucose, a distinct oxidation current peak appeared around 0.60 V, and the current value increased significantly, indicating that the material exhibits good electrocatalytic activity towards glucose. This enhanced activity can be attributed to the increased crystallinity and selenium-enriched surface characteristics, both of which together increased the density of active sites and effectively enhanced electron transfer kinetics.

[0046] Example 5: Optimization of detection conditions and performance testing of a glucose sensor based on IO-Ni3Se4

[0047] (1) Determination of the optimal detection potential: Under stirring conditions, 1 mM glucose was continuously injected into 0.1 M NaOH electrolyte, and the Ampere current response was recorded at constant potentials of 0.50 V, 0.55 V, 0.60 V, and 0.65 V (relative to Ag / AgCl). The results are as follows: Figure 6 As shown, the current response reaches its maximum value at 0.60 V. Therefore, 0.60 V is determined to be the optimal operating potential for glucose detection, which can be attributed to the fact that nickel ions in Ni3Se4 are more likely to undergo redox transformation at this voltage.

[0048] (2) Sensitivity, linear range and detection limit test: At the optimal potential of 0.60 V, the current-time curves of the electrode were recorded by amperometric method (it) when different concentrations of glucose solution were continuously added (the concentration increased cumulatively after each addition), as shown in the figure. Figure 7 As shown, the current response increases in a stepwise manner with increasing glucose concentration. A calibration curve was plotted based on the steady-state current value and glucose concentration, as shown below. Figure 8 As shown. Calculations show that the sensor exhibits good linearity over a wide concentration range (e.g., the specific range needs to be filled in based on actual data; this is just an example). It also has high sensitivity and a low detection limit. These excellent performances are attributed to the open three-dimensional pore structure of IO-Ni3Se4, which facilitates mass transfer and exposes more active sites, thereby enhancing its catalytic activity.

[0049] (3) Selectivity Test: Selectivity was evaluated by amperometric measurement. Common interfering substances (including ascorbic acid (AA), dopamine (DA), sodium chloride (NaCl), sucrose (Suc), and hydrogen peroxide (H2O2)) were added sequentially to a stirred 0.1 M NaOH solution, followed by the addition of 1 mM glucose. The current response was monitored at 0.60 V. The results are as follows: Figure 9 As shown, the current response changes very little when interfering substances are added, while a significant and stable current step is observed when glucose is added, indicating that the IO-Ni3Se4 electrode has excellent selectivity for glucose detection. This is because, at this voltage, glucose molecules can effectively interact with the active sites on the material surface, generating a significant and stable oxidation current; while interfering substances are difficult to undergo efficient oxidation reactions at this potential, only causing minor current fluctuations.

[0050] Analysis results: The inverse opal-structured nickel-selenium compound possesses a three-dimensional ordered macroporous network, resulting in a large specific surface area, high mass transfer efficiency, and the ability to expose more catalytically active sites. Simultaneously, the nickel-selenium compound exhibits superior metallic conductivity and electrochemical activity compared to traditional nickel oxides. The synergistic effect of these two factors significantly enhances the sensitivity, detection range, and selectivity of the electrode based on this material for glucose catalytic activity. This material demonstrates superior performance in glucose sensing and provides a new approach for designing selenide-based electrocatalytic materials with complex nanostructures. It is expected to further promote the development of high-performance, highly stable non-enzymatic electrochemical sensing platforms and has clear application potential in fields such as bioanalysis, clinical testing, and precision medicine.

[0051] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-selenium compound having an anti-opal structure, characterized in that, Includes the following steps: Step S1: Polystyrene nanospheres were prepared by emulsion polymerization. Specifically, 0.1 g of sodium carbonate as a buffer and 0.2 g of sodium dodecyl sulfate as an emulsifier were dissolved in 300 mL of distilled water to form a mixture. The mixture was purged with nitrogen for 30 minutes, and then stirred vigorously for 30 minutes in a water bath at 60 °C. 30 mL of styrene monomer was added, followed by 15 mL of 0.23 M potassium persulfate solution as an initiator. The initiation temperature was 75 °C and maintained for 20 h to obtain polystyrene nanospheres with a particle size of 200 nm. Step S2: A 1×0.5 cm² ITO glass substrate was ultrasonically cleaned sequentially with acetone, ethanol, and deionized water and then dried. The cleaned ITO substrate was then vertically immersed in a polystyrene nanosphere dispersion. Polystyrene nanospheres were self-assembled using a vertical pull-out method to form a uniformly arranged polystyrene nanosphere template film. The polystyrene nanosphere dispersion contained, by mass ratio: 0.3 g polystyrene nanospheres, 0.02 g sodium dodecyl sulfate, and 10 g deionized water. The vertical pull-out process involved slowly removing the substrate at a controlled rate of 0.005 mm / min using a dip-coating apparatus and allowing it to air dry naturally at room temperature to obtain the template film. Step S3: A three-electrode system was used for constant potential electrodeposition, with the template film obtained in step S2 as the working electrode, the platinum plate as the counter electrode, and the Ag / AgCl electrode as the reference electrode. The electrolyte contained 5 mM nickel chloride hexahydrate as the nickel source, 10 mM selenium oxide as the selenium source, and a supporting electrolyte. The potential was set to -0.8 V to allow the nickel selenium compound precursor to fill the template pores. The electrodeposition times were 2 min, 5 min, and 8 min. The supporting electrolyte is lithium chloride; Step S4: Dissolve and remove the above polystyrene nanosphere film with toluene to obtain an inverse opal structure framework with a three-dimensional ordered macroporous network. The processing time is 2-4 h. Step S5: Heat-treat the inverse opal skeleton with a three-dimensional ordered macroporous network structure obtained in step S4. The heat treatment is carried out in a tube furnace, with a high-purity nitrogen atmosphere and a gas flow rate of 50-100 mL / min. The temperature is increased in stages at a heating rate of 5°C / min: from room temperature to 100 °C, 200 °C, and 300 °C, and held at 300 °C for 2 hours, and then naturally cooled to room temperature. The final product obtained is a nickel-selenium compound with an inverse opal structure, namely IO-Ni3Se4.

2. A nickel-selenium compound having an anti-opal structure, characterized in that, It is prepared by the method described in claim 1.

3. A working electrode for an electrochemical sensor, characterized in that, The nickel selenium compound having an anti-opite structure as described in claim 2.

4. An electrochemical detection method for glucose, characterized in that, Includes the following steps: step S1: Using the working electrode of the electrochemical sensor described in claim 3 as the working electrode, its electrocatalytic oxidation activity for glucose was evaluated by cyclic voltammetry in 0.1 M NaOH electrolyte; Step S2: Determine the optimal working potential for glucose detection to be 0.60 V; Step S3: Determine the linear relationship between current response and glucose concentration using the amperometric method, and calculate the sensitivity and linear range; Step S4: Evaluate the selectivity of the sensor by introducing common interfering elements.

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