CN113571716A

CN113571716A - Anode for microbial fuel cell, preparation method of anode and microbial fuel cell

Info

Publication number: CN113571716A
Application number: CN202110784697.6A
Authority: CN
Inventors: 郭伟; 倪天军; 李晓甜; 崔亮; 李向荣; 张慧; 李雨菲
Original assignee: Xinxiang Medical University
Current assignee: Xinxiang Medical University
Priority date: 2021-07-12
Filing date: 2021-07-12
Publication date: 2021-10-29
Anticipated expiration: 2041-07-12
Also published as: CN113571716B

Abstract

The invention relates to an anode for a microbial fuel cell, a preparation method of the anode and the microbial fuel cell, and belongs to the technical field of microbial fuel cells. The anode for the microbial fuel cell comprises an electrode material and a modification material attached to the surface of the electrode material; the modification material comprises molybdenum disulfide nanosheets and carbon nanotubes dispersed among the molybdenum disulfide nanosheets. The modification material attached to the surface of the electrode material in the anode for the microbial fuel cell disperses the carbon nano tubes with good conductivity among the molybdenum disulfide nano sheets, so that the conductivity of the modification material can be obviously enhanced, the electroactive surface area of the anode can be increased, more sites and spaces are provided for the attachment and growth of microbes, a compact biological membrane can be formed on the surface of the anode, the starting time of the microbial fuel cell is shortened, and the maximum output voltage and the maximum output power density of the microbial fuel cell are increased.

Description

Anode for microbial fuel cell, preparation method of anode and microbial fuel cell

Technical Field

The invention relates to an anode for a microbial fuel cell, a preparation method thereof and the microbial fuel cell, and belongs to the field of microbial fuel cells.

Background

Microbial Fuel Cells (MFCs) are a promising clean energy technology, but low output power density is still a bottleneck that hinders practical applications. The composition and structure of the anode is believed to be a key factor affecting the output power of MFCs batteries. Conventional carbon-based materials such as Carbon Felt (CF), Carbon Paper (CP), etc. are widely used due to their advantages of good biocompatibility, conductivity, chemical stability, and low cost. However, the surface area and electrocatalytic activity of these materials are relatively limited, which is detrimental to microbial attachment growth and extracellular electron transfer. In order to improve the power output of the MFCs, designing and preparing a nano-material modified carbon electrode with excellent performance is an effective method.

The two-dimensional transition metal sulfide is a novel electrode material with great development prospect, and is taken as a typical transition metal sulfide, namely molybdenum disulfide (MoS)₂) Have gained increasing attention in the fields of energy storage/conversion, environmental remediation, and the like. In recent years, research has shown that MoS₂Has unique biocompatibility and biological safety, and can be applied to the biomedical fields of drug delivery, photothermal/photodynamic therapy, diagnostic imaging, biosensing and the like. The field of MFCs also relates to MoS₂The research report of the anode, for example, chinese invention patent application with application publication No. CN110729487A discloses a microbial fuel cell based on molybdenum disulfide composite material as the anode, the microbial fuel cell adopts molybdenum disulfide/carbon cloth or conductive polymer/molybdenum disulfide/carbon cloth as the anode, the molybdenum disulfide/carbon cloth anode is formed by placing carbon cloth in solution containing thiourea, sodium molybdate, P123 and deionized water for hydrothermal reaction, washing and drying, but the molybdenum disulfide itself has poor conductivity, and the conductive polymer is compounded on the molybdenum disulfide/carbon cloth anode to extract the molybdenum disulfide/carbon cloth anodeThe conductivity of the anode is high, but the specific surface area of the anode after the conductive polymer is compounded is still small, and sufficient space is difficult to provide for the attachment and growth of microorganisms.

Disclosure of Invention

The invention aims to provide an anode for a microbial fuel cell, which has a larger electroactive surface area and can provide more sites and spaces for the attachment and growth of microorganisms.

The invention also provides a preparation method of the anode for the microbial fuel cell and the microbial fuel cell.

In order to achieve the above object, the anode for a microbial fuel cell of the present invention employs the following technical solution:

an anode for a microbial fuel cell comprises an electrode material and a modification material attached to the surface of the electrode material; the modification material comprises molybdenum disulfide nanosheets and carbon nanotubes dispersed among the molybdenum disulfide nanosheets.

The modification material attached to the surface of the electrode material in the anode for the microbial fuel cell disperses the carbon nano tubes with good conductivity among the molybdenum disulfide nano sheets, so that the conductivity of the modification material can be obviously enhanced, the electroactive surface area of the anode can be increased, more sites and spaces are provided for the attachment and growth of microbes, a compact biological membrane can be formed on the surface of the anode, the starting time of the microbial fuel cell is shortened, and the maximum output voltage and the maximum output power density of the microbial fuel cell are increased.

The molybdenum disulfide nanosheets of the present invention are understood to mean lamellar molybdenum disulfide having an average platelet diameter of 1000nm or less. For example, the average diameter of the molybdenum disulfide nanosheet is 200-300 nm.

The carbon nano tube can increase the conductivity of the nano material, prevent the molybdenum sulfide nanosheets from agglomerating to increase the specific surface area, and fully play the synergistic effect of the composite material, and preferably is a multi-walled carbon nano tube.

In order to reduce the agglomeration of the molybdenum sulfide nanosheets and increase the uniformity of the distribution of the molybdenum sulfide and the carbon nanotubes, preferably, the modification material is obtained by uniformly dispersing a molybdenum source, a sulfur source and the carbon nanotubes in water and then carrying out a hydrothermal reaction. It will be appreciated that the molybdenum source and the sulfur source should be capable of forming molybdenum disulfide under hydrothermal reaction conditions. The molybdenum source is preferably ammonium molybdate. The sulfur source is preferably thiourea. Preferably, the mass ratio of the molybdenum source to the sulfur source to the carbon nanotubes is 0.1075-0.4207:0.2287-0.9162: 0.01. For example, the mass ratio of the molybdenum source, the sulfur source, and the carbon nanotubes is 0.4207:0.9162:0.1, 0.3506:0.7635:0.1, 0.2625:0.5735:0.1, 0.1758:0.3843:0.1, or 0.1075:0.2287: 0.1.

Preferably, the temperature of the hydrothermal reaction is 200-220 ℃. The time of the hydrothermal reaction is 8-12 h.

Preferably, the electrode material is a carbon-based electrode material. The carbon-based electrode material is carbon paper or carbon cloth.

Furthermore, the attaching amount of the modifying material on the electrode material is 1-2 mg/cm²For example, 1.5mg/cm²。

Further, the modifying material is adhered to the surface of the electrode material through a polymer adhesive. The polymeric binder is preferably a perfluorosulfonic acid type polymer. The perfluorosulfonic acid polymer is nafion. CAS number of nafion: 31175-20-9. The mass ratio of the modifying material to the polymer binder is 2-4:1, for example 3: 1.

The preparation method of the anode for the microbial fuel cell adopts the technical scheme that:

a preparation method of an anode for a microbial fuel cell comprises the following steps: spraying the dispersion liquid containing the modification material on the surface of the electrode material, and drying to obtain the electrode material; the modification material comprises molybdenum disulfide nanosheets and carbon nanotubes dispersed among the molybdenum disulfide nanosheets.

The preparation method of the anode for the microbial fuel cell has simple process, and the spraying treatment can increase the surface roughness of the electrode and provide more pore structures, thereby providing more sites and spaces for the attachment and growth of microbes.

Preferably, the electrode material is carbon paper or carbon cloth. Preferably, the coating is performed by spraying a coating liquid on both sides of the conductive material. The spraying is accomplished using a spray gun.

In order to improve the film forming property, better disperse the nano material and prevent the film from falling off, preferably, the modified material-containing dispersion liquid is formed by uniformly mixing the modified material, 5 wt% nafion solution and ethanol. The volume of ethanol used per 200mg of 5 wt% nafion solution was 8-12 mL. The mass ratio of the modifying material to the 5 wt% nafion solution is 30: 200.

The technical scheme adopted by the microbial fuel cell of the invention is as follows:

the anode of the microbial fuel cell is the anode for the microbial fuel cell.

The microbial fuel cell can be a single-chamber microbial fuel cell or a double-chamber microbial fuel cell, and the anode for the microbial fuel cell has shorter start-up time, larger stable output voltage and output power density.

Drawings

FIG. 1 is a graph of pure MoS prepared in comparative example 2₂Scanning electron microscope images of;

FIG. 2 is a scanning electron micrograph of the modified material prepared in example 4;

FIG. 3 is a scanning electron micrograph of an anode for a microbial fuel cell prepared in example 4;

FIG. 4 is a scanning electron micrograph of a carbon paper used in example 4;

FIG. 5 is an XRD pattern obtained from XRD testing conducted in Experimental example 2, in which (a) is pure MoS prepared in comparative example 2₂The XRD pattern of (a), the XRD pattern of the modified material prepared in example 2, and the XRD pattern of the multi-walled carbon nanotube used in example 2;

FIG. 6 shows MoS in Experimental example 3₂/CNTs、CNTs、MoS₂Modified glassy carbon electrode and bare glassy carbon electrode in 10mM K containing 0.1M KCl₃[Fe(CN)₆]Cyclic voltammogram in solution, sweep rate: 20mV s^-1；

FIG. 7 shows MoS in Experimental example 3₂/CNTs、CNTs、MoS₂Modified glassy carbon electrode and bare glassy carbon electrode in 10mM K containing 0.1M KCl₃[Fe(CN)₆]In the solution, the relationship graph of the reduction peak current and the sweeping speed of 1/2 power under different sweeping speeds;

FIG. 8 shows MoS in Experimental example 3₂/CNTs、CNTs、MoS₂Modified glassy carbon electrode and bare glassy carbon electrode in 10mM K containing 0.1M KCl₃[Fe(CN)₆]Nyquist plot in solution;

fig. 9 is a voltage output curve of each microbial fuel cell measured in experimental example 4;

fig. 10 is a power density curve of each microbial fuel cell measured in experimental example 4;

FIG. 11 is a SEM observation of the morphology of different anodic biofilms after approximately 2 months (53 days) of operation in MFCs: (a) bare carbon paper anode, (b) MoS₂Modified carbon paper anode, (c) CNTs modified carbon paper anode, (d) MoS₂/CNTs modified carbon paper anode.

Detailed Description

The technical solution of the present invention will be further described with reference to the following embodiments.

Examples of anodes for microbial fuel cells, examples of methods of making anodes for microbial fuel cells, examples of microbial fuel cells, and comparative examples carbon paper and Nafion 117 proton exchange membranes were purchased from shanghai hesen electrical ltd, ammonium molybdate and thiourea were purchased from carbofuran, and multi-walled carbon nanotubes were purchased from Nanjing Xiapong nanomaterial science and technology ltd, model XFM 31.

Example 1

The anode for the microbial fuel cell comprises carbon paper and modification materials attached to two surfaces of the carbon paper, wherein the modification materials comprise molybdenum disulfide nanosheets and multi-walled carbon nanotubes dispersed among the molybdenum disulfide nanosheets; the amount of the finishing material attached to the carbon paper was 1.5mg cm^-2(ii) a The decorative material is bonded on the carbon paper through nafion; the mass ratio of the modifying material to the nafion is 3: 1; the adopted modifying material is prepared by adopting a method comprising the following steps:

0.3506g of ammonium molybdate and 0.7635g of thiourea are added into 15mL of deionized water, dissolved by ultrasonic for 10 minutes, then 1g of multi-walled carbon nanotube aqueous dispersion (containing 0.1g of multi-walled carbon nanotubes) is added to continue to be dispersed by ultrasonic for 30 minutes, then the reaction system is put into a hydrothermal kettle to carry out hydrothermal reaction for 8 hours at 200 ℃, then a precipitate product is collected, the collected precipitate product is washed by the deionized water for three times, then is washed by absolute ethyl alcohol for three times, and finally is placed in the air to be dried, thus obtaining the compound.

The anode for a microbial fuel cell of this example was produced by the production method of example 4.

Example 2

The method for producing an anode for a microbial fuel cell of the present example is the method for producing an anode for a microbial fuel cell of example 1, and includes the steps of:

1) 0.3506g of ammonium molybdate and 0.7635g of thiourea are added into 15mL of deionized water, dissolved by ultrasonic for 10 minutes, then 1g of multi-walled carbon nanotube aqueous dispersion (containing 0.1g of multi-walled carbon nanotubes) is added to continue to be dispersed by ultrasonic for 30 minutes, then the reaction system is put into a hydrothermal kettle to carry out hydrothermal reaction for 8 hours at 200 ℃, then a precipitate product is collected, the collected precipitate product is washed by the deionized water for three times, then is washed by absolute ethyl alcohol for three times, and finally is placed in the air to be dried, so that a modification material is obtained;

2) mixing a 5 wt% nafion solution with absolute ethyl alcohol to obtain a mixed solution; the volume of the adopted anhydrous ethanol is 8mL for every 200mg of 5 wt% nafion solution;

then adding the modification material prepared in the step 1) into the mixed solution according to the mass ratio of the 5 wt% nafion solution to the modification material of 200:30 for ultrasonic dispersion to obtain dispersion liquid, spraying the dispersion liquid on the two sides of carbon paper with a certain size by using a spray gun, and drying in the air to obtain MoS₂and/CNTs modified carbon paper.

Example 3

The microbial fuel cell of the present embodiment is a dual-chamber microbial fuel cell, and the anode of the microbial fuel cell in embodiment 1 is used as the anode, the carbon paper is used as the cathode, and the Nafion 117 proton exchange membrane is used as the separation membrane; anaerobic sludge is taken as a mixed bacteria source, and a mixed solution is taken as a positiveAn extreme nutrient solution; at a molar ratio of 50mmol L^-1The potassium ferricyanide solution is used as a cathode solution. The mixed solution as anode nutrient solution is 50mmol L per liter^-1Adding 1g of sodium acetate, 12.5mL of vitamin solution and 12.5mL of mineral solution into the phosphate buffer solution (PBS buffer solution) and uniformly mixing to obtain the product; 50mmol L^-1The concentrations of the solutes and solutes in the phosphate buffer solution, the concentrations of the solutes and solutes in the mineral solution, and the concentrations of the solutes and solutes in the vitamin solution are shown in tables 1 to 3, respectively.

TABLE 150 mmol L^-1Solute and concentration of PBS buffer solution

Composition of	Concentration (g L)^-1)
		NaH₂PO₄·2H₂O	3.32
Na₂HPO₄·12H₂O	10.32
		KCl	0.13
NH₄Cl	0.31

TABLE 2 solutes and concentrations of mineral solutions

Composition of	Concentration (mg L)^-1)
		MgSO₄	3.0
MnSO₄	0.5
		NaCl	1.0
FeSO₄·7H₂O	0.1
		CaCl₂·2H₂O	0.1
CoCl₂·6H₂O	0.1
		ZnCl₂	0.13
CuSO₄·5H₂O	0.01
		AlK(SO₄)·12H₂O	0.01
H₃BO₃	0.01
		Na₂MoO₄	0.025
NiCl₂·6H₂O	0.024
		Na₂WO₄·2H₂O	0.025

TABLE 3 solutes and concentrations of vitamin solutions

The microbial fuel cell of this example is denoted as MoS₂CNTs/CP-MFCs, anode as MoS₂/CNTs/CP。

Comparative example 1

The microbial fuel cell of the present comparative example differs from the microbial fuel cell of example 3 only in that: the anode used in the microbial fuel cell of the comparative example was prepared by replacing the modification material in step 2) of example 2 with multi-walled carbon nanotubes of equal mass (not described in the same manner as in step 2) of example 2).

The microbial fuel cell of this comparative example was designated CNTs/CP-MFCs, and the anode was designated CNTs/CP.

Comparative example 2

The microbial fuel cell of the present comparative example differs from the microbial fuel cell of example 3 only in that: the microbial fuel cell of this comparative example used an anode prepared by omitting the addition of 0.1g of carbon nanotubes in step 1) of example 2 (not described and kept the same as example 2)). In this comparative example, the modified material obtained after omitting the step of adding carbon nanotubes was pure MoS₂。

The microbial fuel cell of this comparative example was recorded as MoS₂The anode is represented as MoS₂/CP。

Comparative example 3

The microbial fuel cell of the present comparative example differs from the microbial fuel cell of example 3 only in that: the anode used in the microbial fuel cell of this comparative example was carbon paper.

The microbial fuel cell of this comparative example was designated CP-MFCs and the anode was designated Bare CP.

Experimental example 1

1) The modified material prepared in example 2 and the pure MoS prepared in comparative example 2 were each separately treated₂Scanning electron microscopy testing was performed at 8.2mm × 100k to obtain 500nm scanning electron micrographs of the two materials, see fig. 1 and fig. 2, respectively.

As can be seen from FIG. 1, pure MoS prepared in comparative example 2₂Appear to be composed of petal-shaped MoS₂The nano-sheet assembled flower-shaped or spherical structure, the flower-shaped or spherical shape is due to MoS₂Stacking of the nanosheets.

As can be seen from FIG. 2, in the modified material prepared in example 2, the multi-walled Carbon Nanotubes (CNTs) in the form of wires were dispersed in different MoS₂Forming a nanocomposite between the nanosheets, with pure MoS₂In contrast, modification of MoS in materials₂The nano-sheets are distributed more uniformly and stacked less. It is speculated that the specific surface area of the modified material prepared in example 2 will be greater than the pure MoS in comparative example 2₂. The BET analysis showed pure MoS prepared in example 2₂The specific surface areas of the multi-walled Carbon Nanotubes (CNTs) used in example 2 and the modified material prepared in example 2 were 10.48m² g^-1、39.40m² g^-1And 59.23m² g^-1。

2) Scanning electron microscope tests were performed on the carbon paper used in example 2 and the anode for a microbial fuel cell prepared in example 2, respectively, and the results are shown in fig. 3 and 4.

As can be seen from fig. 3 and 4, the surface of the carbon fiber of the bare carbon paper is smooth, the carbon fiber of the carbon paper has a surface roughness that is significantly increased by the modification material attached to the surface of the carbon paper in the anode for a microbial fuel cell prepared in example 2, and the anode has a multi-stage pore structure, so that the specific surface area of the anode can be significantly increased, and further, more sites and spaces are provided for the attachment and growth of microorganisms.

Experimental example 2

For the modified material prepared in example 2, the pure MoS prepared in comparative example 2₂And the multi-walled carbon nanotubes used in example 2 were subjected to XRD tests, respectively, and the results are shown in fig. 5.

Analysis in conjunction with FIG. 5 reveals that the modified material and pure MoS₂Similar diffraction peaks at 14.1, 33.2, 35.9 and 58.1 deg. matching MoS, respectively₂The (002), (100), (102) and (110) crystal planes of (a). Simultaneously, with pure MoS₂In contrast, a new diffraction peak was observed in the modified material. According to the diffraction pattern of pure multi-wall Carbon Nanotubes (CNTs), they are the characteristic peaks of CNTs, in particular the peak centered at 25.7 DEG, which is assigned to the (002) crystal face of CNTs. In addition, no impurity signal was detected, indicating that the modified material produced was of high purity.

Experimental example 3

The modified material prepared in example 2 and the pure MoS prepared in comparative example 2 were used respectively₂Example 2 preparation of MoS Using multiwalled carbon nanotubes₂/CNTs modified glassy carbon electrode and MoS₂Modifying glassy carbon electrodes and CNTs modifying glassy carbon electrodes.

Specifically, MoS is prepared₂The method for modifying the glassy carbon electrode by the CNTs comprises the following steps: firstly polishing a glassy carbon electrode with the diameter of 3mm and ultrasonically cleaning the glassy carbon electrode in deionized water; mixing MoS₂the/CNTs composite nano material is prepared into 1mg mL^-1The water dispersion system is subjected to ultrasonic treatment for 20 to 30 minutes to ensure that the water dispersion system is uniformly dispersed; then 8 mul of the dispersion liquid is dripped on the surface of a glassy carbon electrode by using a micro-injector and is dried in the air for use.

MoS₂Or when the CNTs modified glassy carbon electrode is prepared, the MoS is used₂MoS in preparation method of/CNTs modified glassy carbon electrode₂Respectively correspondingly replacing/CNTs composite nano materials by equal partsPure MoS of mass₂Or CNTs.

1) Separately for the prepared MoS₂/CNTs modified glassy carbon electrode and MoS₂The electrochemical performance test of the modified glassy carbon electrode, the CNTs modified glassy carbon electrode and the bare glassy carbon electrode is carried out by adopting a cyclic voltammetry method, and the test conditions and the test method of the cyclic voltammetry are as follows: the test was performed using a Versa STAT3(Princeton applied research) electrochemical workstation. Using a conventional three-electrode battery system, MoS₂CNTs or MoS₂Or the CNTs modified glassy carbon electrode or the bare glassy carbon electrode is used as a working electrode, the saturated calomel electrode is used as a reference electrode, and the platinum wire is used as a counter electrode. The base solution is 10mM K containing 0.1M KCl supporting electrolyte₃[Fe(CN)₆]Solution, scan potential range: -0.3-0.8V, sweep rate: 20mVs^-1The measured cyclic voltammogram is shown in FIG. 6, the positions of the vertical lines are drawn in FIG. 6, and the MoS lines are arranged from top to bottom in sequence₂/CNTs modified glassy carbon electrode and MoS₂Modified glassy carbon electrodes, CNTs modified glassy carbon electrodes and bare glassy carbon electrodes. The four electrodes are respectively at 5, 10, 20, 40, 60, 80 and 100mV s^-1Measuring the magnitude of the reduction peak current of several cyclic voltammograms at different sweep rates (under the same other test conditions), and drawing a relation graph of the reduction peak current of different electrodes and the sweep rate of 1/2 th power, as shown in fig. 7. In FIG. 6, FIG. 7 and FIG. 8 below, MoS₂/CNTs、MoS₂CNTs, Bare in turn represent MoS₂/CNTs modified glassy carbon electrode and MoS₂Modified glassy carbon electrodes, CNTs modified glassy carbon electrodes and bare glassy carbon electrodes.

As can be seen from fig. 6: first, at 20mV s^-1CNTs modified glassy carbon electrode and MoS at sweeping speed₂The anodic peak current (ipa) and the cathodic peak current (ipc) on the/CNTs modified glassy carbon electrode are obviously enhanced, and the pure MoS₂The peak current of the modified glassy carbon electrode is similar to that of a bare glassy carbon electrode. The ipc values of the four electrodes were 79.2. mu.A (MoS)₂CNTs modified electrode), 71.6. mu.A (CNTs modified electrode), 63.3. mu.A (MoS)₂Modified electrode) and 63.9 mua (bare electrode), and the electrochemically active surface areas of the four electrodes can be calculated to be 8.74mm, respectively, by sweep rate experiments²(MoS₂/CNTs modified glassy carbon electrode) 8.15mm²(CNTs modified glassy carbon electrode) 6.31mm²(MoS₂Modified glassy carbon electrode) and 6.67mm²(bare glassy carbon electrode), MoS₂the/CNTs modified electrode has the largest electroactive surface area. Next, the peak potential differences (Δ Ep) between the anode and cathode peaks of the four electrodes were respectively 101mV (MoS)₂CNTs modified glassy carbon electrode), 107mV (CNTs modified glassy carbon electrode), 165mV (MoS)₂Modified glassy carbon electrode) and 128mV (bare glassy carbon electrode), a smaller Δ Ep indicates an increase in electron transfer rate.

2) Separately for the prepared MoS₂/CNTs modified glassy carbon electrode and MoS₂And (3) carrying out electrochemical alternating current impedance (EIS) experiments on the modified glassy carbon electrode, the CNTs modified glassy carbon electrode and the bare glassy carbon electrode.

The test conditions and the test method of the electrochemical alternating-current impedance experiment are as follows: the test was performed using a Versa STAT3(Princeton applied research) electrochemical workstation. Using a conventional three-electrode battery system, MoS₂CNTs or MoS₂Or the CNTs modified glassy carbon electrode or the bare glassy carbon electrode is used as a working electrode, the saturated calomel electrode is used as a reference electrode, and the platinum wire is used as a counter electrode. The base solution is 10mM K containing 0.1M KCl supporting electrolyte₃[Fe(CN)₆]The solution was measured at a frequency range of 100kHz to 0.01Hz under a sinusoidal disturbance of 5mV amplitude at an open circuit potential, and a Nyquist plot of the AC impedance was plotted according to the measurement results, as shown in FIG. 8. And analyzing and fitting the obtained data by using ZSimpWin 3.10 software to obtain interface electron transfer resistance (Rct) data.

MoS₂CNTs modified glassy carbon electrode, CNTs modified glassy carbon electrode and MoS₂The modified glassy carbon electrode and the bare glassy carbon electrode are 10mmol L^-1K₃[Fe(CN)₆]Solution (containing 0.1mol L)^-1KCl) showed that the interfacial electron transfer resistances (Rct) were 11.5 Ω · cm, respectively²(MoS₂/CNTs modified glassy carbon electrode), 15.6 omega cm²(CNTs modified glassy carbon electrode) 137.5. omega. cm²(MoS₂Modified glassy carbon electrode), 434.5 Ω · cm²(bare glassy carbon electrode). The results show that MoS₂the/CNTs modified material has the best electrocatalytic activity and can obviously reduce the interfaceAn electron transfer resistance.

Experimental example 4

The start-up time, the maximum stable output voltage, and the maximum output power density of the microbial fuel cells of example 3, comparative example 1, comparative example 2, and comparative example 3 were respectively tested.

The output voltage testing method comprises the following steps: connecting an external resistor of 1000 omega between the cathode and the anode of the MFCs, recording output voltage by adopting a digital recorder, setting data to be automatically acquired every 30 minutes, leading out the data, and drawing a voltage output curve of each microbial fuel cell according to the acquired data, wherein the voltage output curve is shown in figure 9. The cathode and anode solutions were replaced when the voltage was below 50 mV. When the maximum voltage reached in two consecutive periods is the same, the start is considered to be successful, and the maximum output voltage (namely the maximum stable output voltage) is recorded, wherein the start time is the time for reaching the maximum output voltage for the first time.

The maximum output power density is determined by a power density curve determined by a polarization experiment, and the polarization experiment is measured by a method of changing external resistance in a gradient manner. The specific test and calculation method comprises the following steps: in a voltage period, when the output voltage value reaches the maximum and is stable, the circuit is disconnected, the open-circuit voltage is recorded, then the resistance value (10000 omega-50 omega) of the external resistor is adjusted according to the principle that the external resistor decreases from large to small, and the voltage value under each resistance value is recorded. For each resistance value, it is not recorded until the MFCs obtains a stable output voltage, and then it is adjusted to the next resistance value. According to different conditions, 8-10 resistance values are selected for measurement, a group of corresponding voltage values can be obtained, a current value is calculated according to ohm's law I-V/R, and a current density I can be further calculated according to formulas 1 and 2 according to the electrode projection area (A)_AAnd power density P_A：

At a current density I_AAs abscissa, power density P_AAnd drawing a power density curve of the battery by using the ordinate, wherein the maximum value of the ordinate corresponding to the curve is the maximum output power density.

The power density curves of different anode microbial fuel cells obtained from the polarization experiments are shown in fig. 10.

The test results of the start-up time, the maximum stable output voltage, and the maximum output power density of the microbial fuel cell are shown in table 4.

Table 4 performance test results of four microbial fuel cells

As can be seen from Table 4, MoS₂The maximum output voltage of the/CNTs/CP-MFCs is the highest (670 mV). At the same time, CNTs/CP-MFCs (580 mV) and MoS₂The performance of the/CP-MFCs (530 mV) is better than that of the CP-MFCs (490 mV). The start-up times (times to first reach the maximum output voltage) of the four MFCs were 400h, 490h, 560h, and 740h, respectively. MoS compared to CP-MFCs₂the/CNTs nano composite material is beneficial to shortening MoS₂The start-up time of the/CNTs/CP-MFCs was about 46%. The maximum output power densities of the four batteries obtained by measuring the power density curves of the four batteries are 645, 477, 286 and 213mW m respectively^-2，MoS₂The maximum output power density of the/CNTs/CP-MFCs is 3.03 times that of the CP-MFCs. The results show that MoS₂the/CNTs modified material has good electrocatalytic activity, biocompatibility and large specific surface area, is beneficial to the attachment and growth of microorganisms so as to form a compact biological film, improves the interface electron transfer between the microorganisms and an electrode, and has obvious promotion effect on the electrogenesis performance of the MFCs.

Experimental example 5

For example 3 and comparative example respectivelyMorphology observation was performed on the anodes of examples 1 to 3 after 53 days of operation of the microbial fuel cells, and SEM images of the respective anodes are shown in FIG. 11, from which FIG. 11 shows that MoS₂The biological membrane on the surface of the/CNTs modified carbon paper anode is the most compact, because the MoS₂the/CNTs modified material has good biocompatibility, and the rough surface of the hierarchical pore structure has a large specific surface area, so that more space can be provided for the attachment and growth of microorganisms, and a more compact biological membrane can be formed.

Claims

1. An anode for a microbial fuel cell, characterized in that: comprises an electrode material and a modification material attached to the surface of the electrode material; the modification material comprises molybdenum disulfide nanosheets and carbon nanotubes dispersed among the molybdenum disulfide nanosheets.

2. The anode for a microbial fuel cell according to claim 1, characterized in that: the carbon nano-tube is a multi-wall carbon nano-tube.

3. The anode for a microbial fuel cell according to claim 1 or 2, characterized in that: the modification material is obtained by performing hydrothermal reaction after uniformly dispersing a molybdenum source, a sulfur source and a carbon nano tube in water.

4. The anode for a microbial fuel cell according to claim 3, characterized in that: the mass ratio of the molybdenum source to the sulfur source to the carbon nano tube is 0.1075-0.4207:0.2287-0.9162: 0.01; the molybdenum source is ammonium molybdate, and the sulfur source is thiourea.

5. The anode for a microbial fuel cell according to claim 3, characterized in that: the temperature of the hydrothermal reaction is 200-220 ℃, and the time is 8-12 h.

6. The anode for a microbial fuel cell according to claim 1, characterized in that: the electrode material is a carbon-based electrode material; the carbon-based electrode material is carbon paper or carbon cloth; the modifying material is as followsThe adhesion amount on the electrode material is 1-2 mg/cm²。

7. The anode for a microbial fuel cell according to claim 1, characterized in that: the modifying material is adhered to the surface of the electrode material through a polymer adhesive.

8. The anode for a microbial fuel cell according to claim 7, characterized in that: the polymer binder is a perfluorosulfonic acid type polymer.

9. A method of producing an anode for a microbial fuel cell according to any one of claims 1 to 7, characterized in that: the method comprises the following steps: spraying the dispersion liquid containing the modification material on the surface of the electrode material, and drying to obtain the electrode material; the modification material comprises molybdenum disulfide nanosheets and carbon nanotubes dispersed among the molybdenum disulfide nanosheets.

10. A microbial fuel cell, characterized by: the anode of the microbial fuel cell is the anode for a microbial fuel cell according to any one of claims 1 to 8.