Preparation method of iron-doped CoNiFe-LDH / NF nanowire electrode and method for co-producing aviation fuel components by lignin-based fuel cell

Abstract

The invention discloses a method for preparing an iron-doped CoNiFe-LDH / NF nanowire electrode and co-producing aviation fuel components by a lignin-based fuel cell, belonging to the field of high-value utilization of lignin. The preparation method of the CoNiFe-LDH / NF nanowire electrode of the invention comprises the following steps: dissolving a Co source, a Ni source, an Fe source, urea and ammonium fluoride in water to obtain a hydrothermal reaction solution; placing nickel foam in the hydrothermal reaction solution and carrying out a hydrothermal reaction to obtain the CoNiFe-LDH / NF nanowire electrode. The lignin-based fuel cell prepared with this electrode has better lignin degradation activity and can induce the efficient directional depolymerization of lignin macromolecules into aviation fuel precursors, thereby improving the performance of the lignin-based fuel cell and the selectivity of products; the co-produced aviation fuel precursors can be prepared into aviation fuel components through hydrodeoxygenation.

Description

Technical Field

[0001] The present invention relates to the field of high-value utilization of lignin, and particularly to a method for preparing an iron-doped CoNiFe-LDH / NF nanowire electrode and co-producing aviation fuel components by a lignin-based fuel cell. Background Art

[0002] In recent years, the trend of reducing the use of fossil fuels has become increasingly obvious globally, and the development and utilization of clean energy have gradually attracted attention. As the most abundant biomass form on earth, lignocellulose is considered one of the most promising power generation raw materials. Fuel cells can directly convert the energy of lignocellulose into electrical energy without being limited by the Carnot cycle efficiency. However, although a series of lignocellulose fuel cells have been developed in the prior art, various problems still hinder their large-scale application. For example, solid compound fuel cells (SOFCs), microbial fuel cells (MFCs), biomass flow fuel cells (BFFCs), etc., degrade biomass for power generation by means of high temperature, redox couple mediation, or microbial catalysis. Solid oxide fuel cells (SOFCs) are not suitable for large-scale promotion due to the huge energy consumption caused by high temperature. Microbial fuel cells (MFCs) constructed by using microorganisms to degrade lignin for power generation have a low power density of the fuel cell (<0.1 mW / cm 2 ) because of the poor degradation ability of microorganisms. In contrast, biomass flow fuel cells have received extensive attention due to their high power density, low operating temperature, wide applicability, etc., but there is still room for further improvement in aspects such as lignin degradation activity.

[0003] Currently, electrocatalytic technologies have been widely applied in various research fields to accelerate charge transfer at the electrode / electrolyte interface, such as hydrogen fuel cells, carbon dioxide conversion, and water electrolysis. Therefore, using electrocatalysts is an effective method to solve the slow reaction kinetics and charge transfer between the electrode and the electrolyte. However, in the field of biomass flow fuel cells using lignin as fuel, the existing electrocatalysts have low activity for catalyzing lignin degradation, slow electron transfer rate, and complex products after power generation, which are difficult to further utilize and still need to be further improved. Therefore, there is an urgent need to develop an electrocatalyst with high activity, high selectivity, and high electron transfer rate, and to depolymerize lignin in a targeted manner to form valuable products while improving the performance of the fuel cell.

[0004] Converting biomass into aviation fuel components can effectively maintain the carbon balance, improve the atmospheric environment, achieve energy conservation, emission reduction, and adjust the energy structure. Biomass aviation fuel is chemically the same as traditional fossil fuels and can be mixed with existing aviation fuels without modifying the aircraft. Aviation fuel is mainly composed of various chain hydrocarbons, cycloalkanes, and aromatic compounds with C8 - C16, and its specific composition varies depending on the manufacturer and raw materials. Currently, most of the depolymerization of lignin is achieved through pyrolysis, but this method does not collect the energy from the bond breakage in lignin, resulting in a waste of resources. Therefore, there is an urgent need to develop an efficient method for converting biomass into aviation fuel. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing an iron-doped CoNiFe-LDH / NF nanowire electrode and co-producing aviation fuel components from a lignin-based fuel cell to solve the above problems in the background technology.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention: Provide a method for preparing a CoNiFe-LDH / NF nanowire electrode, including the following steps:

[0008] Dissolve a Co source, a Ni source, an Fe source, urea, and ammonium fluoride in water to obtain a hydrothermal reaction solution; place nickel foam in the hydrothermal reaction solution and conduct a hydrothermal reaction to obtain the CoNiFe-LDH / NF nanowire electrode.

[0009] Preferably, the Co source is Co(NO3)2; the Ni source is NiCl2; the Fe source is FeCl3; the molar ratio of Co(NO3)2, NiCl2, FeCl3, urea, and ammonium fluoride is (1 - 6):(1 - 6):(0.2 - 2):(4 - 20):(4 - 20).

[0010] More preferably, the molar ratio of Co(NO3)2, NiCl2, FeCl3, urea, and ammonium fluoride is 4:2:1:10:10.

[0011] Preferably, the temperature of the hydrothermal reaction is 20 - 200 °C, and the time is 1 - 20 h.

[0012] More preferably, the temperature of the hydrothermal reaction is 50 - 150 °C, and the time is 5 - 7 h.

[0013] Another technical solution of the present invention: Provide a CoNiFe-LDH / NF nanowire electrode obtained according to the above preparation method.

[0014] The third technical solution of the present invention: Provide an application of the above CoNiFe-LDH / NF nanowire electrode in the field of lignin-based fuel cells.

[0015] The fourth technical solution of the present invention: Provide a lignin-based fuel cell, which includes an anolyte, a catholyte, a cathode electrode, and an anode electrode; the anolyte is prepared by dissolving lignin in an alkali solution; the catholyte is prepared by dissolving a pentavalent vanadium salt and a cathode regenerative oxidant in an acid solution; the cathode electrode is a graphite felt electrode; the anode electrode is the above CoNiFe-LDH / NF nanowire electrode.

[0016] Preferably, the lignin is one or more of enzymatic lignin, prehydrolyzed lignin, sodium lignosulfonate, and alkali lignin; the pentavalent vanadium salt is vanadium pentoxide, vanadyl sulfate, or vanadyl nitrate; the cathode regenerative oxidant is one or more of nitric acid, oxygen, hydrogen peroxide, and potassium permanganate; the concentration of hydroxide ions of the alkali in the anolyte is 0.05 - 5.0 mol / L, and the content of lignin molecules is 1 - 100 g / L; the concentration of the pentavalent vanadium salt in the catholyte is 0.05 - 5 mol / L; the operating temperature of the lignin-based fuel cell is 10 - 120 °C.

[0017] The present invention needs to preheat the lignin-based fuel cell to 10 - 120 °C before running.

[0018] Preferably, the type of alkali in the alkali solution is one or more of KOH, NaOH, and ammonia water.

[0019] Preferably, the type of acid in the acid solution is one or more of hydrochloric acid, sulfuric acid, and nitric acid; the concentration of the acid in the catholyte is 0.05 - 8 mol / L.

[0020] Preferably, a peristaltic pump is used to respectively introduce the catholyte and the anolyte into the cathode chamber and the anode chamber of the lignin-based fuel cell to operate the lignin-based fuel cell, and depolymerize lignin while generating electricity.

[0021] More preferably, the concentration of hydroxide ions of the alkali in the anolyte is 0.1 - 3 mol / L, and most preferably 1 - 2 mol / L.

[0022] More preferably, the content of lignin molecules in the anolyte is 5 - 70 g / L, and most preferably 20 - 50 g / L.

[0023] Preferably, when the cathode regenerative oxidant is nitric acid, the addition amount is 0.01 - 8 mol / L; when the cathode regenerative oxidant is oxygen, the inlet flow rate of oxygen is 1 - 100 mL / min.

[0024] Fifth technical solution of the present invention: Provide a co - utilization method for the anolyte in the above lignin - based fuel cell, including the following steps:

[0025] Orientedly depolymerize the lignin in the anolyte through the electrolysis reaction of the lignin - based fuel cell, and then co - produce aviation fuel components.

[0026] The oriented depolymerization is to depolymerize until the molar concentration of C8 - C16 components in the anolyte reaches 5 - 30%.

[0027] Preferably, the method for co - producing aviation fuel components includes the following steps: Extract the electrolytic solution obtained after oriented depolymerization with ethyl acetate, then heat and evaporate to remove ethyl acetate to obtain an aviation fuel precursor; Mix the aviation fuel precursor with a catalyst and a solvent, and perform hydrodeoxygenation treatment to obtain the aviation fuel components.

[0028] Preferably, the solvent is cyclohexane, n - octane or n - dodecane.

[0029] Preferably, the catalyst is one or more of Pt - based catalysts, Ni - based catalysts and Pd - based catalysts; The hydrogen pressure for the hydrodeoxygenation treatment is 2 - 5 MPa, the heating temperature is 80 - 400 °C, and the reaction time is 5 - 12 h.

[0030] More preferably, the hydrogen pressure for the hydrodeoxygenation treatment is 3 - 4 MPa, the heating temperature is 150 - 250 °C, and the reaction time is 6 - 8 h.

[0031] The beneficial technical effects of the present invention are as follows:

[0032] The present invention uses a CoNiFe - LDH / NF nanowire electrode prepared from inexpensive and environmentally friendly transition metals to construct a high - performance lignin - based fuel cell and simultaneously orientedly depolymerize lignin, which can co - produce an aviation fuel precursor (aromatic compounds of C8 - C16) while producing clean electric energy, and further produce aviation fuel components through hydrodeoxygenation, thus achieving the dual purposes of power generation and preparing aviation fuel components, and having good application value.

[0033] The present invention grows CoNiFe-LDH nanowires on the surface of nickel foam by a hydrothermal method to prepare a CoNiFe-LDH / NF nanowire electrode, which has the advantages of a large specific surface area, high catalytic activity, excellent electrocatalytic activity, and simple preparation process. As an electrocatalyst, it can improve the electron transfer rate and the specific surface area of the electrochemical reaction. The lignin-based fuel cell prepared with this electrode has better lignin degradation activity, can induce the efficient directional depolymerization of lignin macromolecules into aviation fuel precursors, thereby improving the performance of the lignin-based fuel cell and the selectivity of the products; the co-produced aviation fuel precursors can be prepared into aviation fuel components by hydrodeoxygenation. The lignin-based fuel cell prepared by the present invention has excellent battery power density and open circuit voltage, can achieve efficient conversion from biomass energy to electrical energy, and can co-produce aviation fuel components.

[0034] The anolyte used in the lignin-based fuel cell of the present invention does not need to introduce an external redox couple to assist electron transfer, simplifies the processes of electron transfer and separation and purification of lignin after degradation, and can be used for direct power generation without pre-degrading the electrolyte, avoiding the condensation of lignin, simplifying the power generation process, and reducing energy consumption.

[0035] The lignin-based fuel cell of the present invention generates electricity by directly electrocatalytically oxidizing lignin on the electrode, does not need to introduce external conditions such as microorganisms, is not easily interfered by other factors, and has high fuel cell operation stability. The application of the modified electrode can greatly improve the lignin oxidation rate and electron transfer rate, thereby greatly improving the performance of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0037] Figure 1 It is a current density-voltage-output power diagram of the lignin-based fuel cell prepared in Examples 1-2.

[0038] Figure 2 It is an XRD diagram of the CoNi-LDH / NF nanowire electrode in Example 1 and the CoNiFe-LDH / NF nanowire electrode in Example 2.

[0039] Figure 3 It is an SEM diagram of the CoNi-LDH / NF nanowire electrode in Example 1 at different magnification multiples.

[0040] Figure 4SEM images of the CoNiFe-LDH / NF nanowire electrode in Example 2 at different magnifications.

[0041] Figure 5 Current density-voltage-output power graph of the lignin-based fuel cell prepared in Example 3.

[0042] Figure 6 Current density-voltage-output power graph of the lignin-based fuel cell prepared in Example 4.

[0043] Figure 7 Long-time continuous power generation graph of the lignin-based fuel cell prepared in Example 5.

[0044] Figure 8 GC-MS graph of the extract in Effect Verification 1. Among them, a is the type of compound, and b is the mass spectrum of the corresponding compound.

[0045] Figure 9 Current density-voltage-output power graph of the lignin-based fuel cell prepared in Comparative Example 1.

[0046] Figure 10 Current density-voltage-output power graph of the lignin-based fuel cell prepared in Comparative Example 3. Detailed implementation manners

[0047] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention. It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention.

[0048] In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0049] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention.

[0050] Regarding the "comprising", "including", "having", "containing", etc. used in the present invention, they are all open-ended terms, that is, they mean including but not limited to.

[0051] In the present invention, "room temperature" is calculated as 10 - 30 °C unless otherwise specified.

[0052] The enzymatic lignin used in the following examples and comparative examples of the present invention was purchased from Shandong Lonli Biological Technology Co., Ltd. The nickel foam was purchased from LiGe Technology Co., Ltd. and was ultrasonically cleaned in anhydrous ethanol, acetone, HCl, and deionized water in sequence before use. The graphite felt was purchased from Carbon Energy, Taiwan, China. Before use, it was calcined to remove surface organic matter. The calcination temperature was 420 °C, the calcination time was 4 h, and the heating rate was 5 °C / min. The Pt / C catalyst was purchased from Shanghai Macklin Biochemical Co., Ltd.

[0053] The electrical properties (current density, voltage, output power) of the battery prepared by the present invention were tested by the scanning current method.

[0054] All raw materials used in the following examples and comparative examples of the present invention are commercially available products.

[0055] Example 1

[0056] A preparation method of a lignin-based fuel cell is as follows:

[0057] 1. Preparation of CoNi-LDH / NF nanowire electrode: Dissolve 2 mmol Co(NO3)2·6H2O, 1 mmol NiCl2·6H2O, 5 mmol NH4F, and 5 mmol urea in 50 mL of deionized water, add a 4 cm×1 cm×0.7 cm nickel foam for impregnation, and place it in a high-pressure reaction kettle for hydrothermal reaction at 140 °C for 6 h. After the reaction, take out the sample, wash it with deionized water, and dry it to obtain the CoNi-LDH / NF nanowire electrode.

[0058] 2. Preparation of anode electrolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water, then weigh 2 g of enzymatic lignin and add it to the solution. After stirring for 10 min, filter it to obtain the anode electrolyte.

[0059] 3. Preparation of cathode electrolyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir it at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution; then add 4 mL of nitric acid (mass fraction 68%), continuously stir the solution until a bright yellow clear solution is formed, and then let it stand for 24 h. Measure 100 mL as the cathode electrolyte.

[0060] 4. Preparation of lignin-based fuel cell: Cut the prepared CoNi-LDH / NF nanowire electrode into pieces with dimensions of 4 cm × 0.25 cm × 0.7 cm. Then, use the CoNi-LDH / NF nanowire electrode as the anode electrode in the S-shaped flow channel inside the anode graphite plate, and fill the graphite felt in the S-shaped flow channel inside the cathode graphite plate as the cathode electrode. Then, assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate through the graphite plate, load (LED lamp) wire, fixed end plate, etc., and connect the battery and the load with wires. Then, add the above-mentioned anode electrolyte into the anode electrolyte tank and the cathode electrolyte into the cathode electrolyte tank through a peristaltic pump. Connect the anode electrolyte tank to the anode inlet and outlet of the battery with a tube, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the cathode electrolyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0061] Example 2

[0062] A preparation method of a lignin-based fuel cell is as follows:

[0063] 1. Preparation of CoNiFe-LDH / NF nanowire electrode: Dissolve 2 mmol Co(NO3)2·6H2O, 1 mmol NiCl2·6H2O, 0.5 mmol FeCl3·6H2O, 5 mmol NH4F, and 5 mmol urea in 50 mL of deionized water, add a 4 cm × 1 cm × 0.7 cm nickel foam for impregnation, and place it in a high-pressure reaction kettle for hydrothermal reaction at 140 °C for 6 h. After the reaction, take out the sample, wash it with deionized water, and dry it to obtain the CoNiFe-LDH / NF nanowire electrode.

[0064] 2. Preparation of anode electrolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water. Then weigh 2 g of enzymatically hydrolyzed lignin and add it to the solution. Stir for 10 min and then filter to obtain the anode electrolyte.

[0065] 3. Preparation of cathode electrolyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution. Then add 4 mL of nitric acid (mass fraction 68%), continuously stir the solution until a bright yellow clear solution is formed, and then let it stand for 24 h. Measure 100 mL as the cathode electrolyte.

[0066] 4. Preparation of lignin-based fuel cell: The prepared CoNiFe-LDH / NF nanowire electrode was cut into 4 cm × 0.25 cm × 0.7 cm. Then, the CoNiFe-LDH / NF nanowire electrode was used as the anode electrode in the S-shaped flow channel of the anode graphite plate, and the graphite felt was filled in the S-shaped flow channel of the cathode graphite plate as the cathode electrode. Then, through the graphite plate, load (LED lamp) wire, fixed end plate, etc., the battery was assembled in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate, and the battery and the load were connected with wires. Then, the above-mentioned anode electrolyte was added to the anode electrolyte tank by a peristaltic pump, and the cathode electrolyte was added to the cathode electrolyte tank. The anode electrolyte tank was connected to the anode inlet and outlet of the battery with a tube, and the cathode tank was connected to the cathode inlet and outlet of the battery. Oxygen was introduced into the cathode electrolyte tank at a flow rate of 40 mL / min, and the battery was operated at 90 °C.

[0067] Figure 1 It is the current density-voltage-output power diagram of the lignin-based fuel cell prepared in Examples 1-2.

[0068] Figure 1 In it, CoNiFe-LDH represents Example 2, and CoNi-LDH represents Example 1.

[0069] As Figure 1 shown, the maximum voltage of the lignin-based fuel cell prepared in Example 1 is 1.60 V, the maximum current density is 1323.7 mA / cm 2 ², and the maximum power density is 227.93 mW / cm 2 ². The maximum voltage of the lignin-based fuel cell prepared in Example 2 is 1.65 V, the maximum current density is 1794.4 mA / cm 2 ², and the maximum power density is 282.49 mW / cm 2 ². The battery performance of Example 2 is significantly superior to that of Example 1, indicating that iron doping can effectively improve the electron transfer rate.

[0070] Figure 2 It is the XRD diagram of the CoNi-LDH / NF nanowire electrode in Example 1 and the CoNiFe-LDH / NF nanowire electrode in Example 2.

[0071] In the figure, CoNi-LDH represents Example 1, and CoNiFe-LDH represents Example 2.

[0072] As Figure 2As shown, the CoNi-LDH before iron doping exhibited a peak of cobalt hydroxide, while a new peak of nickel hydroxide appeared after iron doping, indicating that the doping of iron ions significantly changed the coordination structure of the catalyst.

[0073] Figure 3 SEM images of the CoNi-LDH / NF nanowire electrode in Example 1 at different magnifications.

[0074] Figure 4 SEM images of the CoNiFe-LDH / NF nanowire electrode in Example 2 at different magnifications.

[0075] As Figure 3-4 shown, the morphology of the original CoNi-LDH was partially granular and nanowire-like, while after iron doping, it presented a uniform nanowire-like shape, indicating that iron doping promoted the formation of nanowires and greatly increased the electrochemically active surface area.

[0076] Example 3 (only modifying the operating temperature in Step 4 to 25 °C)

[0077] A preparation method of a lignin-based fuel cell, the steps are as follows:

[0078] 1. Preparation of the CoNiFe-LDH / NF nanowire electrode: Dissolve 2 mmol of Co(NO3)2·6H2O, 1 mmol of NiCl2·6H2O, 0.5 mmol of FeCl3·6H2O, 5 mmol of NH4F, and 5 mmol of urea in 50 mL of deionized water, add a 4 cm × 1 cm × 0.7 cm nickel foam for impregnation, and place it in a high-pressure reactor for hydrothermal reaction at 140 °C for 6 h. After the reaction, take out the sample, wash it with deionized water, and dry it to obtain the CoNiFe-LDH / NF nanowire electrode.

[0079] 2. Preparation of the anolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water, then weigh 2 g of enzymatically hydrolyzed lignin and add it to the solution. Stir for 10 min and then filter to obtain the anolyte.

[0080] 3. Preparation of the catholyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution; then add 4 mL of nitric acid (mass fraction 68%), continuously stir the solution until a bright yellow clear solution is formed, and then let it stand for 24 h. Measure 100 mL as the catholyte.

[0081] 4. Preparation of lignin-based fuel cell: Cut the prepared CoNiFe-LDH / NF nanowire electrode into 4 cm×0.25 cm×0.7 cm, and then use the CoNiFe-LDH / NF nanowire electrode as the anode electrode in the S-shaped flow channel in the anode graphite plate, and fill the graphite felt in the S-shaped flow channel in the cathode graphite plate as the cathode electrode; then assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 film, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate through the graphite plate, load (LED lamp) wire, fixed end plate, etc., and connect the battery and the load with wires. Then add the above-mentioned anode electrolyte to the anode electrolyte tank and the cathode electrolyte to the cathode electrolyte tank through a peristaltic pump. Connect the anode electrolyte tank to the anode inlet and outlet of the battery with a pipe, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the cathode electrolyte tank at a flow rate of 40 mL / min, and the battery operates at 25°C.

[0082] Figure 5 It is the current density-voltage-output power diagram of the lignin-based fuel cell prepared in Example 3.

[0083] As Figure 5 shown, the maximum voltage of the lignin-based fuel cell prepared in Example 3 is 1.30 V, the maximum current density is 553.17 mA / cm 2 , and the maximum power density is 73.89 mW / cm 2 . The battery performance is lower than that of Example 2, but the room-temperature power generation process is more energy-efficient.

[0084] Example 4 (only replacing enzymatic lignin with alkali lignin)

[0085] A preparation method of a lignin-based fuel cell is as follows:

[0086] 1. Preparation of CoNiFe-LDH / NF nanowire electrode: Dissolve 2 mmol Co(NO3)2·6H2O, 1 mmol NiCl2·6H2O, 0.5 mmol FeCl3·6H2O, 5 mmol NH4F, and 5 mmol urea in 50 mL of deionized water, add a 4 cm×1 cm×0.7 cm nickel foam for impregnation, and place it in a high-pressure reaction kettle for hydrothermal reaction at 140°C for 6 h. After the reaction is completed, take out the sample, wash it with deionized water, and dry it to obtain the CoNiFe-LDH / NF nanowire electrode.

[0087] 2. Preparation of anode electrolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water, then weigh 2 g of alkali lignin and add it to the solution, stir for 10 min and then filter to obtain the anode electrolyte.

[0088] 3. Preparation of catholyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution. Then add 4 mL of nitric acid (mass fraction 68%), and continuously stir the solution until a bright yellow clear solution is formed. Then let it stand for 24 h, and measure 100 mL as the catholyte.

[0089] 4. Preparation of lignin-based fuel cell: Cut the prepared CoNiFe-LDH / NF nanowire electrode into 4 cm × 0.25 cm × 0.7 cm, and then use the CoNiFe-LDH / NF nanowire electrode as the anode electrode in the S-shaped flow channel in the anode graphite plate, and fill the graphite felt as the cathode electrode in the S-shaped flow channel in the cathode graphite plate. Then, through the graphite plate, load (LED lamp) wire, fixed end plate, etc., assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate, and connect the battery and the load with wires. Then, add the above-mentioned anolyte to the anolyte tank and the catholyte to the catholyte tank through a peristaltic pump. Connect the anolyte tank to the anode inlet and outlet of the battery with a tube, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the catholyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0090] Figure 6 It is the current density-voltage-output power graph of the lignin-based fuel cell prepared in Example 4.

[0091] As Figure 6 shown, the maximum voltage of the lignin-based fuel cell prepared in Example 4 is 1.32 V, the maximum current density is 623.09 mA / cm 2 , and the maximum power density is 169.20 mW / cm 2 . The battery performance is lower than that of Example 2, indicating that the performance of using enzymatically hydrolyzed lignin for power generation is higher than that of using alkali lignin.

[0092] Example 5 (only modify the addition amount of enzymatically hydrolyzed lignin to 1 g)

[0093] A preparation method of a lignin-based fuel cell, the steps are as follows:

[0094] 1. Preparation of CoNiFe-LDH / NF nanowire electrode: Dissolve 2 mmol of Co(NO3)2·6H2O, 1 mmol of NiCl2·6H2O, 0.5 mmol of FeCl3·6H2O, 5 mmol of NH4F, and 5 mmol of urea in 50 mL of deionized water. Add a 4 cm×1 cm×0.7 cm nickel foam for impregnation, and place it in a high-pressure reaction kettle for hydrothermal reaction at 140 °C for 6 h. After the reaction, take out the sample, wash it with deionized water, and dry it to obtain the CoNiFe-LDH / NF nanowire electrode.

[0095] 2. Preparation of anolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water. Then weigh 1 g of enzymatically hydrolyzed lignin and add it to the solution. Stir for 10 min and then filter to obtain the anolyte.

[0096] 3. Preparation of catholyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution. Then add 4 mL of nitric acid (mass fraction 68%), and continuously stir the solution until a bright yellow clear solution is formed. Then let it stand for 24 h, and measure 100 mL as the catholyte.

[0097] 4. Preparation of lignin-based fuel cell: Cut the prepared CoNiFe-LDH / NF nanowire electrode into 4 cm×0.25 cm×0.7 cm. Then use the CoNiFe-LDH / NF nanowire electrode as the anode electrode in the S-shaped flow channel in the anode graphite plate, and fill the graphite felt as the cathode electrode in the S-shaped flow channel in the cathode graphite plate. Then, through the graphite plate, load (LED lamp) wire, fixed end plate, etc., assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate, and connect the battery and the load with wires. Then, add the above-mentioned anolyte to the anolyte tank and the catholyte to the catholyte tank through a peristaltic pump. Connect the anolyte tank to the anode inlet and outlet of the battery with a tube, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the catholyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0098] Effect verification 1

[0099] Perform a long-term continuous discharge test on the lignin-based fuel cell prepared in Example 5 at a voltage of 0.3 V to detect the corresponding battery performance. The test results are as Figure 7 shown.

[0100] The lignin-based fuel cell prepared in Example 5 was subjected to a long-term continuous discharge test at a voltage of 0.3 V. During the long-term continuous discharge experiment, when the molar concentration of C8-C16 components in the anolyte was detected to reach 20%, power generation was stopped. The obtained anolyte was extracted with ethyl acetate, and the resulting extract was the co-produced aviation fuel precursor component, and the types of compounds in the extract were detected. The test results are as Figure 8 shown.

[0101] Figure 7 Figure for the long-term continuous power generation of the lignin-based fuel cell prepared in Example 5.

[0102] As Figure 7 shown, at a voltage of 0.3 V, 1 g of enzymatically hydrolyzed lignin can generate 529 mW h of electricity.

[0103] Figure 8 GC-MS diagram of the extract in Effect Verification 1. Among them, a is the type of compound, and b is the mass spectrum of the corresponding compound.

[0104] Figure 8 It shows that after the anolyte co-produced by power generation is extracted with ethyl acetate, various aviation fuel precursor components such as benzoic acid, benzaldehyde, and acetophenone compounds can be obtained.

[0105] Example 6

[0106] A method for preparing aviation fuel components using the co-produced aviation fuel precursor solution by power generation, the steps are as follows:

[0107] The extract in Effect Verification 1 was subjected to heat evaporation treatment of the solvent to obtain a solid lignin degradation product; 0.01 g of lignin degradation product, 0.05 g of Pt / C catalyst powder and 10 mL of cyclohexane solvent were added to a high-pressure reactor. After removing the air in the reactor, 5 MPa of high-pressure hydrogen was charged, and the mixture was heated and stirred at 180 °C for 8 h, and then the product yield was detected by gas chromatography. Using hexane as the internal standard, the conversion rate, yield and selectivity were calculated by the internal standard method. The calculation formulas are as follows:

[0108]

[0109] Among them, f i and f s are the correction factors of the analyte and the internal standard, respectively, calculated by the effective carbon number method. A i and A s are the peak areas of the analyte and the internal standard, respectively, m s is the mass of the internal standard, and m i is the mass of the analyte. The results show that the yield of aviation fuel components is about 21.3% and the conversion rate is about 65%.

[0110] Comparative Example 1 (foam nickel as the anode electrode)

[0111] A preparation method of a lignin-based fuel cell is as follows:

[0112] 1. Preparation of the anode electrolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water. Then weigh 2 g of enzymatically hydrolyzed lignin and add it to the solution. After stirring for 10 min, filter to obtain the anode electrolyte.

[0113] 2. Preparation of the cathode electrolyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution; then add 4 mL of nitric acid (mass fraction 68%), and continuously stir the solution until a bright yellow clear solution is formed. Then let it stand for 24 h, and measure 100 mL as the cathode electrolyte.

[0114] 3. Preparation of the lignin-based fuel cell: Cut the foam nickel into 4 cm × 0.25 cm × 0.7 cm. Then use the foam nickel as the anode electrode in the S-shaped flow channel in the anode graphite plate, and fill the graphite felt as the cathode electrode in the S-shaped flow channel in the cathode graphite plate; then assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate through the graphite plate, load (LED lamp) wire, fixed end plate, etc., and connect the battery and the load with wires. Then add the above-mentioned anode electrolyte to the anode electrolyte tank and the cathode electrolyte to the cathode electrolyte tank through a peristaltic pump. Connect the anode electrolyte tank to the anode inlet and outlet of the battery with a tube, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the cathode electrolyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0115] Figure 9 It is the current density-voltage-output power diagram of the lignin-based fuel cell prepared in Comparative Example 1.

[0116] As Figure 9 shown, the maximum voltage of the lignin-based fuel cell prepared in Comparative Example 1 is 1.56 V, the maximum current density is 1268.6 mA / cm 2 , and the maximum power density is 223.43 mW / cm 2 . Its performance is not as excellent as that of the CoNiFe-LDH / NF nanowire electrode in Example 2. Therefore, using the CoNiFe-LDH / NF nanowire electrode can achieve more efficient degradation and coupled power generation of lignin.

[0117] Comparative Example 2 (Graphite felt as the anode electrode)

[0118] A preparation method of a lignin-based fuel cell is as follows:

[0119] 1. Preparation of the anode electrolyte: Weigh 2 g of NaOH and dissolve it in 50 mL of deionized water. Then weigh 1 g of enzymatically hydrolyzed lignin and add it to the solution. After stirring for 10 min, filter to obtain the anode electrolyte.

[0120] 2. Preparation of the cathode electrolyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution; then add 4 mL of nitric acid (mass fraction 68%), and continuously stir the solution until a bright yellow clear solution is formed, and then let it stand for 24 h. Measure 100 mL as the cathode electrolyte.

[0121] 3. Preparation of the lignin-based fuel cell: Fill graphite felt as the anode electrode in the S-shaped flow channel in the anode graphite plate, and fill graphite felt as the cathode electrode in the S-shaped flow channel in the cathode graphite plate; then assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 film, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate through the graphite plate, load (LED lamp) wire, fixed end plate, etc., and connect the battery and the load with a wire. Then add the above-mentioned anode electrolyte to the anode electrolyte tank and the cathode electrolyte to the cathode electrolyte tank through a peristaltic pump. Connect the anode electrolyte tank to the anode inlet and outlet of the battery with a tube, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the cathode electrolyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0122] It is measured that the maximum voltage of the lignin-based fuel cell prepared in Comparative Example 2 is 1.45 V, the maximum current density is 397.44 mA / cm 2 and the maximum power density is 108.54 mW / cm 2 . The performance is not as excellent as that of the CoNiFe-LDH / NF nanowire electrode in Example 2. Therefore, the use of the CoNiFe-LDH / NF nanowire electrode can achieve more efficient degradation of lignin and coupled power generation.

[0123] Comparative Example 3 (Only modify the anode material)

[0124] A preparation method of a lignin-based fuel cell is as follows:

[0125] 1. Preparation of sulfur-doped CoNi-LDH / GF electrode: Dissolve 3.75 mmol of Co(NO3)2·6H2O, 3.75 mmol of Ni(CH3COO)2·4H2O, 10 mmol of NH4F, and 25 mmol of urea in 70 mL of deionized water. Add a 5 cm × 0.5 cm× 0.5 cm graphite felt for impregnation, and place it in a high-pressure reaction kettle for hydrothermal reaction at 120 °C for 5 h. After the reaction, take out the sample, wash it with deionized water, and dry it to obtain CoNi-LDH / GF. Then weigh 0.75 mmol of C2H5NS (thioacetamide), dissolve it in 50 mL of ethylene glycol, add CoNi-LDH / GF for impregnation, and place it in a high-pressure reaction kettle for hydrothermal reaction at 120 °C for 2.5 h. After the reaction, take out the sample, wash it with deionized water, and dry it to obtain the CoNi-LDH-S / GF electrode.

[0126] 2. Preparation of anolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water. Then weigh 2 g of enzymatically hydrolyzed lignin and add it to the solution. Stir for 10 min and then filter to obtain the anolyte.

[0127] 3. Preparation of catholyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution. Then add 4 mL of nitric acid (mass fraction 68%), and continuously stir the solution until a bright yellow clear solution is formed. Then let it stand for 24 h, and measure 100 mL as the catholyte.

[0128] 4. Preparation of lignin-based fuel cell: Use the CoNi-LDH-S / GF electrode as the anode electrode in the S-shaped flow channel in the anode graphite plate, and fill the graphite felt as the cathode electrode in the S-shaped flow channel in the cathode graphite plate. Then, through the graphite plate, load (LED lamp) wire, fixed end plate, etc., assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, and metal cover plate, and connect the battery and the load with wires. Then, add the above-mentioned anolyte to the anolyte tank and the catholyte to the catholyte tank through a peristaltic pump. Connect the anolyte tank to the anode inlet and outlet of the battery with a tube, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the catholyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0129] Figure 10 It is the current density-voltage-output power diagram of the lignin-based fuel cell prepared in Comparative Example 3.

[0130] ByFigure 10 It can be seen that the maximum voltage of the lignin-based fuel cell prepared in Comparative Example 3 is 1.69 V, and the maximum current density is 831.76 mA / cm 2 , and the maximum power density is 234.90 mW / cm 2 . Its performance is not as excellent as that of the CoNiFe-LDH / NF nanowire electrode in Example 2. In comparison, the CoNiFe-LDH / NF nanowire electrode can achieve more efficient degradation and coupled power generation of lignin. In addition, in the subsequent hydrodeoxygenation process, the platinum-based catalyst will be poisoned when encountering a sulfur-containing compound system, causing the catalyst to lose its catalytic activity. Therefore, it is not suitable to use sulfur-containing electrocatalysts.

[0131] Comparative Example 4 (only modifying the anode material)

[0132] A preparation method of a lignin-based fuel cell is as follows:

[0133] 1. Preparation of CoNiFe-LDH / CoNiFeS electrode: Dissolve 0.58 g of Co(NO3)2·6H2O and 1.3 g of 2-methylimidazole in 40 mL of deionized water respectively. After stirring for 10 min, mix them. Place a 1 cm × 2 cm carbon cloth in the mixed solution. After standing at room temperature for 4 h, rinse with deionized water and dry to obtain sample Co-MOF. Dissolve 0.054 g of Fe(NO3)3·9H2O, 0.56 g of Ni(NO3)2·6H2O, 0.15 g of NH4F and 0.61 g of urea in 40 mL of deionized water. After dissolution, immerse Co-MOF in the mixed solution and transfer it to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave. Hydrothermal react at 140 °C for 4 h. After naturally cooling to room temperature, take out the sample, rinse with deionized water, and dry overnight at 60 °C in a vacuum drying oven to obtain CoNiFe-LDH. Dissolve 50 mg of thioacetamide in 40 mL of absolute ethanol. After stirring evenly, transfer the ethanol solution of thioacetamide and CoNiFe-LDH to a 100 mL polytetrafluoroethylene-lined stainless steel autoclave. Hydrothermal react at 100 °C for 4 h. After naturally cooling to room temperature, rinse with deionized water and dry to obtain CoNiFe-LDH / CoNiFeS.

[0134] 2. Preparation of anode electrolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water. Then weigh 2 g of enzymatically hydrolyzed lignin and add it to the solution. After stirring for 10 min, filter to obtain the anode electrolyte.

[0135] 3. Preparation of catholyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution. Then add 4 mL of nitric acid (mass fraction 68%), and continuously stir the solution until a bright yellow clear solution is formed. Then let it stand for 24 h, and measure 100 mL as the catholyte.

[0136] 4. Preparation of lignin-based fuel cell: Use CoNiFe-LDH / CoNiFeS as the anode electrode in the S-shaped flow channel of the anode graphite plate, and fill graphite felt in the S-shaped flow channel of the cathode graphite plate as the cathode electrode. Then assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate with graphite felt, and metal cover plate through the graphite plate, load (LED lamp) wire, fixed end plate, etc., and connect the battery and the load with wires. Then add the above-mentioned anolyte to the anolyte tank and the catholyte to the catholyte tank through a peristaltic pump. Connect the anolyte tank to the anode inlet and outlet of the battery with a tube, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the catholyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0137] It was measured that the maximum voltage of the lignin-based fuel cell prepared in Comparative Example 4 was 1.57 V, and the maximum current density was 1356.69 mA / cm 2 , and the maximum power density was 210.53 mW / cm 2 . The performance was not as excellent as that of the CoNiFe-LDH / NF nanowire electrode in Example 2. In comparison, the CoNiFe-LDH / NF nanowire electrode can achieve more efficient degradation and coupled power generation of lignin. In addition, in the subsequent hydrodeoxygenation step, the platinum-based catalyst will be poisoned when encountering a sulfur-containing compound system, causing the catalyst to lose its catalytic activity. Therefore, it is not suitable to use a sulfur-containing electrocatalyst.

[0138] Comparative Example 5 (only modifying the anode material)

[0139] A preparation method of a lignin-based fuel cell is as follows:

[0140] 1. Preparation of CoNiFe-MOF / LDH electrode: Mix CoCl₂·6H₂O (300 mg), NiCl₂·6H₂O (60 mg), FeCl₂·4H₂O (30 mg) and urea (380 mg) in deionized water. After ultrasonic treatment for 1 h, place a 1 cm × 2 cm carbon cloth into the mixed solution, heat it at 120 °C for 12 h. After cooling to room temperature, wash it with deionized water and dry it at 90 °C for 12 h to obtain CoNiFe-LDH. Immerse CoNiFe-LDH into 20 mL of N,N-dimethylformamide solution containing 2,3,6,7,10,11-hexahydroxytriphenylene. The mass ratio of CoNiFe-LDH to 2,3,6,7,10,11-hexahydroxytriphenylene is 1:2. Seal the dispersed solution in a polytetrafluoroethylene-lined autoclave and carry out hydrothermal reaction at 100 °C for 24 h. After natural cooling to room temperature, wash it thoroughly with ultrapure water, N,N-dimethylformamide and ethanol, and dry it in a vacuum drying oven at 90 °C for 12 h to obtain CoNiFe-MOF / LDH electrode.

[0141] 2. Preparation of anolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water. Then weigh 2 g of enzymatically hydrolyzed lignin and add it to the solution. After stirring for 10 min, filter it to obtain the anolyte.

[0142] 3. Preparation of catholyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir it at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution. Then add 4 mL of nitric acid (mass fraction 68%), and continuously stir the solution until a bright yellow clear solution is formed. Then let it stand for 24 h and measure 100 mL as the catholyte.

[0143] 4. Preparation of lignin-based fuel cell: Use CoNiFe-MOF / LDH electrode as the anode electrode in the S-shaped flow channel inside the anode graphite plate, and fill graphite felt as the cathode electrode in the S-shaped flow channel inside the cathode graphite plate. Then, through the graphite plate, load (LED lamp) wire, fixed end plate, etc., assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 membrane, polytetrafluoroethylene film, cathode graphite plate containing graphite felt, metal cover plate, and connect the battery and the load with wires. Then, add the above-mentioned anolyte to the anolyte tank and the catholyte to the catholyte tank through a peristaltic pump. Connect the anolyte tank to the anode inlet and outlet of the battery with a pipe, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the catholyte tank at a flow rate of 40 mL / min, and the battery operates at 90 °C.

[0144] It was measured that the maximum voltage of the lignin-based fuel cell prepared in Comparative Example 5 was 1.56 V, and the maximum current density was 1245.14 mA / cm 2 , and the maximum power density was 246.78 mW / cm 2 . The performance was not as excellent as that of the CoNiFe-LDH / NF nanowire electrode in Example 2. Therefore, the CoNiFe-LDH / NF nanowire electrode can achieve more efficient degradation and coupled power generation of lignin.

[0145] Comparative Example 6 (only modifying the anode material)

[0146] A preparation method of a lignin-based fuel cell is as follows:

[0147] 1. Preparation of nickel foam / manganese cobaltite nanowire electrode: Dissolve 5 mmol Co(NO3)2·6H2O, 2.5 mmol Mn(NO3)2·6H2O, 10 mmol NH4F, and 25 mmol urea in 70 mL of deionized water, add 4 cm×1 cm×0.7 cm nickel foam for impregnation, place it in a high-pressure reaction kettle, hydrothermal react at 120 °C for 5 h, take out the sample after the reaction, wash it with deionized water, and dry it to obtain the nickel foam / manganese cobaltite nanowire electrode.

[0148] 2. Preparation of anode electrolyte: Weigh 5.61 g of KOH and dissolve it in 50 mL of deionized water, then weigh 2 g of enzymatically hydrolyzed lignin and add it to the solution. After stirring for 10 min, filter it to obtain the anode electrolyte.

[0149] 3. Preparation of cathode electrolyte: Weigh 20 g of vanadium pentoxide powder and add it to a beaker containing 524 mL of deionized water, and stir it at room temperature. Then take 76 mL of concentrated sulfuric acid (mass fraction 98.3%) and slowly add it to the solution; then add 4 mL of nitric acid (mass fraction 68%), continuously stir the solution until a bright yellow clear solution is formed, then let it stand for 24 h, and measure 100 mL as the cathode electrolyte.

[0150] 4. Preparation of lignin-based fuel cell: Cut the prepared nickel foam / manganese cobaltate nanowire electrode into 4 cm×0.25 cm×0.7 cm. Then, use the nickel foam / manganese cobaltate nanowire electrode as the anode electrode in the S-shaped flow channel of the anode graphite plate, and fill the graphite felt in the S-shaped flow channel of the cathode graphite plate as the cathode electrode. Then, assemble the battery in the order of metal cover plate, anode graphite plate, polytetrafluoroethylene film, Nafion211 film, polytetrafluoroethylene film, cathode graphite plate with graphite felt, and metal cover plate through the graphite plate, load (LED lamp) wire, fixed end plate, etc., and connect the battery and the load with wires. Then, add the above-mentioned anode electrolyte into the anode electrolyte tank and the cathode electrolyte into the cathode electrolyte tank through a peristaltic pump. Connect the anode electrolyte tank to the anode inlet and outlet of the battery with a pipe, and connect the cathode tank to the cathode inlet and outlet of the battery. Pass oxygen into the cathode electrolyte tank at a flow rate of 40 mL / min, and the battery operates at 90°C.

[0151] It was measured that the maximum voltage of the lignin-based fuel cell prepared in Comparative Example 6 was 1.60 V, and the maximum current density was 796.86 mA / cm 2 , and the maximum power density was 191.42 mW / cm 2 . Its performance was not as excellent as that of the CoNiFe-LDH / NF nanowire electrode in Example 2. Therefore, the use of the CoNiFe-LDH / NF nanowire electrode can achieve more efficient degradation of lignin and coupled power generation.

[0152] The above-mentioned examples and comparative examples were comprehensively compared in terms of operating temperature, open-circuit voltage, maximum power density, etc. The test results are shown in Table 1.

[0153] Table 1 Comprehensive comparison of lignin-based fuel cell systems

[0154]

[0155] Comparing all the examples and comparative examples, it can be seen that the fuel cell with the best power generation performance is the lignin-based fuel cell system constructed with enzymatically hydrolyzed lignin as the raw material in Example 2, with an open-circuit voltage reaching 1.65 V and a maximum power density reaching 282.49 mW / cm 2 , which is much higher than that of the comparative examples.

[0156] The above-mentioned examples are only descriptions of the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for co-utilizing anodic electrolyte in a lignin-based fuel cell, characterized in that, It includes the following steps: Directly depolymerize lignin in the anolyte through the electrolytic reaction of the lignin-based fuel cell, and then co-produce aviation fuel components; The direct depolymerization is to directly depolymerize until the molar concentration of C8-C16 components in the anolyte reaches 5-30%; The method for co-producing aviation fuel components includes the following steps: extract the electrolytic solution obtained after direct depolymerization with ethyl acetate, and then heat and evaporate to remove ethyl acetate to obtain an aviation fuel precursor; mix the aviation fuel precursor with a catalyst and a solvent, and perform hydrodeoxygenation treatment to obtain the aviation fuel components; The lignin-based fuel cell includes an anolyte, a catholyte, a cathode electrode, and an anode electrode; the anolyte is prepared by dissolving lignin in an alkali solution; the catholyte is prepared by dissolving a vanadium pentoxide salt and a cathode regeneration oxidant in an acid solution; the cathode electrode is a graphite felt electrode; the anode electrode is a CoNiFe-LDH / NF nanowire electrode; The preparation method of the CoNiFe-LDH / NF nanowire electrode includes the following steps: Dissolve a Co source, a Ni source, a Fe source, urea, and ammonium fluoride in water to obtain a hydrothermal reaction solution; place nickel foam in the hydrothermal reaction solution and perform a hydrothermal reaction to obtain the CoNiFe-LDH / NF nanowire electrode; The molar ratio of the Co source, the Ni source, the Fe source, urea, and ammonium fluoride is (1-6):(1-6):(0.2-2):(4-20):(4-20); The temperature of the hydrothermal reaction is 20-200 °C, and the time is 1-20 h.

2. The co-production utilization method according to claim 1, characterized in that The Co source is Co(NO3)2; the Ni source is NiCl2; the Fe source is FeCl3.

3. The co-production utilization method according to claim 1, wherein The lignin is one or more of enzymatic hydrolysis lignin, pre-hydrolysis lignin, lignosulfonate, and alkali lignin; the vanadium pentoxide salt is vanadium pentoxide, vanadyl sulfate, or vanadyl nitrate; the cathode regeneration oxidant is one or more of nitric acid, oxygen, hydrogen peroxide, and potassium permanganate; the hydroxide ion concentration of the alkali in the anolyte is 0.05-5.0 mol / L, and the content of lignin molecules is 1-100 g / L; the concentration of the vanadium pentoxide salt in the catholyte is 0.05-5 mol / L; the operating temperature of the lignin-based fuel cell is 10-120 °C.

4. The co-production utilization method according to claim 1, characterized in that, The catalyst is one or more of a Pt-based catalyst, a Ni-based catalyst, and a Pd-based catalyst; the hydrogen pressure for the hydrodeoxygenation treatment is 2-5 MPa, the heating temperature is 80-400 °C, and the reaction time is 5-12 h.

Images