CN112473660A - Palladium-carbon catalyst and preparation method thereof - Google Patents
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Abstract
The invention relates to a palladium-carbon catalyst and a preparation method thereof, comprising the following steps: adjusting the pH value of the solution of the palladium organic complex to be neutral, and carrying out cation exchange to obtain a palladium-containing solution with the conductivity of 20-40 mu S/cm; the ligand of the palladium organic complex contains phosphorus element; adding phosphine-tolerant algae into the palladium-containing solution for fermentation until the palladium content in the solution system is below 1000 ppm; taking out the phosphine-resistant algae, crushing, and performing anaerobic fermentation to obtain anaerobic fermentation biogas residues; and carrying out carbonization reduction reaction on the anaerobic fermentation biogas residues to obtain the palladium-carbon catalyst. Thus, the palladium organic complex solution containing the phosphorus element is adjusted to be neutral, cation exchange is carried out to remove most metal cations, and the specific conductivity of the palladium-containing solution after cation exchange is controlled; and then adding the palladium-containing solution into the phosphine-resistant algae, fermenting until the palladium content is reduced to below 1000ppm, and carrying out carbonization reduction reaction on the phosphine-resistant algae after anaerobic fermentation to obtain the high-dispersion palladium-carbon catalyst, thereby greatly improving the effective utilization rate of palladium.
Description
Technical Field
The invention relates to the technical field of catalysts, in particular to a palladium-carbon catalyst and a preparation method thereof.
Background
The palladium-carbon catalyst is a catalyst which loads metal palladium on the surface of active carbon, and has a very wide application scene. Generally, the synthesis of palladium on carbon can be classified into chemical methods and physical methods. The physical method is generally used for depositing metal atoms on the surface of the activated carbon by using a physical method, and is not widely applied. Chemical methods are commonly used in industrial production for preparation, and are generally divided into impregnation and reduction. However, the current solutions produce palladium-on-carbon catalysts with a low degree of dispersion of palladium, where the degree of dispersion is the proportion of the number of atoms of the active component exposed on the surface of the catalyst to the total number of atoms of the component in the catalyst, and usually the degree of dispersion of palladium does not exceed 40%, i.e. over 60% of the palladium is not effectively utilized. Therefore, how to improve the dispersity of the palladium-carbon catalyst is an urgent technical problem to be solved.
Disclosure of Invention
Accordingly, there is a need for a palladium-carbon catalyst with improved dispersion and a method for preparing the same.
A preparation method of a palladium-carbon catalyst comprises the following steps:
adjusting the pH value of the solution of the palladium organic complex to be neutral, and carrying out cation exchange to remove metal cation impurities to obtain a palladium-containing solution with the conductivity of 20-40 mu S/cm; the ligand of the palladium organic complex contains phosphorus;
adding phosphine-tolerant algae into the palladium-containing solution for fermentation until the palladium content in the solution system is below 1000 ppm;
taking out the phosphine-resistant algae, crushing, and performing anaerobic fermentation to obtain anaerobic fermentation biogas residues;
and carrying out a carbonization reduction reaction on the anaerobic fermentation biogas residue to obtain the palladium-carbon catalyst.
Research shows that inorganic palladium solution without phosphorus is added into the phosphine-resistant algae for fermentation, and palladium cannot enter the algae; further, the subsequent step of taking out and crushing the phosphine-tolerant algae for anaerobic fermentation cannot be performed, and the subsequent carbonization-reduction reaction cannot be performed, so that the palladium-carbon catalyst cannot be prepared by the preparation method. And the method is very critical for removing metal cation impurities by adjusting the pH value of the solution of the palladium organic complex to be neutral and carrying out cation exchange, and further controlling the conductivity of the obtained palladium-containing solution to be 20-40 mu S/cm. If the conductivity of the controlled palladium-containing solution is not within the above range, palladium does not enter the algae well; further, the subsequent step of taking out and crushing the phosphine-tolerant algae for anaerobic fermentation cannot be performed, and the subsequent carbonization-reduction reaction cannot be performed, so that the palladium-carbon catalyst cannot be prepared by the preparation method.
According to the preparation method of the palladium-carbon catalyst, the palladium organic complex containing the phosphorus element is used, the palladium organic complex solution is adjusted to be neutral, cation exchange is carried out to remove most of metal cations, the influence of metal cation impurities is avoided, and the specific conductivity of the palladium-containing solution after cation exchange is controlled; and then adding the palladium-containing solution into the phosphine-resistant algae, fermenting until the palladium content is reduced to below 1000ppm, and carrying out anaerobic fermentation on the phosphine-resistant algae, and then carrying out a carbonization reduction reaction to obtain the high-dispersion palladium-carbon catalyst, thereby greatly improving the effective utilization rate of palladium.
Further, controlling the conductivity of the palladium-containing solution to be 25 to 35 mu S/cm; in some specific examples, the conductivity of the palladium-containing solution is controlled to be 30. mu.S/cm. Therefore, the dispersion degree of the prepared palladium-carbon catalyst can be favorably improved by controlling the conductivity of the palladium-containing solution.
In some embodiments, the ligand of the palladium organic complex is at least one of triphenylphosphine and a derivative of triphenylphosphine. It is understood that derivatives of triphenylphosphine include, but are not limited to, sulfonated triphenylphosphine, triarylphosphine oxides, and fluorine-containing phosphine ligands. Further, in some specific examples thereof, the palladium organic complex may be palladium chloride triphenylphosphine. In some embodiments, the palladium-containing solution has a mass concentration of 0.01% to 1%. By controlling the mass concentration of the palladium-containing solution within a suitable range, the fermentation step of the phosphine-tolerant algae in the palladium-containing solution of step S200 can be facilitated to be better performed.
In some of these embodiments, the phosphine-tolerant algae is selected from at least one of chlorella and cyanobacteria. It is understood that the species of the phosphine-tolerant algae include, but are not limited to, these.
In some of these examples, the fermentation time with the addition of the phosphine-tolerant algae is 3 to 5 days. By controlling the time for adding the phosphine-tolerant algae to the palladium-containing solution for fermentation within the above-mentioned suitable range, the fermentation step of the phosphine-tolerant algae in the palladium-containing solution can be better performed.
In some of these embodiments, the anaerobic fermentation is performed for a period of 2 to 4 days. By controlling the time of anaerobic fermentation within the proper range, the prepared palladium-carbon catalyst has better dispersity.
In some of these embodiments, the cation exchange is performed using a cation exchange resin. Further, the cation exchange resin may be a hydrogen type cation exchange resin, such as cation exchange resin 201, to exchange impurities such as sodium ions therein.
In some of these embodiments, the temperature of the carbomorphism reduction reaction is 180 ℃ to 240 ℃. Further, the temperature of the carbonization-reduction reaction is 180 ℃ to 210 ℃. A large number of researches show that the dispersity of the prepared palladium-carbon catalyst is further improved by controlling the hydrogen reduction temperature of the fluidized bed.
In some of these embodiments, the carbomorphism reduction reaction is carried out in a fluidized bed of hydrogen; the temperature of the hydrogen fluidized bed is 180-210 ℃, and the residence time of the fluid is 0.5-1 second.
The palladium-carbon catalyst is prepared by adopting the preparation method of any one of the palladium-carbon catalysts.
The mass fraction of palladium atoms in the palladium-carbon catalyst prepared by the preparation method of the palladium-carbon catalyst is 0.01-1%. The dispersity of the prepared palladium-carbon catalyst is 70-90%.
The palladium-carbon catalyst prepared by the method has high dispersity, high effective utilization rate of palladium noble metal and wide application range, can be widely applied to catalytic hydrogenation of unsaturated hydrocarbon or CO, and has the excellent characteristics of high hydrogenation reducibility, good selectivity, stable performance, small feed ratio in use, repeated application, easy recovery and the like.
Detailed Description
In order that the invention may be more fully understood, a more particular description of the invention will now be rendered by reference to specific embodiments thereof that are illustrated in the appended drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The palladium-carbon catalyst is a supported catalyst formed by loading metal palladium into active carbon, mainly plays a role in catalytic hydrogenation of unsaturated hydrocarbon or CO, and has the characteristics of high hydrogenation reducibility, good selectivity, stable performance, small feed ratio in use, repeated application, easy recovery and the like. The palladium-carbon catalyst is widely used in the hydrogenation reduction refining process of petrochemical industry, pharmaceutical industry, electronic industry, perfume industry, dye industry and other fine chemical industry. In some embodiments, palladium on carbon catalysts may be used to purify terephthalic acid feedstocks to produce purified terephthalic acid.
One embodiment of the present invention provides a method for preparing a palladium-carbon catalyst, including the following steps S100 to S400.
Step S100: adjusting the pH value of the solution of the palladium organic complex to be neutral, and carrying out cation exchange to remove metal cation impurities to obtain a palladium-containing solution with the conductivity of 20-40 mu S/cm; the ligand of the palladium organic complex contains phosphorus element.
In some of these embodiments, the ligand of the palladium organic complex is at least one of triphenylphosphine and a derivative of triphenylphosphine. It is understood that derivatives of triphenylphosphine include, but are not limited to, sulfonated triphenylphosphine, triarylphosphine oxides, and fluorine-containing phosphine ligands. Further, in some specific examples thereof, the palladium organic complex may be palladium chloride triphenylphosphine.
A large number of researches show that under the condition of keeping other conditions unchanged, inorganic palladium solution without phosphorus is adopted and phosphine-resistant algae is added for fermentation, and palladium cannot enter the algae; further, the subsequent step of taking out and crushing the phosphine-tolerant algae for anaerobic fermentation cannot be performed, and the subsequent carbonization-reduction reaction cannot be performed, so that the palladium-carbon catalyst cannot be prepared by the preparation method. Reference may be made specifically to example 1 and comparative example 1 of the specific examples section of the present invention.
A great deal of research shows that the method is very critical to remove metal cation impurities by adjusting the pH value of the solution of the palladium organic complex to be neutral and performing cation exchange in step S100, and further controlling the conductivity of the obtained palladium-containing solution to be 20-40 mu S/cm. With specific reference to example 1 and comparative example 2 of the specific examples section of the present invention, under otherwise unchanged conditions, if the conductivity of the palladium-containing solution is not within the above range, palladium does not enter the algae well; further, the subsequent step of taking out and crushing the phosphine-tolerant algae for anaerobic fermentation cannot be performed, and the subsequent carbonization-reduction reaction cannot be performed, so that the palladium-carbon catalyst cannot be prepared by the preparation method.
Further, controlling the conductivity of the palladium-containing solution to be 25 to 35 mu S/cm; in some specific examples, the conductivity of the palladium-containing solution is controlled to be 30. mu.S/cm. Therefore, the dispersion degree of the prepared palladium-carbon catalyst can be favorably improved by controlling the conductivity of the palladium-containing solution.
It is understood that in other embodiments, the conductivity of the palladium-containing solution can be controlled to 20. mu.S/cm, 22. mu.S/cm, 24. mu.S/cm, 25. mu.S/cm, 26. mu.S/cm, 28. mu.S/cm, 31. mu.S/cm, 33. mu.S/cm, 36. mu.S/cm, 38. mu.S/cm, 40. mu.S/cm, and the like.
In some of these embodiments, the reagent used to adjust the ph to neutrality is liquid caustic (i.e., sodium hydroxide in liquid form). It is understood that in other embodiments, the agent used to adjust the ph to neutrality may be a sodium hydroxide solution, including but not limited to.
In some of these embodiments, the cation exchange is performed using a cation exchange resin; further, the cation exchange resin may be a hydrogen type cation exchange resin, such as cation exchange resin 201, to exchange impurities such as sodium ions therein.
Step S200: adding phosphine-tolerant algae into the palladium-containing solution for fermentation until the palladium content in the solution system is below 1000 ppm.
The fermentation step of step S200 can reduce the palladium content in the solution system to below 1000ppm, which indicates that the phosphine-tolerant algae has high utilization rate for palladium metal materials and greatly reduces the environmental problem caused by the emission of palladium metal.
In some embodiments, the palladium-containing solution has a mass concentration of 0.01% to 1%. By controlling the mass concentration of the palladium-containing solution within a suitable range, the fermentation step of the phosphine-tolerant algae in the palladium-containing solution of step S200 can be facilitated to be better performed. In some specific examples thereof, the mass concentration of the palladium-containing solution may be 0.05%, 0.1%, 0.2%, 0.3%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%.
It is understood that the phosphine-tolerant algae can be adapted to grow in an environment containing phosphorus, and the solution of palladium organic complex containing phosphorus element in the ligand in step S100 is matched, so that the fermentation step in step S200 can promote the normal growth of the phosphine-tolerant algae in the palladium-containing solution.
In some of these embodiments, the phosphine-tolerant algae is selected from at least one of chlorella and cyanobacteria. It is understood that the species of the phosphine-tolerant algae include, but are not limited to, these. Further, step S200 is performed in an algae pond containing phosphine-tolerant algae. In other words, step S200 is to ferment the palladium-containing solution prepared in step S100 in an algae pond containing phosphine-tolerant algae.
The fermentation in step S200 is to promote the normal growth of the phosphine-tolerant algae in the palladium-containing solution, and is performed at normal temperature. It should be noted that the "normal temperature" in the present invention is 25 ℃ ± 5 ℃, in other words, the "normal temperature" is 20 ℃ ± 30 ℃.
In some embodiments, the fermentation is conducted with the addition of the phosphine-tolerant algae for a period of time ranging from 3 days to 5 days, such as 3 days, 4 days, or 5 days. By controlling the time for adding the phosphine-tolerant algae to the palladium-containing solution for fermentation within the above-mentioned suitable range, the fermentation step of the phosphine-tolerant algae in the palladium-containing solution can be better performed.
In some embodiments, the solution system is fermented in step S200 until the palladium content is 1ppm to 1000 ppm; further fermenting until the palladium content in the solution system is 3 ppm-10 ppm, and further fermenting until the palladium content in the solution system is 3 ppm-7 ppm.
Step S300: and taking out the phosphine-resistant algae, crushing, and performing anaerobic fermentation to obtain anaerobic fermentation biogas residues.
Anaerobic fermentation is carried out under anaerobic conditions, for example, under an air-free environment.
In some embodiments, the anaerobic fermentation is for a period of 2 days to 4 days, e.g., 2 days, 3 days, or 4 days. By controlling the time of the anaerobic fermentation in the step S300 within the appropriate range, the prepared palladium-carbon catalyst can be further dispersed well.
Step S400: and carrying out carbonization reduction reaction on the anaerobic fermentation biogas residues to obtain the palladium-carbon catalyst.
Step S400, carrying out carbonization-reduction reaction on the anaerobic fermentation biogas residues to carbonize and reduce organic matters in the anaerobic fermentation biogas residues to form carbon; and then the palladium metal catalyst which is highly dispersed and loaded on the carbon is obtained, namely the palladium carbon catalyst.
In some of these embodiments, the temperature of the carbomorphism reduction reaction is between 180 ℃ and 240 ℃. Further, the temperature of the carbonization-reduction reaction is 180 ℃ to 210 ℃. A large number of researches show that the dispersity of the prepared palladium-carbon catalyst is further improved by controlling the hydrogen reduction temperature of the fluidized bed. Reference is made in particular to example 1 and example 3 of the detailed description of the invention. Example 1 by controlling the temperature of the fluidized bed hydrogen reduction of step 4), the degree of dispersion of the palladium carbon catalyst prepared in example 1 was much greater than that of the palladium carbon catalyst prepared in example 3.
In some of these embodiments, the carbomorphism reduction reaction is carried out in a fluidized bed of hydrogen gas. Furthermore, the temperature of the hydrogen fluidized bed is 180-210 ℃, and the residence time of the fluid is 0.5-1 second.
In some embodiments, before the anaerobic fermentation biogas residue is subjected to the carbonization reduction reaction, the method further comprises the step of drying the anaerobic fermentation biogas residue and crushing the anaerobic fermentation biogas residue into powder. Further, the drying step can adopt vacuum drying, and the temperature of the vacuum drying can be 70-100 ℃.
According to the preparation method of the palladium-carbon catalyst, the palladium organic complex containing the phosphorus element is used, the palladium organic complex solution is adjusted to be neutral, cation exchange is carried out to remove most of metal cations, the influence of metal cation impurities is avoided, and the specific conductivity of the palladium-containing solution after cation exchange is controlled; and then adding the palladium-containing solution into the phosphine-resistant algae, fermenting until the palladium content is reduced to below 1000ppm, and carrying out anaerobic fermentation on the phosphine-resistant algae, and then carrying out a carbonization reduction reaction to obtain the high-dispersion palladium-carbon catalyst, thereby greatly improving the effective utilization rate of palladium.
The mass fraction of palladium atoms in the palladium-carbon catalyst prepared by the preparation method of the palladium-carbon catalyst is 0.01-1%. The dispersity of the prepared palladium-carbon catalyst is 70-90%.
Another embodiment of the present invention provides a palladium carbon catalyst, which is prepared by any one of the above methods for preparing a palladium carbon catalyst.
The palladium-carbon catalyst has high dispersity, and the dispersity of the palladium-carbon catalyst is 70-90% through detection.
In order to make the objects, technical solutions and advantages of the present invention more concise and clear, the present invention is described with the following specific embodiments, but the present invention is by no means limited to these embodiments. The following described examples are only preferred embodiments of the present invention, which can be used to describe the present invention and should not be construed as limiting the scope of the present invention. It should be understood that any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
In order to better illustrate the invention, the following examples are given to further illustrate the invention. The following are specific examples.
Example 1
The palladium-carbon catalyst and the preparation method thereof comprise the following specific steps:
1) preparing triphenylphosphine palladium chloride solution containing 100 g palladium atoms; adjusting the palladium chloride solution of triphenylphosphine to be neutral by using liquid alkali, and removing most of cations by using cation exchange resin 201 to obtain a palladium-containing solution with the conductivity of 30 mu S/cm and the mass concentration of 0.15%;
2) adding 15kg of phosphine-tolerant algae (chlorella) into the palladium-containing solution, and fermenting for 3 days to reduce the palladium content in the solution system to 7 ppm;
3) taking out and crushing the phosphine-tolerant algae, and performing anaerobic fermentation for 4 days to obtain anaerobic fermentation biogas residues; then drying in vacuum at 70 ℃ and crushing into anaerobic fermentation powder;
4) and (3) reducing the anaerobic fermentation powder in a fluidized bed at 180 ℃ by hydrogen, and staying for 0.5 second to obtain 10kg of the high-dispersion palladium-carbon catalyst.
Through detection, the palladium-carbon catalyst prepared in this example has a palladium atom content of 0.5 wt%, and the dispersity of the palladium-carbon catalyst measured by a chemical adsorption apparatus is 75%.
Example 2
The palladium-carbon catalyst and the preparation method thereof comprise the following specific steps:
1) preparing triphenylphosphine palladium chloride solution containing 10 g of palladium atoms; adjusting the palladium chloride solution of triphenylphosphine to be neutral by using liquid alkali, and removing most of cations by using cation exchange resin 201 to obtain a palladium-containing solution with the conductivity of 30 mu S/cm and the mass concentration of 0.15%;
2) adding 15kg of phosphine-tolerant algae (chlorella) into the palladium-containing solution, and fermenting for 3 days to reduce the palladium content in the solution system to 3 ppm;
3) taking out and crushing the phosphine-tolerant algae, and performing anaerobic fermentation for 4 days to obtain anaerobic fermentation biogas residues; then drying in vacuum at 70 ℃ and crushing into anaerobic fermentation powder;
4) and (3) reducing the anaerobic fermentation powder in a fluidized bed at 210 ℃ by hydrogen, and staying for 1 second to obtain 10kg of the high-dispersion palladium-carbon catalyst.
Through detection, the palladium-carbon catalyst prepared in this example has a palladium atom content of 0.05 wt%, and the dispersity of the palladium-carbon catalyst measured by a chemical adsorption apparatus is 87%.
Example 3
Example 3 is essentially the same as example 1, except that: step 4) the temperature of the fluidized bed hydrogen reduction was 240 ℃. Specifically, the palladium-carbon catalyst of example 3 and the preparation method thereof specifically include the following steps:
1) preparing triphenylphosphine palladium chloride solution containing 100 g palladium atoms; adjusting the palladium chloride solution of triphenylphosphine to be neutral by using liquid alkali, and removing most of cations by using cation exchange resin 201 to obtain a palladium-containing solution with the conductivity of 30 mu S/cm and the mass concentration of 0.15%;
2) adding 15kg of phosphine-tolerant algae (chlorella) into the palladium-containing solution, and fermenting for 3 days to reduce the palladium content in the solution system to 7 ppm;
3) taking out and crushing the phosphine-tolerant algae, and performing anaerobic fermentation for 4 days to obtain anaerobic fermentation biogas residues; then drying in vacuum at 70 ℃ and crushing into anaerobic fermentation powder;
4) and (3) reducing the anaerobic fermentation powder in a fluidized bed at 240 ℃ by hydrogen, and staying for 2 seconds to obtain 10kg of the high-dispersion palladium-carbon catalyst.
Through detection, the palladium-carbon catalyst prepared in this example has a palladium atom content of 0.5 wt%, and the dispersity of the palladium-carbon catalyst measured by a chemical adsorption apparatus is 50%.
Comparative example 1
Comparative example 1 is essentially the same as example 1 except that: replacing the triphenylphosphine palladium chloride solution prepared in the step 1) with palladium nitrate solution with the same molar concentration of palladium atoms. Specifically, the palladium-carbon catalyst of comparative example 1 and the preparation method thereof specifically include the following steps: 1) preparing a palladium nitrate solution containing 100 g of palladium atoms; adjusting the palladium nitrate solution to be neutral by using liquid alkali, and removing most of cations by using cation exchange resin 201 to obtain a palladium-containing solution with the conductivity of 30 mu S/cm and the mass concentration of 0.15%;
2) 15kg of phosphine-tolerant algae (chlorella) is added into the palladium-containing solution to be fermented for 3 days, and the palladium content in the solution system does not change greatly, which indicates that palladium can not enter the algae under the condition.
Comparative example 2
Comparative example 2 is essentially the same as example 1, except that: the conductivity of the palladium-containing solution controlled in step 1) was 48. mu.S/cm. Specifically, the palladium-carbon catalyst of comparative example 2 and the preparation method thereof have the following specific steps:
1) preparing triphenylphosphine palladium chloride solution containing 100 g palladium atoms; regulating the palladium chloride solution of triphenylphosphine to be neutral by using liquid alkali, and removing cations by using cation exchange resin 201 to obtain a palladium-containing solution with the conductivity of 48 mu S/cm;
2) 15kg of phosphine-tolerant algae (chlorella) is added into the palladium-containing solution to be fermented for 3 days, and the palladium content is only reduced by 11 percent, which indicates that the palladium cannot enter the algae well.
As can be seen from comparison between example 1 and comparative example 1, under the condition of not changing other conditions, the phosphorus-free inorganic palladium solution is adopted and the phosphine-resistant algae is added for fermentation, and palladium can not enter the algae; further, the subsequent step of taking out and crushing the phosphine-tolerant algae for anaerobic fermentation cannot be performed, and the subsequent carbonization-reduction reaction cannot be performed, so that the palladium-carbon catalyst cannot be prepared by the preparation method.
As can be seen from comparison between example 1 and comparative example 2, under the condition of keeping other conditions unchanged, the conductivity of the controlled palladium-containing solution is 48 muS/cm, and the palladium content is only reduced by 10% after 3 days of fermentation in step 2), which indicates that palladium can not enter algae well; further, the subsequent step of taking out and crushing the phosphine-tolerant algae for anaerobic fermentation cannot be performed, and the subsequent carbonization-reduction reaction cannot be performed, so that the palladium-carbon catalyst cannot be prepared by the preparation method.
Examples 1 and 2 show that a higher degree of dispersion, specifically 75% to 87%, can be achieved with palladium atoms at 0.5 wt% or 0.05 wt%.
As can be seen from comparison between example 1 and example 3, in example 1, the dispersity of the palladium-carbon catalyst prepared in example 1 is much greater than that of the palladium-carbon catalyst prepared in example 3 by controlling the temperature of the fluidized bed hydrogen reduction in step 4). Specifically, the dispersion degree of the palladium-carbon catalyst prepared in example 1 was 75%, and the dispersion degree of the palladium-carbon catalyst prepared in example 3 was 50%.
Therefore, the steps of the preparation method of the palladium-carbon catalyst provided by the invention act synergistically to form an organic integral technical scheme. Specifically, in the preparation method of the palladium-carbon catalyst, the palladium organic complex containing the phosphorus element is used, the palladium organic complex solution is adjusted to be neutral, cation exchange is carried out to remove most of metal cations, the influence of metal cation impurities is avoided, and the specific conductivity of the palladium-containing solution after cation exchange is controlled; and then adding the palladium-containing solution into the phosphine-resistant algae, fermenting until the palladium content is reduced to below 1000ppm, and carrying out anaerobic fermentation on the phosphine-resistant algae, and then carrying out a carbonization reduction reaction to obtain the high-dispersion palladium-carbon catalyst, thereby greatly improving the effective utilization rate of palladium.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The preparation method of the palladium-carbon catalyst is characterized by comprising the following steps of:
adjusting the pH value of the solution of the palladium organic complex to be neutral, and carrying out cation exchange to remove metal cation impurities to obtain a palladium-containing solution with the conductivity of 20-40 mu S/cm; the ligand of the palladium organic complex contains phosphorus;
adding phosphine-tolerant algae into the palladium-containing solution for fermentation until the palladium content in the solution system is below 1000 ppm;
taking out the phosphine-resistant algae, crushing, and performing anaerobic fermentation to obtain anaerobic fermentation biogas residues; and
and carrying out a carbonization reduction reaction on the anaerobic fermentation biogas residue to obtain the palladium-carbon catalyst.
2. The method of preparing a palladium on carbon catalyst as claimed in claim 1, wherein the ligand of the palladium organic complex is at least one of triphenylphosphine and a derivative of triphenylphosphine.
3. The method of preparing a palladium-on-carbon catalyst according to claim 1, wherein the mass concentration of the palladium-containing solution is 0.01 to 1%.
4. The method of preparing a palladium-on-carbon catalyst according to claim 1, wherein the phosphine-tolerant algae is at least one selected from chlorella and cyanobacteria.
5. The method of preparing a palladium-on-carbon catalyst according to claim 1, wherein the time for adding the phosphine-tolerant algae for fermentation is 3 to 5 days.
6. The method of preparing a palladium on carbon catalyst as claimed in claim 1, wherein the anaerobic fermentation is carried out for a period of 2 to 4 days.
7. The method of preparing a palladium on carbon catalyst according to claim 1, wherein the cation exchange is carried out using a cation exchange resin.
8. The method for preparing a palladium-carbon catalyst according to any one of claims 1 to 7, wherein the temperature of the carbomorphism reduction reaction is 180 ℃ to 240 ℃.
9. The method of preparing a palladium-on-carbon catalyst according to claim 8, wherein the carbomorphism reduction reaction is carried out in a hydrogen fluidized bed; the temperature of the hydrogen fluidized bed is 180-210 ℃, and the residence time of the fluid is 0.5-1 second.
10. A palladium-carbon catalyst characterized by being produced by the method for producing a palladium-carbon catalyst according to any one of claims 1 to 9.
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| CN114653373A (en) * | 2022-05-10 | 2022-06-24 | 中国矿业大学 | High-selectivity nickel resin carbon catalyst and preparation method and application thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114653373A (en) * | 2022-05-10 | 2022-06-24 | 中国矿业大学 | High-selectivity nickel resin carbon catalyst and preparation method and application thereof |
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