Anion intercalation graphite catalyst as well as preparation method and application thereof

Abstract

The invention discloses an anion intercalated graphite catalyst and a preparation method and application thereof, belongs to the technical field of new energy chemical industry, and particularly relates to a graphite catalyst with an anion intercalation layer obtained by adding specific anion salt in an electrooxidation reaction process of carboxylate taking a graphite flake as a working electrode. The interlayer spacing is increased by 0.01-0.2 nm compared with that of a graphite catalyst without intercalation. The composite electrode is applied to carboxylate electrooxidation reaction, catalytic activity, catalytic stability and Faraday efficiency can be improved at the same time, efficient and sustainable deacidification reaction is achieved, higher current density can be obtained under the condition that low potential is applied, and the technical problem that a traditional graphite electrode is prone to passivation in the using process is successfully solved. The preparation method disclosed by the invention is simple, free from special process condition requirements, low in cost and convenient for industrial application.

Description

Technical Field

[0001] The invention belongs to the technical field of new energy chemical industry, and specifically relates to an anion intercalated graphite catalyst and a preparation method and application thereof. Background Art

[0002] In recent years, carbon dioxide / carbon monoxide (CO x ) Significant progress has been made in new sustainable production methods such as electroreduction, waste plastic degradation and biomass conversion. Since the above reactions are usually carried out under alkaline or weakly alkaline conditions, the resulting products are usually in the form of carboxylates. If these carboxylates are converted into corresponding organic acids with utilization value, it is necessary to add an acid stronger than the corresponding carboxylic acid to the carboxylates. This conversion step has the characteristics of high energy consumption and high material consumption, which greatly increases its production cost. In response to this problem, various thermochemical, electrochemical and photochemical technologies for catalytic conversion of carboxylates or carboxylic acids have developed rapidly. Among them, electrocatalytic technology has attracted much attention because it uses green renewable energy electricity and mild reaction conditions. This process can not only achieve efficient conversion of carboxylates, but also make full use of clean electricity generated by sustainable energy such as wind energy and light energy, reducing the phenomena of "abandoning wind" and "abandoning light".

[0003] In summary, the electro-oxidation reaction of carboxylates is extremely economically promising and is in line with the current trend of developing clean energy technologies and transforming energy structures. The electrochemical transformation of carboxylic acids, namely the Kolbe electrolysis reaction, can be traced back to the nineteenth century. During the reaction, carboxylates lose electrons at the anode to form alkyl radicals. These active species can undergo dimerization reactions to generate Kolbe products such as long-chain alkanes (such as paraffin), or be further oxidized to carbon cations, rearranged or combined with other groups to produce high-value-added non-Kolbe products (such as olefins, alcohols, esters, etc.). Despite more than a century of extensive research, the application of this reaction is still limited due to its stringent solvent selection (mainly organic solvents) and stability challenges caused by catalyst passivation.

[0004] In order to comply with the requirements of sustainable development, it is of far-reaching significance to develop stable and efficient aqueous carboxylate electrolysis technology to achieve green production of high value-added products. Although there have been reports on the electrolysis of aqueous carboxylates in recent years, it has encountered challenges such as low Faraday efficiency and poor stability when using graphite electrodes. In order to fully cover the electrode surface with alkoxy or alkyl groups to inhibit the oxygen production reaction, a high potential of more than 2 volts relative to the reversible hydrogen electrode needs to be applied, which may lead to electrode dissolution or catalytic active surface passivation. Therefore, it is of great significance to solve the deactivation of the catalyst surface and improve the electrolysis efficiency. Summary of the invention

[0005] In view of the problems that traditional graphite electrodes are easy to passivate during use, and have low Faraday efficiency and poor stability, the present invention provides an anion intercalated graphite catalyst and a preparation method and application thereof. An intercalation aid is added during the carboxylate electro-oxidation reaction to obtain a graphite catalyst with anion intercalation. While ensuring high catalytic activity, the catalytic stability and Faraday efficiency can be improved to achieve an efficient and sustainable deacidification reaction. The catalyst has the advantages of a simple preparation method, low cost, and ease of industrial application.

[0006] The technical solution adopted by the present invention is as follows:

[0007] A graphite catalyst with anion intercalation, wherein anions are inserted between the layers of the graphite catalyst, and the interlayer spacing is increased by 0.01 to 0.2 nanometers compared with a non-intercalated graphite catalyst.

[0008] Furthermore, the anion is perchlorate, sulfate, nitrate or phosphate.

[0009] A method for preparing an anion intercalated graphite catalyst comprises the following steps:

[0010] Step 1, obtaining a graphite sheet, and washing and drying it;

[0011] Step 2: Using the graphite sheet obtained in step 1 as a working electrode, a carboxylate electro-oxidation reaction is carried out in an electrolysis device to obtain an anion intercalated graphite catalyst; wherein the electrolyte required for the reaction is composed of a carboxylate and an anion salt, and the anion salt is one or more of a perchlorate, a sulfate, a nitrate, and a phosphate.

[0012] Furthermore, the carboxylate is one or more of acetate, propionate, butyrate, valerate, pivalate, succinate, and levulinate.

[0013] Furthermore, the concentration of the carboxylate in the electrolyte is 0.1 to 5 mol / L.

[0014] Furthermore, the concentration of the anion salt is 0.01 to 5 mol / L.

[0015] Furthermore, the electrolyte also includes a soluble carboxylic acid corresponding to the added carboxylate, specifically acetic acid, propionic acid, butyric acid, valeric acid, pivalic acid, succinic acid or levulinic acid corresponding to the carboxylate.

[0016] Furthermore, the concentration of the carboxylic acid is 0.1 to 5 mol / L.

[0017] Furthermore, the electrolysis device is a two-electrode system or a three-electrode system, specifically a three-port electrolytic cell, an H-type electrolytic cell or a flow-type electrolytic cell.

[0018] Furthermore, the reference electrode of the electrolysis device is a mercurous sulfate electrode, a silver / silver chloride electrode or a saturated calomel electrode, and the diaphragm is a proton exchange membrane, an anion exchange membrane or a bipolar membrane.

[0019] Furthermore, the specific process of the cleaning is: ultrasonic cleaning in dilute hydrochloric acid, anhydrous ethanol and deionized water in sequence, wherein the anhydrous ethanol can be replaced by acetone.

[0020] Furthermore, the duration of the ultrasonic cleaning is 5 to 60 minutes.

[0021] Furthermore, the concentration of the dilute hydrochloric acid is 0.1 to 3 mol / L.

[0022] Furthermore, the specific process of the drying is: drying in a vacuum oven at 40 to 80 degrees Celsius for at least 12 hours.

[0023] Furthermore, the graphite sheet has a thickness of 0.1 to 2 cm and a plane size of 1×1 cm2 to 3×3 cm2.

[0024] The present invention also provides application of the anion intercalated graphite catalyst obtained by the preparation method in the electro-oxidation reaction of carboxylate.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention proposes an anion intercalated graphite catalyst and a preparation method and application thereof. A graphite catalyst with anion intercalation is obtained by adding a specific anion salt during the electro-oxidation reaction of carboxylate using a graphite sheet as a working electrode. The graphite catalyst is applied to the electro-oxidation reaction of carboxylate to improve the catalytic activity, catalytic stability and Faraday efficiency, achieve efficient and sustainable deacidification reaction, and obtain a higher current density at a lower applied potential, thus successfully solving the technical problem of easy passivation of traditional graphite electrodes during use.

[0027] 2. The preparation method of the present invention is simple, has no special process conditions, is low in cost, and is convenient for industrial application. x )It is applicable to many scenarios such as electro-reduction, waste plastic degradation and biomass conversion, and has high economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 The X-ray diffraction spectra of the graphite catalyst before passivation without the addition of perchlorate (i.e., initial graphite), the graphite catalyst after passivation without the addition of perchlorate, and the graphite catalyst after the addition of perchlorate (i.e., anion intercalation) in Example 1 of the present invention;

[0030] Figure 2 This is a high-resolution transmission electron micrograph of the graphite catalyst after passivation without the addition of perchlorate in Example 1 of the present invention;

[0031] Figure 3 This is a high-resolution transmission electron micrograph of the graphite catalyst after the reaction with the addition of perchlorate in Example 1 of the present invention;

[0032] Figure 4 is the Faraday efficiency of methanol and methyl acetate in the acetate electrooxidation reaction of the graphite catalyst before the addition of perchlorate passivation in Example 1 of the present invention;

[0033] Figure 5 is the Faraday efficiency of methanol and methyl acetate in the acetate electrooxidation reaction of the graphite catalyst without the addition of perchlorate passivation in Example 1 of the present invention;

[0034] Figure 6 is the Faraday efficiency of methanol and methyl acetate in the acetate electro-oxidation reaction of the graphite catalyst after the addition of perchlorate in Example 1 of the present invention;

[0035] Figure 7 The current density-voltage curves of the graphite catalyst before passivation without the addition of perchlorate, the graphite catalyst after passivation without the addition of perchlorate, and the graphite catalyst after the addition of perchlorate in Example 1 of the present invention in the acetate electro-oxidation reaction;

[0036] Figure 8 The constant current stability test data of the graphite catalyst in Example 1 of the present invention without adding perchlorate in the electro-oxidation reaction of acetate, including the potential-time curve, and the Faraday efficiency-time curve of methanol, methyl acetate, and the total liquid phase product;

[0037] Fig. 9 The constant current stability test data of the graphite catalyst added with perchlorate in Example 1 of the present invention in the electro-oxidation reaction of acetate, including the potential-time curve, and the Faraday efficiency-time curve of methanol, methyl acetate, and the total liquid phase product;

[0038] Fig.10The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in the propionate electro-oxidation reaction in Example 2 of the present invention, including the potential-time comparison curve, and the Faraday efficiency-time curve of ethylene, ethanol, ethyl propionate and the total product of the graphite catalyst with perchlorate reaction;

[0039] Fig.11 The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in the electro-oxidation reaction of succinate in Example 3 of the present invention, including the potential-time comparison curve, and the Faraday efficiency-time curve of ethylene and acrylic acid of the graphite catalyst with perchlorate reaction;

[0040] Fig.12 The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in the butyrate electrooxidation reaction in Example 4 of the present invention, including the potential-time comparison curve, and the Faraday efficiency-time curve of propylene, n-propanol, isopropanol and total product of the graphite catalyst with perchlorate reaction;

[0041] Fig.13 The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in Example 5 of the present invention in the electro-oxidation reaction of levulinate, including a potential-time comparison curve, and a Faraday efficiency-time curve of methyl vinyl ketone of the graphite catalyst with perchlorate reaction;

[0042] Fig.14 The current density-voltage curves of the graphite catalyst without adding anionic salt to react and the graphite catalyst with adding perchlorate, nitrate, sulfate and phosphate to react in the acetate electro-oxidation reaction in Example 6 of the present invention;

[0043] Fig.15 It is the total Faraday efficiency of the liquid phase product of the graphite catalyst in Example 6 of the present invention without adding anionic salt to the reaction and the graphite catalyst in which perchlorate, nitrate, sulfate and phosphate are added to the reaction respectively in the electro-oxidation reaction of acetate. DETAILED DESCRIPTION

[0044] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the invention.

[0045] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0046] There is no particular limitation on the purity of all raw materials in the present invention. The present invention preferably adopts analytically pure materials or materials with conventional purity requirements in the field of atomic layer deposition.

[0047] All raw materials and process steps of the present invention, their brands or abbreviations are conventional brands or abbreviations in the art, and each brand or abbreviation is clear and definite in the field of its related use. Those skilled in the art can purchase them from the market or prepare them by conventional methods, or implement them with corresponding equipment according to the brands, abbreviations and corresponding uses.

[0048] The present invention provides an anion intercalated graphite catalyst, and the preparation method thereof specifically comprises the following steps:

[0049] Step 1, obtaining a graphite sheet, and washing and drying it;

[0050] Step 2: Using the graphite sheet obtained in step 1 as a working electrode, a carboxylate electro-oxidation reaction is carried out in an electrolysis device to obtain an anion intercalated graphite catalyst; wherein the electrolyte required for the reaction is composed of a carboxylate and an anion salt, and the anion salt is one or more of a perchlorate, a sulfate, a nitrate, and a phosphate.

[0051] Preferably, the anionic salt is perchlorate.

[0052] Furthermore, the carboxylate is one or more of acetate, propionate, butyrate, valerate, pivalate, succinate, and levulinate; preferably, the carboxylate is acetate.

[0053] Furthermore, the electrolyte also includes a soluble carboxylic acid corresponding to the added carboxylate, specifically acetic acid, propionic acid, butyric acid, valeric acid, pivalic acid, succinic acid or levulinic acid corresponding to the carboxylate; preferably, the carboxylic acid is acetic acid.

[0054] Furthermore, the concentration of carboxylate in the electrolyte is 0.1 to 5 mol per liter, the concentration of carboxylic acid is 0.1 to 5 mol per liter, and the concentration of anionic salt is 0.01 to 5 mol per liter; preferably, the concentration of carboxylate in the electrolyte is 0.1 to 2 mol per liter, the concentration of carboxylic acid is 0.1 to 2 mol per liter, and the concentration of anionic salt is 0.05 to 1 mol per liter.

[0055] Furthermore, the electrolysis device is a two-electrode system or a three-electrode system, specifically a three-port electrolytic cell, an H-type electrolytic cell or a flow-type electrolytic cell.

[0056] Furthermore, the reference electrode of the electrolysis device is a mercurous sulfate electrode, a silver / silver chloride electrode or a saturated calomel electrode, and the diaphragm is a proton exchange membrane, an anion exchange membrane or a bipolar membrane; preferably, the reference electrode is a silver / silver chloride electrode, and the diaphragm is a proton exchange membrane.

[0057] Furthermore, the specific process of the cleaning is: ultrasonic cleaning in dilute hydrochloric acid, anhydrous ethanol and deionized water in sequence, wherein the anhydrous ethanol can be replaced by acetone.

[0058] Furthermore, the duration of the ultrasonic cleaning is 5 to 60 minutes; preferably, the duration of the ultrasonic cleaning is 30 minutes.

[0059] Furthermore, the concentration of the dilute hydrochloric acid is 0.1 to 3 mol / L; preferably, the concentration of the dilute hydrochloric acid is 1 mol / L.

[0060] Furthermore, the specific process of the drying is: drying in a vacuum oven at 40 to 80 degrees Celsius for at least 12 hours; preferably, the temperature is 60 degrees Celsius and drying overnight.

[0061] Furthermore, the graphite sheet has a thickness of 0.1 to 2 cm, and a plane size of 1×1 cm2 to 3×3 cm2; preferably, the graphite sheet has a thickness of 0.5 cm, and a plane size of 1×2 cm2.

[0062] The present invention will be further described below in conjunction with embodiments:

[0063] Example 1

[0064] In order to explore the effect of adding specific anion salts on the catalytic performance during the electro-oxidation reaction of carboxylate using graphite sheets as working electrodes, three graphite catalysts were prepared in this example for performance testing, namely, the graphite catalyst before passivation without the addition of perchlorate, the graphite catalyst after passivation without the addition of perchlorate, and the graphite catalyst after the addition of perchlorate (i.e., anion intercalation).

[0065] The electrolysis device required for the preparation process is a flow-type electrolytic cell, with three graphite catalysts as working electrodes, platinum-coated titanium mesh as counter electrode, silver / silver chloride as reference electrode, and a proton exchange membrane as diaphragm. The electrolysis process is a constant current method; the electrolyte is pumped into the anode side at a rate of 2 ml per minute, and the working area is 1.5×0.5 square centimeters; 0.5 mol per liter sulfuric acid solution is pumped into the cathode side at a rate of 2 ml per minute, and the working area is 1.5×0.5 square centimeters.

[0066] The preparation process of the three graphite catalysts specifically includes the following steps:

[0067] Step 1, obtain a commercial graphite sheet with a thickness of 0.5 cm, cut it into three pieces with a plane size of 1×2 cm2, ultrasonically clean it in 1 mol / L dilute hydrochloric acid, anhydrous ethanol and deionized water for 30 minutes respectively, place it in a vacuum oven at 60 degrees Celsius and dry it overnight to complete the pretreatment of the graphite sheet, and take one of the pretreated graphite sheets as a graphite catalyst before adding perchlorate passivation;

[0068] Step 2, using a pretreated graphite sheet obtained in step 1 as a working electrode, performing a perchlorate electro-oxidation reaction in an electrolysis device, and reacting at a current density of 0.15 amperes per square centimeter for 2 hours to obtain a graphite catalyst that is not passivated by adding perchlorate; wherein the electrolyte required for the reaction is composed of 2 mol / L sodium acetate and 2 mol / L acetic acid solution;

[0069] Step 3: Using the pretreated graphite sheet obtained in step 1 as a working electrode, a perchlorate electro-oxidation reaction is carried out in an electrolysis device to obtain a graphite catalyst after the addition of perchlorate, i.e., an anion intercalated graphite catalyst; wherein the electrolyte required for the reaction is composed of 2 mol / L sodium acetate, 2 mol / L acetic acid solution and 0.1 mol / L sodium perchlorate.

[0070] 1) The graphite catalyst before passivation without the addition of perchlorate, the graphite catalyst after passivation without the addition of perchlorate, and the graphite catalyst after the addition of perchlorate in this example are characterized respectively.

[0071] Figure 1 3 are X-ray diffraction spectra of the graphite catalyst before passivation without adding perchlorate, the graphite catalyst after passivation without adding perchlorate, and the graphite catalyst after reaction with perchlorate in this embodiment. It can be seen that the peak values ​​of the graphite catalyst before passivation without adding perchlorate and the graphite catalyst after passivation without adding perchlorate do not change, while the peak value of the graphite catalyst after reaction with perchlorate shifts to a low angle, indicating that the lattice has expanded and the anions have been successfully intercalated.

[0072] Figure 2 is a high-resolution transmission electron micrograph of the graphite catalyst without the addition of perchlorate passivation in this example, Figure 3 This is a high-resolution transmission electron microscopy photograph of the graphite catalyst after the reaction with perchlorate. It can be seen that the interlayer spacing of the graphite catalyst after passivation without the addition of perchlorate is 0.353 nanometers, while the interlayer spacing of the graphite catalyst after the reaction with perchlorate is significantly increased to 0.363 nanometers and 0.418 nanometers, which also indicates that the anions are successfully intercalated.

[0073] 2) The catalytic performance of the graphite catalyst before passivation without the addition of perchlorate, the graphite catalyst after passivation without the addition of perchlorate, and the graphite catalyst after the addition of perchlorate were tested.

[0074] Specifically, a constant current test was carried out in a flow-type electrolytic cell of a three-electrode system. The current densities of the graphite catalyst before and after passivation with perchlorate were 0.05, 0.1, 0.2, and 0.3 amperes per square centimeter, respectively. The current densities of the graphite catalyst after the reaction with perchlorate were 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1 ampere per square centimeter, respectively. After 10 to 15 minutes of continuous electrolysis in the three-electrode system, 5 ml of liquid product was collected for detection, and the potential corresponding to different current densities was recorded.

[0075] The collected liquid reaction products are detected by liquid nuclear magnetic resonance spectrometer. Figure 4 is the Faradaic efficiency of methanol and methyl acetate in the electrooxidation reaction of acetate on the graphite catalyst before perchlorate passivation, Figure 5 is the Faradaic efficiency of methanol and methyl acetate in the electrooxidation reaction of acetate over the graphite catalyst without perchlorate passivation, Figure 6 The Faraday efficiency of methanol and methyl acetate in the acetate electro-oxidation reaction of the graphite catalyst after the addition of perchlorate reaction. By comparison, the Faraday efficiency of the graphite catalyst after passivation without the addition of perchlorate is significantly lower than that of the graphite catalyst before passivation without the addition of perchlorate, while the Faraday efficiency of the graphite catalyst after the addition of perchlorate reaction is significantly improved, and it can still maintain excellent Faraday efficiency at high current density. Figure 7 The current density-voltage curves of the graphite catalyst before passivation with perchlorate, the graphite catalyst after passivation with perchlorate, and the graphite catalyst after reaction with perchlorate in the electro-oxidation reaction of acetate are shown. It can be seen that the current density-voltage curve of the graphite catalyst after the reaction with perchlorate is consistent with that of the graphite catalyst before passivation with perchlorate at 0.05-0.3 amperes per square centimeter, and a higher current density can be achieved at the same time. The graphite catalyst after passivation without the addition of perchlorate requires a larger potential to achieve electrolysis of 0.05-0.3 amperes per square centimeter, indicating that perchlorate as an anion intercalated into the graphite catalyst can effectively solve the passivation problem.

[0076] 3) The catalytic stability tests were performed on the graphite catalyst without adding perchlorate in step 2 of this embodiment and the graphite catalyst with adding perchlorate in step 3.

[0077] Specifically, a constant current test was carried out in a flow-type electrolytic cell of a three-electrode system with a current density of 0.15 amperes per square centimeter. The potential-time curve was recorded, and liquid products were collected regularly and detected by a liquid nuclear magnetic resonance spectrometer.

[0078] Figure 8 The constant current stability test data of the graphite catalyst in the acetate electrooxidation reaction without adding perchlorate reaction, Fig. 9 The constant current stability test data of the graphite catalyst with perchlorate reaction in the acetate electro-oxidation reaction include the potential-time curve, as well as the Faraday efficiency-time curve of methanol, methyl acetate, and the total liquid phase product. It can be seen that the graphite catalyst without perchlorate reaction was passivated after 2 hours of electrolysis, the potential increased significantly, and the Faraday efficiency of methanol and methyl acetate decreased significantly, while the stability of the graphite catalyst with perchlorate reaction was significantly better than the former, and the decarboxylation reaction could be completed at a lower potential, and the good Faraday efficiency of methanol and methyl acetate was maintained.

[0079] Example 2

[0080] This example explores the catalytic stability test of the graphite catalyst without adding perchlorate reaction and the graphite catalyst with adding perchlorate reaction in the propionate decarboxylation reaction. Compared with Example 1, the only difference is that the electrolyte corresponding to the graphite catalyst without adding perchlorate reaction consists of 1 mol per liter of sodium propionate and 1 mol per liter of propionic acid solution, and the electrolyte corresponding to the graphite catalyst with adding perchlorate reaction consists of 1 mol per liter of sodium propionate, 1 mol per liter of propionic acid solution and 0.05 mol per liter of sodium perchlorate. Other conditions and processes remain unchanged.

[0081] A constant current test was carried out in a three-electrode flow electrolytic cell with a current density of 0.3 amperes per square centimeter. The potential-time curve was recorded, and liquid products were collected regularly and detected by a liquid nuclear magnetic resonance spectrometer.

[0082] Fig.10 The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in the propionate electro-oxidation reaction in this embodiment include a potential-time comparison curve and a Faraday efficiency-time curve of ethylene, ethanol, ethyl propionate and the total product of the graphite catalyst with perchlorate reaction. It can be seen that in the propionate decarboxylation reaction, the stability of the graphite catalyst with perchlorate reaction is significantly better.

[0083] Example 3

[0084] This example explores the catalytic stability test of the graphite catalyst without adding perchlorate to the reaction and the graphite catalyst with adding perchlorate to the reaction in the decarboxylation reaction of succinate. Compared with Example 1, the only difference is that the electrolyte corresponding to the graphite catalyst without adding perchlorate to the reaction is composed of 0.5 mol / L sodium succinate, and the electrolyte corresponding to the graphite catalyst with adding perchlorate to the reaction is composed of 0.5 mol sodium succinate solution and 0.025 mol / L sodium perchlorate. Other conditions and processes remain unchanged.

[0085] A constant current test was carried out in a three-electrode flow electrolytic cell with a current density of 0.1 ampere per square centimeter. The potential-time curve was recorded, and liquid products were collected regularly and detected by a liquid nuclear magnetic resonance spectrometer.

[0086] Fig.11 The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in the electro-oxidation reaction of succinate in this embodiment include a potential-time comparison curve and a Faraday efficiency-time curve of ethylene and acrylic acid of the graphite catalyst with perchlorate reaction. It can be seen that in the decarboxylation reaction of succinate, the stability of the graphite catalyst with perchlorate reaction is significantly better.

[0087] Example 4

[0088] This example explores the catalytic stability test of the graphite catalyst without adding perchlorate reaction and the graphite catalyst with adding perchlorate reaction in the butyrate decarboxylation reaction. Compared with Example 1, the only difference is that the electrolyte corresponding to the graphite catalyst without adding perchlorate reaction consists of 1 mol per liter of sodium butyrate and 1 mol per liter of butyric acid solution, and the electrolyte corresponding to the graphite catalyst with adding perchlorate reaction consists of 1 mol per liter of sodium butyrate, 1 mol per liter of butyric acid solution and 0.05 mol per liter of sodium perchlorate. Other conditions and processes remain unchanged.

[0089] A constant current test was carried out in a three-electrode flow electrolytic cell with a current density of 0.2 amperes per square centimeter. The potential-time curve was recorded, and liquid products were collected regularly and detected by a liquid nuclear magnetic resonance spectrometer.

[0090] Fig.12 The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in the butyrate electro-oxidation reaction in this embodiment include a potential-time comparison curve and a Faraday efficiency-time curve of propylene, n-propanol, isopropanol and the total product of the graphite catalyst with perchlorate reaction. It can be seen that in the butyrate decarboxylation reaction, the stability of the graphite catalyst with perchlorate reaction is significantly better.

[0091] Example 5

[0092] This example explores the catalytic stability test of the graphite catalyst without the addition of perchlorate reaction and the graphite catalyst with the addition of perchlorate reaction in the decarboxylation reaction of levulinate. Compared with Example 1, the only difference is that the electrolyte corresponding to the graphite catalyst without the addition of perchlorate reaction consists of 1 mol per liter of sodium levulinate and 1 mol per liter of levulinic acid solution, and the electrolyte corresponding to the graphite catalyst with the addition of perchlorate reaction consists of 1 mol per liter of levulinic acid, 1 mol per liter of levulinic acid solution and 0.5 mol per liter of sodium perchlorate. Other conditions and processes remain unchanged.

[0093] A constant current test was carried out in a three-electrode flow electrolytic cell with a current density of 0.1 ampere per square centimeter. The potential-time curve was recorded, and liquid products were collected regularly and detected by a liquid nuclear magnetic resonance spectrometer.

[0094] Fig.13 The constant current stability test data of the graphite catalyst without perchlorate reaction and the graphite catalyst with perchlorate reaction in the electro-oxidation reaction of levulinate in this embodiment include a potential-time comparison curve and a Faraday efficiency-time curve of methyl vinyl ketone of the graphite catalyst with perchlorate reaction. It can be seen that in the decarboxylation reaction of levulinate, the stability of the graphite catalyst with perchlorate reaction is significantly better.

[0095] Example 6

[0096] This example explores the effect of adding different anion salts (including perchlorate, nitrate, sulfate, and phosphate) on the catalytic performance of the acetate decarboxylation reaction. Compared with Example 1, the only difference is that the sodium perchlorate in the electrolyte composition required for the reaction in step 3 is adjusted to sodium nitrate, sodium sulfate, and sodium phosphate, respectively, and the concentration is consistent with Example 1, all of which are 0.1 mol / L. Other conditions and processes remain unchanged.

[0097] A constant current test was conducted in a three-electrode system flow-type electrolytic cell, with current densities of 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1 ampere per square centimeter, respectively. After 10 to 15 minutes of continuous electrolysis in the three-electrode system, 5 ml of liquid products were collected for detection, and the potential corresponding to different current densities was recorded at the same time. The collected liquid reaction products were detected by a liquid nuclear magnetic resonance spectrometer.

[0098] Fig.14 : is the current density-voltage curve of the graphite catalyst without adding anion salt to the reaction and the graphite catalyst with adding perchlorate, nitrate, sulfate and phosphate to the reaction in the acetate electrooxidation reaction in this embodiment, Fig.15It is the total Faraday efficiency of the liquid phase product of the graphite catalyst without the addition of anionic salts and the graphite catalyst with the addition of perchlorate, nitrate, sulfate, and phosphate in the electrooxidation reaction of acetate. It can be seen that compared with the graphite catalyst without the addition of anionic salts, the catalytic performance of the graphite catalyst with the addition of perchlorate, nitrate, sulfate, or phosphate is significantly improved, and a higher current density can be achieved, but the Faraday efficiency of the graphite catalyst with the addition of perchlorate is the best.

[0099] The above is a detailed introduction to an anion intercalated graphite catalyst, a preparation method and its application in a carboxylate oxidation reaction provided by the present invention. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method and its core ideas of the present invention, including the best mode, and also enables any technician in the field to practice the present invention, including the manufacture and use of any device or system, and the implementation of any combined method. It should be pointed out that for ordinary technicians in the field of this technology, without departing from the principles of the present invention, the present invention can also be improved and modified in a number of ways, and these improvements and modifications also fall within the scope of protection of the claims of the present invention. The scope of patent protection of the present invention is defined by the claims and may include other embodiments that can be thought of by those skilled in the art. If these other embodiments have structural elements that are not different from the text of the claims, or if they include equivalent structural elements that are not substantially different from the text of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. An anion intercalated graphite catalyst, characterized in that Anions are inserted between the layers of the graphite catalyst, and the interlayer spacing increases by 0.01 to 0.2 nanometers compared to the non-intercalated graphite catalyst.

2. The anion intercalated graphite catalyst according to claim 1, characterized in that: The anion is perchlorate, sulfate, nitrate or phosphate.

3. A method for preparing an anion intercalated graphite catalyst, characterized in that: The following steps are involved: Step 1, obtaining a graphite sheet, and washing and drying it; Step 2: Using the graphite sheet obtained in step 1 as a working electrode, a carboxylate electro-oxidation reaction is carried out in an electrolysis device to obtain an anion intercalated graphite catalyst; wherein the electrolyte required for the reaction is composed of a carboxylate and an anion salt, and the anion salt is one or more of perchlorate, sulfate, nitrate, and phosphate.

4. The method for preparing the anion intercalated graphite catalyst according to claim 3, characterized in that: The concentration of the anion salt is 0.01 to 5 mol / L.

5. The method for preparing the anion intercalated graphite catalyst according to claim 3, characterized in that: The carboxylate is one or more of acetate, propionate, butyrate, valerate, pivalate, succinate, and levulinate.

6. The method for preparing the anion intercalated graphite catalyst according to claim 5, characterized in that: The concentration of the carboxylate in the electrolyte is 0.1 to 5 mol / L.

7. The method for preparing the anion intercalated graphite catalyst according to claim 3, characterized in that: The electrolyte also includes a soluble carboxylic acid corresponding to the added carboxylate.

8. The method for preparing the anion intercalated graphite catalyst according to claim 7, characterized in that: The concentration of the carboxylic acid is 0.1 to 5 mol / L.

9. The method for preparing the anion intercalated graphite catalyst according to claim 3, characterized in that: The electrolysis device is a two-electrode system or a three-electrode system, specifically a three-port electrolysis cell, an H-type electrolysis cell or a flow-type electrolysis cell.

10. Use of the anion intercalated graphite catalyst obtained according to the preparation method according to any one of claims 3 to 9 in the electro-oxidation reaction of carboxylate.

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