A sensor for detecting thiophene sulfides in diesel fuel and a method of making and using the same

Abstract

The application discloses a sensor for detecting thiophene sulfides in diesel oil and a preparation method and application thereof. The sensor comprises a substrate, the surface of the substrate is etched with an interdigital conductive layer, and the interdigital part is provided with molybdenum disulfide nanomaterial or ZnS-ZnO shell-core structure nanorod material. The sensor for detecting thiophene sulfides in diesel oil is prepared by growing zinc sulfide-zinc oxide shell-core structure nanorods on the substrate with an interdigital conductive layer on the surface by using a hydrothermal growth method. The sensor can stably exist in diesel oil for a long time. The sensitive material can interact with thiophene sulfides in diesel oil, influence the charge density at the interdigital part, and thus change the capacitance. The change of the sensor capacitance is detected by LCR, so as to detect the concentration of thiophene sulfides in diesel oil. The application has the advantages of low preparation cost, simple preparation method, high portability of the sensor, good sensitivity, and the like, and can realize rapid and accurate measurement of thiophene sulfides in diesel oil.

Description

Technical Field

[0001] This invention belongs to the field of sensor technology, and relates to a sensor, its preparation method and application, specifically to a sensor for detecting thiophene sulfides in diesel fuel, its preparation method and application. Background Technology

[0002] Excessive sulfur content in diesel fuel can reduce the lifespan of vehicle power components, accelerate the corrosion of oil refining equipment, and produce sulfur dioxide and other gases that are toxic and harmful to humans and the natural environment when burned.

[0003] Currently, most methods for measuring sulfur content in oil, such as coulometric methods, ultraviolet fluorescence methods, and X-ray fluorescence methods, require large instruments, resulting in poor portability and high costs. Therefore, we need a portable, rapid, highly sensitive, and highly selective detection method. Summary of the Invention

[0004] To address the issues of poor portability and high cost in current methods for detecting sulfur content in diesel fuel, this invention provides a sensor for detecting thiophene sulfides in diesel fuel, along with its preparation method and application. This invention utilizes a hydrothermal growth method to grow zinc sulfide-zinc oxide core-shell structured nanorods on a substrate with an interdigitated conductive layer to fabricate a sensor for detecting thiophene sulfides in diesel fuel. The sensor can remain stable in diesel fuel for extended periods. The sensitive material interacts with the thiophene sulfides in the diesel fuel, affecting the charge density at the interdigitated points, thereby causing changes in capacitance. The concentration of thiophene sulfides in the diesel fuel is detected by measuring the changes in sensor capacitance using a digital bridge (LCR) instrument.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A sensor for detecting thiophene sulfides in diesel fuel includes a substrate, the surface of which is etched with an interdigitated conductive layer, and molybdenum disulfide nanomaterials or ZnS-ZnO core-shell structured nanorods are disposed at the interdigitations, wherein:

[0007] The substrate is a conductive glass (FTO) substrate;

[0008] The interdigitated conductive layer is formed by laser etching of the substrate;

[0009] The material of the interdigitated conductive layer is fluorine-doped tin dioxide;

[0010] The interdigitated conductive layer has a finger spacing of 50-100 μm. If the finger spacing is too large, it will lead to a decrease in the sensitivity of the sensor. If the finger spacing is too small, the requirements for the sensor manufacturing process will be too high, resulting in an increase in manufacturing costs.

[0011] The interdigitated area is hydrothermally grown with molybdenum disulfide nanomaterials or zinc sulfide-zinc oxide core-shell structured nanorods. This sensor and its sensitive material can exist stably in diesel fuel. The interaction between the sensitive material and thiophene sulfides affects the charge density at the interdigitated area, thereby causing a change in capacitance. The sensitive material is mainly ZnS material, and ZnO is the part left by incomplete conversion. It can also be molybdenum disulfide or other metal sulfide materials with interfacial acids or soft acids as metal ions.

[0012] A method for preparing the above-mentioned sensor for detecting thiophene sulfides in diesel fuel includes the following steps:

[0013] Step 1: Laser etching of the conductive surface of the FTO substrate to obtain an interdigitated conductive layer;

[0014] Step 2: Molybdenum disulfide nanomaterials or ZnS-ZnO nanorods are grown on the interdigitated conductive layer using a hydrothermal method, wherein:

[0015] During hydrothermal reactions, the substrate needs to be fixed on a support and placed in the reactor with the conductive side facing down;

[0016] When growing ZnS-ZnO core-shell structured nanorods on interdigitated conductive layers using a hydrothermal method, ZnO nanorods are first prepared using a hydrothermal method, and then the ZnO surface is transformed into ZnS by hydrothermal sulfidation treatment.

[0017] The aforementioned sensor can be used to test the content of thiophene sulfides in diesel fuel. The specific test method is as follows: Connect the external wire of the sensor to a digital bridge measuring instrument (LCR), place the sensor in diesel fuel, and test the capacitance change of the sensor in diesel fuel samples with different concentrations of benzothiophene. Specifically, after the sensor is connected to the LCR, it is first immersed in a hexane solution to obtain a baseline value. When testing the sensor capacitance, the LCR measuring instrument is set to a voltage of 1V and a frequency of 10kHz.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. Zinc sulfide-zinc oxide core-shell structured nanorods grow firmly on the substrate surface. The rough surface of the nanorods provides many binding sites for thiophene sulfides.

[0020] 2. Using LCR to detect real-time changes in sensor capacitance provides a rapid response and high sensitivity, enabling the identification of even small capacitance changes.

[0021] 3. This sensor can exist stably in diesel fuel. The interaction between its sensitive material and thiophene sulfides affects the charge density at the interdigitated points, thereby causing a change in capacitance. The content of thiophene sulfides can be detected by the change in the sensor's capacitance.

[0022] 4. The preparation cost is low, the preparation method is simple, the sensor is highly portable, and it has good sensitivity, which can realize the rapid and accurate measurement of thiophene sulfides in diesel. Attached Figure Description

[0023] Figure 1 A schematic diagram of a sensor in which the FTO conductive surface is etched into an interdigitated shape;

[0024] Figure 2 Scanning electron microscope image of zinc sulfide / zinc oxide core-shell nanorods on an FTO substrate for the sensor;

[0025] Figure 3 XRD patterns of zinc sulfide / zinc oxide core-shell nanorods and FTO substrates.

[0026] Figure 4 The graphs show the capacitive response of the zinc sulfide-zinc oxide sensor to benzothiophene at a concentration of 20 ppm.

[0027] Figure 5 The graph shows the sensitivity test of the zinc sulfide-zinc oxide sensor for the same concentration of benzothiophene.

[0028] Figure 6 This is a scanning electron microscope image of molybdenum disulfide material on the FTO substrate of the sensor.

[0029] Figure 7 This is a graph showing the sensitivity test of the molybdenum disulfide sensor for different concentrations of benzothiophene. Detailed Implementation

[0030] The technical solution of the present invention will be further described below with reference to the embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention.

[0031] Example 1:

[0032] Step 1: The FTO substrate with the conductive layer laser-etched into an interdigitated shape is first placed in ethanol for ultrasonic cleaning for 10 minutes, then placed in deionized water for ultrasonic cleaning for 10 minutes, and then taken out and dried in an oven at 50°C.

[0033] Step 2: Prepare a mixed solution of 50 mmol / L zinc nitrate hexahydrate and 50 mmol / L hexamethylenetetramine, and stir for 1 hour.

[0034] Step 3: Prepare a 0.2 mol / L thioacetamide solution and stir for 30 min.

[0035] Step 4: Fix the cleaned FTO substrate onto the support and place it in a 50ml reactor with the conductive side facing down.

[0036] Step 5: Add 30 ml of the solution prepared in Step 2 to a 50 ml reaction vessel, place the reaction vessel in a homogeneous reactor, and heat at 88°C for 12 h. Allow it to cool naturally to room temperature, remove the FTO substrate with zinc oxide nanorods grown at the interdigitated ends, wash with deionized water, and dry in a 50°C oven.

[0037] Step 6: Place the FTO substrate with zinc oxide nanorods grown on it into a 50ml polytetrafluoroethylene reactor and add 30ml of the thioacetamide solution prepared in Step 3.

[0038] Step 7: Place the polytetrafluoroethylene reaction vessel in a homogeneous reactor and heat at 130°C for 18 hours. After naturally cooling to room temperature, remove the FTO substrate with zinc sulfide-zinc oxide core-shell structured nanorods at the interdigitated fingers, wash with deionized water, and dry in a 50°C oven.

[0039] Step 8: Connect the external wires at both ends of the FTO conductor to the LCR tester, and set the LCR voltage to 1V and the frequency to 10kHz.

[0040] Step 9: Place the sensor in n-hexane to obtain a stable baseline value, and then place it in benzothiophene diesel fuel solutions of different concentrations. The sensor obtains different capacitive responses in benzothiophene diesel fuel solutions of different concentrations, and the concentration of benzothiophene in the diesel fuel is determined based on the sensor's capacitive response.

[0041] Step 10: Place the sensor in n-hexane to obtain a stable baseline value, then place it in a 20 ppm benzothiophene diesel solution. Test the sensor's capacitive response after repeated use in the 20 ppm benzothiophene diesel solution to test the reproducibility of the sensor's response to benzothiophene.

[0042] A schematic diagram of a sensor with the FTO conductive surface etched into an interdigitated shape is shown below. Figure 1 As shown, the conductive layer is F-doped SnO2 with a finger spacing of 100 μm. The scanning electron microscope image of the zinc sulfide / zinc oxide core-shell nanorods on the FTO substrate of the sensor is shown below. Figure 2 As shown, by Figure 2 It can be seen that the nanorods grow densely and uniformly. The XRD patterns of the zinc sulfide / zinc oxide core-shell nanorods and the FTO substrate are shown below. Figure 3 As shown, by Figure 3 It can be seen that the nanorods prepared in this embodiment are composed of ZnS and ZnO. The capacitive response of the zinc sulfide-zinc oxide sensor to a 20 ppm concentration of benzothiophene is shown in the following graphs after multiple tests. Figure 4 As shown, by Figure 4It can be seen that the capacitance response value of the sensor remained basically consistent after multiple tests in benzothiophene of the same concentration, indicating that the sensor has good reproducibility. The sensitivity test graph of the zinc sulfide-zinc oxide sensor for different concentrations of benzothiophene is shown below. Figure 5 As shown, by Figure 5 It can be seen that the sensor produces different capacitive responses in benzothiophene at different concentrations, indicating that the sensor has good sensitivity.

[0043] Example 2:

[0044] Step 1: The FTO substrate with the conductive layer laser-etched into an interdigitated shape is first placed in ethanol for ultrasonic cleaning for 10 minutes, then placed in deionized water for ultrasonic cleaning for 10 minutes, and then taken out and dried in an oven at 50°C.

[0045] Step 2: Prepare a mixed solution of 13 mmol / L sodium molybdate dihydrate and 30 mmol / L thiourea, and stir for 1 hour.

[0046] Step 3: Fix the cleaned FTO substrate onto the support and place it in a 50ml reactor with the conductive side facing down.

[0047] Step 4: Add 30 ml of the solution prepared in Step 2 to a 50 ml reaction vessel, place the reaction vessel in a homogeneous reactor, and heat at 200°C for 24 h. Allow it to cool naturally to room temperature, remove the FTO substrate with molybdenum disulfide growing at the interdigitated area, wash it with deionized water, and dry it in a 50°C oven.

[0048] Step 5: Connect the external wires at both ends of the FTO conductive terminals to the LCR tester, and set the LCR voltage to 1V and the frequency to 10kHz.

[0049] Step Six: Place the sensor in n-hexane to obtain a stable baseline value, and then place it in benzothiophene diesel fuel solutions of different concentrations. The sensor obtains different capacitive responses in benzothiophene diesel fuel solutions of different concentrations, and the concentration of benzothiophene in the diesel fuel is determined based on the sensor's capacitive response.

[0050] Scanning electron microscope image of molybdenum disulfide material on FTO substrate of sensor as shown in the figure. Figure 6 As shown, by Figure 6 It can be seen that a dense and uniform anemone-like MoS2 material was grown in the FTO conductive layer. The sensitivity test results of the molybdenum disulfide sensor for different concentrations of benzothiophene are shown in the figure below. Figure 7 As shown, by Figure 7 It can be seen that the sensor has different responses to different concentrations of benzothiophene, and has good sensitivity.

Claims

1. A sensor for detecting thiophene sulfides in diesel fuel, characterized in that... The sensor includes a substrate, on the surface of which an interdigitated conductive layer is etched. Molybdenum disulfide nanomaterials or ZnS-ZnO core-shell structured nanorods are hydrothermally grown at the interdigitation points. The material of the interdigitated conductive layer is fluorine-doped tin dioxide, and the interdigitation distance of the interdigitated conductive layer is 50~100µm.

2. The sensor for detecting thiophene sulfides in diesel fuel according to claim 1, characterized in that... The interdigitated conductive layer is formed by laser etching of the substrate.

3. The sensor for detecting thiophene sulfides in diesel fuel according to claim 1 or 2, characterized in that... The substrate is a conductive glass substrate.

4. A method for preparing a sensor for detecting thiophene sulfides in diesel fuel according to any one of claims 1-3, characterized in that... The method includes the following steps: Step 1: Laser etching of the conductive surface of the FTO substrate to obtain an interdigitated conductive layer; Step 2: Molybdenum disulfide nanomaterials or ZnS-ZnO nanorods are grown on the interdigitated conductive layer using a hydrothermal method.

5. The application of the sensor according to any one of claims 1-3 in testing the content of thiophene sulfides in diesel fuel.

6. The application of the sensor according to claim 5 in testing the content of thiophene sulfides in diesel fuel, characterized in that... The method for testing the thiophene sulfide content in diesel fuel is as follows: connect the sensor's external wires to the LCR, immerse the sensor in diesel fuel, and test the capacitance change of the sensor in diesel fuel samples with different benzothiophene concentrations.

7. The application of the sensor according to claim 6 in testing the content of thiophene sulfides in diesel fuel, characterized in that... After the sensor is connected to the LCR, it is first immersed in a hexane solution to obtain a baseline value; when testing the sensor capacitance, the LCR tester is set to a voltage of 1V and a frequency of 10kHz.

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