CN111604048B - Method for synthesizing ammonia by electrocatalytic reduction of nitrogen and catalyst used in same - Google Patents
Method for synthesizing ammonia by electrocatalytic reduction of nitrogen and catalyst used in same Download PDFInfo
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Abstract
The invention discloses a transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia, which is prepared by adopting a photo-deposition method and comprises the following steps: preparing a carbon material serving as a carrier by using carbon powder, sodium nitrate, concentrated sulfuric acid, potassium permanganate, deionized water and the like; dispersing TiO in a mixed solvent composed of water and an organic solvent 2 And carbon material, adding transition metal salt, mixing homogeneously, cooling to room temperature, freezing to solidify, vacuum freeze drying and transition metal monoatomic catalyst. The invention also provides a synthetic ammonia method for electrocatalytically reducing nitrogen by using the transition metal monoatomic catalyst. The method for synthesizing ammonia has the characteristics of simple and economic process, environmental protection, high yield and the like.
Description
Technical Field
The invention relates to an electrochemical synthesis method of ammonia.
Background
Ammonia is an important inorganic chemical product and is a main raw material for chemical fertilizer industry and basic organic chemical industry. In addition, ammonia is also a carbon-free energy carrier, combustion products of the ammonia are nitrogen and water, and ammonia produced in large scale can replace most of liquid fuel consumption at present, is considered to be one of environment-friendly sustainable fuel substances with great prospect in the future, and is actively developed for application of the ammonia in the fields of heavy transportation, power generation, distributed energy storage and the like. The amount of ammonia is very large, and with the development of industry and agriculture, the demand of ammonia is still increasing. The current world sources of ammonia are mostly synthetic ammonia, except for small amounts of by-products recovered from coke oven gas.
The traditional industrial process for synthesizing ammonia is the Haber-Bosch process, which requires severe conditions of high temperature and high pressure (about 300-500 ℃ C., 20.26-30.40 MPa), and the annual energy consumption is about 1.4% of the total energy consumption worldwide. The raw material hydrogen is mainly prepared by decomposing fossil energy, the natural gas consumed in the process accounts for about 3-5% of the total consumption of the global natural gas, and a large amount of greenhouse gases are generated.
So far, the synthesis of ammonia has undergone three generations of technical changes. The first generation of ammonia synthesis technology involved the use of carbon sequestration or compensation to reduce the net carbon impact of ammonia production to zero. Based on the existing H-B technology, the carbon fixation part in ammonia production increases cost and plant complexity, only represents a transitional solution, and is helpful for establishing ammonia markets outside chemical fertilizers and chemical industries.
The second generation ammonia synthesis technology still adopts the H-B method, but the raw material hydrogen is hydrogen produced by electrolysis of water. Siemens technicians produce hydrogen through a Proton Exchange Membrane (PEM) electrolytic cell by using fully renewable electric energy generated by a 20kW wind turbine to form about 30 kg of ammonia (Physical Chemistry Chemical Physics,2012,14 (3): 1235-1245) per day, which effectively solves the problem that the prior art consumes too much natural gas for preparing hydrogen, but still has the defect of too large input energy of high temperature and high pressure in the synthesis process.
The third generation of ammonia synthesis technology is to generate ammonia by directly or indirectly electrically reducing nitrogen, and the technology is completely separated from the H-B process. The synthesis reaction is driven by electrochemical reduction, while the hydrogen source is derived from water. The reaction condition (normal temperature and normal pressure) in the process is mild, the raw material sources are rich, and the electric energy can come from sustainable energy sources such as solar energy, wind energy and the like, so that the method has important development prospect. Haiyuan Zou reported an ultra-thin chlorine-doped graphene catalyst for electrocatalytic reduction of nitrogen inAt a potential of-0.45V (vs RHE), the ammonia production rate is 10.7 mu g.h -1 ·cm -2 mg -1 Cat. The faraday efficiency was 8.7% (ACS Catalysis,2019,9 (12): 10649-10655.), and it was seen that electrocatalytic nitrogen reduction was relatively stable with nitrogen, and had the effect of competing reactions for hydrogen evolution, with the problems of low ammonia yield and low faraday efficiency. Hongjie Yu reported a film material mAu 3 Pd/NF is used for electrocatalytic nitrogen reduction, and the ammonia production rate is 24.02 mug.h -1 ·cm -2 mg -1 Cat. The Faraday efficiency was 18.16% (ACS Applied Materials)&The catalyst performance is slightly improved compared with the prior work, but the catalyst material used by the catalyst is expensive and has higher cost. Wenjie Zang reported a nitrogen-doped carbon-supported copper monoatomic catalyst for electrocatalytic nitrogen reduction, yielding an ammonia yield of 49.3. Mu.g.h in HCl electrolyte -1 ·cm -2 mg -1 Cat. Faraday efficiency is 11.7% (ACSCatalysis, 2019,9 (11): 10166-10173.), but the method has the problem that the test result is inaccurate due to the introduction of nitrogen impurities, and the source of nitrogen in the product is verified.
In summary, the early H-B method for synthesizing ammonia has the problems of harsh conditions, high energy consumption and the like, and the recent electrochemical method for synthesizing ammonia has the problems of low yield, low Faraday efficiency, expensive catalyst materials, non-uniform test standards and the like, so that the efficient green production of ammonia is realized, and the method not only relates to the design of an electrochemical system, but also relates to the efficient and economic catalyst development.
Disclosure of Invention
The invention solves the technical problem of providing a mild, efficient and green ammonia synthesis method.
In order to solve the technical problems, the invention provides a transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia, which is prepared by adopting a photo-deposition method according to the following steps:
1) Preparing a carbon material as a carrier (carbon material carrier):
uniformly stirring 1g of carbon powder (high-purity carbon powder with purity more than or equal to 95 percent), (1+/-0.1) g of sodium nitrate and (46+/-2) mL of concentrated sulfuric acid (sulfuric acid solution with mass concentration of 95-98 percent) in an ice bath, and then adding (6+/-0.6) g of potassium permanganate to react for (1+/-0.2) h at 30-40 ℃; then adding (40+/-10) mL deionized water, and heating at (90+/-10) ℃ for reaction for 30-50 min;
terminating the reaction after the reaction time is reached; post-processing the reaction product to obtain a carbon material;
description: sealing the carbon material and then preserving at 16-25 ℃;
2) Preparation of transition metal monoatomic catalyst:
firstly, mixing water and an organic solvent to form a mixed solvent;
according to TiO 2 : carbon material = 1: (1.+ -. 0.1) dispersing TiO in the mixed solvent 2 Adding transition metal salt into the carbon material, uniformly mixing, then placing the mixture in the room temperature under illumination to react for 1 to 6 hours, and after the reaction product is frozen and solidified, performing vacuum freeze drying to obtain the transition metal monoatomic catalyst;
in the transition metal monoatomic catalyst, the loading of the transition metal element (as an active center) is 0.1 to 10%, preferably 1 to 10%, more preferably 1 to 5%, and most preferably 1%.
In general: every 50mgTiO 2 Mixing 20-40 ml of mixed solvent;
as an improvement of the transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia according to the invention, in the step 2): the transition metal is vanadium (V), niobium (Nb), tantalum (Ta). The transition metal salt is sodium metavanadate, sodium pyrovanadate, sodium orthovanadate, niobium oxalate, potassium niobate, tantalum pentachloride, potassium fluorotantalate, and potassium metatantalate.
As a further improvement of the transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia according to the invention, in said step 2): the organic solvent is methanol, ethanol, isopropanol, butanol, dioxane, dioxolane, diethylene glycol dimethyl ether, ethylene glycol diether dimethyl ether;
the volume ratio of water to organic solvent is 1:1-10:1.
As a further improvement of the transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia according to the invention, in said step 2): the reaction product is frozen and solidified for 1.5 to 2.5 hours at the temperature of minus 15 ℃ to minus 25 ℃ and then is frozen and dried in vacuum to obtain the transition metal monoatomic catalyst.
As a further improvement of the transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia of the present invention, in the step 1), after the reaction time is reached, (100.+ -. 10) mL of deionized water is added to stop the reaction, and then (6.+ -. 1) mL of hydrogen peroxide solution is added; repeatedly cleaning with 3% (mass%) hydrochloric acid and deionized water until the pH of the cleaning solution is neutral; ultrasonic dispersing (the dispersing time is 1-3 h) and vacuum freeze drying the cleaned product to obtain the carbon material.
Description: the hydrogen peroxide acts to reduce the residual oxidizing agent, potassium permanganate.
The invention also provides an electrocatalytic reduction ammonia synthesis method of nitrogen by using the transition metal monoatomic catalyst, wherein an electrocatalytic device of a three-electrode system is used, a reference electrode RE and a working electrode WE are arranged in a cathode electrolytic cell, a counter electrode CE is arranged in an anode electrolytic cell, and electrolyte is filled in both the cathode electrolytic cell and the anode electrolytic cell; a transition metal monoatomic catalyst coating is arranged on the surface of a working electrode WE, nitrogen is introduced into electrolyte in a cathode electrolytic cell until the electrolyte is saturated, and voltage is applied to carry out electrolysis.
The voltage is, for example, -0.4V (vs RHE), and the ammonia-containing electrolyte is obtained after 2h electrolysis by performing a chronoamperometric test (CA). The ammonia production rate can reach 136.4 mug.h -1 ·cm -2 mg -1 Cat. The Faraday efficiency was 53.5%.
According to the preparation method, graphene Oxide (GO) is firstly prepared as a carbon material carrier for supporting the catalyst, and then the types of the organic solvents are screened in the process of preparing the single-atom catalyst, so that the proportion of water and the organic solvents in the mixed solvent is optimized, the electronic structure of the catalyst is regulated, and the catalytic activity of the catalyst is enhanced. The invention also screens the transition metal serving as the active center, optimizes the load of the active center of the catalyst, and is beneficial to improving the activity of a single site in the catalyst.
A schematic view of an electrochemical device of the present invention is shown in fig. 1.
The invention discloses an electrocatalytic nitrogen ammonia synthesis method, which develops a high-efficiency single-atom catalyst with transition metal as an active center, and performs electrocatalytic nitrogen reduction to generate ammonia; has the following technical advantages:
1. the prepared monoatomic transition metal catalyst has high activity, the preparation method is relatively simple, and the yield of catalytic synthesis ammonia is high;
2. in the electrochemical process, nitrogen and water (mainly water in electrolyte) are used as raw materials, the sources of the raw materials are wide, no pollution gas is generated, and the environment-friendly production process is ensured;
3. the method for synthesizing ammonia has the characteristics of simple and economic process, environmental protection, high yield and the like.
In summary, the invention establishes a technical development route for electrocatalytic synthesis of ammonia by directly utilizing a transition metal monoatomic catalyst by taking nitrogen and water as raw materials through comparing reaction characteristics of different routes and comprehensively considering the difficulty of industrialization of a reaction process. The key technical difficulty is in developing a high-efficiency monoatomic catalyst.
Drawings
The following describes the embodiments of the present invention in further detail with reference to the accompanying drawings.
FIG. 1 is a schematic view of an electrochemical device;
RE represents a reference electrode, WE represents a working electrode, and CE represents a counter electrode.
Detailed Description
The invention will be further described with reference to the following specific examples, but the scope of the invention is not limited thereto:
hereinafter, the reaction is carried out under conventional stirring conditions; the conditions for vacuum freeze drying are: vacuum degree of 0.001MPa, -50 ℃.
Example one preparation of carbon material as support (carbon material support):
uniformly mixing and stirring 1g of high-purity carbon powder (the purity is more than or equal to 95%), 1g of sodium nitrate and 46mL of concentrated sulfuric acid (the mass concentration is 95-98 percent sulfuric acid solution) in an ice bath (about 0 ℃), adding 6g of potassium permanganate, then reacting for 1h at 30-40 ℃, continuously adding 40mL of deionized water, putting the mixture into a water bath at 90 ℃ for heating for 30-50 min, taking out, adding 100mL of deionized water to stop the reaction, and adding 6mL of hydrogen peroxide solution (the mass concentration is 30 percent hydrogen peroxide solution, which is used for reducing residual oxidant potassium permanganate); finally, the washing is repeatedly performed by using 3 percent (mass percent) hydrochloric acid and deionized water until the pH value of the washing liquid is close to neutral. After washing, about 20ml of water is added into the product, ultrasonic dispersion is carried out for 2 hours (ultrasonic dispersion is carried out at 25 ℃, power is 400W, frequency is 20 kHz), vacuum freeze drying is carried out for 20 hours, and the carbon material is obtained, and is stored at 16-25 ℃ after being sealed.
The following examples all employ this carbon material.
Example 1, preparation of V/G monoatomic catalyst by photo deposition:
in water: 50mgTiO was dispersed in 30ml of a mixed solvent of methanol=8:1 (v/v) 2 And 50mg of carbon material up to TiO 2 Uniformly dispersing the carbon material and dispersing the carbon material into a dispersion liquid;
adding about 2.39mg of sodium metavanadate (containing 1mg of vanadium) into the dispersion, then placing under irradiation of a light source, stirring at room temperature for reaction for 5 hours, freezing in a refrigerator (-20 ℃) for 2 hours until the solution is solidified into solid, and finally performing vacuum freeze-drying for 24 hours to obtain 101.0mg of V/G monoatomic catalyst with the mass fraction of 1.0%;
the short-arc xenon lamp current stabilizing power supply provides a light source, the current is 10A, the power of the xenon lamp is 500W, and the wavelength range of the light source is 320-780nm.
Example 2 preparation of Nb/G monoatomic catalyst by photo deposition:
in water: 50mgTiO was dispersed in 30ml of a mixed solvent of isopropanol=10:1 (v/v) 2 And 50mg of carbon material up to TiO 2 Uniformly dispersing the carbon material and dispersing the carbon material into a dispersion liquid;
about 5.79mg of niobium oxalate (containing 1mg of Nb) was added to the above dispersion, followed by stirring and reacting at room temperature under irradiation of a light source for 3 hours, then freezing in a refrigerator for 2 hours until the solution solidified into a solid, and finally vacuum freeze-drying for 24 hours, to obtain 101.0mg of Nb/G monoatomic catalyst with a mass fraction of 1.0%.
Example 3 preparation of Ta/G monoatomic catalyst by photo deposition:
in water: ethanol=9:1 (v/v) blend50mgTiO is dispersed in 30ml of a mixed solvent 2 And 50mg of carbon material up to TiO 2 Uniformly dispersing the carbon material and dispersing the carbon material into a dispersion liquid;
about 0.99mg of tantalum pentachloride (containing Ta 1 mg) was added to the above dispersion; then placing the mixture under a light source for irradiation and stirring reaction for 4 hours, then freezing the mixture in a refrigerator for 2 hours until the solution is solidified into solid, and finally performing vacuum freeze drying for 24 hours to obtain 101.0mg of Ta/G monoatomic catalyst with the mass fraction of 1.0%.
Example 4 preparation of V/G monoatomic catalyst by photo deposition:
in water: 50mg of TiO was dispersed in 30ml of a mixed solvent of dioxane=9:1 (v/v) 2 And 50mg of carbon material up to TiO 2 Uniformly dispersing the carbon material and dispersing the carbon material into a dispersion liquid;
about 3.61mg of sodium orthovanadate (containing V1 mg) was added to the above dispersion; then placing the mixture under a light source for irradiation and stirring reaction for 6 hours, then freezing the mixture in a refrigerator for 2 hours until the solution is solidified into solid, and finally performing vacuum freeze drying for 24 hours to obtain 101.0mg of the V/G monoatomic catalyst with the mass fraction of 1.0%.
Example 5 preparation of Nb/G monoatomic catalyst by photo deposition:
in water: 50mgTiO is dispersed in 30ml of mixed solvent of diethylene glycol dimethyl ether=6:1 (v/v) 2 And 50mg of carbon material up to TiO 2 Uniformly dispersing the carbon material and dispersing the carbon material into a dispersion liquid;
about 9.70mg potassium niobate (containing Nb 5 mg) was added to the above dispersion; then placing the mixture under a light source for irradiation and stirring reaction for 5 hours, then freezing the mixture in a refrigerator for 2 hours until the solution is solidified into solid, and finally performing vacuum freeze drying for 24 hours to obtain 101.0mg of Nb/G monoatomic catalyst with the mass fraction of 5.0%.
Example 6 preparation of Ta/G monoatomic catalyst by photo deposition:
in water: 50mgTiO was dispersed in 30ml of a mixed solvent of ethylene glycol dimethyl ether=1:1 (v/v) 2 And 50mg of carbon material up to TiO 2 Uniformly dispersing the carbon material and dispersing the carbon material into a dispersion liquid;
about 6.51mg of potassium fluorotantalate (containing Ta 3 mg) was added to the above dispersion; then placing the mixture under a light source for irradiation and stirring reaction for 3 hours, then freezing the mixture in a refrigerator for 2 hours until the solution is solidified into solid, and finally performing vacuum freeze drying for 24 hours to obtain 101.0mg of Ta/G monoatomic catalyst with the mass fraction of 3.0%.
Experiment 1, setting up an electrocatalytic device by adopting a three-electrode system, setting a reference electrode RE and a working electrode WE in a cathode electrolytic cell of an H-type electrolytic cell, setting a counter electrode CE in an anode electrolytic cell, and filling electrolyte in the cathode electrolytic cell and the anode electrolytic cell, wherein for example, 0.1mol/L sodium sulfate solution is used as electrolyte; the voltage is applied to the working electrode WE, which is well known.
The monoatomic catalysts obtained in examples 1 to 6 were each subjected to the following experiments: 1mg of monoatomic catalyst was taken and dissolved in ethanol: nafion solution=9:1 (v/v) in about 30ml of the mixed solution, and sonicated for 1h to obtain a uniform catalyst solution, which was completely smeared on 1cm×1cm carbon paper, and dried overnight.
The working electrode is carbon paper coated with a catalyst, the counter electrode is a Pt electrode, and the reference electrode is a saturated calomel electrode. Before the test, nitrogen is introduced at a gas speed of 10mL/min, after the electrolyte is saturated with nitrogen (30 mL of electrolyte is required for about 30 min), a voltage of-0.4V (vs RHE) is applied, and a timing current test (CA) is performed, so that an ammonia-containing electrolyte is obtained after 2h, and the ammonia production rate and Faraday efficiency are as shown in the following table 1.
Description: the Nafion solution is a perfluorosulfonic acid type polymer solution having a concentration of 5wt% and is available in a conventional commercially available manner.
The calculation formula of the ammonia production rate is
In the above, c NH3 The concentration of ammonia is expressed in mug.mL -1 The method comprises the steps of carrying out a first treatment on the surface of the V is the volume of electrolyte in the cathode electrolytic cell, and the unit is mL; m is m Cat. The unit is mg of the supported catalyst mass; a is the area of catalyst loading in cm -2 The method comprises the steps of carrying out a first treatment on the surface of the t is the electrolysis time in h.
TABLE 1
| Catalyst | Ammonia production rate | Faraday efficiency | |
| Example 1 | 1.0% of V/G monoatomic catalyst | 56.4μg·h -1 ·cm -2 mg -1 Cat | 19.8％ |
| Example 2 | 1.0% of Nb/G monoatomic catalyst | 95.6μg·h -1 ·cm -2 mg -1 Cat | 25.4％ |
| Example 3 | 1.0% Ta/G monoatomic catalyst | 136.4μg·h -1 ·cm -2 mg -1 Cat | 53.5％ |
| Example 4 | 1.0% of V/G monoatomic catalyst | 52.6μg·h -1 ·cm -2 mg -1 Cat | 18.9％ |
| Example 5 | 5.0% of Nb/G monoatomic catalyst | 75.6μg·h -1 ·cm -2 mg -1 Cat | 20.1％ |
| Example 6 | 3.0% of Ta/G monoatomic catalyst | 106.5μg·h -1 ·cm -2 mg -1 Cat | 40.1％ |
The amounts of the mixed solvents used in the single-atom catalyst processes of comparative example 1 and example 3 were changed as shown in Table 2 below, and the remainder was identical to example 3.
Comparison of the results of the final ammonia production rates is shown in Table 2 below.
TABLE 2
Comparative example 2 tantalum pentachloride containing 1mg of Ta in example 3 was changed to the following salt containing the same amount of Ta, and the remainder was identical to example 3.
The test was performed as described in experiment 1. Comparison of the results of the final ammonia production rates is shown in Table 3 below.
TABLE 3 Table 3
| Ammonia production rate (mug.h) -1 ·cm -2 mg -1 Cat. ) | ||
| Example 3 | Tantalum pentachloride | 136.4 |
| Comparative example 2 | Potassium fluorotantalate | 126.3 |
| Potassium metatantalate | 119.5 |
Comparative example 3 tantalum pentachloride 0.99mg in example 3 was changed to copper chloride 2.10mg, the remainder being identical to example 3. Namely, a Cu/G monoatomic catalyst having a mass fraction of 1.0% was obtained.
The test was performed as described in experiment 1. The results obtained were: the ammonia production rate is 26.5 mug.h -1 ·cm -2 mg -1 Cat. 。
Comparative example 4, the carbon material in example 3 was directly changed to commercially available "Graphene Oxide (GO)", with the amount unchanged, still 50mg; the remainder was identical to example 3.
The test was performed as described in experiment 1. The results obtained were: the ammonia production rate is 33.4 mug.h -1 ·cm -2 mg -1 Cat. 。
Finally, it should also be noted that the above list is merely a few specific embodiments of the present invention. Obviously, the invention is not limited to the above embodiments, but many variations are possible. All modifications directly derived or suggested to one skilled in the art from the present disclosure should be considered as being within the scope of the present invention.
Claims (4)
1. The transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia is characterized in that: the preparation method adopts a photo-deposition method and comprises the following steps:
1) Preparing a carbon material as a carrier:
uniformly stirring 1g of carbon powder, (1+/-0.1) g of sodium nitrate and (46+/-2) mL of concentrated sulfuric acid in an ice bath, and then adding (6+/-0.6) g of potassium permanganate to react for (1+/-0.2) h at 30-40 ℃; then adding (40+/-10) mL of deionized water, and heating at (90+/-10) ℃ for reaction for 30-50 min;
after the reaction time was reached, (100.+ -.10) mL of deionized water was added to stop the reaction, and then (6.+ -.1) mL of hydrogen peroxide solution was added; repeatedly cleaning with 3% hydrochloric acid and deionized water until the pH of the cleaning solution is neutral; ultrasonic dispersing and vacuum freeze drying the cleaned product to obtain a carbon material;
2) Preparation of transition metal monoatomic catalyst:
firstly, mixing water and an organic solvent to form a mixed solvent, wherein the volume ratio of the water to the organic solvent is 6:1-10:1; the organic solvent is methanol, ethanol, isopropanol, butanol, dioxane, dioxolane, diethylene glycol dimethyl ether and ethylene glycol diether dimethyl ether;
according to TiO 2 : carbon material = 1: (1.+ -. 0.1) dispersing TiO in the mixed solvent 2 Adding transition metal salt into the carbon material, uniformly mixing, then placing the mixture in the illumination to react for 1 to 6 hours at room temperature, and performing vacuum freeze drying on the obtained product after the reaction is frozen and solidified;
in the transition metal monoatomic catalyst, the mass loading of the transition metal element is 0.1-10%;
in the step 2): the transition metal is vanadium (V), niobium (Nb) or tantalum (Ta);
the transition metal salt is sodium metavanadate, sodium pyrovanadate, sodium orthovanadate, niobium oxalate, potassium niobate, tantalum pentachloride, potassium fluorotantalate, and potassium metatantalate.
2. The transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia according to claim 1, wherein:
in the step 2): and (3) freezing and solidifying the reaction product for 1.5-2.5 hours at the temperature of minus 15-25 ℃, and then performing vacuum freeze drying to obtain the transition metal monoatomic catalyst.
3. The transition metal monoatomic catalyst for electrocatalytic synthesis of ammonia according to claim 2, wherein: the Ta/G monoatomic catalyst is prepared by a photo-deposition method and comprises the following steps:
in water: 50mgTiO was dispersed in 30ml of ethanol=9:1, v/v mixed solvent 2 And 50mg of carbon material up to TiO 2 Uniformly dispersing the carbon material and dispersing the carbon material into a dispersion liquid;
adding 0.99mg of tantalum pentachloride to the dispersion; then placing the mixture under a light source for irradiation and stirring reaction for 4 hours, then freezing the mixture in a refrigerator for 2 hours until the solution is solidified into solid, and finally performing vacuum freeze drying for 24 hours to obtain 101.0mg of Ta/G monoatomic catalyst with the mass fraction of 1.0%.
4. An electrocatalytic reduction method for synthesizing nitrogen by using the transition metal monoatomic catalyst as claimed in any one of claims 1 to 3, wherein a three-electrode electrocatalytic device is used, a reference electrode RE and a working electrode WE are arranged in a cathode electrolytic cell, a counter electrode CE is arranged in an anode electrolytic cell, and electrolyte is filled in both the cathode electrolytic cell and the anode electrolytic cell; the method is characterized in that:
a transition metal monoatomic catalyst coating is arranged on the surface of a working electrode WE, nitrogen is introduced into electrolyte in a cathode electrolytic cell until the electrolyte is saturated, and voltage is applied to carry out electrolysis.
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| CN112226781B (en) * | 2020-09-30 | 2021-09-17 | 湖南大学 | Device and method for generating ammonia gas from nitrogen |
| CN113235123B (en) * | 2021-04-06 | 2022-05-06 | 三峡大学 | Preparation method of defect graphene anchored double-transition metal monoatomic synthetic ammonia catalyst |
| CN113215597B (en) * | 2021-04-06 | 2022-04-22 | 三峡大学 | Preparation method of defective foam graphene loaded transition metal monatomic catalyst |
| CN113106470B (en) * | 2021-04-06 | 2024-05-03 | 宁波烯固数造电池科技有限公司 | Vanadium-doped titanium dioxide/graphene electrocatalyst suitable for electrochemical nitrogen reduction and preparation method thereof |
| CN114752952A (en) * | 2022-04-14 | 2022-07-15 | 浙江大学 | Electrocatalytic nitrogen fixation device and method for simultaneously generating nitric acid and ammonia double products |
| CN115142079B (en) * | 2022-07-06 | 2024-04-02 | 中国华能集团清洁能源技术研究院有限公司 | Dual-functional electrolysis method and system for producing ammonia and hydrogen |
| CN115261923B (en) * | 2022-08-16 | 2024-05-17 | 西南科技大学 | Preparation and application of monoatomic uranium-titanium dioxide catalyst for electrocatalytic nitrogen synthesis of ammonia |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105655604A (en) * | 2016-01-11 | 2016-06-08 | 福建师范大学 | Preparation method of direct methanol fuel cell anode electro-optic synergistic catalyst |
| EP3216771A1 (en) * | 2016-03-08 | 2017-09-13 | Technion Research & Development Foundation Limited | Compositions with increased photocatalytic activity |
| CN109494381A (en) * | 2017-09-12 | 2019-03-19 | 中国科学院大连化学物理研究所 | The monatomic iron-based carbon material of one kind and preparation method and electro-catalysis application |
| WO2019245792A1 (en) * | 2018-06-22 | 2019-12-26 | The Curators Of The University Of Missouri | Novel method of manufacture of metal nanoparticles and metal single-atom materials on various substrates and novel compositions |
| CN111100100A (en) * | 2020-01-14 | 2020-05-05 | 浙江大学衢州研究院 | Green synthesis method of furan dicarboxylic acid and used catalyst |
| CN111116444A (en) * | 2020-01-14 | 2020-05-08 | 浙江大学衢州研究院 | Green synthesis method of caprolactam |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2404830C (en) * | 2002-10-17 | 2011-03-22 | University Of Windsor | Metallic mesoporous transition metal oxide molecular sieves, room temperature activation of dinitrogen and ammonia production |
| CN107262117B (en) * | 2017-07-25 | 2020-06-19 | 华中师范大学 | Single-atom metal-doped few-layer molybdenum disulfide electrocatalytic material, synthesis method and electrocatalytic nitrogen fixation method thereof |
-
2020
- 2020-05-25 CN CN202010445565.6A patent/CN111604048B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105655604A (en) * | 2016-01-11 | 2016-06-08 | 福建师范大学 | Preparation method of direct methanol fuel cell anode electro-optic synergistic catalyst |
| EP3216771A1 (en) * | 2016-03-08 | 2017-09-13 | Technion Research & Development Foundation Limited | Compositions with increased photocatalytic activity |
| CN109494381A (en) * | 2017-09-12 | 2019-03-19 | 中国科学院大连化学物理研究所 | The monatomic iron-based carbon material of one kind and preparation method and electro-catalysis application |
| WO2019245792A1 (en) * | 2018-06-22 | 2019-12-26 | The Curators Of The University Of Missouri | Novel method of manufacture of metal nanoparticles and metal single-atom materials on various substrates and novel compositions |
| CN111100100A (en) * | 2020-01-14 | 2020-05-05 | 浙江大学衢州研究院 | Green synthesis method of furan dicarboxylic acid and used catalyst |
| CN111116444A (en) * | 2020-01-14 | 2020-05-08 | 浙江大学衢州研究院 | Green synthesis method of caprolactam |
Non-Patent Citations (1)
| Title |
|---|
| 陈润锋等.有机化学与光电材料实验教程.《有机化学与光电材料实验教程》.东南大学出版社,2019,第233-234页. * |
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