CN117594807A - Method for synthesizing Ir-Co heteronuclear monoatomic catalyst by one-step annealing method and application - Google Patents
Method for synthesizing Ir-Co heteronuclear monoatomic catalyst by one-step annealing method and application Download PDFInfo
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- 239000003054 catalyst Substances 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 32
- 238000000137 annealing Methods 0.000 title claims abstract description 19
- 230000002194 synthesizing effect Effects 0.000 title claims abstract description 13
- BDAGIHXWWSANSR-UHFFFAOYSA-N methanoic acid Natural products OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 claims abstract description 32
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 25
- OSWFIVFLDKOXQC-UHFFFAOYSA-N 4-(3-methoxyphenyl)aniline Chemical compound COC1=CC=CC(C=2C=CC(N)=CC=2)=C1 OSWFIVFLDKOXQC-UHFFFAOYSA-N 0.000 claims abstract description 16
- 235000019253 formic acid Nutrition 0.000 claims abstract description 16
- QGBSISYHAICWAH-UHFFFAOYSA-N dicyandiamide Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 claims abstract description 13
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- 238000007254 oxidation reaction Methods 0.000 claims abstract description 11
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- 238000001035 drying Methods 0.000 claims abstract description 3
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 claims abstract description 3
- 239000000243 solution Substances 0.000 claims description 53
- 239000007864 aqueous solution Substances 0.000 claims description 37
- 239000002243 precursor Substances 0.000 claims description 28
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 21
- UFMZWBIQTDUYBN-UHFFFAOYSA-N cobalt dinitrate Chemical compound [Co+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O UFMZWBIQTDUYBN-UHFFFAOYSA-N 0.000 claims description 18
- 229910001981 cobalt nitrate Inorganic materials 0.000 claims description 18
- 239000008367 deionised water Substances 0.000 claims description 15
- 229910021641 deionized water Inorganic materials 0.000 claims description 15
- 239000007787 solid Substances 0.000 claims description 14
- 239000003153 chemical reaction reagent Substances 0.000 claims description 11
- 239000000843 powder Substances 0.000 claims description 9
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- 238000005859 coupling reaction Methods 0.000 claims description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 11
- 229910052741 iridium Inorganic materials 0.000 abstract description 9
- 230000003647 oxidation Effects 0.000 abstract description 8
- 229910052751 metal Inorganic materials 0.000 abstract description 7
- 239000002184 metal Substances 0.000 abstract description 7
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- 238000001354 calcination Methods 0.000 abstract 1
- 239000003426 co-catalyst Substances 0.000 abstract 1
- 230000000052 comparative effect Effects 0.000 description 9
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 2
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- 230000009286 beneficial effect Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- GWXLDORMOJMVQZ-UHFFFAOYSA-N cerium Chemical compound [Ce] GWXLDORMOJMVQZ-UHFFFAOYSA-N 0.000 description 2
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- 229910021397 glassy carbon Inorganic materials 0.000 description 2
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- 229910002514 Co–Co Inorganic materials 0.000 description 1
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- 229910021607 Silver chloride Inorganic materials 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
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- 125000004435 hydrogen atom Chemical group [H]* 0.000 description 1
- 239000005457 ice water Substances 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
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- HKZLPVFGJNLROG-UHFFFAOYSA-M silver monochloride Chemical compound [Cl-].[Ag+] HKZLPVFGJNLROG-UHFFFAOYSA-M 0.000 description 1
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Abstract
The invention relates to the field of metal monoatomic catalysts, and discloses a method for synthesizing an Ir-Co heteronuclear monoatomic catalyst by a one-step annealing method, which comprises the following steps: s1, weighing 5g of dicyandiamide, adding the dicyandiamide into a beaker, slowly adding 40mL of water and 4.4mL of formaldehyde, and adding a certain amount of IrCl 3 ·3H 2 O and different amounts of Co (NO) 3 ) 2 ·6H 2 O, transferring the beaker into an oil bath pot, heating to 80 ℃, stirring for 24 hours, placing into a 60 ℃ oven for drying,after the sample has been completely dried, N is introduced into a tube furnace 2 Calcining for 2 hours at 900 ℃ in atmosphere, and fully grinding the black block product to obtain Ir-Co heteronuclear monoatomic catalysts with different atomic ratios. According to the invention, the heteronuclear monoatomic catalyst with different atomic ratios is obtained by fixing the Ir content and adjusting the Co content, the nitrogen-doped carbon material has a good anchoring effect, so that monoatoms are not agglomerated, and the Ir-Co catalyst has excellent electrocatalytic formic acid oxidation performance due to the synergistic effect between Ir and Co components.
Description
Technical Field
The invention relates to the field of metal monoatomic catalysts, in particular to a method for synthesizing an Ir-Co heteronuclear monoatomic catalyst by a one-step annealing method and application thereof.
Background
The Direct Formic Acid Fuel Cell (DFAFC) has the advantages of high energy density, high chemical kinetics speed, safety, low toxicity and the like, is a very promising energy conversion device, has only one carbon atom in formic acid molecules, only needs to break two hydrogen atoms in the oxidation process, has fast reaction kinetics, is beneficial to better quick discharge, and meanwhile, has the advantage of low Nafion permeability of the formic acid fuel cell that other small molecules cannot be compared, thereby ensuring the stability of the formic acid fuel cell under the working condition, and has great development potential and application space.
Currently, catalysts for formic acid oxidation reactions at anodes are mainly focused on Pt, pd-based metal particles, such as the cerium oxide-palladium/carbon catalyst for formic acid electrooxidation and the preparation method thereof provided in application patent number CN202210758470.9, wherein the cerium oxide-palladium/carbon catalyst is Pd and CeO 2 Loaded on C carrier, ceO 2 Spherical particles with the size less than or equal to 10nm and spherical nano CeO 2 Not only increases Pd load uniformity, thereby improving the electrochemical active area of the catalyst; simultaneous nano CeO 2 The activity, CO poisoning resistance and stability of the catalyst are improved by the cooperation of Pd.
However, in the prior art, as proposed in patent application number CN202210758470.9, pt and Pd-based metal particles have low mass activity, and face the problems of high price and low reserves, so that the development of formic acid fuel cells is restricted, and secondly, noble metal particles easily generate indirect oxidation paths in the process of catalyzing formic acid oxidation, and generated CO intermediates occupy active sites, so that the catalyst is deactivated, and the problems of low activity and poor stability exist.
Disclosure of Invention
In order to solve the defects in the background art, the invention aims to provide a preparation method and application of Ir-Co heteronuclear monoatomic catalysts with high catalytic activity and stability and different atomic ratios.
The aim of the invention can be achieved by the following technical scheme: the method for synthesizing the Ir-Co heteronuclear monoatomic catalyst by the one-step annealing method comprises the following steps:
s1, 250mg of IrCl 3 ·3H 2 O was added to 20mL of deionized water to prepare a 12.5mg/mL aqueous solution of Epichloride, and 1000mg of Co (NO) 3 ) 2 ·6H 2 Adding the O reagent into 20mL of deionized water to prepare 50mg/mL of cobalt nitrate aqueous solution;
s2, weighing 5g of dicyandiamide, adding the dicyandiamide into a beaker with a magnet, then adding 40mL of water and then 4.4mL of formaldehyde, and then dropwise adding 400 mu L of an aqueous solution of the trichlorinated coupling compound and 50-400 mu L of an aqueous solution of cobalt nitrate to obtain a precursor solution;
s3, transferring the precursor solution into an oil bath pot, heating to 80 ℃, stirring for 24 hours, cooling to room temperature, transferring the precursor solution into a 60 ℃ oven, and drying for 24 hours to finally obtain a pink solid sample;
s4, transferring the pink solid obtained above into a ceramic ark, and N in a tube furnace 2 Annealing for 2 hours at 900 ℃ to obtain a black block sample, and grinding the black block sample into uniformly dispersed black powder after the temperature is reduced to room temperature to obtain the Ir-Co heteronuclear monoatomic catalyst.
In the step S1, the prepared aqueous solution of the elctrolyte and the aqueous solution of the cobalt nitrate are both ultrasonically shaken for 30min to ensure complete dissolution of the solution, and the solution after shaking dissolution is stored in a refrigerating chamber of a refrigerator, so that the addition of the precursor is accurately controlled later.
In the step S2, formaldehyde and the precursor solution are added dropwise, and the solution containing water and dicyandiamide is continuously stirred during the addition.
In the step S2, a pipette is used for adding an aqueous solution of the trichlorination and an aqueous solution of the cobalt nitrate to realize accurate control of the volume of the precursor solution, and the added volume of the aqueous solution of the cobalt nitrate is 50 mu L, 100 mu L, 200 mu L or 400 mu L.
In the step S4, the temperature of the tube furnace is raised to 900 ℃ at a speed of 5 ℃/min, and the temperature is reduced to room temperature after the environment of 900 ℃ is maintained for 2 hours.
In the step S4, the annealed block sample is ground by using a mortar for 10min to obtain uniformly dispersed black powder.
The method for synthesizing the Ir-Co heteronuclear monoatomic catalyst by the one-step annealing method is applied to the electrocatalytic formic acid oxidation reaction.
The invention has the beneficial effects that:
according to the method, the heteronuclear monoatomic catalyst with different atomic ratios is obtained by fixing the content of Ir in a precursor source and changing the content of Co, the nitrogen-doped carbon material has a good anchoring effect, the monoatomic is not agglomerated due to the strong interaction between metal and a carrier, the heteronuclear monoatomic catalyst with different atomic ratios is key to obtaining the heteronuclear monoatomic catalyst with Ir-Co, the introduction of Co with an inactive site brings about great improvement of performance, and the synergistic effect between Ir and Co is key to performance improvement.
The Ir-Co heteronuclear monoatomic catalyst prepared by the method realizes efficient monoatomic catalytic formic acid oxidation, has excellent atomic activity and excellent stability, and also has better CO poisoning resistance, so that the monoatomic catalyst not only reduces the dosage of noble metals, reduces the cost of the catalyst and improves the atomic utilization rate, thereby realizing efficient catalytic performance, but also effectively regulates and controls the electronic structure of Ir by introducing non-noble metal Co, and the synergistic effect between the heteronuclear monoatomic atoms of Ir-Co effectively improves the performance of the catalyst, so that the adsorption of reactants and the adsorption of reaction intermediates are more favorable, and a faster kinetic process is realized, thereby realizing higher current density and stability.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to those skilled in the art that other drawings can be obtained according to these drawings without inventive effort;
FIG. 1 is an X-ray diffraction pattern of comparative example 1 and examples 1, 2, 3, 4;
FIG. 2 is a TEM image of comparative example 1;
FIG. 3 is a TEM image of example 1;
FIG. 4 is a TEM image of example 2;
FIG. 5 is a TEM image of example 3;
FIG. 6 is a TEM image of example 4;
FIG. 7 is a Fourier transform X-ray fine structure absorption spectrum of Ir element in examples 1, 2, 3, 4 and Irfoil;
FIG. 8 is a Fourier transform X-ray fine structure absorption spectrum of Co element in examples 1, 2, 3, 4 and Cofoil;
FIG. 9 is a comparative histogram of the performance of comparative example 1 and examples 1, 2, 3, 4;
FIG. 10 is a graph comparing performance before and after the stability test of example 2;
FIG. 11 is a graph comparing commercial Pt/C and commercial Pd/C performance and stability for example 2.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Comparative example 1
250mg of IrCl 3 ·3H 2 Adding the O reagent into 20mL of deionized water to prepare 12.5mg/mL of aqueous solution of the Epichloride, and storing the aqueous solution in a refrigerating chamber of a refrigerator for later use;
5g of dicyandiamide is weighed and added into a beaker with a magnet, 40mL of water is added first, then 4.4mL of formaldehyde is added dropwise, then 400uL of aqueous solution of trichlorination is removed by a pipette and slowly added into the beaker under stirring to obtain a precursor solution, the precursor solution is transferred into an oil bath pot and heated to 80 ℃, stirring is continued for 24 hours, cooling to room temperature, and then the precursor solution is transferred into a baking oven at 60 ℃ and dried for 24 hours, so that a light yellow solid sample is obtained.
Transferring the obtained yellowish solid sample into a ceramic ark, then heating to 900 ℃ at a heating rate of 5 ℃/min in a tube furnace under the condition of N2, annealing for 2 hours, cooling to room temperature, collecting a block sample, transferring to a mortar, and fully grinding for 10 minutes to obtain black powder which is uniformly dispersed, namely the Ir monoatomic catalyst.
Example 1
250mg of IrCl 3 ·3H 2 Adding O reagent into 20mL deionized water to prepare 12.5mg/mL aqueous solution of Epichloride, taking the solution as precursor solution, and simultaneously adding 1000mg of Co (NO) 3 ) 2 ·6H 2 Adding the reagent O into 20mL of deionized water to prepare 50mg/mL of cobalt nitrate aqueous solution, and storing the two solutions in a refrigerating chamber of a refrigerator for later use;
5g of dicyandiamide is weighed and added into a beaker with a magnet, 40mL of water is added first, then 4.4mL of formaldehyde is added dropwise, then 400 mu L of aqueous solution of trichlorination and 50 mu L of aqueous solution of cobalt nitrate are removed by a pipette and slowly added into the beaker under stirring to obtain a precursor solution, the precursor solution is transferred into an oil bath pot to be heated to 80 ℃, stirring is continued for 24 hours, and the solution is transferred into an oven at 60 ℃ to be dried for 24 hours after the solution is cooled to room temperature, so that a pink solid sample is obtained.
Transferring the pink solid sample obtained above into a ceramic ark, then heating to 900 ℃ in a tube furnace under the condition of N2 at a heating rate of 5 ℃/min, keeping for 2 hours, collecting a block sample after the temperature is reduced to room temperature, transferring into a mortar, and fully grinding for 10 minutes to obtain black powder which is uniformly dispersed, namely the Ir-Co heteronuclear monoatomic catalyst.
Example 2
250mg of IrCl 3 ·3H 2 Adding O reagent into 20mL deionized water to prepare 12.5mg/mL aqueous solution of Epichloride, taking the solution as precursor solution, and simultaneously adding 1000mg of Co (NO) 3 ) 2 ·6H 2 Adding the O reagent into 20mL of deionized water to prepare a cobalt nitrate aqueous solution with the concentration of 50mg/mL, and storing the two solutions in a refrigerating chamber of a refrigerator for later use;
5g of dicyandiamide is weighed and added into a beaker with a magnet, 40mL of water is added first, then 4.4mL of formaldehyde is added dropwise, then 400 mu L of aqueous solution of trichlorination and 100 mu L of aqueous solution of cobalt nitrate are removed by a pipette and slowly added into the beaker under stirring to obtain a precursor solution, the precursor solution is transferred into an oil bath pot to be heated to 80 ℃, stirring is continued for 24 hours, and the solution is transferred into an oven at 60 ℃ to be dried for 24 hours after the solution is cooled to room temperature, so that a pink solid sample is obtained.
Transferring the pink solid sample obtained above into a ceramic ark, then heating to 900 ℃ at a heating rate of 5 ℃/min in a tube furnace under the condition of N2, annealing for 2 hours, collecting a block sample after the temperature is reduced to room temperature, transferring into a mortar, and fully grinding for 10 minutes to obtain black powder which is uniformly dispersed, namely the Ir-Co heteronuclear monoatomic catalyst.
Example 3
250mg of IrCl 3 ·3H 2 Adding O reagent into 20mL deionized water to prepare 12.5mg/mL aqueous solution of Epichloride, taking the solution as precursor solution, and simultaneously adding 1000mg of Co (NO) 3 ) 2 ·6H 2 Adding the reagent O into 20mL of deionized water to prepare 50mg/mL of cobalt nitrate aqueous solution, and storing the two solutions in a refrigerating chamber of a refrigerator for later use;
5g of dicyandiamide is weighed and added into a beaker with a magnet, 40mL of water is added first, then 4.4mL of formaldehyde is added dropwise, then 400 mu L of aqueous solution of trichlorination and 200 mu L of aqueous solution of cobalt nitrate are slowly added dropwise into the stirring beaker by a pipette, so as to obtain a precursor solution, the precursor solution is transferred into an oil bath pot to be heated to 80 ℃, stirring is continued for 24 hours, and the solution is transferred into an oven at 60 ℃ to be dried for 24 hours after the solution is cooled to room temperature, so that a red solid sample is obtained.
Transferring the obtained red solid sample into a ceramic ark, then heating to 900 ℃ at a heating rate of 5 ℃/min in a tube furnace under the condition of N2, annealing for 2 hours, cooling to room temperature, collecting a block sample, transferring into a mortar, and fully grinding for 10 minutes to obtain black powder which is uniformly dispersed, namely the Ir-Co heteronuclear monoatomic catalyst.
Example 4
250mg of IrCl 3 ·3H 2 Adding O reagent into 20mL deionized water to prepare 12.5mg/mL aqueous solution of Epichloride, taking the solution as precursor solution, and simultaneously adding 1000mg of Co (NO) 3 ) 2 ·6H 2 Adding the O reagent into 20mL of deionized water to prepare a cobalt nitrate aqueous solution with the concentration of 50mg/mL, and storing the two solutions in a refrigerating chamber of a refrigerator for later use;
5g of dicyandiamide is weighed and added into a beaker with a magnet, 40mL of water is added first, then 4.4mL of formaldehyde is added dropwise, then 400uL of aqueous solution of trichlorination and 400uL of aqueous solution of cobalt nitrate are slowly added dropwise into the stirring beaker by a pipette, so as to obtain a precursor solution, the precursor solution is transferred into an oil bath pot to be heated to 80 ℃, stirring is continued for 24 hours, and the solution is transferred into a baking oven at 60 ℃ to be dried for 24 hours after the solution is cooled to room temperature, so that a purple solid sample is obtained.
Transferring the obtained purple solid sample into a ceramic ark, then heating to 900 ℃ at a heating rate of 5 ℃/min in a tube furnace under the condition of N2, annealing for 2 hours, cooling to room temperature, collecting a block sample, transferring to a mortar, and fully grinding for 10 minutes to obtain black powder which is uniformly dispersed, namely the Ir-Co heteronuclear monoatomic catalyst.
Structure detection
As can be seen from the XRD results of fig. 1, the samples of comparative example 1 and examples 1, 2, 3, and 4 do not have the diffraction peaks associated with the Ir and Co metal particles, indicating that the Ir and Co atoms do not aggregate at high temperatures to form a crystalline structure of nanoparticles.
As can be seen from the high-resolution TEM images of fig. 2, 3, 4, 5 and 6, the samples of comparative example 1 and examples 1, 2, 3 and 4 did not find obvious Ir and Co particles, and the presence of Co particles was not found even if the content of Co was increased, and the combination of XRD results demonstrated that no Ir and Co particles or small clusters were found, which were considered to be monoatomic sites, indicating that the method was effective in preparing heteronuclear monoatomic catalysts of Ir and Co.
To further confirm the existence form of Ir in examples 1, 2, 3 and 4 and the influence of coordination environment on formic acid oxidation performance, we use Fourier transform X-ray fine structure absorption spectrum (FT-EXAFS, fig. 7 and 8) to characterize materials, and can see that examples 2, 3, 4 and 5 are all nonmetallic coordination of Ir-N, no metal coordination peak of Ir-Ir appears, meanwhile Co element in examples 2, 3, 4 and 5 also shows coordination peak of Co-N, no Co-Co metal coordination peak is found, co-Co metal coordination peak is not found in the sample in example 5 with highest Co content, and by combining the conclusion of XRD and an electron microscope, the existence forms of Ir and Co are judged to be in a single atom form, so that heteronuclear single-atom catalysts of Ir and Co with different contents can be synthesized effectively verified.
Performance detection
To evaluate the activity and stability of formic acid oxidation of the Ir metal catalysts of comparative example 1 and examples 1, 2, 3, 4, we performed performance evaluations under the same test conditions, with the specific test procedures and results as follows
(1) 0.49mL of isopropanol, 0.49mL of deionized water, 5mg of catalyst, 2mg of carbon powder, and 20. Mu. LNafion solution were mixed in an ice-water bath for 2 hours with sonication, and dispersed as ink.
(2) 27.2mL of analytically pure concentrated H 2 SO 4 Adding the solution and 19.2mL of formic acid solution with 98% content into deionized water, transferring into 1000mL volumetric flask, and preparing into 0.5MH 2 SO 4 +0.5MHCOOH electrolyte.
(3) And (3) weighing 80mL of the prepared reaction solution, adding the reaction solution into a test bottle, respectively selecting a carbon rod, an Ag/AgCl electrode and a glassy carbon electrode as a counter electrode, a reference electrode and a working electrode, dripping the prepared ink onto the glassy carbon electrode, naturally airing, and forming a film to obtain the working electrode, and testing.
As shown in fig. 9 and 11, after Co is introduced, the performances of examples 1, 2, 3 and 4 are greatly improved compared with the performance of comparative example 1 without Co, and experiments prove that Co is an inactive site, and the synergistic effect between the active site Ir and the inactive site Co effectively promotes the catalytic performance of Ir monoatoms. At the same time, with the increase of Co content, the volcanic appearance of the performance diagram is foundThe type curve, the Ir-Co heteronuclear monoatomic catalyst prepared in example 2 shows the best electrocatalytic activity, which shows that the introduction of a proper amount of Co effectively regulates and controls the electronic structure of Ir, thereby obtaining the optimal structure for catalyzing formic acid oxidation, and the mass activity of the Ir-Co heteronuclear monoatomic catalyst is 35.29A/mgIr -1 Meanwhile, as shown in fig. 10, the Ir-Co heteronuclear monoatomic catalyst prepared in example 2 is subjected to stability circulation under a certain voltage, and the activity of the catalyst can still be kept to 98% of the initial activity after the stability test is finished, which indicates that the introduction of Co not only improves the activity of the catalyst, but also effectively improves the stability of the catalyst, which further illustrates the important influence of the atomic ratio of inactive sites on the active sites.
The foregoing has shown and described the basic principles, principal features and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims.
Claims (7)
1. The method for synthesizing the Ir-Co heteronuclear monoatomic catalyst by the one-step annealing method is characterized by comprising the following steps of:
s1, 250mg of IrCl 3 ·3H 2 O was added to 20mL of deionized water to prepare a 12.5mg/mL aqueous solution of Epichloride, and 1000mg of Co (NO) 3 ) 2 ·6H 2 Adding the O reagent into 20mL of deionized water to prepare 50mg/mL of cobalt nitrate aqueous solution;
s2, weighing 5g of dicyandiamide, adding the dicyandiamide into a beaker with a magnet, then adding 40mL of water and then 4.4mL of formaldehyde, and then dropwise adding 400 mu L of an aqueous solution of the trichlorinated coupling compound and 50-400 mu L of an aqueous solution of cobalt nitrate to obtain a precursor solution;
s3, transferring the precursor solution into an oil bath pot, heating to 80 ℃, stirring for 24 hours, cooling to room temperature, transferring the precursor solution into a 60 ℃ oven, and drying for 24 hours to finally obtain a pink solid sample;
s4, transferring the pink solid obtained above into a ceramic ark, and N in a tube furnace 2 Annealing for 2 hours at 900 ℃ to obtain a black block sample, and grinding the black block sample into uniformly dispersed black powder after the temperature is reduced to room temperature to obtain the Ir-Co heteronuclear monoatomic catalyst.
2. The method for synthesizing the Ir-Co heteronuclear monoatomic catalyst by the one-step annealing method according to claim 1, wherein in the step S1, the prepared aqueous solution of the trichlorination and the prepared aqueous solution of the cobalt nitrate are both subjected to ultrasonic shaking for 30min so as to ensure complete dissolution of the solution, and the solution after shaking dissolution is stored in a refrigerating chamber of a refrigerator so as to facilitate the follow-up accurate control of the addition of the precursor.
3. The method for synthesizing an Ir-Co heteronuclear monoatomic catalyst by the one-step annealing method according to claim 1, wherein in the step S2, the formaldehyde and the precursor solution are added dropwise, and the solution containing water and dicyandiamide is continuously stirred during the addition.
4. The method for synthesizing the Ir-Co heteronuclear monoatomic catalyst by the one-step annealing method according to claim 1, wherein in the step S2, a pipette is used for adding an aqueous solution of the elctrodine chloride and an aqueous solution of the cobalt nitrate to realize accurate control of the volume of the precursor solution, and the volume of the added aqueous solution of the cobalt nitrate is 50 mu L, 100 mu L, 200 mu L or 400 mu L.
5. The method for synthesizing the Ir-Co heteronuclear monoatomic catalyst by the one-step annealing method according to claim 1, wherein in the step S4, the tubular furnace is heated to 900 ℃ at a speed of 5 ℃/min, and is cooled to room temperature after being kept at 900 ℃ for 2 hours.
6. The method for synthesizing an Ir-Co heteronuclear monoatomic catalyst by a one-step annealing method according to claim 1, wherein in the step S4, the annealed massive sample is ground by using a mortar for 10min, and uniformly dispersed black powder is obtained.
7. The method for synthesizing an Ir-Co heteronuclear monoatomic catalyst by a one-step annealing method according to any one of claims 1 to 6, wherein the prepared Ir-Co heteronuclear monoatomic catalyst is applied to electrocatalytic formic acid oxidation reaction.
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