CN116190683A - Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell - Google Patents

Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell Download PDF

Info

Publication number
CN116190683A
CN116190683A CN202310208182.0A CN202310208182A CN116190683A CN 116190683 A CN116190683 A CN 116190683A CN 202310208182 A CN202310208182 A CN 202310208182A CN 116190683 A CN116190683 A CN 116190683A
Authority
CN
China
Prior art keywords
lignin
graphite felt
fuel cell
electrode
manganese cobaltate
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310208182.0A
Other languages
Chinese (zh)
Inventor
俎喜红
梁藤达
邱学青
谢子鑫
张文礼
秦延林
林绪亮
陈理恒
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Guangdong University of Technology
Original Assignee
Guangdong University of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Guangdong University of Technology filed Critical Guangdong University of Technology
Priority to CN202310208182.0A priority Critical patent/CN116190683A/en
Publication of CN116190683A publication Critical patent/CN116190683A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/88—Processes of manufacture
    • H01M4/8878—Treatment steps after deposition of the catalytic active composition or after shaping of the electrode being free-standing body
    • H01M4/8882—Heat treatment, e.g. drying, baking
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material
    • H01M4/9016—Oxides, hydroxides or oxygenated metallic salts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M8/00—Fuel cells; Manufacture thereof
    • H01M8/02—Details
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M2004/8678—Inert electrodes with catalytic activity, e.g. for fuel cells characterised by the polarity
    • H01M2004/8689—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Inert Electrodes (AREA)

Abstract

The invention discloses a graphite felt/manganese cobaltate nanowire electrode, a preparation method and a lignin-based fuel cell. The preparation method of the graphite felt/manganese cobaltate nanowire electrode comprises the following steps: mn (NO) 3 ) 2 ·6H 2 O、Co(NO 3 ) 2 ·6H 2 O, urea and ammonium fluoride are dissolved in water to obtain a hydrothermal reaction solution; and (3) placing the graphite felt into a hydrothermal reaction solution, performing hydrothermal reaction in a high-pressure reaction kettle, taking out a sample after the reaction is finished, washing and drying to obtain the product. The graphite felt/manganese cobaltate nanowire electrode is used for assembling the lignin-based fuel cell, so that the high power density of the lignin-based fuel cell and the high biomass to electric energy are realizedAnd (5) effect conversion. In addition, the invention synchronously prepares the low molecular weight lignin, and has important significance for high-value utilization of lignin, ecological environment protection and energy crisis alleviation.

Description

Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell
Technical Field
The invention belongs to the field of lignin high-value utilization, and particularly relates to a graphite felt/manganese cobaltate nanowire electrode, a preparation method and a lignin-based fuel cell.
Background
With the exhaustion of fossil energy, the search for renewable energy alternatives has become an urgent need. Lignin is used as a renewable energy source and is an aromatic polymer with the most abundant content except petroleum in nature. The paper industry produces a large amount of lignin as a byproduct every day, but most lignin is used as waste to burn to produce heat energy or burn to generate electricity. To further increase its utility value, reduce carbon dioxide emissions, researchers have adopted a number of strategies such as using lignin as a precursor to carbon-based materials, preparing lignin hydrogels, converting lignin into uv-protective absorbers, and the like. However, complex process conditions and high energy consumption limit their further large-scale application. Developing a simple and energy-efficient method for utilizing lignin remains a great challenge.
In order to respond to the national 'carbon peak, carbon neutralization' call, the lignin is used for replacing the traditional fossil fuel power generation, and is an effective way for realizing the high-valued utilization of lignin. Currently, a series of fuel cell technologies have been developed to convert biomass energy into electrical energy, such as solid compound fuel cells (SOFCs), microbial Fuel Cells (MFCs), biomass Flow Fuel Cells (BFFCs), etc., that degrade biomass to generate electricity in a high temperature, redox pair-mediated or microbial catalytic manner. Solid Oxide Fuel Cells (SOFC) are unsuitable because of the huge energy consumption caused by high temperatures And (5) large-scale popularization. A Microbial Fuel Cell (MFC) constructed by microbial degradation lignin power generation has lower power density (< 0.1 mW/cm) due to poor degradation capability of microorganisms 2 ). In contrast, the biomass flow fuel cell has been widely focused on the advantages of high power density, low operating temperature, wide applicability, and the like.
In previous studies, lignin-fueled biomass flow fuel cells often require redox active materials as electron carriers for the reason that lignin-based fuel cells have high performance, PMO has now been developed Ox /PMO Re 、Fe 3+ /Fe 2+ 、[Fe(CN)6] 3- /[Fe(CN)6] 4- 、Cu 2+ /Cu + 、TiO 2+ /Ti 3+ And an iso-redox couple. However, the addition of redox active species makes the electron transport pathway relatively complex, and the alternative redox couple is limited, and the introduced redox active species are difficult to separate from degraded lignin after reaction, so that the degraded solid residues are difficult to reuse, and direct discharge is also environmental-friendly. In addition, the power density of the presently reported lignin-fueled fuel cells is still far lower than the performance of the fuel cells when glucose, starch, bagasse, etc. are fueled. In view of this problem, methods by heating, microbial degradation, and irradiation of light are disclosed in the prior art, however, these methods have disadvantages:
1) Increasing the rate of electron transport and electrochemical reactions by heating is a currently common method of improving the performance of biomass fuel cells. However, when used for lignin power generation, too high a temperature tends to polycondense lignin to be difficult to thoroughly degrade, and the electrolyte preheating process is slow and energy-consuming. 2) The adoption of microbial degradation lignin is also a method for realizing lignin power generation, but microorganisms are easy to be inactivated due to the influence of pH or temperature, the continuous and stable operation of a fuel cell is seriously influenced, and the power density of the microbial fuel cell is lower. 3) The existing illumination method is simple to operate, environment-friendly and low in cost, but lignin cannot be fully degraded due to low photocatalytic activity of a redox couple, so that the power density of a fuel cell is low. 4) The electrocatalytic technology is one of potential technologies hopeful to realize efficient power generation without adding redox active substances into the electrolyte. However, the electrode material currently commonly used in biomass fuel cells is graphite felt without any modification. The carbon material has the advantages of high stability, high conductivity and the like, but the graphite felt electrode has the defects of small specific surface area, poor wettability, low electrochemical catalytic activity and the like, so that a new modification treatment method is required to be researched.
Disclosure of Invention
In order to solve the defects and shortcomings in the prior art, the primary purpose of the invention is to provide a preparation method of a graphite felt/manganese cobaltate nanowire electrode. According to the invention, the manganese cobaltate nanowire grows on the surface of the graphite felt by a hydrothermal method, and the prepared graphite felt/manganese cobaltate nanowire electrode has excellent electrocatalytic activity and larger specific surface area, and can be used as an electrocatalyst to improve the electron transmission rate and the specific surface area of electrochemical reaction, so that lignin macromolecules are efficiently degraded and clean electric energy is generated.
It is another object of the present invention to provide a graphite felt/manganese cobaltate nanowire electrode manufactured by the above method.
It is still another object of the present invention to provide a lignin-based fuel cell constructed of the graphite felt/manganese cobaltate nanowire electrode described above. The lignin-based fuel cell has high power density and high open-circuit voltage, and the used materials are cheap and easy to obtain, safe and environment-friendly. According to the invention, lignin alkali solution is used as an anode electrolyte, vanadyl sulfate oxygen and nitric acid are used as a cathode electrolyte, oxygen is used as a cathode electrolyte regenerant, graphite felt/manganese cobaltate nanowire is used as an anode electrode material, and graphite felt is used as a cathode electrode material, so that the lignin-based fuel cell is assembled, the power density of the obtained cell is high, the open-circuit voltage is high, and the used materials are low in cost, easy to obtain, safe and environment-friendly.
The invention aims at realizing the following technical scheme:
a preparation method of a graphite felt/manganese cobaltate nanowire electrode comprises the following steps:
mn (NO) 3 ) 2 ·6H 2 O、Co(NO 3 ) 2 ·6H 2 O, urea and ammonium fluoride are dissolved in water to obtain a hydrothermal reaction solution; and placing the graphite felt into a hydrothermal reaction solution, performing hydrothermal reaction in a high-pressure reaction kettle at a certain temperature, taking out a sample after the reaction is finished, washing, and drying to obtain the graphite felt/manganese cobaltate nanowire electrode.
Preferably, the Mn (NO 3 ) 2 ·6H 2 O、Co(NO 3 ) 2 ·6H 2 The mol ratio of O, urea and ammonium fluoride is 0.5-3: 1 to 3: 7-12: 3 to 6, more preferably 1:2:10:4.
preferably, before the graphite felt is used, the surface-attached organic matters are removed by calcination, the calcination temperature is 200-600 ℃, the calcination time is 0.5-20 h, and the temperature rising rate is 1-50 ℃/min.
Preferably, the temperature of the hydrothermal reaction is 20-200 ℃, and the time of the hydrothermal reaction is 1-20 h.
More preferably, the temperature of the hydrothermal reaction is 50-150 ℃ and the time of the hydrothermal reaction is 5-7 h.
Preferably, the washed solution is at least one of ethanol, deionized water and acetone.
Use of a graphite felt/manganese cobaltate nanowire electrode in a lignin-based fuel cell comprising:
(1) The lignin is dissolved in an alkali solution to prepare an anolyte, pentavalent vanadium salt, an acid solution and a cathode regeneration oxidant are used as the catholyte, a graphite felt electrode is used as a cathode electrode, and the graphite felt/manganese cobaltate nanowire electrode prepared by the method is used as an anode electrode, and the lignin-based fuel cell is formed by assembly.
(2) And (3) pre-heating the electrolyte and the battery to a certain temperature, and respectively introducing the catholyte and the anolyte into a cathode chamber and an anode chamber of the battery by adopting a peristaltic pump so as to enable the lignin-based fuel cell to operate.
Preferably, the lignin in the step (1) is at least one of enzymatic hydrolysis lignin, prehydrolysis lignin, sodium lignin sulfonate and alkali lignin.
Preferably, the alkali in the step (1) is one or two of KOH, naOH and ammonia water.
Preferably, the hydroxide ion concentration of the base in the anolyte of step (1) is from 0.05 to 20.0mol/L, more preferably from 0.1 to 3mol/L, most preferably from 0.2 to 2mol/L.
Preferably, the content of lignin molecules in the anolyte of step (1) is 1-100 g/L, more preferably 5-70 g/L, most preferably 10-50 g/L.
Preferably, the pentavalent vanadium salt in the step (1) is at least one selected from the group consisting of vanadium pentoxide, vanadyl sulfate and vanadyl nitrate.
Preferably, the acid solution in step (1) is at least one selected from the group consisting of aqueous hydrochloric acid, aqueous sulfuric acid and aqueous nitric acid.
Preferably, the cathode regenerated oxidant in step (1) is at least one selected from nitric acid, oxygen, hydrogen peroxide or potassium permanganate.
Preferably, the concentration of the pentavalent vanadium salt in the catholyte in the step (1) is 0.05-5 mol/L.
Preferably, the concentration of acid in the catholyte in the step (1) is 0.05-8.0 mol/L.
Preferably, in the cathode regenerated oxidant in the step (1), the concentration of the nitric acid is 0.01-8 mol/L, and the flow rate of the oxygen is 1-100 mL/min.
Preferably, the heating temperature in the step (2) is 10-120 ℃, namely the operation temperature of the lignin-based fuel cell is 10-120 ℃.
Compared with the prior art, the invention has the following advantages:
1. the graphite felt/manganese cobaltate nanowire electrode prepared by adopting the cheap and environment-friendly transition metal has higher specific surface area and excellent electrocatalytic activity, and the preparation process is simple, and the optimal preparation process is that calcination treatment is not needed.
2. The graphite felt/manganese cobaltate nanowire electrode prepared by the invention is applied to lignin-based fuel cells and has higher power density compared with other types of designs.
3. The anode electrolyte used in the lignin-based fuel cell does not need to introduce an external oxidation-reduction pair to assist in electron transmission, simplifies the processes of electron transfer and separation and purification of degraded lignin, can be used for direct power generation without preheating the electrolyte, avoids polycondensation of lignin, simplifies the power generation process and reduces energy consumption.
4. The lignin-based fuel cell directly performs electrocatalytic oxidation on lignin on the electrode to generate electricity, does not need to introduce microorganisms, has low possibility of being influenced by other factors, and can continuously and stably operate. The application of the modified electrode can greatly improve the lignin oxidation rate and the electron transmission rate, thereby greatly improving the performance of the fuel cell.
5. The lignin-based fuel cell provided by the invention adopts the manganese cobaltate micro-nano modified carbon felt electrode, has the advantages of large specific surface area, high catalytic activity and the like, can induce deep degradation of a large number of lignin macromolecules, and improves various performances of the lignin-based fuel cell.
Drawings
FIG. 1 is a graph of current density versus voltage versus output power for lignin-based fuel cells constructed with graphite felt/manganese cobaltate nanowire electrodes at different hydrothermal times of example 1.
Fig. 2 is an SEM image of graphite felt/manganese cobaltate nanowire electrode prepared hydrothermally for 5 hours in example 1.
Fig. 3 is a graph of current density versus voltage versus output power for lignin-based fuel cells constructed with graphite felt/manganese cobaltate nanowire electrodes before and after calcination treatment in example 2.
Fig. 4 is an XRD pattern of manganese cobaltate nanowires before and after calcination treatment in example 2.
FIG. 5 is a graph of current density versus voltage versus output power for lignin-based fuel cells constructed with varying NaOH concentration anolyte of example 3.
FIG. 6 is a graph of current density versus voltage versus output power for lignin-based fuel cells constructed from different lignin-type anolyte solutions of example 4.
FIG. 7 is a graph of current density versus voltage versus output power for lignin-based fuel cells constructed with varying lignin concentration anolyte of example 5.
Fig. 8 is a sustained stable discharge pattern for a lignin-based fuel cell assembled using graphite felt/manganese cobaltate nanowire electrodes of example 6 for a long period of time.
Fig. 9 is a graph of current density versus voltage versus output power for a lignin-based fuel cell constructed with graphite felt electrodes of comparative example 1.
Fig. 10 is a graph of current density versus voltage versus output power for lignin-based fuel cells constructed with different copper content doped graphite felt/copper doped manganese cobaltate nanowire electrodes and graphite felt electrodes of comparative example 2.
Fig. 11 is a graph of current density versus voltage versus output power for a lignin-based fuel cell constructed with a graphite felt/iron-doped manganese cobaltate nanowire electrode and a graphite felt electrode of comparative example 3.
FIG. 12 is a graph of current density versus voltage versus output power for a lignin-based fuel cell constructed with a graphite felt/CoS electrode and a graphite felt electrode of comparative example 4.
Fig. 13 is a graph of current density versus voltage versus output power for a lignin-based fuel cell constructed with comparative example 10 graphite felt/manganese cobaltate electrode and graphite felt electrode.
FIG. 14 is an SEM image of a graphite felt/manganese cobaltate electrode prepared according to comparative example 10.
Detailed Description
The present invention will be described in further detail with reference to examples and drawings, but embodiments of the present invention are not limited thereto. The raw materials related to the invention can be directly purchased from the market, and the process parameters which are not specially noted can be carried out by referring to the conventional technology.
Alkali lignin, sodium lignin sulfonate, and enzymatic lignin used in the following examples and comparative examples were purchased from Shandong Lignoto Biotechnology Co., ltd. The graphite felt used in the following examples and comparative examples was purchased from taiwan carbon energy and calcined to remove surface organics prior to use at 420 c for 4 hours at a ramp rate of 5 c/min.
Example 1: influence of graphite felt/manganese cobaltate nanowire electrodes prepared at different hydrothermal times on fuel cells
1. Preparation of graphite felt/manganese cobaltate nanowire electrode: 5mmol Co (NO) 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol of urea is dissolved in 70ml of deionized water, 4 parts of mixed solution are prepared in sequence, and 5cm multiplied by 0.5cm graphite felt is added for soaking, and the mixture is placed in a high-pressure reaction kettle for hydrothermal reaction at 120 ℃ for 1h, 3h, 5h and 7h respectively. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 2g NaOH was weighed and dissolved in 50ml deionized water. And weighing 1g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
3. Preparation of a catholyte: 20g of vanadium pentoxide powder was weighed into a beaker containing 524ml of deionized water and stirred at room temperature. 76ml of concentrated sulfuric acid (98.3% by mass) was then slowly added to the solution. Then, 4ml of nitric acid (68% by mass) was added, the solution was continuously stirred until a clear solution was formed, which appeared bright yellow, and left to stand for 24 hours to obtain a catholyte of high-valence vanadium, and 100ml was measured as the catholyte.
4. Battery system construction and electrical performance testing: 4 groups of battery systems are constructed, graphite felt/manganese cobaltate nanowires with different hydrothermal times are respectively used as anode electrodes, and other structures are the same. The S-shaped flow channels in the anode graphite plates are filled with graphite felt/manganese cobaltate nanowires as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
Using scanning current methods for batteriesAs a result of testing the electrical properties, as shown in FIG. 1, the battery performance of the electrode of the graphite felt/manganese cobaltate nanowire grown in 7 hours by hydrothermal reaction was optimal, the maximum voltage was 1.53V, and the maximum current density was 642.7mA/cm as the hydrothermal time was increased 2 Maximum power density of 157.16mW/cm 2 Whereas the battery performance of the graphite felt/manganese cobaltate nanowire electrode grown hydrothermally for 5 hours is not much different from that of the electrode grown hydrothermally for 7 hours, the optimal hydrothermal time of 5 hours is illustrated from the viewpoint of energy saving.
In this example, SEM images of the graphite felt/manganese cobaltate nanowire electrode grown hydrothermally for 5 hours are shown in fig. 2, and the originally smooth graphite felt surface is uniformly coated with manganese cobaltate nanowires, and shows a needle-like radiation morphology, which indicates that the manganese cobaltate nanowires can be well grown on the graphite felt surface under the conditions.
Example 2: influence of graphite felt/manganese cobaltate nanowire electrode on fuel cell before and after calcination treatment
1. Preparation of graphite felt/manganese cobaltate nanowire electrode: 5mmol Co (NO) 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol of urea was dissolved in 70ml of deionized water, impregnated with a 5 cm. Times.0.5 cm graphite felt, and placed in a autoclave at 120℃for 5h under hydrothermal conditions. After the reaction, the sample was taken out, washed with deionized water for several times, and dried (dried sample was used as graphite felt/manganese cobaltate nanowire electrode before calcination treatment).
And (3) placing the dried sample in a muffle furnace, and calcining for 2 hours at 350 ℃ to obtain the calcined graphite felt/manganese cobaltate nanowire electrode, wherein the heating rate is 5 ℃/min.
2. Preparation of an anolyte: 2g NaOH was weighed and dissolved in 50ml deionized water. And weighing 1g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: and constructing a battery system of 2 groups, wherein the graphite felt/manganese cobaltate nanowires before and after the calcination treatment are respectively used as anode electrodes, and other structures are the same. The S-shaped flow channels in the anode graphite plates are filled with graphite felt/manganese cobaltate nanowires as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by the scanning current method, and as shown in FIG. 3, the uncalcined graphite felt/manganese cobaltate nanowire electrode had the best cell properties, a maximum voltage of 1.5V and a maximum current density of 646.61mA/cm 2 Maximum power density of 152.64mW/cm 2 It is demonstrated that the performance of the battery can be improved well with a small amount of hydroxide doping in the uncalcined graphite felt/manganese cobaltate nanowire electrode.
The XRD patterns of the manganese cobaltate nanowires before and after firing in this example are shown in FIG. 4.
Example 3: effect of anolyte prepared with different NaOH concentration on fuel cell
1. Preparation of graphite felt/manganese cobaltate nanowire electrode: 5mmol Co (NO) 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol of urea was dissolved in 70ml of deionized water, impregnated with a 5 cm. Times.0.5 cm graphite felt, and placed in a autoclave at 120℃for 5h under hydrothermal conditions. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 1g, 2g and 4g NaOH were weighed and dissolved in 50ml deionized water, respectively. And weighing 3 parts of 1g of enzymolysis lignin, respectively adding into NaOH solution, stirring for 10min, and filtering to obtain the anolyte of lignin alkali solutions with different NaOH concentrations. The NaOH concentrations were 0.5M, 1M and 2M, respectively.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: the S-shaped flow channels in the anode graphite plates are filled with graphite felt/manganese cobaltate nanowires as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by the scanning current method, and as shown in FIG. 5, the cells with 2M NaOH anolyte added had the best performance, the maximum voltage of 1.5V, and the maximum current density of 772.59mA/cm 2 Maximum power density of 179.46mW/cm 2 。
Example 4: effect of anolyte prepared from different lignin species on fuel cell
1. Preparation of graphite felt/manganese cobaltate nanowire electrode: 5mmol Co (NO) 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol of urea was dissolved in 70ml of deionized water, impregnated with a 5 cm. Times.0.5 cm graphite felt, and placed in a autoclave at 120℃for 5h under hydrothermal conditions. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: three portions of 4g NaOH were weighed and dissolved in 50ml deionized water, respectively. And then weighing 1g of enzymolysis lignin, 1g of alkali lignin and 1g of sodium lignin sulfonate, respectively adding into the NaOH solution, stirring for 10min, and filtering to obtain lignin alkali solution anolyte of different lignin types.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: the S-shaped flow channels in the anode graphite plates are filled with graphite felt/manganese cobaltate nanowires as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical performance of the cells was tested by scanning current method, and the results are shown in FIG. 6, in which the anode electrolyte added with alkali lignin has the best cell performance and the maximum power density of 192.04mW/cm 2 。
Example 5: effect of anolyte prepared with different lignin concentrations on fuel cell
1. Preparation of graphite felt/manganese cobaltate nanowire electrode: 5mmol Co (NO) 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol of urea was dissolved in 70ml of deionized water, impregnated with a 5 cm. Times.0.5 cm graphite felt, and placed in a autoclave at 120℃for 5h under hydrothermal conditions. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 2g NaOH was weighed and dissolved in 50ml deionized water. And weighing 1g and 2g of enzymolysis lignin, respectively adding the enzymolysis lignin and the solution, stirring for 10min, and filtering to obtain lignin alkali solution anolyte with different lignin concentrations.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: the S-shaped flow channels in the anode graphite plates are filled with graphite felt/manganese cobaltate nanowires as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by the scanning current method, and as shown in FIG. 7, the cell performance of the anolyte with 2g of enzymatically hydrolyzed lignin added was optimal, the maximum voltage was 1.6V, and the maximum current density was 792.74mA/cm 2 Maximum power density of 209.56mW/cm 2 。
Example 6: lignin-based fuel cell long-time sustained stable discharge investigation
1. Preparation of graphite felt/manganese cobaltate nanowire electrode: 5mmol Co (NO) 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol of urea was dissolved in 70ml of deionized water, impregnated with a 5 cm. Times.0.5 cm graphite felt, and placed in a autoclave at 120℃for 5h under hydrothermal conditions. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 40g NaOH was weighed out and dissolved in 500ml deionized water. Weighing 5g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain lignin alkali solution anolyte.
3. Preparation of a catholyte: 20g of vanadium pentoxide powder was weighed into a beaker containing 524ml of deionized water and stirred at room temperature. 76mL of concentrated sulfuric acid (98.3% by mass) was then slowly added to the solution. Then 4ml of nitric acid (68% by mass) was added and the solution was continuously stirred until a clear solution was formed, which appeared bright yellow, and left to stand for 24 hours to give a catholyte of high valence vanadium.
4. Battery system construction and electrical performance testing: the S-shaped flow channels in the anode graphite plates are filled with graphite felt/manganese cobaltate nanowires as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The battery can realize continuous and stable discharge for more than 9 hours under the voltage of 0.3V as shown in the result of testing by adopting a constant current discharge method in FIG. 8.
Comparative example 1: effect of Using graphite felt as anode electrode on lignin-based Fuel cells
1. Preparation of an anolyte: 2g NaOH was weighed and dissolved in 50ml deionized water. And weighing 1g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
2. The catholyte was prepared as in example 1.
3. Battery system construction and electrical performance testing: and filling graphite felt in an S-shaped runner in the graphite plate, then assembling the graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of the metal cover plate, the anode graphite plate containing the graphite felt, the polyethylene film, the Nafion211 film, the polytetrafluoroethylene film, the cathode graphite plate containing the graphite felt and the metal cover plate, and connecting the battery with the load through the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by the scanning current method, and the results are shown in FIG. 9, wherein the maximum voltage is 1.45V and the maximum current density is 397.44mA/cm 2 Maximum power density of 108.54mW/cm 2 The performance is not excellent in the graphite felt/manganese cobaltate nanowire electrode in the embodiment 1, so the high-efficiency degradation of lignin and coupling power generation can be realized by adopting the graphite felt/manganese cobaltate nanowire electrode.
Comparative example 2: effect of using different copper content doped graphite felt/copper doped manganese cobaltate nanowires as anode electrode on lignin-based fuel cells
1. Preparation of graphite felt/copper-doped manganese cobaltate nanowire electrodes doped with different copper contents: 5mmol Co (NO) 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol urea was dissolved in 70ml deionized water and 2 parts of this solution was prepared; 1.25mmol and 0.5mmol Cu (NO) were added respectively 3 ) 2 ·3H 2 O, adding graphite felt of 5cm multiplied by 0.5cm for soaking, and placing the mixture in a high-pressure reaction kettle for hydrothermal treatment for 5h. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 2g NaOH was weighed and dissolved in 50ml deionized water. And weighing 1g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: and constructing a 2-group battery system, wherein the two graphite felts/copper-doped manganese cobaltate nanowires with different copper contents are respectively used as anode electrodes, and other structures are the same. And filling graphite felt/copper-doped manganese cobaltate nanowires into the S-shaped flow channels in the anode graphite plates to serve as anode electrodes, and filling graphite felt into the S-shaped flow channels in the cathode graphite plates to serve as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/copper doped manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by the scanning current method, and the results are shown in FIG. 10, in which the constructed fuel cell had a maximum voltage of 1.4V and a maximum power density of 144.58mW/cm 2 . The voltage and the power density are lower than the application, which shows that the copper doping does not obviously improve the electrocatalytic performance of manganese cobaltate, so that the power density of a battery is not obviously improved, and the transition metal compound of any kind can be used for electrocatalytically depolymerizing lignin and accelerating the electron transmission rate, and only the transition metal compound with specific composition and structure has the effects of electrocatalytically depolymerizing lignin and accelerating the electron transmission rate.
Comparative example 3: influence of graphite felt/iron doped manganese cobaltate as anode electrode on lignin-based fuel cells
1. Preparation of graphite felt/iron doped manganese cobaltate nanowire electrode: 1.25mmol Fe (NO) 3 ) 3 ·9H 2 O、5mmol Co(NO 3 ) 2 ·6H 2 O、2.5mmol Mn(NO 3 ) 2 ·6H 2 O、10mmol NH 4 F. 25mmol of urea was dissolved in 70ml of deionized water and impregnated with a 5 cm. Times.0.5 cm graphite feltSoaking, and placing in a high-pressure reaction kettle to carry out hydrothermal treatment for 5 hours. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 2g NaOH was weighed and dissolved in 50ml deionized water. And weighing 1g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: and filling graphite felt/iron-doped manganese cobaltate nanowires into the S-shaped flow channels in the anode graphite plates to serve as anode electrodes, and filling graphite felt into the S-shaped flow channels in the cathode graphite plates to serve as cathode electrodes. And then assembling a graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of a metal cover plate, an anode graphite plate containing graphite felt/iron doped manganese cobaltate nanowire, a polyethylene film, a Nafion211 film, a polytetrafluoroethylene film, a cathode graphite plate containing graphite felt and a metal cover plate, and connecting the battery with the load by using the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by the scanning current method, and the results are shown in FIG. 11, in which the constructed fuel cell had a maximum voltage of 1.51V and a maximum power density of 135.22mW/cm 2 . The power density is lower than that of the application, which shows that the iron doping does not obviously improve the electrocatalytic performance of manganese cobaltate, so that the power density of a battery is not obviously improved, and the transition metal compound of any kind can be used for electrocatalytically depolymerizing lignin and accelerating the electron transmission rate, and only the transition metal compound with specific composition and structure has the effects of electrocatalytically depolymerizing lignin and accelerating the electron transmission rate.
Comparative example 4: effect of Using graphite felt/CoS as anode electrode on lignin-based Fuel cells
1. Graphite feltPreparation of CoS electrode: 2mmol Co (NO) 3 ) 2 ·6H 2 O, 10mmol of urea and 25mmol of sublimed sulfur are dissolved in a mixed solution containing 23.33ml of ethylene glycol and 46.67ml of DMF, stirred for 1h, then impregnated with a graphite felt of 5cm multiplied by 0.5cm, and placed in a high-pressure reaction kettle for hydrothermal reaction at 180 ℃ for 12h. And taking out the sample after the reaction is finished, washing the sample with ethanol for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 4g NaOH was weighed out and dissolved in 50ml deionized water. And weighing 2g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: the S-shaped flow channels in the anode graphite plates are filled with graphite felt/CoS to serve as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt to serve as cathode electrodes. And then assembling the graphite plate, the lead of the load (LED lamp), the fixed end plate and the like into a battery according to the sequence of the metal cover plate, the anode graphite plate containing graphite felt/CoS, the polyethylene film, the Nafion211 film, the polytetrafluoroethylene film, the cathode graphite plate containing graphite felt and the metal cover plate, and connecting the battery and the load by the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by the scanning current method, and the results are shown in FIG. 13, in which the constructed fuel cell had a maximum voltage of 1.38V and a maximum power density of 138.54mW/cm 2 . Both voltage and power density are lower than the present application.
Comparative example 5: cuCl 2 /TiOSO 4 Synergistically mediated lignin-based fuel cells (ref. Chemical Engineering Journal 452 (2023) 139266)
1. Preparation of an anolyte: dissolving 61.4g of copper chloride dihydrate and 30mL of concentrated hydrochloric acid in deionized water, then adding 6g of straw and 45g of titanyl sulfate, adding water to a mixed solution with a constant volume of 180mL, uniformly stirring, heating to 90 ℃, and carrying out heat preservation reaction for 3 hours to obtain the straw electrolyte with copper-titanium synergistic degradation.
2. Preparation of a catholyte: weighing 20g of vanadium pentoxide powder, adding into a beaker containing deionized water, stirring at room temperature, adding 100mL of concentrated sulfuric acid (with the mass fraction of 98.3%) into the solution, stirring for 12 hours to prepare 500mL of solution, adding 2 mL of nitric acid (with the mass fraction of 68%), continuing stirring until the solution is bright yellow, and standing for 24 hours to obtain the high-valence vanadium catholyte.
3. Battery system construction and electrical performance testing: and (3) independently adding the copper-titanium synergistic degradation straw electrolyte prepared in the step (1) into an 80 ℃ anode electrolyte tank, and storing the catholyte prepared in the step (2) into the 80 ℃ cathode electrolyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Meanwhile, high-purity oxygen is introduced into the catholyte tank at a flow rate of 40mL/min, and the tetravalent vanadium is reduced by the oxygen, so that the regeneration of the catholyte is realized. Oxygen was introduced into the catholyte tank and the cell was operated at 80 ℃.
The electrical performance of the cell was tested by a scanning current method, and a fuel cell was constructed having a maximum voltage of 0.56V and a maximum current density of 830.2mA/cm 2 The maximum power density is 131mW/cm 2 . Either voltage or power density is much lower than the present application.
Comparative example 6: fe (Fe) 3+ /TiO 2 Different light sources of the composite system catalyze and degrade lignin to generate electricity (refer to patent CN 114551953A)
1. Preparation of an anolyte: 6.75g of ferric trichloride hexahydrate, 2.0g of nano titanium dioxide (60 nm) and 4.2mL of concentrated hydrochloric acid (12 mo 1/L) were dissolved in deionized water, and then 1g of sodium lignin sulfonate was added to prepare 25mL of FeCl consisting of 1mo1/L 3 +80g/L nano titanium dioxide+40 g/L sodium lignin sulfonate (H) + Concentration is 2 mol/L), and the mixture is transferred into a photoreactor and placed under sunlight (about 30 ℃) for reaction for 4 hours to prepare the sunlightAnd (3) a degraded anolyte. And preparing another two 25mL mixed solutions by adopting the same method, and respectively placing the mixed solutions under a xenon lamp and ultraviolet light (room temperature of 30 ℃) to carry out irradiation reaction for 4 hours to prepare the anode electrolyte for the induced degradation of the xenon lamp and the anode electrolyte for the induced degradation of the ultraviolet light.
2. Preparation of a catholyte: v under vigorous stirring 2 O 5 (10g) Added to water (22 mL) and 38mL of concentrated H was added in an ice bath 2 SO 4 (98%) drop wise addition to V 2 O 5 In the suspension, 1mL of nitric acid (42%) was added to make a catholyte (vanadium ion concentration 0.8mol/L, H) + The concentration is as follows: 2.2mo 1/L).
3. Battery system construction and electrical performance testing: and filling graphite felt in an S-shaped runner in the graphite plate, assembling the graphite plate, a lead of a load (LED lamp), a fixed end plate and the like into a battery according to the sequence of the metal cover plate, the anode graphite plate, the polyethylene film, the Nafion117 film, the polytetrafluoroethylene film, the cathode graphite plate and the metal cover plate, and connecting the battery with the lead. The anolyte in step 1 is added to the anolyte tank at room temperature, and the catholyte in step 2 is added to the catholyte tank. And then connecting the anode electrolyte tank with the anode inlet and outlet of the battery and the anode pump by using a guide pipe, and connecting the cathode tank with the cathode inlet and outlet of the battery and the cathode pump to complete the assembly of the power generation device. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 80 ℃.
After the power generation device is started, a scanning current method is adopted to test the electrical performance of the battery, and the result shows that the battery consisting of electrolyte subjected to solar irradiation treatment has the optimal performance, the maximum voltage is 0.54V, and the maximum current density is 532.7mA/cm 2 The maximum power density is 64.5mW/cm 2 . In contrast, the cell performance of the electrolyte composition irradiated with the UV lamp was inferior and the cell performance of the electrolyte composition irradiated with the dense lamp was the worst. Fe (Fe) 3+ /TiO 2 The lignin-based fuel cell constructed by the composite photocatalytic system is far lower than the application in voltage and power density, and lignin cannot be effectively degraded to generate electricity.
Comparative example 7: solar-induced hybrid lignin-based fuel cells (referenced from literature Nat. Commun.5 (2014) 1-8.)
1. Preparation of an anolyte: 10.95g of phosphomolybdic acid (H) was weighed out 3 (PMo 12 O 40 ) Dissolving in 20ml deionized water, and adding 0.3g of enzymolysis lignin into the solution. The mixed solution was maintained at 6 ℃ using a circulating water bath. The reaction solution was irradiated with simulated solar light using a SoLux solar simulator for 8 hours until the solution changed from yellow to deep blue, and the light source was 10cm from the surface of the solution.
2. Battery system construction and electrical performance testing: the anode adopts 5 layers of carbon cloth as an electrode, and the cathode electrode adopts 5 layers of carbon cloth with the loading capacity of 60mg/cm 2 Is separated by a Nafion 117 membrane. And (2) adding the anolyte prepared in the step (1) into an anolyte tank at 25 ℃, connecting the anolyte tank with an anode inlet and an anode outlet of a battery by using a pipe, and introducing high-purity oxygen into a cathode tank according to the flow rate of 40 mL/min.
The electrical performance of the cell was tested by a scanning current method, and a fuel cell was constructed having a maximum voltage of 0.36V and a maximum current density of 3.3mA/cm 2 Maximum power density of 0.55mW/cm 2 . Either voltage or power density is much lower than the present application.
Comparative example 8: methylene blue mediated lignin-based fuel cells
1. Preparation of an anolyte: 1.6g of methylene blue was weighed and dissolved in 50ml of deionized water, and a certain amount of concentrated sulfuric acid (98.3% by mass) was added so that the concentration thereof in the solution became 1mol/L. Then, 2g of sodium lignin sulfonate was added to the solution, and the mixed solution was reacted at 45℃for 5 hours.
2. Preparation of a catholyte: weigh 13g FeCl 3 Dissolved in 100ml of deionized water, and a certain amount of concentrated sulfuric acid (98.3% by mass) was added to make the concentration thereof in the solution 1mol/L.
3. Battery system construction and electrical performance testing: and (2) independently adding the methylene blue degradation lignin electrolyte prepared in the step (1) into a 90 ℃ anolyte tank, and storing the catholyte prepared in the step (2) in the catholyte tank at 90 ℃. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Meanwhile, high-purity oxygen is introduced into the catholyte tank at a flow rate of 40mL/min, and the oxygen is used for reducing iron ions, so that the regeneration of the catholyte is realized, and a proton exchange membrane is adopted as an ion exchange membrane.
The electrical performance of the cell was tested by a scanning current method, and the constructed fuel cell had a maximum voltage of 0.56V and a maximum power density of 11.41mW/cm 2 . Either voltage or power density is much lower than the present application.
Comparative example 9: multi-stage nickel-iron phosphide (NiFeP) nanosheets as anode catalysts for lignin-based fuel cells
1. Synthesis of NiFeP: first, nickel foam (2 cm. Times.5 cm) was sonicated in 6M HCl, ethanol and water, respectively, for 15 minutes. The cleaned foam nickel was then immersed in a bath containing 4mmol NH 4 F,10mmol urea, 4mmol Ni (NO 3 ) 2 ·6H 2 O and 4mmol Fe (NO) 3 ) 3 ·9H 2 O and 40ml H 2 O in solution. The mixture was transferred to a 50mL autoclave and hydrothermal at 120℃for 6h. After the hydrothermal treatment, the nickel foam was separated from the solution, ultrasonically washed at room temperature, and dried at 60 ℃. Nickel foam and 1.0g NaH 2 PO 2 ·H 2 O is arranged in two porcelain boats and put into a tube furnace, naH 2 PO 2 ·H 2 O is placed upstream of the gas flow. The furnace was heated to 300℃at a heating rate of 2℃per minute and kept under argon for 2 hours. After synthesis, the nickel foam was cut into 2cm by 2.5cm and used directly as anode.
2. Preparation of an anolyte: 2.8g KOH was weighed and dissolved in 50ml deionized water. And weighing 2.5g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
3. Preparation of a catholyte: 13.5g of ferric chloride hexahydrate was weighed and dissolved in 100ml of deionized water to obtain a catholyte of ferric chloride solution.
4. Battery systemAnd (3) construction and electrical property test: the cell consisted of two graphite bipolar plates, acting as anode and cathode electrodes, respectively. A Membrane Electrode Assembly (MEA) is sandwiched between two bipolar plates that divide the fuel cell into an anode chamber and a cathode chamber. The effective area is 5cm 2 Is composed of anode, nafion membrane and carbon cloth as cathode backing layer. The prepared anolyte and catholyte were continuously circulated through the cathode and anode chambers using peristaltic pumps at a flow rate of 20 ml/min. The cell was run at 90 ℃.
The electrical performance of the cell was tested by a scanning current method, and the constructed fuel cell had a maximum voltage of 1.49V and a maximum power density of 24mW/cm 2 . The power density is much lower than in the present application.
Comparative example 10: morphology of graphite felt/manganese cobaltate electrode prepared by different raw material ratios and power generation performance of assembled battery
1. Preparation of graphite felt/manganese cobaltate nanosphere electrode: 2mmol Co (NO) 3 ) 2 ·6H 2 O、1mmol Mn(NO 3 ) 2 ·6H 2 O、5mmol NH 4 F. 5mmol of urea was dissolved in 50ml of deionized water, impregnated with a 5 cm. Times.0.5 cm graphite felt, and placed in a autoclave at 140℃for 6h under hydrothermal conditions. And taking out the sample after the reaction is finished, washing the sample with deionized water for a plurality of times, and drying the sample.
2. Preparation of an anolyte: 2g NaOH was weighed and dissolved in 50ml deionized water. And weighing 1g of enzymolysis lignin, adding the enzymolysis lignin into the solution, stirring for 10min, and filtering to obtain the anolyte of the lignin alkali solution.
3. The catholyte was prepared as in example 1.
4. Battery system construction and electrical performance testing: the S-shaped flow channels in the anode graphite plates are filled with graphite felt/manganese cobaltate to serve as anode electrodes, and the S-shaped flow channels in the cathode graphite plates are filled with graphite felt to serve as cathode electrodes. And then assembling the graphite plate, the lead of the load (LED lamp), the fixed end plate and the like into a battery according to the sequence of the metal cover plate, the anode graphite plate containing graphite felt/manganese cobaltate, the polyethylene film, the Nafion211 film, the polytetrafluoroethylene film, the cathode graphite plate containing graphite felt and the metal cover plate, and connecting the battery and the load by the lead. The electrolyte in 2 is added into an anolyte tank, and the electrolyte in 3 is added into a catholyte tank. The anode electrolyte tank is connected with the anode inlet and outlet of the battery by a pipe, and the cathode tank is connected with the cathode inlet and outlet of the battery. Oxygen was introduced into the catholyte tank at a flow rate of 40mL/min and the cell was operated at 90 ℃.
The electrical properties of the cells were tested by a scanning current method, and as shown in FIG. 13, the lignin-based fuel cell using graphite felt/manganese cobaltate nanospheres as the anode had a voltage of 1.4V and a maximum power density of 134.45mW/cm 2 The battery performance is lower than when graphite felt/manganese cobaltate nanowires are used as anode electrode.
As shown in the SEM graph of the graphite felt/manganese cobaltate electrode in the comparative example in FIG. 14, when the concentration of the raw materials is low, the graphite felt/manganese cobaltate nanowire electrode cannot be prepared, but the graphite felt/manganese cobaltate nanosphere electrode is scattered, and the graphite felt/manganese cobaltate nanosphere electrode is not beneficial to the catalytic degradation of lignin for power generation.
Summary
Table 1 is a comprehensive comparison of the above examples and comparative examples in terms of operating temperature, open circuit voltage, maximum power density, etc.
Table 1 comprehensive comparisons of lignin-based fuel cell systems
Figure BDA0004111615250000201
Figure BDA0004111615250000211
Comparing all examples with comparative examples, the battery with the best power generation performance is a lignin-based fuel cell system constructed by adopting enzymatic hydrolysis lignin as a raw material in example 5, the open-circuit voltage reaches 1.6V, and the maximum power density reaches 209.56mW/cm 2 Much higher than the comparative example.
The above examples are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above examples, and any other changes, modifications, substitutions, combinations, and simplifications that do not depart from the spirit and principle of the present invention should be made in the equivalent manner, and the embodiments are included in the protection scope of the present invention.

Claims (10)

1. The preparation method of the graphite felt/manganese cobaltate nanowire electrode is characterized by comprising the following steps of:
mn (NO) 3 ) 2 ·6H 2 O、Co(NO 3 ) 2 ·6H 2 O, urea and ammonium fluoride are dissolved in water to obtain a hydrothermal reaction solution; and placing the graphite felt into a hydrothermal reaction solution, performing hydrothermal reaction in a high-pressure reaction kettle, taking out a sample after the reaction is finished, washing, and drying to obtain the graphite felt/manganese cobaltate nanowire electrode.
2. The method for preparing a graphite felt/manganese cobaltate nanowire electrode according to claim 1, wherein the Mn (NO 3 ) 2 ·6H 2 O、Co(NO 3 ) 2 ·6H 2 The mol ratio of O, urea and ammonium fluoride is 0.5-3: 1 to 3: 7-12: 3 to 6, more preferably 1:2:10:4.
3. the method for preparing a graphite felt/manganese cobaltate nanowire electrode according to claim 1, wherein the hydrothermal reaction is carried out at a temperature of 20-200 ℃ for 1-20 hours.
4. The method for preparing a graphite felt/manganese cobaltate nanowire electrode according to claim 3, wherein the hydrothermal reaction is carried out at a temperature of 50-150 ℃ for 5-7 h.
5. The method for preparing the graphite felt/manganese cobaltate nanowire electrode according to claim 1, wherein the graphite felt is calcined to remove organic matters attached to the surface before use, the calcining temperature is 200-600 ℃, the calcining time is 0.5-20 h, and the heating rate is 1-50 ℃/min.
6. A manganese cobaltate compound modified fuel cell electrode, characterized in that it is produced by the method of any one of claims 1-5.
7. A lignin-based fuel cell comprising an anolyte, a catholyte, a cathode electrode, and an anode electrode, characterized in that: the anode electrolyte is prepared by dissolving lignin in an alkali solution, the cathode electrolyte is prepared by pentavalent vanadium salt, an acid solution and a cathode regenerated oxidant, the cathode electrode is a graphite felt electrode, and the anode electrode is the manganese cobaltate compound modified fuel cell electrode of claim 6.
8. A lignin-based fuel cell according to claim 7 wherein the lignin is at least one of enzymatically hydrolyzed lignin, pre-hydrolyzed lignin, sodium lignin sulfonate, alkali lignin; the alkali is one or two of KOH, naOH and ammonia water.
9. A lignin-based fuel cell according to claim 7 wherein the hydroxide ion concentration of the base in the anolyte is between 0.05 and 5.0mol/L;
the content of lignin molecules in the anolyte is 1-100 g/L.
10. A lignin-based fuel cell according to claim 7 wherein the lignin-based fuel cell is operated at a temperature in the range of 10 to 120 ℃.
CN202310208182.0A 2023-03-07 2023-03-07 Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell Pending CN116190683A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310208182.0A CN116190683A (en) 2023-03-07 2023-03-07 Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310208182.0A CN116190683A (en) 2023-03-07 2023-03-07 Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell

Publications (1)

Publication Number Publication Date
CN116190683A true CN116190683A (en) 2023-05-30

Family

ID=86448643

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310208182.0A Pending CN116190683A (en) 2023-03-07 2023-03-07 Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell

Country Status (1)

Country Link
CN (1) CN116190683A (en)

Similar Documents

Publication Publication Date Title
Ifkovits et al. Decoupled electrochemical water-splitting systems: a review and perspective
Liu et al. Carbon nanotube/chitosan nanocomposite as a biocompatible biocathode material to enhance the electricity generation of a microbial fuel cell
CN105529473B (en) The electrode material that energy storage flow battery is modified with graphene oxide
CN110560117A (en) Bimetallic cobalt ruthenium-nitrogen phosphorus doped porous carbon electrocatalyst and preparation method and application thereof
Chen et al. Enhanced electrochemical performance in microbial fuel cell with carbon nanotube/NiCoAl-layered double hydroxide nanosheets as air-cathode
CN113437305A (en) 2D-Co @ NC composite material and preparation method and application thereof
CN111041508A (en) Cobaltosic oxide array/titanium mesh water decomposition oxygen generation electrode and preparation method thereof
Hossain et al. Evolution of vanadium redox flow battery in electrode
CN102694143A (en) Air/vanadium redox flow battery
Chen et al. A membrane electrode assembled photoelectrochemical cell with a solar-responsive cadmium sulfide-zinc sulfide-titanium dioxide/mesoporous silica photoanode
CN111206256B (en) Biochar electrochemical reforming hydrogen production method based on biomass multistage utilization
CN109728332B (en) Method for directly converting lignocellulose biomass into electric energy
CN113215616B (en) IrCoFe @ MXene composite catalyst and preparation method and application thereof
CN116190683A (en) Graphite felt/manganese cobaltate nanowire electrode, preparation method and lignin-based fuel cell
CN113036195B (en) Electrolyte of biomass flow fuel cell, preparation method of electrolyte and biomass flow fuel cell
CN114941155A (en) Preparation process of difunctional electrolytic cell
Yan et al. A hydrogen iron flow battery with high current density and long cyclability enabled through circular water management
CN114551953B (en) High-value utilization method of industrial lignin
CN110804739A (en) System and method for directly producing hydrogen by electrolyzing low-quality coal
CN110592607A (en) System for coupling organic matter direct fuel cell and electrolytic hydrogen production
CN115125578B (en) Preparation method of B-S co-doped nickel-cobalt-based electrolytic water oxygen evolution catalyst
CN212750932U (en) Cathode capable of accelerating chromium reduction and microbial fuel cell reactor
Ghangrekar et al. Enhancing microbial fuel cell performance by carbon nitride-based nanocomposites
Zhou et al. A hybrid fuel cell for water purification and simultaneously electricity generation
Gao et al. Development and Application of Green Hydrogen Energy Production Technology

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination