ECL-based MoS2 nano material vacancy defect identification method

Abstract

The invention discloses a MoS2 nano material vacancy defect identification method based on ECL. The method comprises the following steps: (1) synthesizing a MoS2 material without S vacancy and Mo vacancy defects; (2) preparing a CN / MoS2 nano composite material suspension; (3) preparing a CN / MoS2 nano composite material modified glassy carbon electrode; (4) performing cyclic voltammetry on the CN / MoS2 nanocomposite modified glassy carbon electrode, and recording an ECL signal which is recorded as E0; (5) carrying out detection on the MoS2 sample with unknown vacancy defects to be detected according to the steps (2)-(4), and recording an ECL signal as Ei; (6) comparing Ei with E0 to obtain Eigt; when E0 is greater than E1t and E0 is greater than E1t, judging that the MoS2 sample is the MoS2 material with the Mo vacancy defect; when E0 is greater than E0, judging that the MoS2 sample is the MoS2 material with the S vacancy defect. The CN / MoS2 nano composite material is prepared by taking CN as a probe, and an ECL detection platform is constructed for quickly identifying and screening vacancy defect types of the MoS2 nano material, so that high-sensitivity detection on the vacancy defect types of the MoS2 nano material based on an ECL technology is realized.

Description

Technical Field

[0001] The present invention relates to the field of electrochemiluminescence detection and analysis, and in particular to a method for identifying vacancy defects in MoS2 nanomaterials based on electrochemiluminescence (ECL). Background Art

[0002] Molybdenum disulfide (MoS2), a typical 2D TMD (two-dimensional transition metal dichalcogenide), holds great promise for applications in diverse fields, including electronics, catalysis, and energy storage, due to its unique electronic and optical properties. Defect engineering has emerged as a key strategy for manipulating the properties of MoS2 and has garnered significant attention in recent years. The limited processing capabilities of monolayer MoS2 inevitably introduce intrinsic defects such as vacancies. While imperceptible at the microscopic level, these defects have profound impacts on MoS2 material properties. For example, vacancy defects alter the charge distribution within the material, significantly affecting carrier mobility and, consequently, altering electrical properties. Optically, defects act as luminescence centers or energy traps, altering luminescence efficiency and wavelength. By precisely controlling the type, concentration, and distribution of defects, the performance of MoS2 can be purposefully optimized to better meet the needs of diverse application scenarios.

[0003] According to current reports, commonly used vacancy defect detection methods include scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Although these detection and analysis methods can provide certain defect information, they are still insufficient for accurately analyzing complex defect structures and electronic states. Therefore, it is of great significance to find an efficient and convenient analytical method to detect different vacancy defects in MoS2.

[0004] ECL offers significant advantages, including high sensitivity, fast reaction speed, low background signal, and simple detection equipment. It is well known that in nanomaterial research, ECL analysis can accurately reveal structural information. By detecting changes in the luminescence signal, it can delve into key characteristics of nanomaterials, such as their crystal structure, surface morphology, particle size, and elemental composition. Generally, structural changes in nanomaterials, such as crystallinity, alter electron distribution. For example, increased crystallinity leads to a more uniform electron distribution and enhanced conductivity, thereby improving electron transfer efficiency and ultimately altering ECL signal intensity. Some nanomaterials also possess catalytic properties. Differences in surface atomic arrangement, active site distribution, and electron cloud density can lead to varying catalytic properties, accelerating the conversion of reactants in ECL reactions and enhancing ECL signal intensity. In summary, by analyzing these ECL signal variations, ECL analysis has the potential to become a new technology for detecting MoS2 defects, thereby enabling structural probing of nanomaterials.

[0005] In the study of identifying different vacancy defects in MoS2 nanomaterials based on ECL technology, although this technology has demonstrated unique advantages, such as the ability to keenly capture the changes in luminescence signals caused by S vacancies and Mo vacancies in MoS2 materials, providing a new perspective for detecting vacancy defects in MoS2. However, the current technology still has obvious limitations. There are various types of vacancy defects in MoS2, including molybdenum vacancies, sulfur vacancies, etc. Each type of vacancy defect will theoretically have different degrees of influence on the ECL intensity due to factors such as the missing atoms and changes in the electron cloud distribution. However, at this stage, due to the limitations of the accuracy of the detection instrument, the complexity of the detection environment, and the lack of in-depth understanding of the ECL reaction mechanism, it is still difficult to accurately determine the quantitative relationship between different vacancy defects and ECL intensity. This has largely restricted the further application and expansion of this technology in the precise control of material properties and high-sensitivity detection. Summary of the Invention

[0006] The present invention aims to provide an ECL-based method for identifying vacancy defects in MoS2 nanomaterials. This method can effectively and rapidly screen the types and concentrations of vacancy defects in MoS2 nanomaterials, providing a basis for further constructing MoS2 electrocatalysts with excellent performance.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: A method for identifying vacancy defects in MoS2 nanomaterials based on ECL comprises the following specific steps: (1) Synthesis of MoS2 materials without S vacancy and Mo vacancy defects; (2) The synthesized MoS2 material and graphite carbon nitride were dispersed in deionized water, ultrasonically treated, and the resulting suspension was centrifuged to remove the residual bulk powder, thereby obtaining a CN / MoS2 nanocomposite suspension; (3) The glassy carbon electrode was polished with alumina slurry and then ultrasonically treated in ultrapure water and ethanol in sequence. 5 μL of CN / MoS2 nanocomposite suspension was dropped onto the bare GCE surface and then dried in air at 25 °C to obtain a CN / MoS2 nanocomposite modified glassy carbon electrode. (4) Using an electrochemical workstation, a three-electrode system consisting of a CN / MoS2 nanocomposite modified glassy carbon electrode as the working electrode, Pt as the auxiliary electrode, and Ag / AgCl saturated with KCl as the reference electrode was formed. Cyclic voltammetry was performed on the electrode modified with the CN / MoS2 nanocomposite in a 0.1 M Na2S2O8 solution [0.1 M PBS, pH = 7.4, 0.1 M NaCl]. The ECL signal was recorded and recorded as E0. (5) The MoS2 sample with unknown type of vacancy defect to be tested is subjected to steps (2)-(4) and the ECL signal is recorded, which is recorded as Ei ; (6) Compare E i with E0. When E i > E0, it is determined that the MoS2 sample is MoS2 material with Mo vacancy defects. When E i < E0, it is determined that the MoS2 sample is MoS2 material with S vacancy defects.

[0008] As a preferred embodiment of the present invention, in step (1), 2.8 mmol of thiourea (CH4N2S) and 0.2 mmol of ammonium molybdate ((NH4)6Mo7O 24 ·4H2O) are dissolved in 40 mL of deionized water, stirred for 30 min, and then the solution is transferred to a stainless-steel autoclave with a polytetrafluoroethylene liner and reacted at 220 °C for 18 h. After naturally cooling to room temperature, it is washed three times with deionized water and ethanol respectively, and the black solid product is collected. Then, the obtained black solid powder is vacuum dried at 60 - 100 °C to obtain MoS2 material.

[0009] As a preferred embodiment of the present invention, in step (2), the preparation method of graphitic carbon nitride (CN) is: 10 g of melamine is placed in a muffle furnace, heated to 550 °C at a heating rate of 3 °C / min in air and then heated for 4 h. After cooling, the massive agglomerates are ground into powder to obtain graphitic carbon nitride (CN), which is stored at room temperature before use.

[0010] As a preferred embodiment of the present invention, in step (2), the dosage ratio of CN to MoS2 material is 100 mg:3 mg, and the ultrasonic treatment time is 16 h.

[0011] As a preferred embodiment of the present invention, in step (4), the cyclic voltammetry measurement is scanned from 0 V to -1.8 V at a scanning rate of 0.1 V / s.

[0012] Compared with the prior art, the beneficial technical effects of the present invention: The present invention uses graphitic carbon nitride as a probe to prepare CN / MoS2 nanocomposites and construct an ECL detection platform for rapid identification and screening of the vacancy defect types of MoS2 nanomaterials. The strong interaction between MoS2 and CN leads to the formation of a Mo-N coordination interface. Through the mechanisms of resonance energy transfer and promotion of co-reactants, more sensitive detection of the vacancy defect types of MoS2 nanomaterials is achieved by ECL. Description of the Drawings

[0013] Figure 1 For CN, CN / MoS2 (V[[ID=3S]] S ) in Test Example 1 of the present invention, CN / MoS2 (VMo ), and the I of CN / MoS2 ECL -time curve; Figure 2 In Test Example 1 of the present invention, CN, CN / MoS2 (V S ), CN / MoS2 (V Mo ), and the I of CN / MoS2 ECL -V curve; Figure 3 In Test Example 1 of the present invention, CN, CN / MoS2 (V S ), CN / MoS2 (V Mo ), and the ECL spectrum of CN / MoS2; Figure 4 (A) is the XRD pattern of CN, MoS2, and CN / MoS2 in Test Example 2 of the present invention, Figure 4 (B) is the FT-IR spectrum of CN, MoS2, CN / MoS2, CN / MoS2 (V Mo ), and CN / MoS2 (V S ), Figure 4 (C) is the XPS spectra of S 2p, Mo3d, C 1s, N 1s, and O 1s in the CN / MoS2 nanocomposite, Figure 4 (D) is the high-resolution scan of the N 1s electrons in the CN / MoS2 nanocomposite; Figure 5 (A) is the differential pulse voltammetry (DPV) spectrum of the samples prepared in Test Example 3 of the present invention, Figure 5 (B) is the ECL spectrum of CN and the ultraviolet absorption spectrum of MoS2, Figure 5 (C) is the transient photocurrent response curve, Figure 5 (D) is the electrochemical impedance spectroscopy (EIS) of CN, CN / MoS2 (V Mo ), CN / MoS2, and CN / MoS2 (V S ).

[0014] Figure 6 In Test Example 4 of the present invention, MoS2, V S -MoS2 (30 s), and V S -MoS2 (60 s) of the I ECL -time curve; Figure 7 In Test Example 4 of the present invention, MoS2, 2.5:1 Mo 1-x S2, and 3.5:1 Mo 1-x S2 of the I ECL -time curve. Detailed implementation manners

[0015] The technical solutions in the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0016] Embodiment A method for identifying vacancy defects of MoS2 nanomaterials based on ECL provided in this embodiment includes: (1) Synthesize MoS2 materials without S vacancies and Mo vacancies; (2) Disperse the synthesized MoS2 materials and graphitic carbon nitride in deionized water, and perform ultrasonic treatment. The obtained suspension is centrifuged to remove residual bulk powders, thereby obtaining a CN / MoS2 nanocomposite suspension; (3) Polish the glassy carbon electrode with alumina slurry, then perform ultrasonic treatment in ultrapure water and ethanol in sequence. Drop 5 μL of the CN / MoS2 nanocomposite suspension on the surface of the bare GCE, and then dry it in the air at 25 °C to obtain a CN / MoS2 nanocomposite modified glassy carbon electrode; (4) Use an electrochemical workstation to form a three-electrode system with the CN / MoS2 nanocomposite modified glassy carbon electrode as the working electrode, Pt as the auxiliary electrode, and saturated KCl Ag / AgCl as the reference electrode. In a solution of 0.1 M Na2S2O8 [0.1 M PBS, pH = 7.4, 0.1 M NaCl], perform cyclic voltammetry measurement on the CN / MoS2 nanocomposite modified electrode, and record the ECL signal, denoted as E0; (5) Perform the MoS2 sample with unknown type vacancy defects to be measured according to steps (2)-(4), and record the ECL signal, denoted as E i ; (6) Compare E i with E0. When E i > E0, it is determined that the MoS2 sample is MoS2 material with Mo vacancy defects. When E i < E0, it is determined that the MoS2 sample is MoS2 material with S vacancy defects.

[0017] In some embodiments, in step (1), 2.8 mmol of thiourea (CH4N2S) and 0.2 mmol of ammonium molybdate ((NH4)6Mo7O 24·4H2O) was dissolved in 40 mL of deionized water and stirred for 30 min. The solution was then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and reacted at 220°C for 18 h. After naturally cooling to room temperature, the product was washed with deionized water and ethanol three times each to collect the black solid product. The obtained black solid powder was then vacuum dried at 60-100°C to obtain MoS2 material.

[0018] In some embodiments, in step (2), the preparation method of CN is as follows: 10 g of melamine is placed in a muffle furnace, heated to 550 °C at a heating rate of 3 °C / min in air and maintained for 4 h, after cooling, the block agglomerates are ground into powder to obtain original CN, which is stored at room temperature before use.

[0019] In some embodiments, in step (2), the ratio of CN and MoS2 materials is 100 mg:3 mg, and the ultrasonic treatment time is 16 h.

[0020] In some embodiments, in step (4), the cyclic voltammetry measurement is performed by scanning from 0 V to -1.8 V at a scan rate of 0.1 V / s.

[0021] Test Example 1 Feasibility of Electrochemiluminescence Detection of Sulfur (S) and Molybdenum (Mo) Vacancies in MoS2 According to the preparation method of MoS2 material in the embodiment, ammonium molybdate and thiourea were mixed at different molar ratios of Mo:S of 4:1, 5:1, 1:4, and 1:5 to prepare S vacancy MoS2 material and Mo vacancy MoS2 material under the same conditions. The obtained samples were marked as 4:1 MoS2 (V S )、5:1 MoS2(V S )、1:4 MoS2(V Mo ) and 1:5 MoS2 (V Mo ).

[0022] In order to gain a deeper understanding of the effects of different vacancy defects in MoS2 on the ECL signal of CN, the CN / MoS2 (V S )、CN / MoS2(V Mo ) and cathode ECL performance of CN / MoS2.

[0023] like Figure 1 As shown, the ECL signal of CN is about 80000 au, CN / MoS2 and CN / MoS2 (V S ) composites have relatively weak ECL signals, which are 9000 au and 6000 au respectively, while CN / MoS2 (V Mo) is significantly enhanced compared to CN, among which CN / 1:5 MoS2 (V Mo ) reaches the highest ECL signal, which is about 140000 au. The results show that when CN is combined with MoS2 and MoS2 (V S ) are combined with CN / MoS2 and CN / MoS2 (V S ) nanocomposites significantly suppressed the ECL signal. However, when CN was combined with MoS2 (V Mo ) combined, CN / MoS2 (V Mo ) nanocomposites promote the occurrence of ECL process.

[0024] like Figure 2 As shown, when CN and MoS2 (V S ) and MoS2, compared with CN, CN / MoS2 (V S ) and CN / MoS2 composite materials have a certain negative shift in onset potential and ECL peak potential, however, CN / MoS2 (V Mo ) composite materials' ECL onset potential and maximum luminescence peak potential shifted toward the positive direction, which further illustrates the relationship between MoS2 and MoS2 (V S ) suppressed the ECL signal of CN, MoS2 (V Mo ) promotes the full reduction of the co-reactant Na2S2O8 and the early injection of electrons into the conductivity of CN, which reduces the ECL reaction barrier.

[0025] In order to explore the effects of different vacancy defect-type MoS2 on CN luminescent materials, the ECL spectra of MoS2 and CN nanocomposites with different vacancies were analyzed by combining an electrochemical workstation with a fluorescence spectrometer.

[0026] like Figure 3 As shown, CN, CN / MoS2 (V S )、CN / MoS2(V Mo The ECL spectra of the composite and CN / MoS2 have similar characteristics, with the maximum ECL emission wavelength observed at 461 nm, corresponding to the luminescence of the CN* excited state. This indicates that the vacancies in the guest MoS2 material in the composite do not affect the luminescence pathway of CN.

[0027] It can be seen that the present invention uses MoS2 as a model material and CN as a probe to achieve the screening of MoS2 with different defects.

[0028] Test Example 2 Characterization of CN / MoS2 Nanocomposite Materials XRD was used to analyze CN, MoS2 and CN / MoS2 in the examples, and the results were as follows: Figure 4As shown in Figure A, there are two obvious peaks in the prepared CN, located at 12.9° and 27.5°, corresponding to the (100) crystal plane of the CN aromatic ring layer and the (002) crystal plane of the interlayer stacking, respectively. The MoS2 diffraction peak corresponds to the standard 2H-MoS2. The introduction of MoS2 leads to the weakening of the CN (002) diffraction peak. The XRD spectrum of the CN / MoS2 nanocomposite shows four obvious characteristic diffraction peaks, corresponding to the (100) and (002) crystal planes of CN and the (002) and (101) crystal planes of MoS2, respectively, which indicates the successful preparation of the CN / MoS2 nanocomposite.

[0029] FT-IR was used to investigate the changes in the existence of functional groups or chemical bonds of CN, MoS2 and CN / MoS2 in the examples. Figure 4 As shown in B, the broad peak vibration of OH (3444 cm -1 ) and NH (3292 cm -1 ) bonds originate from the adsorption of water molecules on the CN surface and uncondensed amino groups. Located at 1642, 1552, 1467, 1409, 1324, 1242 cm -1 A series of absorption peaks are derived from the stretching vibration of the CN heterocycle in the CN skeleton, at 805 cm -1 An obvious peak is observed near the MoS2(V S ), MoS2 (V Mo ) and MoS2 have basically the same absorption peak structure as that of the original CN, but the peak intensity is reduced, indicating that the interfacial coupling weakens the vibration of the groups in CN, which may be a sign of the successful synthesis of CN / MoS2.

[0030] XPS was used to investigate the surface chemical structures of S 2p, Mo 3d, C 1s, N 1s, and O 1s in the CN / MoS2 nanocomposite samples, e.g. Figure 4 C, and detailed analysis of the high-resolution spectrum of N 1s electrons in CN / MoS2 nanocomposites, such as Figure 4 As shown in Figure D, the N 1s spectrum has three peaks at 294.6, 298.1, and 299.8 eV. It is worth noting that the first peak at 394.6 eV is attributed to the formation of Mo-N bonds, indicating that there is a strong electrical interaction between Mo and CN, forming an interfacial Mo-N coordination. The second peak is located at 298.1, corresponding to the CNC of CN. The third peak is located at 299.8 eV, which can be attributed to the C-NH3 in CN.

[0031] Test Example 3 In order to further clarify the signal amplification strategy of the co-reactant acceleration sensor formed by CN and MoS2 materials, differential pulse voltammetry (DPV) was used to study the MoS2 (V Mo ) for S2O8 2- electrocatalytic effect.

[0032] Photoelectrochemical measurements were monitored using a CHI 760E electrochemical workstation and a conventional three-electrode cell. The working electrode was prepared by coating the prepared nanocomposite on FTO glass. Measurements were performed in a 0.1 M Na₂SO₄ aqueous solution, with an Ag / AgCl (saturated with KCl) reference electrode and a Pt counter electrode. The Mott-Schottky curve measurement procedure was identical to that described above.

[0033] like Figure 5 As shown in A, the DPV curve of bare GCE has a reduction peak at about -0.7 V, which is caused by the reduction of Na2S2O8. The DPV curve of CN in PBS solution shows that no redox reaction occurs in PBS solution. However, in 0.1 M Na2S2O8 solution, a strong reduction peak is observed at about -0.93 V, with significant current generation, which is stronger than that of CN / MoS2 and CN / MoS2 (V S ), however CN / MoS2 (V Mo ) exhibited the strongest current, and the reduction peak shifted positively to -0.9 V, indicating that MoS2 (V Mo ) synergistic enhancement effect. Based on the above experimental results, it can be inferred that MoS2 (V Mo ) as a co-reaction accelerator, promoting the S2O8 2- The reduction rate is increased, thereby enhancing the ECL signal.

[0034] In addition, Figure 5 As shown in Figure B, the ECL spectrum of CN and the UV absorption spectrum of MoS2 partially overlap in the range of 450 nm to 625 nm. The close contact between MoS2 and CN and the spectral overlap lead to the occurrence of resonance energy transfer (RET). The results indicate that there is effective resonance energy transfer between MoS2 and CN, which reduces the ECL intensity of the CN / MoS2 composite.

[0035] like Figure 5 As shown in C, in the transient photocurrent response curve, CN / MoS2 (V Mo ) has a higher photocurrent density than CN, indicating that its photogenerated carrier concentration is higher and the charge transfer rate is faster.

[0036] Electrochemical impedance spectroscopy (EIS) measurements were performed in 50 μM K3[Fe(CN)6] / K4[Fe(CN)6] (0.1 M KCl) solution with a frequency range of 0.1 Hz to 100 kHz. The working electrode was prepared by dispersing 5 mg of CN powder in a solution consisting of 50 μL H2O and 20 μL 5% Nafion to form a suspension, which was then dropped onto a 2 × 1 cm 2 The FTO surface was coated with 2% MgCl2 and dried in an oven at 50 °C. The preparation method of CN / MoS2 nanocomposite photoelectrode followed the same steps.

[0037] like Figure 5 As shown in D, the electrochemical impedance spectroscopy is consistent with the transient photocurrent measurement results. Compared with CN, MoS2 (V Mo ) has a smaller radius of the Nyquist curve, indicating a smaller carrier mobility.

[0038] Test Case 4: Universality Verification According to the existing reported literature 1-x S2 and V S -Synthesis of MoS2.

[0039] 0.50 g MoS2 and a certain amount of NaBH4 were ground in a mortar for 20 min and then placed in a tube furnace and calcined at 550 °C for 2 h under nitrogen. The obtained sample was washed with 1 mM HCl for 8 h, and then washed three times with ethanol and deionized water respectively. The sample was dried at 80 °C for 12 h. According to the different molar ratios of NaBH4 and MoS2, 2.5:1 MoS2 was obtained. 1-x S2 and 3.5:1 Mo 1-x S2 sample.

[0040] Preparation of V by chemical etching S -MoS2. 0.50g MoS2 was immersed in a 5M H2O2 solution. At room temperature, the MoS2 surface reacted with hydrogen peroxide for 60 s and 30 s respectively. After the etching reaction was completed, the product was filtered out, washed three times with distilled water, and then dried for later use. The resulting powders were collected and labeled V S -MoS2 (30 s) and V S -MoS2 (60 s).

[0041] In order to verify the versatility of the method of the present invention, S vacancy MoS2 (V S -MoS2) and Mo vacancy MoS2 (Mo 1-x S2). Subsequently, CN / V was synthesized according to the same steps as in Example 1. S-MoS2 and CN / Mo 1-x S2 nanocomposites. The effects of different vacancy defects in MoS2 on the ECL performance of CN were also studied. Figure 6 and Figure 7 As shown, CN / V prepared by H2O2 treatment S -MoS2 composites have an ECL intensity of about 4000 au. In comparison, the ECL intensity of CN / Mo prepared by NaBH4 treatment is about 4000 au. 1-x The ECL strength of S2 composite material is about 100000 au. Compared with CN, V S After the composite of -MoS2 and CN, the ECL signal weakened. On the contrary, CN / Mo 1-x The ECL performance of the S2 composite material is significantly enhanced, and its ECL signal intensity exceeds that of CN / V S -MoS2 composite material. This shows that V S There is an effective resonance energy transfer between -MoS2 and CN, which weakens the ECL performance of CN. 1-x S2 vs. S2O8 2- The reduction of α-(2-hydroxy-1-oxo-2-nitrogen)-2-nitrogen (2-hydroxy-1-oxo-2-nitrogen) exhibited a certain electrocatalytic effect, thereby enhancing the ECL performance of CN in a more general way. Therefore, these results strongly confirm the general applicability of the method of the present invention for rapid differentiation of different vacancy defect types of MoS2.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the technical solution and conceptual invention of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for identifying vacancy defects in MoS2 nanomaterials based on ECL, characterized in that: The specific steps include: (1) Synthesis of MoS2 materials without S vacancy and Mo vacancy defects; (2) The synthesized MoS2 material and graphite carbon nitride were dispersed in deionized water, ultrasonically treated, and the resulting suspension was centrifuged to remove the residual bulk powder, thereby obtaining a CN / MoS2 nanocomposite suspension; (3) The glassy carbon electrode was polished with alumina slurry and then ultrasonically treated in ultrapure water and ethanol in sequence. 5 μL of CN / MoS2 nanocomposite suspension was dropped onto the bare GCE surface and then dried in air at 25 °C to obtain a CN / MoS2 nanocomposite modified glassy carbon electrode. (4) Using an electrochemical workstation, a three-electrode system consisting of a CN / MoS2 nanocomposite modified glassy carbon electrode as the working electrode, Pt as the auxiliary electrode, and Ag / AgCl saturated with KCl as the reference electrode was formed. Cyclic voltammetry was performed on the CN / MoS2 nanocomposite modified electrode in a 0.1 M Na2S2O8 solution [0.1 MPBS, pH = 7.4, 0.1 M NaCl], and the ECL signal was recorded and recorded as E0. (5) The MoS2 sample with unknown type of vacancy defect to be tested is subjected to steps (2)-(4) and the ECL signal is recorded, which is recorded as E i ; (6) Compare E i with E0. When E i > E0, it is determined that the MoS2 sample is a MoS2 material with Mo vacancy defects. When E i < E0, it is determined that the MoS2 sample is a MoS2 material with S vacancy defects.

2. The method for identifying vacancy defects in MoS2 nanomaterials based on ECL according to claim 1, wherein: In step (1), 2.8 mmol of thiourea and 0.2 mmol of ammonium molybdate were dissolved in 40 mL of deionized water and stirred for 30 min. The solution was then transferred to a polytetrafluoroethylene-lined stainless steel autoclave and reacted at 220 °C for 18 h. After naturally cooling to room temperature, the product was washed three times with deionized water and ethanol respectively, and the black solid product was collected. The obtained black solid powder was then vacuum dried at 60-100 °C to obtain MoS2 material.

3. The method for identifying vacancy defects in MoS2 nanomaterials based on ECL according to claim 1, wherein: In step (2), the preparation method of graphite phase carbon nitride is as follows: 10 g of melamine is placed in a muffle furnace, heated to 550 ° C at a heating rate of 3 ° C / min in air, and then heated for 4 hours. After cooling, the block agglomerates are ground into powder to obtain graphite phase carbon nitride, which is stored at room temperature before use.

4. The method for identifying vacancy defects in MoS2 nanomaterials based on ECL according to claim 1, wherein: In step (3), the amount ratio of CN and MoS2 materials was 100 mg:3 mg, and the ultrasonic treatment time was 16 h.

5. The method for identifying vacancy defects in MoS2 nanomaterials based on ECL according to claim 1, wherein: In step (4), the cyclic voltammetry measurement was performed from 0 V to -1.8 V at a scan rate of 0.1 V / s.

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