A double-shell composite electrode material and a preparation method and application thereof

Abstract

The application discloses a double-shell composite electrode material and a preparation method and application thereof. A reducing agent is dissolved in purified water, polyvinylpyrrolidone and a cobalt salt are added and stirred to obtain solution A; cerium nitrate and urea are dissolved in purified water to obtain solution B, the solution B is added dropwise into an equal volume of the solution A, and is uniformly mixed, and then is transferred into a stainless steel reaction kettle with a polytetrafluoroethylene liner to perform hydrothermal reaction, and after cooling, centrifugal washing and drying, a core-shell material is formed; the core-shell material is dissolved in a glucose solution, polyvinylpyrrolidone is added, and the mixture is stirred at room temperature, and then is transferred into a stainless steel high-pressure reaction kettle with a Teflon liner to perform hydrothermal reaction, and after filtration separation, deionized water washing and drying, a Co@CeO2@C precursor is obtained; the Co@CeO2@C precursor is heated at a speed of 5 DEG C / min to 600-1000 DEG C under an inert atmosphere, and is calcined for 4-48 h, and finally, a Co@CeO2@C core-shell material is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of water pollutant treatment, in particular to a double-shell composite electrode material and a preparation method and application thereof. BACKGROUND

[0002] High-salinity wastewater has complex water quality composition, and the existing treatment methods mainly include electrolysis, incineration, membrane separation, ion exchange, biological treatment, etc. These methods have problems such as high energy consumption, poor system stability, and secondary pollution, so seeking resourceful treatment of high-salinity wastewater has been a concern of researchers in the environmental field.

[0003] Compared with traditional methods, the catalytic method is suitable for different types of high-salinity wastewater, can treat wastewater containing high-salinity, and can be applied to different treatment processes, including catalytic oxidation, catalytic reduction, catalytic decomposition, etc., and is suitable for different wastewater treatment needs. Using a catalyst to degrade pollutants in high-salinity wastewater not only can save a lot of energy, but also can accelerate the chemical reaction rate, effectively degrade organic matter and pollutants in wastewater, and make the degradation effect more significant. In addition, the catalyst has high selectivity and can selectively catalyze certain components in the wastewater, reducing the impact on the environment. The catalyst can be reused, reducing the consumption and processing cost of the catalyst. However, high-salinity wastewater contains a large amount of salt, which will deposit on the surface of the catalyst and form a salt layer, resulting in reduced catalyst activity or even deactivation. Secondly, the salt in high-salinity wastewater can corrode the surface of the catalyst, damaging the surface structure of the catalyst and affecting the progress of the catalytic reaction. Then, the salt in high-salinity wastewater can compete for the active sites on the surface of the catalyst, reducing the selectivity of the catalyst to the target substance, thereby affecting the effect of the catalytic reaction. Finally, the salt in high-salinity wastewater may affect the physical and chemical properties of the catalyst, such as thermal stability, stability of surface active sites, etc., thereby reducing the stability of the catalyst.

[0004] Therefore, it is an urgent problem to prepare a salt-tolerant, hydrophobic, and biocompatible catalyst for treating high-salinity wastewater. SUMMARY

[0005] The technical problem solved is to improve the corrosion of Cl- on the active sites of the catalytic material in a high-salinity environment. The present application provides a double-shell composite electrode material and a preparation method and application thereof. When used in a catalytic system, it can improve the stability of the catalyst in a high-salinity environment and the catalytic activity of the catalyst to pollutants. When used in a biological electrocatalytic system, it can construct a salt-tolerant electricity-producing microbial system, improve the cathode ORR activity, optimize the degradation ability of the biological electrochemical system to pollutants in a high-salinity environment, and solve the problem of decreased electricity production capacity.

[0006] Technical solution: A preparation method of a double-shell composite electrode material, comprising the following steps: 1) dissolving a reducing agent in purified water, then adding polyvinylpyrrolidone and a cobalt salt and stirring, the molar ratio of the reducing agent to the cobalt salt being 1:(1-9), the mass concentration of the polyvinylpyrrolidone in the reaction system being 0.5%-10%, to obtain a solution A; dissolving cerium nitrate and urea in purified water to obtain a solution B, the molar ratio of the urea to the cerium nitrate being 1:(1-20), then adding the solution B dropwise into an equal volume of the solution A, uniformly mixing, and then transferring into a stainless steel reaction kettle with a polytetrafluoroethylene lining, and then performing hydrothermal reaction at 150-300 DEG C for 12-48 h, after cooling, centrifugal washing and drying, and then performing reaction at 500-1000 DEG C for 4-12 h to form a Co@CeO2 core-shell material; 2) dissolving the Co@CeO2 core-shell material in a glucose solution, the mass ratio of the Co@CeO2 core-shell material to the glucose being 1:(1-9), then adding 0.5%-10% of polyvinylpyrrolidone (PVP) based on the total mass of the Co@CeO2 core-shell material and the glucose, stirring at room temperature, transferring the mixed system into a stainless steel high-pressure reaction kettle with a Teflon lining, performing hydrothermal reaction at 150-200 DEG C for 4-48 h, and then naturally cooling to room temperature, filtering and separating, and then drying after deionized water washing to obtain a Co@CeO2@C precursor; 3) heating the Co@CeO2@C precursor to 600-1000 DEG C at a rate of 5 DEG C / min under an inert atmosphere, and then performing calcination for 4-48 h, and finally forming a Co@CeO2@C core-shell material.

[0007] The reducing agent is ascorbic acid, glucose or tea polyphenol.

[0008] The cobalt salt is CoCl2, (CH3COO)2Co or Co(NO3)2.

[0009] The molar ratio of the reducing agent to the cobalt salt is 1:1.

[0010] The molar ratio of the urea to the cerium nitrate is 1:1.

[0011] In the step 1), the hydrothermal reaction temperature is 200 DEG C, and the reaction time is 24 h; the reaction temperature is 600 DEG C, and the reaction time is 8 h.

[0012] In the step 2), the mass ratio of the Co@CeO2 core-shell material to the glucose is 1:2; the hydrothermal reaction temperature is 180 DEG C, and the reaction time is 24 h.

[0013] In the step 3), the reaction temperature is 800 DEG C, and the reaction time is 24 h.

[0014] The double-shell composite electrode material prepared by the method.

[0015] The double-shell composite electrode material is applied to construction of a salt-resistant bioelectrochemical catalytic system.

[0016] Beneficial effects: The Co@CeO2@C double-shell material prepared by the application can control the size of the pore diameter and the hydrophobic property of the catalytic material by adjusting the ratio of organic ligand and metal, the reaction temperature and the reaction time. In addition, the corrosion of Cl- on the cathode catalyst can be improved, the electrochemical reaction kinetics can be exhibited faster, and a salt-resistant bioelectrochemical catalytic system can be constructed. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 For the TEM characterization diagram of the Co@CeO2@C double-shell material, the double-shell structure can be clearly seen.

[0018] Figure 2 For 600mM NaCl, the degradation efficiency of 10mg / L diclofenac by the catalysts of activated carbon (AC), Co3O4, CeO2, Co@CeO2, and Co@CeO2@C, respectively.

[0019] Figure 3 For 600mM NaCl, the degradation efficiency of 10mg / L norfloxacin by the catalysts of activated carbon (AC), Co3O4, CeO2, Co@CeO2, and Co@CeO2@C, respectively.

[0020] Figure 4 For 600mM NaCl, the degradation efficiency of 10mg / L polycyclic aromatic hydrocarbons by the catalysts of activated carbon (AC), Co3O4, CeO2, Co@CeO2, and Co@CeO2@C, respectively.

[0021] Figure 5 For 600mM NaCl, the cyclic voltammogram of the catalysts of activated carbon (AC), Co3O4, CeO2, Co@CeO2, and Co@CeO2@C, respectively.

[0022] Figure 6 For 600mM NaCl and 10mg / L norfloxacin, the long-term degradation efficiency curve of norfloxacin by the catalysts of activated carbon (AC), Co3O4, CeO2, Co@CeO2, and Co@CeO2@C, respectively, for 61 days of continuous reaction.

[0023] Figure 7 For the water contact angle column chart between ten examples.

[0024] Figure 8 For 600mM NaCl and 10mg / L polycyclic aromatic hydrocarbons, the degradation efficiency column chart of polycyclic aromatic hydrocarbons between ten examples.

[0025] Figure 9For 600 mM NaCl, norfloxacin concentration of 10 mg / L, the degradation efficiency of norfloxacin column chart between ten examples.

[0026] Figure 10 For water contact angle column chart when active carbon (AC), Co3O4, CeO2, Co@CeO2, Co@CeO2@C.

[0027] Cyclic voltammetry curve test: Pt sheet electrode as the counter electrode, Ag / Ag Cl as the reference electrode, cathode as the working electrode of CV analysis, using electrochemical workstation to carry out cyclic voltammetry curve (CV) test. The voltage scanning range of CV is -0.8~ -0.8V, and the scanning speed is 10m V / s.

[0028] Norfloxacin, polycyclic aromatic hydrocarbon, diclofenac degradation rate test: norfloxacin, polycyclic aromatic hydrocarbon, diclofenac is detected by high performance liquid chromatography (HPLC, Agilent, U.S.). Specifically, the column temperature box runs at 40℃, and the degradation efficiency of norfloxacin is calculated according to formula (1):

[0029] Degradation rate = (1-C1 / C0) × 100% formula (1)

[0030] C0: Influent concentration (mg / L); C1: effluent concentration (mg / L)

[0031] Wettability characterization: optical contact angle measuring instrument is used, and the contact angle (CA) of the coating surface is tested by 2uL water drop at room temperature, 3 times for each sample, and the arithmetic mean is taken as the measurement value.

[0032] TEM test: transmission electron microscope (TEM) image is monitored by Philips Tecnai G2 F20 microscope at an acceleration voltage of 200kV, and is used for analyzing the morphology of the sample. Before the test, the double-shell composite electrode material is crushed, and the catalyst powder is dispersed in methanol by ultrasonic wave. DETAILED DESCRIPTION

[0033] Example 1

[0034] In this embodiment, the specific preparation method of Co@CeO2@C core-shell material is as follows:

[0035] (1) 33.03 g ascorbic acid was dissolved in 50 mL purified water, then 0.15 g polyvinylpyrrolidone (PVP) and 8.12 g CoCl2 were added and stirred. Then 20.34 g cerium nitrate and 7.58 g urea were dissolved in 50 mL purified water, and then the solution was added dropwise into the previous solution, mixed uniformly for 15 min, then transferred into a stainless steel reactor with a polytetrafluoroethylene liner, and hydrothermally reacted at 180°C for 24 h. After cooling, centrifugal washing and drying at 100°C for 8 h, the Co@CeO2 core-shell material was finally formed by placing it in a muffle furnace at 600°C for 8 h;

[0036] (2) The Co@CeO2 core-shell material prepared in step (1) was added to 50 mL of a 1.3512 g / L glucose solution, and 0.10 g of polyvinylpyrrolidone (PVP) was added, and stirred at room temperature for 4 h. The mixture was transferred to a Teflon-lined stainless steel high-pressure reactor, and reacted at 180°C for 18 h, then naturally cooled to room temperature, filtered and separated, washed with deionized water 3 times, and dried at 80°C for 12 h to obtain the precursor;

[0037] (3) The precursor prepared in step (2) was placed in a crucible, then heated to 800°C at a heating rate of 5°C / min in a tube furnace under N2 atmosphere, and calcined for 24 h, finally forming the Co@CeO2@C core-shell material.

[0038] The prepared Co@CeO2@C core-shell material was used to treat high-salinity wastewater in a bioelectrochemical system, to resist the corrosion of high-salinity environment on the cathode catalyst and to construct a salt-tolerant microbial system for power generation, thereby improving the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0039] Example 2

[0040] (1) 54.1 g glucose was dissolved in 50 mL purified water, then 0.15 g polyvinylpyrrolidone (PVP) and 31.73 g cobalt acetate were added and stirred. Then 18.34 g cerium nitrate and 15.16 g urea were dissolved in 50 mL purified water, and then the solution was added dropwise into the previous solution, mixed uniformly for 15 min, then transferred into a stainless steel reactor with a polytetrafluoroethylene liner, and hydrothermally reacted at 280°C for 16 h. After cooling, centrifugal washing and drying at 100°C for 8 h, the Co@CeO2 core-shell material was finally formed by placing it in a muffle furnace at 650°C for 9 h;

[0041] (2) The Co@CeO2core-shell material of step (1) is added to 50 mL of 0.2252 g / L glucose solution, and polyvinylpyrrolidone (PVP, 0.10 g) is added, and stirred at room temperature for 4 h. The mixed system is transferred to a Teflon-lined stainless steel high-pressure reaction kettle, and after reaction at 160 ℃ for 24 h, it is naturally cooled to room temperature, filtered and separated, washed with deionized water for 3 times, and dried at 80 ℃ for 12 h to obtain a precursor;

[0042] (3) The precursor prepared in step (2) is placed in a crucible, and then heated to 850 ℃ at a heating rate of 5 ℃ / min under N2atmosphere in a tube furnace, and calcined for 24 h, and finally Co@CeO2@C core-shell material is formed.

[0043] The prepared Co@CeO2@C core-shell material is used to treat high-salt wastewater in a bioelectrochemical system, to resist the corrosion of high-salt environment on the cathode catalyst and to construct a salt-tolerant power-generating microbial system, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0044] Example 3

[0045] (1) 45.75 g of tea polyphenol is dissolved in 50 mL of purified water, and then 0.15 g of polyvinylpyrrolidone (PVP) and 11.43 g of Co(NO3)2are added and stirred. Then 10.17 g of cerium nitrate and 3.79 g of urea are dissolved in 50 mL of purified water, and then the solution is added dropwise to the previous solution, mixed uniformly for 15 min, and then transferred to a polytetrafluoroethylene-lined stainless steel reaction kettle, and hydrothermally reacted at 260 ℃ for 24 h. After cooling, centrifugal washing and drying at 100 ℃ for 8 h, it is finally placed in a muffle furnace at 700 s ℃ for 8 h to form a Co@CeO2core-shell material;

[0046] (2) The Co@CeO2core-shell material of step (1) is added to 50 mL of 0.2252 g / L glucose solution, and polyvinylpyrrolidone (PVP, 0.10 g) is added, and stirred at room temperature for 4 h. The mixed system is transferred to a Teflon-lined stainless steel high-pressure reaction kettle, and after reaction at 160 ℃ for 24 h, it is naturally cooled to room temperature, filtered and separated, washed with deionized water for 3 times, and dried at 80 ℃ for 12 h to obtain a precursor;

[0047] (3) The precursor prepared in step (2) is placed in a crucible, and then heated to 850 ℃ at a heating rate of 5 ℃ / min under N2atmosphere in a tube furnace, and calcined for 24 h, and finally Co@CeO2@C core-shell material is formed.

[0048] The prepared Co@CeO2@C core-shell material is used for treating high-salt wastewater in a bioelectrochemical system, corrosion of the cathode catalyst in a high-salt environment and construction of a salt-tolerant power-generating microbial system, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0049] Example 4

[0050] (1) 11.26 g of tea polyphenols was dissolved in 50 mL of purified water, and then 0.15 g of polyvinylpyrrolidone (PVP) and 11.43 g of Co(NO3)2 were added and stirred. Then 10.34 g of cerium nitrate and 7.58 g of urea were dissolved in 50 mL of purified water, and then the solution was added dropwise into the previous solution, mixed uniformly for 15 min, and then transferred into a stainless steel reactor with a polytetrafluoroethylene liner, and hydrothermal reaction was carried out at 180℃ for 12 h. After cooling, centrifugal washing and drying at 100℃ for 8 h were carried out. Finally, it was placed in a muffle furnace, and reaction was carried out at 500℃ for 6 h to form a Co@CeO2 core-shell material;

[0051] (2) The Co@CeO2 core-shell material prepared in step (1) was added into 50 mL of 0.2252 g / L glucose solution, and 0.10 g of polyvinylpyrrolidone (PVP) was added, and stirring was carried out at room temperature for 4 h. The mixed system was transferred into a stainless steel high-pressure reactor with a Teflon liner, and reaction was carried out at 160℃ for 24 h, and then natural cooling was carried out to room temperature. Filtration separation was carried out, and deionized water washing was carried out for 3 times, and then drying was carried out at 80℃ for 12 h to obtain a precursor;

[0052] (3) The precursor prepared in step (2) was placed in a crucible, and then the temperature was raised to 800℃ at a temperature raising rate of 5℃ / min under N2 atmosphere in a tube furnace, and calcination was carried out for 20 h, and finally a Co@CeO2@C core-shell material was formed.

[0053] The prepared Co@CeO2@C core-shell material is used for treating high-salt wastewater in a bioelectrochemical system, corrosion of the cathode catalyst in a high-salt environment and construction of a salt-tolerant power-generating microbial system, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0054] Example 5

[0055] (1) 22.52 g of glucose was dissolved in 50 mL of purified water, and then 0.15 g of polyvinylpyrrolidone (PVP) and 22.86 g of Co(NO3)2 were added and stirred. Then 20.34 g of cerium nitrate and 7.78 g of urea were dissolved in 50 mL of purified water, and then the solution was added dropwise into the previous solution, mixed uniformly for 15 min, and then transferred into a stainless steel reactor with a polytetrafluoroethylene liner, and hydrothermal reaction was carried out at 200℃ for 12 h. After cooling, centrifugal washing and drying at 100℃ for 8 h were carried out. Finally, it was placed in a muffle furnace, and reaction was carried out at 680℃ for 8 h to form a Co@CeO2 core-shell material;

[0056] (2) The Co@CeO2core-shell material prepared in step (1) was added to 50 mL of a 0.4504 g / L glucose solution, and 0.10 g of polyvinylpyrrolidone (PVP) was added, and stirring was performed at room temperature for 4 h. The mixture was transferred to a Teflon-lined stainless steel high-pressure reaction kettle, and after reaction at 180 ℃ for 24 h, the system was naturally cooled to room temperature, filtered and separated, washed with deionized water 3 times, and dried at 80 ℃ for 12 h to obtain a precursor;

[0057] (3) The precursor prepared in step (2) was placed in a crucible, and then in a tube furnace, the temperature was raised to 760 ℃ at a rate of 5 ℃ / min under N2atmosphere, and calcination was performed for 8 h, and finally Co@CeO2@C core-shell material was formed.

[0058] The prepared Co@CeO2@C core-shell material was used to treat high-salt wastewater in a bioelectrochemical system, to resist corrosion of the cathode catalyst in a high-salt environment and to construct a salt-tolerant microbial system for power generation, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0059] Example 6

[0060] (1) 11.26 g of glucose was dissolved in 50 mL of purified water, and then 0.15 g of polyvinylpyrrolidone (PVP) and 22.86 g of Co(NO3)2were added and stirred. Then 10.17 g of cerium nitrate and 15.16 g of urea were dissolved in 50 mL of purified water, and then the solution was added dropwise to the previous solution, mixed uniformly and reacted for 15 min, and then transferred to a polytetrafluoroethylene-lined stainless steel reaction kettle, and hydrothermal reaction was performed at 160 ℃ for 24 h. After cooling, centrifugal washing and drying at 100 ℃ for 8 h were performed. Finally, the sample was placed in a muffle furnace, and calcination was performed at 660 ℃ for 8 h to form Co@CeO2core-shell material;

[0061] (2) The Co@CeO2core-shell material prepared in step (1) was added to 50 mL of a 0.4514 g / L glucose solution, and 0.30 g of polyvinylpyrrolidone (PVP) was added, and stirring was performed at room temperature for 4 h. The mixture was transferred to a Teflon-lined stainless steel high-pressure reaction kettle, and after reaction at 180 ℃ for 6 h, the system was naturally cooled to room temperature, filtered and separated, washed with deionized water 3 times, and dried at 80 ℃ for 12 h to obtain a precursor;

[0062] (3) The precursor prepared in step (2) was placed in a crucible, and then in a tube furnace, the temperature was raised to 1000 ℃ at a rate of 5 ℃ / min under N2atmosphere, and calcination was performed for 24 h, and finally Co@CeO2@C core-shell material was formed.

[0063] The prepared Co@CeO2@C core-shell material is used for treating high-salt wastewater in a bioelectrochemical system, corrosion of the cathode catalyst in a high-salt environment, and construction of a salt-tolerant power-generating microbial system, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0064] Example 7

[0065] (1) 11.26 g of glucose was dissolved in 50 mL of purified water, and then 0.15 g of polyvinylpyrrolidone (PVP) and 11.43 g of Co(NO3)2 were added and stirred. Then 20.34 g of cerium nitrate and 3.79 g of urea were dissolved in 50 mL of purified water, and then the solution was added dropwise into the previous solution, mixed uniformly for 15 min, and then transferred into a stainless steel reactor with a polytetrafluoroethylene liner, and hydrothermal reaction was carried out at 180℃ for 7 h. After cooling, centrifugal washing and drying at 100℃ for 8 h were carried out. Finally, it was placed in a muffle furnace, and reaction was carried out at 580℃ for 7 h to form a Co@CeO2 core-shell material;

[0066] (2) The Co@CeO2 core-shell material prepared in step (1) was added into 50 mL of a 0.2252 g / L glucose solution, and 0.20 g of polyvinylpyrrolidone (PVP) was added, and stirring was carried out at room temperature for 4 h. The mixed system was transferred into a stainless steel high-pressure reactor with a Teflon liner, and reaction was carried out at 180℃ for 24 h, and then natural cooling was carried out to room temperature. Filtration separation was carried out, and deionized water washing was carried out for 3 times, and drying was carried out at 80℃ for 12 h to obtain a precursor;

[0067] (3) The precursor prepared in step (2) was placed in a crucible, and then the temperature was raised to 900℃ at a temperature raising rate of 5℃ / min under N2 atmosphere in a tube furnace, and calcination was carried out for 24 h, and finally a Co@CeO2@C core-shell material was formed.

[0068] The prepared Co@CeO2@C core-shell material is used for treating high-salt wastewater in a bioelectrochemical system, corrosion of the cathode catalyst in a high-salt environment, and construction of a salt-tolerant power-generating microbial system, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0069] Example 8

[0070] (1) 11.26 g of glucose was dissolved in 50 mL of purified water, and then 0.15 g of polyvinylpyrrolidone (PVP) and 11.43 g of Co(NO3)2 were added and stirred. Then 20.34 g of cerium nitrate and 3.79 g of urea were dissolved in 50 mL of purified water, and then the solution was added dropwise into the previous solution, mixed uniformly for 15 min, and then transferred into a stainless steel reactor with a polytetrafluoroethylene liner, and hydrothermal reaction was carried out at 180℃ for 24 h. After cooling, centrifugal washing and drying at 100℃ for 8 h were carried out. Finally, it was placed in a muffle furnace, and reaction was carried out at 800℃ for 8 h to form a Co@CeO2 core-shell material;

[0071] (2) The Co@CeO2core-shell material prepared in step (1) was added to 50 mL of a 0.2252 g / L glucose solution, and 0.10 g of polyvinylpyrrolidone (PVP) was added. The mixture was stirred at room temperature for 4 h. The mixture was transferred to a Teflon-lined stainless steel high-pressure reaction kettle, and was naturally cooled to room temperature after being reacted at 180 °C for 24 h. The product was separated by filtration, washed with deionized water three times, and dried at 80 °C for 12 h to obtain a precursor;

[0072] (3) The precursor prepared in step (2) was placed in a crucible, and then was heated to 800 °C at a heating rate of 5 °C / min under a N2atmosphere in a tube furnace. The precursor was calcined for 24 h, and finally the Co@CeO2@C core-shell material was formed.

[0073] The prepared Co@CeO2@C core-shell material was used to treat high-salinity wastewater in a bioelectrochemical system, to resist corrosion of the cathode catalyst in a high-salinity environment and to construct a salt-tolerant microbial system for power generation, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0074] Example 9

[0075] (1) 11.26 g of glucose was dissolved in 50 mL of purified water, and then 0.15 g of polyvinylpyrrolidone (PVP) and 11.43 g of Co(NO3)2were added and stirred. Then 20.34 g of cerium nitrate and 3.79 g of urea were dissolved in 50 mL of purified water, and then the solution was added dropwise to the previous solution, mixed uniformly, and reacted for 15 min. Then the mixture was transferred to a Teflon-lined stainless steel reaction kettle, and was hydrothermally reacted at 180 °C for 24 h. After cooling, the product was washed by centrifugation, and was dried at 100 °C for 8 h. Finally, the product was placed in a muffle furnace, and was reacted at 800 °C for 12 h to form a Co@CeO2core-shell material;

[0076] (2) The Co@CeO2core-shell material prepared in step (1) was added to 50 mL of a 0.6756 g / L glucose solution, and 0.20 g of polyvinylpyrrolidone (PVP) was added. The mixture was stirred at room temperature for 4 h. The mixture was transferred to a Teflon-lined stainless steel high-pressure reaction kettle, and was naturally cooled to room temperature after being reacted at 160 °C for 12 h. The product was separated by filtration, washed with deionized water three times, and dried at 80 °C for 12 h to obtain a precursor;

[0077] (3) The precursor prepared in step (2) was placed in a crucible, and then was heated to 800 °C at a heating rate of 5 °C / min under a N2atmosphere in a tube furnace. The precursor was calcined for 9 h, and finally the Co@CeO2@C core-shell material was formed.

[0078] The prepared Co@CeO2@C core-shell material is used for treating high-salt wastewater in a bioelectrochemical system, corrosion of a cathode catalyst in a high-salt environment and construction of a salt-tolerant power-generating microbial system, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0079] Example 10

[0080] (1) 22.52 g of glucose was dissolved in 50 mL of purified water, then 0.3 g of polyvinylpyrrolidone (PVP) and 11.43 g of Co(NO3)2 were added and stirred. Then 20.34 g of cerium nitrate and 11.37 g of urea were dissolved in 50 mL of purified water, then the solution was added dropwise into the previous solution, mixed uniformly for 15 min, then transferred into a polytetrafluoroethylene-lined stainless steel reaction kettle, and hydrothermally reacted at 160 DEG C for 12 h. After cooling, centrifugal washing and drying at 100 DEG C for 8 h, finally placed in a muffle furnace, 800 DEG C, reacted for 12 h, to form Co@CeO2 core-shell material;

[0081] (2) The Co@CeO2 core-shell material in step (1) was added into 50 mL of 0.6756 g / L glucose solution, and polyvinylpyrrolidone (PVP, 0.10 g) was added, and stirred at room temperature for 4 h. The mixed system was transferred into a Teflon-lined stainless steel high-pressure reaction kettle, reacted at 180 DEG C for 15 h, and then naturally cooled to room temperature, filtered and separated, washed with deionized water for 3 times, and dried at 80 DEG C for 12 h to obtain a precursor;

[0082] (3) The precursor prepared in step (2) was placed in a crucible, then heated to 1000 DEG C at a heating rate of 5 DEG C / min under N2 atmosphere in a tube furnace, and calcined for 12 h, finally forming Co@CeO2@C core-shell material.

[0083] The prepared Co@CeO2@C core-shell material is used for treating high-salt wastewater in a bioelectrochemical system, corrosion of a cathode catalyst in a high-salt environment and construction of a salt-tolerant power-generating microbial system, so as to improve the pollutant degradation capacity and power generation capacity of the bioelectrochemical system.

[0084] The present application is not limited to the above-mentioned embodiments, and for those skilled in the art, after learning the content described in the present application, without departing from the principles of the present application, a number of equivalent transformations and substitutions can also be made, which should also be considered to belong to the protection scope of the present application.

Claims

1. A method for preparing a double-shell composite electrode material, characterized in that, Includes the following steps: 1) Dissolve the reducing agent in purified water, then add polyvinylpyrrolidone and cobalt salt and stir. The molar ratio of reducing agent to cobalt salt is 1:(1~9), and the mass concentration of polyvinylpyrrolidone in the reaction system is 0.5%-10%, yielding solution A. Dissolve cerium nitrate and urea in purified water to obtain solution B. The molar ratio of urea to cerium nitrate is 1:(1~20). Then, add solution B dropwise to an equal volume of solution A, mix thoroughly, and then transfer to a stainless steel reactor lined with polytetrafluoroethylene. React hydrothermally at 150-300℃ for 12-48 hours. After cooling, centrifuge, wash, and dry for 500-1000 seconds. 1) React at ℃ for 4-12h to form Co@CeO2 core-shell material; 2) Dissolve Co@CeO2 core-shell material in glucose solution, with a mass ratio of Co@CeO2 core-shell material to glucose of 1:(1~9), then add 0.5%-10% polyvinylpyrrolidone of the total mass of Co@CeO2 core-shell material and glucose, stir at room temperature, transfer this mixture to a Teflon-lined stainless steel high-pressure reactor, hydrothermal reaction at 150-200℃, react for 4-48h, then naturally cool to room temperature, filter and separate, wash with deionized water and dry to obtain Co@CeO2@C precursor; 3) Heat the Co@CeO2@C precursor to 600-1000℃ at 5℃ / min under an inert atmosphere, calcine for 4-48h, and finally form Co@CeO2@C core-shell material.

2. The method for preparing the double-shell composite electrode material according to claim 1, characterized in that, The reducing agent is ascorbic acid, glucose, or tea polyphenols.

3. The method for preparing the double-shell composite electrode material according to claim 1, characterized in that, The cobalt salt is CoCl2, (CH3COO)2Co, or Co(NO3)2.

4. The method for preparing the double-shell composite electrode material according to claim 1, characterized in that, The molar ratio of the reducing agent to the cobalt salt is 1:

1.

5. The method for preparing the double-shell composite electrode material according to claim 1, characterized in that, The molar ratio of urea to cerium nitrate is 1:

1.

6. The method for preparing the double-shell composite electrode material according to claim 1, characterized in that, In step 1), the hydrothermal reaction temperature is 200℃ and the reaction time is 24h; the reaction temperature is 600℃ and the reaction time is 8h.

7. The method for preparing the double-shell composite electrode material according to claim 1, characterized in that, In step 2), the mass ratio of Co@CeO2 core-shell material to glucose is 1:2; the hydrothermal reaction temperature is 180℃ and the reaction time is 24h.

8. The method for preparing the double-shell composite electrode material according to claim 1, characterized in that, The reaction temperature in step 3) is 800℃ and the reaction time is 24h.

9. The double-shell composite electrode material prepared by any one of claims 1-8.

10. The application of the double-shell composite electrode material of claim 9 in the construction of a salt-resistant bioelectrochemical catalytic system.

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