A nitrogen-doped black phosphorus nanosheet / graphene composite material and its preparation method and application

Abstract

The present invention discloses a nitrogen-doped black phosphorus nanosheet / graphene composite material, its preparation method, and application. First, amorphous red phosphorus, a nitrogen-containing compound, and graphene oxide are added to a solvent, followed by a solvothermal reaction at 150-200°C. After the reaction, a product is obtained, which is filtered, washed, and dried to prepare the nitrogen-doped black phosphorus nanosheet / graphene composite material. The prepared nitrogen-doped black phosphorus nanosheet / graphene composite material is modified on a carbon ethylenediamine (CGE) and used for the detection of trace amounts of hydroquinone in the environment, demonstrating excellent sensitivity and promising application prospects.

Description

Technical Field

[0001] The present invention belongs to the field of electrochemical detection, and in particular relates to a nitrogen-doped black phosphorus nanosheet / graphene composite material, a preparation method thereof, and an application thereof. Background Art

[0002] Hydroquinone (1,2-dihydroxybenzene, HQ) is widely used in fragrances, dyes, electroplating materials, and pharmaceuticals. However, due to its low degradability and high toxicity, HQ is considered an environmental pollutant in ecosystems. Therefore, it is imperative to develop simple, rapid, and effective methods for tracking and detecting HQ levels in the environment. Currently, methods for detecting HQ primarily rely on high-performance liquid chromatography, gas chromatography, and chemiluminescence. However, these methods suffer from time-consuming processes, high equipment costs, and cumbersome sample pre-processing. Given these factors, electrochemical techniques have gained widespread application in the detection and analysis of HQ due to their rapid response, low cost, high sensitivity, and excellent selectivity. However, in most cases, the electrochemical oxidation of HQ on a bare glassy carbon electrode (GCE) is insensitive, making the tracking and monitoring of trace amounts of HQ in the environment a significant challenge in electrochemical analysis. Summary of the Invention

[0003] To address the shortcomings of existing technologies and enhance the electrocatalytic activity of working electrodes in electrochemical detection, thereby expanding the detection range, the present invention provides a nitrogen-doped black phosphorus nanosheet / graphene composite material, its preparation method, and its application. The nitrogen-doped black phosphorus nanosheet / graphene composite prepared in this invention was modified onto a carbon-encapsulated gaseous condensate (CGE) to construct a sensitive hydroquinone sensor.

[0004] The purpose of the present invention is achieved through the following technical solutions:

[0005] A method for preparing a nitrogen-doped black phosphorus nanosheet / graphene composite material comprises the following steps:

[0006] First, amorphous red phosphorus, a nitrogen-containing compound and graphene oxide are added to a solvent, and then a solvent thermal reaction is carried out at 150-200° C. After the reaction is completed, a product is obtained. Finally, the product is filtered, washed and dried to prepare the nitrogen-doped black phosphorus nanosheet / graphene composite material.

[0007] Preferably, the mass ratio of amorphous red phosphorus to the nitrogen-containing compound is 1:5 to 10:1.

[0008] Preferably, the mass ratio of amorphous red phosphorus to graphene oxide is 1:1 to 10:1.

[0009] Preferably, the nitrogen-containing compound is at least one of urea, thiourea, melamine, amino acid, ammonium chloride and ammonium sulfate.

[0010] Preferably, the solvent is at least one of ethylenediamine, propylenediamine, butylenediamine and diethylamine.

[0011] Preferably, the solvent thermal reaction time is 5 to 20 hours.

[0012] The nitrogen-doped black phosphorus nanosheet / graphene composite material is prepared by the above-mentioned method for preparing the nitrogen-doped black phosphorus nanosheet / graphene composite material.

[0013] Application of the nitrogen-doped black phosphorus nanosheet / graphene composite material in preparing a hydroquinone electrochemical sensor.

[0014] Preferably, the application includes the following steps: dispersing the nitrogen-doped black phosphorus nanosheets / graphene composite material in water, then drop-coating it on the surface of a glassy carbon electrode, and finally drying it to prepare a hydroquinone electrochemical sensor.

[0015] Preferably, the amount of the nitrogen-doped black phosphorus nanosheets / graphene composite material added to water is 1 mg / ml.

[0016] Preferably, the amount of drop coating is 5 to 10 μl.

[0017] Preferably, the drying method is to use an infrared lamp for drying.

[0018] The reaction mechanism or principle involved in the present invention is as follows: an amine solvent acts as a template. Under certain temperature and pressure conditions and the action of the amine template, red phosphorus undergoes atomic rearrangement to form black phosphorus crystals with a more stable chair-like structure. The added nitrogen-containing compound decomposes under high temperature and high pressure and is doped into the black phosphorus crystals. Simultaneously, graphite oxide is reduced under the action of high temperature, high pressure and the solvent and coated on the surface of the black phosphorus crystals, improving the conductivity of the composite material. The present invention can prepare nitrogen-doped black phosphorus in situ under low-temperature conditions. The production process is simple and does not require complicated operations, resulting in low production costs, large scale-up potential, and mature technology.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The nitrogen-doped black phosphorus nanosheet / graphene composite material prepared by the present invention is modified on CGE and used for the detection of trace hydroquinone in the environment, showing excellent sensitivity and having good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 These are the XRD diffraction patterns of the nitrogen-doped black phosphorus nanosheet / graphene composite material and the black phosphorus standard card prepared in Example 1.

[0022] Figure 2 Comparison of the cyclic voltammetry curves of the hydroquinone electrochemical sensor prepared in Example 1, the bare glassy carbon electrode, and the black phosphorus-graphene modified electrode prepared in Comparative Example 1 for HQ detection, where a corresponds to the bare glassy carbon electrode, b corresponds to the black phosphorus-graphene / GCE modified electrode, and c corresponds to the hydroquinone electrochemical sensor.

[0023] Figure 3 This is a calibration curve diagram of the oxidation peak current of HQ on the hydroquinone electrochemical sensor prepared in Example 1 and the HQ concentration. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] The glassy carbon electrode was purchased from Baisheng Instrument (Guangzhou) Co., Ltd., model 3mm polytetrafluoroethylene; the amorphous red phosphorus was purchased from Aladdin Reagent Company.

[0026] Example 1

[0027] A method for preparing a nitrogen-doped black phosphorus nanosheet / graphene composite material, comprising the following steps:

[0028] 0.6 g of amorphous red phosphorus, 0.1 g of urea, and 0.2 g of graphene oxide were added to 80 ml of ethylenediamine solvent, stirred thoroughly, and ultrasonicated for 30 minutes to obtain a dispersion. The dispersion was then added to a 100 ml reactor and reacted at 160°C for 10 hours to obtain a reaction product. The product was filtered, washed, and then dried with an infrared lamp to prepare a nitrogen-doped black phosphorus nanosheet / graphene composite material.

[0029] 1 mg of the nitrogen-doped black phosphorus nanosheets / graphene composite material prepared in Example 1 was dispersed in 1 mL of water to obtain a dispersion. 8 μl of the dispersion was evenly drop-coated on the surface of a glassy carbon electrode and dried with an infrared lamp to obtain a hydroquinone electrochemical sensor (denoted as a nitrogen-doped black phosphorus-graphene / GCE modified electrode). The electrochemical behavior of hydroquinone on the electrochemical sensor electrode was then detected.

[0030] Figure 1 The XRD diffraction patterns of the nitrogen-doped black phosphorus nanosheet / graphene composite material and the black phosphorus standard card prepared in Example 1 are compared with the black phosphorus standard card PDF:73-1358. It can be seen that the composite material prepared in Example 1 contains black phosphorus and the amount of graphene incorporated is small, so no diffraction peak is observed.

[0031] Figure 2The cyclic voltammetry curves of the hydroquinone electrochemical sensor prepared in Example 1, the bare glassy carbon electrode, and the black phosphorus-graphene modified electrode prepared in Comparative Example 1 for HQ detection are compared. Figure 2 It can be observed that the hydroquinone electrochemical sensor prepared in Example 1 has a higher oxidation peak current and a smaller peak potential difference. On the nitrogen-doped black phosphorus-graphene / GCE modified electrode, the oxidation peak current of HQ is 22.07μA (about 1.09 times that of the black phosphorus-graphene / GCE modified electrode; about 1.56 times that of the GCE modified electrode), and the peak potential difference is 0.082mV (about 0.58 times that of the black phosphorus-graphene / GCE modified electrode; about 0.51 times that of the GCE modified electrode), showing a higher electrocatalytic activity. The specific steps of the cyclic voltammetry method are: a test electrode (selected from one of the nitrogen-doped black phosphorus-graphene / GCE modified electrode, the black phosphorus-graphene / GCE modified electrode and the GCE modified electrode), a counter electrode (platinum wire), and a reference electrode are assembled into a three-electrode system of a saturated calomel electrode, and a cyclic voltammetry test is performed at 50mV / s using a Chenhua electrochemical workstation, wherein the configured HQ concentration is 2.0×10 -4 mol / L (PBS concentration is 0.1 mol / L, pH=7.0).

[0032] Figure 3 The calibration curve of the peak current of HQ oxidation on the hydroquinone electrochemical sensor prepared in Example 1 and the HQ concentration is shown in FIG. Figure 3 A good linear relationship was observed between the HQ anodic peak current and concentration, and a detection limit of 0.05 μM was calculated based on a 3x signal-to-noise ratio. The calibration curve was generated by first measuring the differential pulse (DPV) curves of HQ at different concentrations on a nitrogen-doped black phosphorus-graphene / GCE modified electrode using the differential pulse technique (DPV). Then, the peak current at different HQ concentrations was read from the DPV curves to generate a calibration curve between peak current and concentration.

[0033] Comparative Example 1

[0034] A method for preparing a black phosphorus-graphene composite material, comprising the following steps:

[0035] 0.6 g of amorphous red phosphorus and 0.2 g of graphene oxide were added to 80 ml of ethylenediamine solvent, stirred thoroughly, and ultrasonicated for 30 minutes to obtain a dispersion. The dispersion was then added to a 100 ml reactor and reacted at 160°C for 10 hours to obtain a reaction product. The product was filtered, washed, and then dried with an infrared lamp to prepare a black phosphorus-graphene composite material.

[0036] The black phosphorus-graphene composite material prepared in Comparative Example 1 was used to modify the electrode for HQ detection, and the process was the same as that in Example 1.

[0037] Figure 2 The cyclic voltammograms of the hydroquinone electrochemical sensor prepared in Example 1 and the bare glassy carbon electrode and the black phosphorus-graphene modified electrode prepared in Comparative Example 1 for HQ detection are shown in FIG. Figure 2 It can be observed that the oxidation peak current of HQ on the black phosphorus-graphene / GCE modified electrode is 20.33 μA, which is significantly lower than the oxidation peak current (22.07 μA) of HQ detected by the nitrogen-doped black phosphorus-graphene / GCE modified electrode prepared in Example 1; the peak potential difference is 0.142 mV, which is significantly higher than the peak potential difference (0.082 mV) of HQ detected by the nitrogen-doped black phosphorus-graphene modified electrode prepared in Example 1.

[0038] Example 2

[0039] 0.6 g of amorphous red phosphorus, 0.6 g of urea, and 0.2 g of graphene oxide were added to 80 ml of ethylenediamine solvent, stirred thoroughly, and ultrasonicated for 30 minutes to obtain a dispersion. The dispersion was then added to a 100 ml reactor and reacted at 180°C for 10 hours to obtain a reaction product. The product was filtered, washed, and then dried with an infrared lamp to prepare a nitrogen-doped black phosphorus nanosheet / graphene composite material.

[0040] The nitrogen-doped black phosphorus nanosheets / graphene composite material prepared in Example 2 was used to construct an electrochemical sensor for HQ detection. The process was the same as that in Example 1, and the detection results were roughly the same as those in Example 1, also showing excellent electrochemical sensitivity.

[0041] Example 3

[0042] 0.6 g of amorphous red phosphorus, 1.2 g of urea, and 0.3 g of graphene oxide were added to 80 ml of ethylenediamine solvent, stirred thoroughly, and ultrasonicated for 30 minutes to obtain a dispersion. The dispersion was then added to a 100 ml reactor and reacted at 180°C for 8 hours to obtain a reaction product. The product was filtered, washed, and then dried with an infrared lamp to prepare a nitrogen-doped black phosphorus nanosheet / graphene composite material.

[0043] The nitrogen-doped black phosphorus nanosheets / graphene composite material prepared in Example 3 was used to construct an electrochemical sensor for HQ detection. The process was the same as that in Example 1, and the detection results were roughly the same as those in Example 1, also showing excellent electrochemical sensitivity.

[0044] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a hydroquinone electrochemical sensor, characterized in that: The method comprises the following steps: dispersing a nitrogen-doped black phosphorus nanosheet / graphene composite material in water, then drop-coating the composite material onto the surface of a glassy carbon electrode, and finally drying the composite material to prepare a hydroquinone electrochemical sensor; The preparation method of the nitrogen-doped black phosphorus nanosheet / graphene composite material comprises the following steps: First, amorphous red phosphorus, a nitrogen-containing compound, and graphene oxide are added to a solvent, and then a solvothermal reaction is carried out at 150-200°C. After the reaction is completed, a product is obtained, which is filtered, washed, and then dried to prepare the nitrogen-doped black phosphorus nanosheet / graphene composite material. The nitrogen-containing compound is at least one of urea, thiourea, melamine, amino acid, ammonium chloride and ammonium sulfate; The solvent is at least one of ethylenediamine, propylenediamine, butylenediamine and diethylamine.

2. The method for preparing a hydroquinone electrochemical sensor according to claim 1, wherein: The mass ratio of the amorphous red phosphorus to the nitrogen-containing compound is 1:5 to 10:

1.

3. The method for preparing a hydroquinone electrochemical sensor according to claim 2, wherein: The mass ratio of the amorphous red phosphorus to the graphene oxide is 1:1 to 10:

1.

4. The method for preparing a hydroquinone electrochemical sensor according to any one of claims 1 to 3, characterized in that: The solvent thermal reaction time is 5 to 20 hours.

5. The method for preparing a hydroquinone electrochemical sensor according to claim 1, wherein: The amount of the nitrogen-doped black phosphorus nanosheet / graphene composite material added to water is 1 mg / ml.

6. The method for preparing a hydroquinone electrochemical sensor according to claim 1, characterized in that: The amount of the drop coating is 5-10 μl; The drying method is to use infrared lamp drying.

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