Tungsten-based nanoparticle material as well as preparation method and application thereof
By modifying the carbon electrode with tungsten-based nanoparticle materials, the problems of small specific capacitance and poor hydrophilicity of the carbon electrode were solved, and the power generation performance and electron transfer efficiency of the microbial fuel cell were improved.
Patent Information
- Application Number
- CN202510814793.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2025-04-01
- Filing Date
- 2025-06-18
- Publication Date
- 2025-09-26
AI Technical Summary
Existing carbon electrodes in microbial fuel cells have low specific capacitance and poor hydrophilicity, which makes it difficult for microorganisms to attach and transfer extracellular electrons, affecting power generation performance.
Tungsten-based nanoparticles are used to modify the carbon electrode. Tungsten-based nanoparticles are prepared by hydrothermal reaction and mixed with Nafion solution to modify the carbon paper anode to improve the conductivity and hydrophilicity of the electrode.
The charge transfer resistance of the microbial fuel cell was improved, the output voltage and power were increased, the microbial attachment and electron transfer efficiency were enhanced, and the power generation performance was improved.
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Figure CN120698505A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of microbial fuel cells, and in particular to a tungsten-based nanoparticle material, a preparation method thereof, and an application thereof in preparing anodes of microbial fuel cells. Background Art
[0002] Microbial fuel cells (MFCs) are a new energy technology that uses electroactive microorganisms to directly convert the chemical energy in organic matter into electrical energy. Since MFCs can save a large amount of energy consumption caused by aeration in wastewater treatment processes, they are also considered to be an economical alternative to traditional sewage treatment technologies. Currently, feasible methods to improve output performance include modifying electrodes, cultivating dominant electricity-producing microorganisms, optimizing device structure, etc., among which electrode modification is a particularly critical and popular method. Currently, carbon electrodes widely used in MFCs generally have problems such as low specific capacitance and poor hydrophilicity, which makes it difficult for microorganisms to attach and transfer extracellular electrons. Therefore, it is necessary to design and develop high-performance and inexpensive modification materials for anode carbon electrodes to promote the application of MFCs.
[0003] Transition metal oxides are considered a promising candidate for modifying carbon electrodes due to their widespread availability, low cost, and excellent catalytic activity and pseudocapacitive properties. However, most transition metal oxides inherently have low electrical conductivity, which creates significant resistance to electron transport within the electrode material and increases the battery's ohmic internal resistance. To improve conductivity, transition metal oxides are often modified to enhance their electrocatalytic and power generation properties. Summary of the Invention
[0004] The present invention addresses the problems of low specific capacitance and poor hydrophilicity of carbon electrodes, which lead to insufficient microbial attachment and power generation. A tungsten-based nanoparticle material, a preparation method thereof, and its application in preparing anodes for microbial fuel cells are proposed.
[0005] To achieve the above purpose, the present invention adopts the following technical solutions:
[0006] A preparation method of tungsten-based nanoparticle material is characterized by: using Na2WO4·2H2O and C2H2O4·H2O as raw materials, carrying out a hydrothermal reaction in an acidic environment in the presence of thiourea, and drying after the reaction to obtain the tungsten-based nanoparticle material.
[0007] Further,
[0008] S1. Dissolve Na2WO4·2H2O and C2H2O4·H2O in water, add thiourea to the solution and stir evenly, and adjust the pH of the solution to 1-2 with hydrochloric acid to obtain a hydrothermal reaction solution;
[0009] S2. The hydrothermal reaction solution in step S1 is placed in a hydrothermal reactor, the reactor is transferred to a blast drying oven, and the hydrothermal reaction is maintained at 180 ° C for 24h;
[0010] S3. Filter and repeatedly rinse the black solid obtained by the reaction with deionized water and ethanol; then dry the solid to obtain a tungsten-based nanoparticle material.
[0011] In step S1, the mass ratio of Na2WO4·2H2O, C2H2O4·H2O, and water is 1:0.63-1.26:100. Na2WO4·2H2O and C2H2O4·H2O are dissolved, and thiourea is added to the solution and stirred evenly to make the concentration of thiourea in the system 0.8-1.6 g / 100 mL. The pH of the solution is adjusted to 1-2 with hydrochloric acid.
[0012] Furthermore, in step S1, the mass ratio of Na2WO4·2H2O to C2H2O4·H2O and water is 1:0.63:100, and Na2WO4·2H2O and C2H2O4·H2O are dissolved, and then thiourea is added to the solution and stirred evenly to make the concentration of thiourea in the system 0.8g / 100mL, and the pH of the solution is adjusted to 2 with hydrochloric acid to obtain tungsten-based nanoparticle material (WO3 nanoparticles).
[0013] Alternatively, in step S1, the mass ratio of Na2WO4·2H2O, C2H2O4·H2O, and water is 1:1.26:100, and Na2WO4·2H2O and C2H2O4·H2O are dissolved, and then thiourea is added to the solution and stirred evenly so that the concentration of thiourea in the system is 1.6 g / 100 mL, and the pH of the solution is adjusted to 1 with hydrochloric acid to obtain tungsten-based nanoparticle material (WS2 / WO3 nanoparticles).
[0014] A tungsten-based nanoparticle material prepared by the method, and a tungsten-based nanoparticle material with a nanoflower or nanorod structure prepared by the method.
[0015] An application of the tungsten-based nanoparticle material is the application of the tungsten-based nanoparticle material in preparing anode materials for microbial fuel cells.
[0016] A microbial fuel cell anode material contains the tungsten-based nanoparticle material.
[0017] The tungsten-based nanoparticle material is mixed with Nafion solution, deionized water, and anhydrous ethanol, and ultrasonically treated to obtain a dispersion. The dispersion is then added dropwise onto the treated carbon paper and dried to obtain a tungsten-based nanomaterial-modified microbial fuel cell anode material.
[0018] The usage ratio of the tungsten-based nanoparticle material to the Nafion solution, deionized water, and anhydrous ethanol is: 7.5 mg: 60 μL: 340 μL: 600 μL.
[0019] The beneficial effects of the present invention are:
[0020] 1. The present invention modifies the carbon-based anode by modifying tungsten-based nanomaterials to obtain a microbial fuel cell anode. The electrode has low charge transfer resistance, high output voltage and output power, and good microbial fuel cell power generation performance.
[0021] 2. The tungsten-based nano-modified carbon paper anode material prepared by the present invention has the advantages of low contact angle and good biocompatibility, and can be used as an effective anode material for microbial fuel cells to facilitate the attachment of power-generating microorganisms. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 Scanning electron microscope images of tungsten-based nanoparticles provided in embodiments of the present invention, wherein: (a) SEM image of Example 1; (b) SEM image of Example 2; (c, e) HRTEM images of Example 1, and (d, f) HRTEM images of Example 2.
[0023] Figure 2 X-ray photoelectron spectra of tungsten-based nanoparticles provided by embodiments of the present invention, wherein (a) is the O1s spectrum of Example 1, (b) is the W 4f spectrum of Example 1, and (c) is the S2p spectrum of Example 1; (d) is the O1s spectrum of Example 2, (e) is the W 4f spectrum, and (f) is the S2p spectrum.
[0024] Figure 3 Schematic diagrams of contact angles of tungsten-based nanoparticles provided in embodiments of the present invention, wherein (a) is a schematic diagram of the contact angle of a comparative example, (b) is a schematic diagram of the contact angle of Example 1, and (c) is a schematic diagram of the contact angle of Example 2.
[0025] Figure 4 The CV curves and EIS curves of the tungsten-based nano-anode provided in the comparative examples and examples in a mixed solution of 5 mM potassium ferrocyanide and 5 mM phosphate buffer solution are shown in Figure 1. (a) is the CV curve, and (b) is the EIS curve.
[0026] Figure 5 The CV curves and EIS curves of the microbial fuel cell with tungsten-based nanoparticles as the anode provided in the comparative example and the embodiment are shown in Figure 1. (a) is the CV curve and (b) is the EIS curve.
[0027] Figure 6The voltage and time curves during the acclimation period of the tungsten-based nano-anode microbial fuel cell provided in the comparative examples and embodiments of the present invention, wherein (a) is the electrode potential curve of the fuel cell cathode and anode, and (b) is the polarization curve and power density curve of the fuel cell anode.
[0028] Figure 7 The COD removal rate and sulfate removal rate of the tungsten-based nano-anode microbial fuel cell modified with tungsten-based nano-materials provided in the embodiment of the present invention. DETAILED DESCRIPTION
[0029] The present invention is further described below by specific examples, which will help those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way.
[0030] Example 1
[0031] A method for preparing anode materials for microbial fuel cells comprises the following steps:
[0032] (1) Dissolve 1 g of Na2WO4·2H2O and 0.63 g of C2H2O4·H2O in 100 mL of deionized water and stir to dissolve. Then, add 0.8 g of thiourea to the solution and stir evenly. Adjust the pH of the solution to 2 with hydrochloric acid to obtain a hydrothermal reaction solution.
[0033] (2) transferring the hydrothermal reaction solution in step (1) into a hydrothermal reactor and then into a forced air drying oven, and maintaining the temperature at 180° C. for 24 h;
[0034] (3) The reaction product in step (2) was filtered and the black solid obtained by the reaction was repeatedly washed with deionized water and ethanol; the solid was then transferred to a forced air drying oven at 60° C. and dried overnight to obtain WO3 nanoparticles.
[0035] (4) The carbon paper electrode was washed alternately with deionized water and ethanol and dried in a forced air drying oven. 7.5 mg of WO3 nanoparticles was mixed with 60 μL of 5 wt% Nafion solution, 340 μL of deionized water, and 600 μL of anhydrous ethanol, and ultrasonically treated to obtain a dispersion. The dispersion was added dropwise to the treated carbon paper, and the carbon paper was then dried to obtain a WO3-carbon paper electrode.
[0036] Example 2
[0037] A method for preparing anode materials for microbial fuel cells comprises the following steps:
[0038] (1) Dissolve 1 g of Na2WO4·2H2O and 1.26 g of C2H2O4·H2O in 100 mL of deionized water and stir to dissolve. Then, add 1.6 g of thiourea to the solution and stir evenly. Adjust the pH of the solution to 1 with hydrochloric acid to obtain a hydrothermal reaction solution.
[0039] (2) transferring the hydrothermal reaction solution in step (1) into a hydrothermal reactor and then into a forced air drying oven, and maintaining the temperature at 180° C. for 24 h;
[0040] (3) The reaction product in step (2) was filtered and the black solid obtained by the reaction was repeatedly washed with deionized water and ethanol; the solid was then transferred to a blast drying oven at 60°C and dried overnight to obtain tungsten-based nanoparticle material (WS2 / WO3 nanoparticles) (see Figure 1 and 2 ).
[0041] (4) The carbon paper electrode was washed alternately with deionized water and ethanol and dried in a forced air drying oven. 7.5 mg of the WS2 / WO3 nanoparticles obtained in step (3) above were mixed with 60 μL of a 5 wt% Nafion solution, 340 μL of deionized water, and 600 μL of anhydrous ethanol, and ultrasonically treated to obtain a dispersion. The dispersion was added dropwise to the treated carbon paper, and the carbon paper was then dried to obtain a WS2 / WO3-carbon paper electrode.
[0042] The tungsten-based nanomaterials prepared above were analyzed by X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) to analyze the crystal structure and high-resolution images. Figure 1 and 2 visible, Figure 1 The nano-WO3 prepared in (a) and (c) of Example 1 has a uniform rod-like structure, and the length of each nano-rod is about 300-500nm. In addition, Figure 1 (b) and (d) show that the WS2 / WO3 synthesized in Example 2 has a stacked nanosheet structure at the microscopic level rather than a typical nanoflower or nanorod structure; Figure 1 (e) and (f) show annotated HRTEM images of WO3 and WS2 / WO3, respectively. WO3 exhibits characteristic interplanar spacings of 0.225 nm and 0.321 nm, corresponding to the (004) and (210) planes of the monoclinic unit cell, respectively. WS2 / WO3, on the other hand, exhibits not only lattice fringes corresponding to the (100) plane of the hexagonal WS2 phase, but also a characteristic interplanar spacing of 0.238 nm for WO3 (004), indicating the successful creation of a WS2 / WO3 nanomaterial.
[0043] In addition, the contact angle test was used to compare the hydrophilicity of different modified electrodes. During the test, 10 μL of deionized water was always dropped on the electrode surface, and the contact angle value of the droplet in the steady state was recorded (see Figure 3 ) At the same time, the unmodified carbon paper substrate was used as a control. Figure 3 It can be seen that for the unmodified carbon paper substrate (as a comparative example) ( Figure 3 .a), its contact angle is about 131.2°, showing a weak hydrophobic property. In addition, it was observed that the carbon paper modified by WO3 ( Figure 3 .b) The contact angle of the surface stabilized at 121° in a short time, and its hydrophilicity was slightly enhanced compared with carbon paper. It is worth noting that the WS2 / WO3-carbon paper electrode ( Figure 3 .c) When it first contacts the droplet, the contact angle reaches 55.7°, indicating that the composite nanomaterial further improves the hydrophilicity of the electrode.
[0044] Building a microbial fuel cell
[0045] Using unmodified carbon paper as a comparative example, the microbial fuel cell anode materials prepared in the above examples were fabricated into microbial fuel cells, with a conductive carbon brush serving as the cathode. The anolyte composition consisted of sodium lactate (5 g / L), KH2PO4 (0.5 g / L), NH4Cl (1 g / L), CaCl2·2H2O (0.06 g / L), Na2SO4 (1 g / L), MgSO4·7H2O (2 g / L), and yeast extract (1 g / L). The anolyte pH was adjusted to approximately 7.2 using NaOH solution. The catholyte consisted of K3[Fe(CN)6] (16.46 g / L), KCl (0.13 g / L), Na2HPO4 (11.4 g / L), NaH2PO4 (2.77 g / L), and NH4Cl (0.31 g / L). After assembly, the bacterial solution was mixed with the cooled fresh anolyte obtained after high-temperature sterilization at 121°C (volume ratio of 1:4). At this time, cysteine was added to the anolyte and N2 was passed through for 40 minutes to remove the dissolved oxygen in the solution and maintain the anaerobic environment in the chamber. The exposed parts of the electrodes of the fuel cell were connected to a 1000Ω variable resistor box through wires, and the voltage reading across the resistor was monitored in real time by a data acquisition card (DAQ3005, USA). When the voltage value across the detected resistor was lower than 50mV, the anolyte was replaced, but 20mL of the original anolyte containing the bacterial solution was retained to ensure the rapid restart of the fuel cell (see Figure 4 and 5 ).
[0046] The bacterial solution was obtained by taking the flowback fluid from a shale gas well station in my country and adding it to a treated enrichment culture medium at room temperature. The culture medium was placed in a biochemical incubator at 30°C for one month, and the liquid was changed once a week during this period.
[0047] The enrichment was carried out by anaerobic culture by passing nitrogen gas through the enrichment liquid culture medium after high-pressure sterilization at 121° C. for 40 minutes.
[0048] The culture medium contains 1.0 g / L of NH4Cl, 0.5 g / L of K2HPO4·3H2O, 1.0 g / L of (NH4)2Fe(SO4)2·6H2O, 2.0 g / L of MgSO4·7H2O, 5.0 g / L of C6H5Na3O7·2H2O, 5.0 g / L of sodium lactate, 1.0 g / L of yeast extract, 1.0 mL / L of Wolfe's mineral solution, and 1.0 mL / L of Wolfe's vitamin solution per liter of water.
[0049] Power generation performance test
[0050] Electrochemical impedance spectroscopy (EIS) was performed using a Gamry Reference 2000 potentiostat (Gamry, USA) at a perturbation rate of 5 mV / s from 0.01 Hz to 10,000 Hz. Cyclic voltammetry (CV) was performed using a CHI 660E electrochemical workstation (Shanghai Chenhua Instruments, China) at a scan rate of 50 mvs⁻¹ from -0.8 V to 0.2 V. All measurements were performed in a three-electrode system with the anode as the working electrode, a Pt sheet (1 x 1 cm⁻¹) as the counter electrode, and a saturated calomel electrode (SCE) as the reference electrode. The electrolyte was the anolyte.
[0051] During the above measurement process, pure carbon paper electrode was used as a control.
[0052] It is not difficult to see from the area and shape of the cyclic voltammetry curves that the WO3-carbon paper and WS2 / WO3-carbon paper synthesized in Example 1 and Example 2, respectively, have larger scanning areas than the control pure carbon paper electrode. This indicates that WO3-carbon paper and WS2 / WO3-carbon paper have higher electrochemical active areas and pseudocapacitance, and theoretically can have better conductive properties, and WS2 / WO3-carbon paper has better performance than WO3-carbon paper.
[0053] Figure 4 (b) EIS test results of the three electrodes in a mixed solution of 5mM potassium ferrocyanide and 5mM phosphate buffer solution show that the charge transfer resistance value of the material and the size of the charge transfer are evaluated and explained in more depth through the EIS fitting process ( Figure 5b) The solution resistance values of the three electrodes were roughly the same, but the unmodified carbon paper electrode had the highest charge transfer resistance, approximately 425.2Ω. The charge transfer resistances of the WO3-CP and WS2 / WO3-carbon paper electrodes were 58.2 and 45.18Ω, respectively, significantly lower than the pure carbon paper electrode in the control example. Therefore, it can be concluded that the modified Examples 1 and 2 reduced the material resistance to a certain extent, resulting in higher electron transfer efficiency in the fuel cell anode.
[0054] Figure 5 As shown in (a), the cyclic voltammetry curves for the pure carbon paper bioanode, the WO3-carbon paper bioanode, and the WS2 / WO3-carbon paper bioanode show increasing areas, indicating a sequential increase in conductivity and capacitance. Fitting reveals that the pure carbon paper bioanode has the highest charge transfer resistance, at 179.3Ω, while the WO3-carbon paper and WS2 / WO3-carbon paper bioanodes have charge transfer resistances of 122.6Ω and 74.75Ω, respectively. Therefore, during MFC operation, the WS2 / WO3-carbon paper bioanode exhibits the highest charge transfer efficiency and superior catalytic performance.
[0055] Depend on Figure 6 It can be seen that in the stage of stable output voltage of the fuel cell, the MFC with WS2 / WO3-carbon paper as the anode has an output voltage of about 0.552V, and the MFC with WO3-carbon paper has an output voltage (0.528V), both of which are higher than the voltage of the MFC with pure carbon paper (0.344V) as the anode. The microbial fuel cell equipped with WS2 / WO3-CP electrode showed the highest power density output, about 2.32W / m 2 , followed by WO3-carbon paper (1.73W / m 2 ), which are higher than the comparative carbon paper (0.75W / m 2 ) is the maximum power density of the anode MFC.
[0056] The SO4 in the anolyte was measured by UV spectrophotometer. 2- The concentration change and removal rate of COD were tested (see Figure 7 ). The removal rate is expressed by formula 1
[0057] Removal rate % = (C0-C1) / C0*100% (1)
[0058] Where C0 is SO4 2- Or the initial concentration of COD in the influent, C1 is the voltage output recording after the end of SO4 2- Or the effluent concentration of COD. By adjusting the resistance of the resistance box, the power of the microbial fuel cell can be approximately obtained from Formula 2:
[0059] P=UI=U 2 / R(2)
[0060] Where U is the terminal voltage of the resistance box, and R is the resistance value of the resistance box.
[0061] Depend on Figure 7 It can be seen that in the degradation of sulfate, WO3-carbon paper and WS2 / WO3-carbon paper electrodes have excellent performance, and the microbial fuel cells in which they are located have a good effect on SO4 2- The removal rates were 88.79% and 91.07% respectively. The performance of pure carbon paper electrode was weaker, SO4 2- The removal rate is 76.00%.
Claims
1. A method for preparing a tungsten-based nanoparticle material, characterized by: Na2WO4·2H2O and C2H2O4·H2O are used as raw materials, a hydrothermal reaction is carried out in an acidic environment in the presence of thiourea, and tungsten-based nanoparticle materials are obtained by drying after the reaction.
2. The method for preparing tungsten-based nanoparticle material according to claim 1, wherein: S1. Dissolve Na2WO4·2H2O and C2H2O4·H2O in water, add thiourea to the solution and stir evenly, and adjust the pH of the solution to 1-2 with hydrochloric acid to obtain a hydrothermal reaction solution; S2. The hydrothermal reaction solution in step S1 is placed in a hydrothermal reactor, the reactor is transferred to a blast drying oven, and the hydrothermal reaction is maintained at 160-200 ° C for 20-30h; S3. Filter and repeatedly rinse the black solid obtained by the reaction with deionized water and ethanol; then dry the solid to obtain a tungsten-based nanoparticle material.
3. The method for preparing tungsten-based nanoparticle material according to claim 2, characterized in that: In step S1, the mass ratio of Na2WO4·2H2O, C2H2O4·H2O, and water is 1:0.63-1.26:
100. Na2WO4·2H2O and C2H2O4·H2O are dissolved, and thiourea is added to the solution and stirred evenly to make the concentration of thiourea in the system 0.8-1.6 g / 100 mL. The pH of the solution is adjusted to 1-2 with hydrochloric acid.
4. The method for preparing a tungsten-based nanoparticle material according to any one of claims 1 to 3, characterized in that: In step S1, the mass ratio of Na2WO4·2H2O, C2H2O4·H2O and water is 1:0.63:100, and Na2WO4·2H2O and C2H2O4·H2O are dissolved, and then thiourea is added to the solution and stirred evenly so that the concentration of thiourea in the system is 0.8 g / 100 mL, and the pH of the solution is adjusted to 2 with hydrochloric acid to obtain tungsten-based nanoparticle material (WO3 nanoparticles).
5. The method for preparing tungsten-based nanoparticle material according to any one of claims 1 to 3, characterized in that: In step S1, the mass ratio of Na2WO4·2H2O, C2H2O4·H2O and water is 1:1.26:100, and Na2WO4·2H2O and C2H2O4·H2O are dissolved, and then thiourea is added to the solution and stirred evenly so that the concentration of thiourea in the system is 1.6 g / 100 mL, and the pH of the solution is adjusted to 1 with hydrochloric acid to obtain tungsten-based nanoparticle material (WS2 / WO3 nanoparticles).
6. A tungsten-based nanoparticle material prepared by the method of claim 1, characterized in that: The tungsten-based nanoparticle material with a nanoflower or nanorod structure is prepared according to the method of claim 1.
7. Use of the tungsten-based nanoparticle material according to claim 6, characterized in that: The tungsten-based nanoparticle material is used to prepare anode materials for microbial fuel cells.
8. A microbial fuel cell anode material, characterized by: Containing the tungsten-based nanoparticle material according to claim 4.
9. The microbial fuel cell anode material according to claim 8, characterized in that: The tungsten-based nanoparticle material is mixed with Nafion solution, deionized water, and anhydrous ethanol, and ultrasonically treated to obtain a dispersion. The dispersion is then added dropwise onto the treated carbon paper and dried to obtain a tungsten-based nanomaterial-modified microbial fuel cell anode material.
10. The microbial fuel cell anode material according to claim 9, characterized in that: The usage ratio of the tungsten-based nanoparticle material to the Nafion solution, deionized water, and anhydrous ethanol is: 7.5 mg: 60 μL: 340 μL: 600 μL.