Electrocatalytic material and preparation method and application thereof
1. An electrocatalytic material, characterized by: the method comprises the following steps:
a conductive substrate;
elemental cobalt is an elemental cobalt nanosheet, and the elemental cobalt grows on the conductive substrate to form an elemental cobalt nanosheet array;
and the cobalt-molybdenum oxide layer is coated on the surface of the elemental cobalt nanosheet array.
2. The electrocatalytic material of claim 1, wherein: the thickness of the electrocatalytic material is 30 nm-40 nm.
3. The electrocatalytic material of claim 1, wherein: the thickness of the cobalt molybdenum oxide layer is 3 nm-5 nm.
4. The electrocatalytic material of claim 1, wherein: the thickness of the simple substance cobalt nanosheet in the electrocatalytic material is 20 nm-100 nm.
5. A method of preparing an electrocatalytic material as set forth in any one of claims 1 to 4, wherein: the method comprises the following steps:
s1: immersing a conductive substrate into a cobalt precursor solution, carrying out solvothermal reaction, and growing a cobalt precursor nanosheet array on the conductive substrate;
s2: depositing cobalt molybdenum oxide on the cobalt precursor nanosheet array by a chemical deposition method, and reducing in an inert environment to obtain the electro-catalytic material.
6. The method of preparing an electrocatalytic material as set forth in claim 5, wherein: the preparation method of the cobalt precursor solution comprises the following steps: cobalt salt, organic base and surfactant are dissolved in alcohol and/or water solution and mixed.
7. The method of preparing an electrocatalytic material as set forth in claim 5, wherein: the mass ratio of the cobalt salt, the organic base and the surfactant is 1: (1.2-3.5): (1.2-3.5).
8. The method of preparing an electrocatalytic material as set forth in claim 6, wherein: when the alcohol and/or the water solution is the alcohol and the water solution, the volume ratio of water to alcohol is (3-5): 1, mixing to obtain the product.
9. The method of preparing an electrocatalytic material as set forth in claim 5, wherein: the preparation method of the electrocatalytic material further comprises the step of infiltrating the cobalt precursor nanosheet array in a cobalt salt solution before S2.
10. A hydrogen evolution electrocatalyst, characterized by: the material comprises an electrocatalytic material, wherein the electrocatalytic material is the electrocatalytic material disclosed by any one of claims 1-4 or prepared by a preparation method of the electrocatalytic material disclosed by any one of claims 5-9.
Background
The hydrogen is used as an environment-friendly energy source, has the advantages of high energy density, no pollution waste generation and the like, and is an ideal substitute of fossil fuel. The hydrogen production by water electrolysis is an important half reaction of water electrolysis, is one of the most promising hydrogen production methods at present, and has gained wide attention in recent decades.
The electrolytic water is carried out in an alkaline medium, so that the corrosion and the dissolution of transition metal can be avoided, better stability is provided for the transition metal, the catalysis time is prolonged, and the transition metal oxide has rich valence and a variable electronic structure, and is an electro-catalytic hydrogen production material with development prospect. CoMoOxHas high catalytic activity, low price, abundant contents on the earth and easy acquisition. However, CoMoOxThe conductivity of the catalyst is poor, the specific surface area is small, the charge transmission efficiency is low, the actual catalytic performance is poor, and the application of the catalyst is greatly limited.
Disclosure of Invention
The present invention is directed to solving at least one of the problems of the prior art described above. Therefore, the first aspect of the present invention provides an electrocatalytic material, which can overcome the defects of poor conductivity, small specific surface area or low charge transfer efficiency of cobalt molybdenum oxide.
In a second aspect, the invention provides a method for preparing the above electrocatalytic material.
A third aspect of the invention provides the use of an electrocatalytic material as described above.
According to a first aspect of the present invention, there is provided an electrocatalytic material comprising:
a conductive substrate;
elemental cobalt which is an elemental cobalt nanosheet and grows on the conductive substrate to form an elemental cobalt nanosheet array;
and the cobalt-molybdenum oxide layer is coated on the surface of the elemental cobalt nanosheet array.
In the present invention,a large number of oxygen vacancies exist around the cobalt nano-particles, which can serve as electron donors and improve the charge conversion rate, and then the metal cobalt is used as a core and coated in a cobalt molybdenum oxide layer to form an electrocatalytic material Co @ CoMoOxThe nanosheet array composite material has the advantages that the metal cobalt can improve the electron transmission capability on the surface of the catalytic material, more active sites can be exposed due to the cobalt nanoparticles with good dispersibility, the cobalt molybdenum oxide layer has high catalytic activity, and the original microscopic morphology and chemical environment of cobalt can be maintained in the catalytic process, so that the electro-catalytic material disclosed by the invention can maintain good stability in the catalytic process.
In some embodiments of the invention, the thickness of the electrocatalytic material is between 30nm and 40 nm.
In some preferred embodiments of the present invention, the cobalt molybdenum oxide layer has a thickness of 3nm to 5 nm.
In some preferred embodiments of the invention, the cobalt molybdenum oxide layer is a CoMoOxExemplary forms include CoMoO4And Co2Mo3O8And the like.
In some more preferred embodiments of the present invention, the thickness of the elemental cobalt nanosheets is 20nm to 100nm, and the elemental cobalt nanosheets can stably function within the thickness range, and have a small influence on the overall performance of the electrocatalytic material.
In some more preferred embodiments of the present invention, the conductive substrate is selected from any one of Nickel Foam (NF), carbon cloth, and carbon paper.
According to a second aspect of the present invention, there is provided a method of preparing an electrocatalytic material, comprising the steps of:
s1: immersing a conductive substrate into a cobalt precursor solution, carrying out solvothermal reaction, and growing a cobalt precursor nanosheet array on the conductive substrate;
s2: depositing cobalt molybdenum oxide on the cobalt precursor nanosheet array by a chemical deposition method, and reducing in an inert environment to obtain the electro-catalytic material.
In some embodiments of the present invention, the cobalt precursor solution is prepared by: cobalt salt, organic base and surfactant are dissolved in alcohol and/or water solution and mixed.
In some preferred embodiments of the present invention, the mass ratio of the cobalt salt, the organic base, and the surfactant is 1: (1.2-3.5): (1.2-3.5).
In some more preferred embodiments of the present invention, the cobalt salt is any one selected from the group consisting of cobalt chloride hexahydrate, cobalt nitrate, cobalt bromide, and cobalt sulfate.
In some more preferred embodiments of the invention, the organic base is hexamethylenetetramine (C)6H12N4) And urea.
In some more preferred embodiments of the present invention, the surfactant is any one of polyvinylpyrrolidone (PVP), Sodium Dodecyl Sulfate (SDS), and sodium dodecyl benzene sulfonate (LAS).
In some more preferred embodiments of the present invention, when the alcohol and/or aqueous solution is an alcohol and aqueous solution, the volume ratio of water to alcohol is (3-5): 1, mixing to obtain the product.
In some more preferred embodiments of the present invention, the alcohol is any one of methanol and ethanol.
In some more preferred embodiments of the present invention, the water is any one of purified water and deionized water.
In some more preferred embodiments of the present invention, the reaction temperature of the solvothermal reaction is 120 ℃ to 160 ℃ and the reaction time is 6h to 24 h.
In some more preferred embodiments of the present invention, the temperature rise rate of the solvothermal reaction is (3-10) ° c/min.
In some more preferred embodiments of the invention, the solvothermal reaction is carried out in a teflon-lined stainless steel autoclave.
In some more preferred embodiments of the present invention, the method for preparing the electrocatalytic material further comprises purifying the material prepared in S1 after S1, wherein the purification is drying after washing with an alcohol aqueous solution.
In some more preferred embodiments of the present invention, the deposition in S2 is a deposition at 60 ℃ to 80 ℃ for 10min to 100 min.
In some more preferred embodiments of the present invention, the reducing agent used in the reduction in S2 is hydrogen.
In some more preferred embodiments of the present invention, the reaction temperature of the reduction in S2 is 350 to 500 ℃.
In some more preferred embodiments of the present invention, the preparation method of the electrocatalytic material further comprises infiltrating the cobalt precursor nanosheet array in a cobalt salt solution prior to S2. Before depositing the cobalt-molybdenum oxide, firstly soaking the cobalt precursor nanosheet array in a cobalt salt solution, so that cobalt ions can be fully adsorbed on the surface of the cobalt precursor nanosheet array, and particularly nanosheets at deeper layers of the solution are not easy to contact, and the cobalt-molybdenum oxide is more fully coated.
In some more preferred embodiments of the present invention, the temperature of the infiltration is 60 ℃ to 80 ℃ and the time is 30min to 180 min.
According to a third aspect of the present invention, there is provided a hydrogen evolution electrocatalyst, comprising an electrocatalytic material, which is the above electrocatalytic material or is prepared by the above preparation method of the electrocatalytic material.
When the electrocatalytic material is used as an electrocatalyst for preparing hydrogen by electrolyzing water, the cobalt-molybdenum oxide layer can maintain high catalytic activity, and meanwhile, a simple substance cobalt core is introduced, so that the electron transmission rate can be accelerated, the electrochemical active area can be increased, and the catalytic performance of the electrocatalytic material is greatly improved.
The invention has the beneficial effects that:
1. the molybdenum element with various valence states coexisting in the cobalt-molybdenum oxide layer is subjected to rich oxidation-reduction reaction, so that the cobalt-molybdenum oxide layer has high catalytic activity, and a nanosheet array with good catalytic performance and a stable structure can be obtained.
2. The composition of the metal cobalt and the cobalt-molybdenum oxide layer enables the cobalt to improve the inherent defect of poor conductivity of the cobalt-molybdenum oxide layer, thereby greatly improving the catalytic performance of the electrocatalytic material.
3. In the process of preparing the electrocatalytic material, a hydrogenation reduction reaction can generate a large number of defects on the surface while reducing the nanosheet material, so that the exposure of the electrochemical active sites is increased.
4. The Co @ CoMoO of the invention compares with the catalytic performance of a cobalt molybdenum oxide layerxThe nano-sheet array composite material has better catalytic performance, and can greatly improve the catalytic hydrogen evolution performance of equipment when being used as a hydrogen evolution electrocatalyst.
Drawings
The invention is further described with reference to the following figures and examples, in which:
FIG. 1 shows an electrocatalytic material Co @ CoMoO prepared in example 1 of the present inventionxX-ray powder diffraction pattern of the composite.
Fig. 2 is an electron microscope scanning photograph of the nanosheet array (a) before hydrogenation and the nanosheet array (b) after hydrogenation in example 1 of the present invention.
FIG. 3 shows the electrocatalytic material Co @ CoMoO prepared in example 1 of the present inventionxLow power transmission electron micrographs (a) and high power transmission electron micrographs (b) of the composite.
FIG. 4 shows the electrocatalytic material Co @ CoMoO prepared in example 1 of the present inventionxComposite and electrocatalytic material CoMoO prepared in comparative example 1xElectrocatalytic performance diagram of (c).
FIG. 5 shows the electrocatalytic material Co @ CoMoO prepared in example 1 of the present inventionxComposite and electrocatalytic material CoMoO prepared in comparative example 1xImpedance spectrum of (1).
FIG. 6 shows the electrocatalytic material Co @ CoMoO prepared in example 1 of the present inventionxAnd (5) a stability test result chart of the composite material.
Detailed Description
The concept and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments to fully understand the objects, features and effects of the present invention. It is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and those skilled in the art can obtain other embodiments without inventive effort based on the embodiments of the present invention, and all embodiments are within the protection scope of the present invention.
Example 1
The embodiment prepares the electrocatalytic material, and the specific process is as follows:
s1: ultrasonically cleaning a piece of NF (2.4cm by 3cm) with ethanol, acetone and 3mol/L hydrochloric acid aqueous solution for 30min respectively to remove oil stains and nickel oxide on the surface, then sequentially cleaning with deionized water for 10min, and repeating for 3 times. Thereafter 146mg of Co (NO)3)2·6H2O, 210mg of C6H12N4And 255mg of PVP were dissolved in 40mL of a mixed solution of deionized water and ethanol (H)2O: ethanol ═ 3: 1, v/v). Transferring the mixed solution into a stainless steel autoclave lined with 50mL of Teflon, immersing a piece of cleaned NF into the mixed solution, raising the temperature to 120 ℃ from room temperature, raising the temperature at a speed of 5 ℃/min, maintaining the temperature at 120 ℃ for reaction for 12h, naturally cooling to room temperature, washing with deionized water, and drying in an oven at 70 ℃;
s2: 582.1mg of Co (NO)3)2·6H2Dissolving O in 120mL deionized water, heating to 80 ℃, immersing the nanosheet array prepared from S1, keeping for 10min, and transferring to 83.9mg of Na2MoO4·2H2Reacting for 10min in a molybdate solution formed by O and 30mL of deionized water (the solution is heated to 80 ℃) and naturally cooling to room temperature, taking out, washing with deionized water and drying in a 70 ℃ oven;
s3: placing the material prepared in S2 into a quartz boat, placing the quartz boat into a tube furnace, and introducing H2Heating to 450 ℃ at the heating rate of 5 ℃/min and reacting for one hour at 450 ℃ in the atmosphere of hydrogen-argon mixed gas to obtain the electrocatalytic material Co @ CoMoO (5:95, 100sccm)xA composite material.
Example 2
The embodiment prepares the electrocatalytic material, and the specific process is as follows:
s1: ultrasonically cleaning a piece of NF (2.4cm x 3cm) with ethanol, acetone and 3mol/L hydrochloric acid water solution for 30min, respectively, removingRemoving oil stain and nickel oxide on the surface, then sequentially cleaning with deionized water for 10min, and repeating for 3 times. Thereafter 146mg of Co (NO)3)2·6H2O, 210mg of C6H12N4And 255mg of PVP was dissolved in 40mL of deionized water. Transferring the mixed solution into a stainless steel autoclave lined with 50mL of Teflon, immersing a piece of cleaned NF into the mixed solution, raising the temperature to 120 ℃ from room temperature, raising the temperature at a speed of 5 ℃/min, maintaining the temperature at 120 ℃ for reaction for 12h, naturally cooling to room temperature, washing with deionized water, and drying in an oven at 70 ℃;
s2: 582.1mg of Co (NO)3)2·6H2Dissolving O in 120mL deionized water, heating to 80 ℃, immersing the nanosheet array prepared from S1, keeping for 10min, and transferring to 83.9mg of Na2MoO4·2H2Reacting for 10min in a molybdate solution formed by O and 30mL of deionized water (the solution is heated to 80 ℃) and naturally cooling to room temperature, taking out, washing with deionized water and drying in a 70 ℃ oven;
s3: placing the material prepared in S2 into a quartz boat, placing the quartz boat into a tube furnace, and introducing H2Heating to 450 ℃ at the heating rate of 5 ℃/min and reacting for one hour at 450 ℃ in the atmosphere of hydrogen-argon mixed gas to obtain the electrocatalytic material Co @ CoMoO (5:95, 100sccm)xA composite material.
Example 3
The embodiment prepares the electrocatalytic material, and the specific process is as follows:
s1: ultrasonically cleaning a piece of NF (2.4cm by 3cm) with ethanol, acetone and 3mol/L hydrochloric acid aqueous solution for 30min respectively to remove oil stains and nickel oxide on the surface, then sequentially cleaning with deionized water for 10min, and repeating for 3 times. Thereafter 146mg of Co (NO)3)2·6H2O, 210mg of C6H12N4And 255mg of SDS were dissolved in 40mL of a mixed solution of deionized water and ethanol (H)2O: ethanol ═ 5: 1, v/v). The mixed solution was transferred to a stainless steel autoclave lined with 50mL of Teflon, and a piece of cleaned NF was immersed in the mixed solution and raised in temperature from room temperature toAt the temperature of 140 ℃, the heating rate is 5 ℃/min, the reaction is maintained at the temperature of 120 ℃ for 12h, after the reaction is naturally cooled to the room temperature, the reaction product is washed clean by deionized water and dried in an oven at the temperature of 70 ℃;
s2: 1.1642g of Co (NO)3)2·6H2Dissolving O in 120mL deionized water, heating to 80 ℃, immersing the nanosheet array prepared from S1, keeping for 10min, and transferring to 167.8mg of Na2MoO4·2H2Reacting for 10min in a molybdate solution formed by O and 30mL of deionized water (the solution is heated to 80 ℃) and naturally cooling to room temperature, taking out, washing with deionized water and drying in a 70 ℃ oven;
s3: placing the material prepared in S2 into a quartz boat, placing the quartz boat into a tube furnace, and introducing H2Heating to 500 ℃ at the heating rate of 5 ℃/min and reacting for one hour at 500 ℃ in the atmosphere of hydrogen-argon mixed gas to obtain the electrocatalytic material Co @ CoMoO (wherein: 5:95, 100sccm)xA composite material.
Example 4
The embodiment prepares the electrocatalytic material, and the specific process is as follows:
s1: ultrasonically cleaning a piece of NF (2.4cm by 3cm) with ethanol, acetone and 3mol/L hydrochloric acid aqueous solution for 30min respectively to remove oil stains and nickel oxide on the surface, then sequentially cleaning with deionized water for 10min, and repeating for 3 times. After that 119mg of CoCl were added2·6H2O, 210mg of urea and 255mg of LAS were dissolved in 40mL of a mixed solution of deionized water and ethanol (H)2O: ethanol ═ 4: 1, v/v). Transferring the mixed solution into a stainless steel autoclave lined with 50mL of Teflon, immersing a piece of cleaned NF into the mixed solution, raising the temperature to 130 ℃ from room temperature, raising the temperature at a speed of 5 ℃/min, maintaining the temperature at 120 ℃ for reaction for 12h, naturally cooling to room temperature, washing with deionized water, and drying in an oven at 70 ℃;
s2: 582.1mg of CoCl2·6H2Dissolving O in 120mL deionized water, keeping the temperature at room temperature, immersing the nanosheet array prepared by S1, keeping the temperature for 10min, and transferring to 83.9mg of (NH)4)6Mo7O24·4H2O and 30mL deionizationReacting for 10min in a molybdate solution formed by water (the solution is kept at room temperature), naturally cooling to room temperature, taking out, washing with deionized water, and drying in an oven at 70 ℃;
s3: placing the material prepared in S2 into a quartz boat, placing the quartz boat into a tube furnace, and introducing H2Heating to 300 ℃ at the heating rate of 5 ℃/min and reacting for one hour at 300 ℃ in the atmosphere of hydrogen-argon mixed gas to obtain the electrocatalytic material Co @ CoMoO (wherein: 5:95, 100sccm)xA composite material.
Example 5
The embodiment prepares the electrocatalytic material, and the specific process is as follows:
s1: ultrasonically cleaning a piece of NF (2.4cm by 3cm) with ethanol, acetone and 3mol/L hydrochloric acid aqueous solution for 30min respectively to remove oil stains and nickel oxide on the surface, then sequentially cleaning with deionized water for 10min, and repeating for 3 times. Thereafter 146mg of Co (NO)3)2·6H2O, 210mg of C6H12N4And 255mg of PVP were dissolved in 40mL of a mixed solution of deionized water and ethanol (H)2O: ethanol ═ 3: 1, v/v). Transferring the mixed solution into a stainless steel autoclave lined with 50mL of Teflon, immersing a piece of cleaned NF into the mixed solution, raising the temperature to 120 ℃ from room temperature, raising the temperature at a speed of 5 ℃/min, maintaining the temperature at 120 ℃ for reaction for 12h, naturally cooling to room temperature, washing with deionized water, and drying in an oven at 70 ℃;
s2: 582.1mg of Co (NO)3)2·6H2O was dissolved in 120mL deionized water, heated to 80 ℃ and 83.9mg of Na was added2MoO4·2H2Preparing a molybdate solution from O and 30mL of deionized water, heating to 80 ℃, mixing the two solutions, immersing the nanosheet array prepared from S1, reacting for 10min, naturally cooling to room temperature, taking out, washing with deionized water, and drying in an oven at 70 ℃;
s3: placing the material prepared in S2 into a quartz boat, placing the quartz boat into a tube furnace, and introducing H2Heating to 400 ℃ at a heating rate of 5 ℃/min and maintaining the temperature at 400 ℃ in the atmosphere of hydrogen-argon mixture for reaction IObtaining the electrocatalytic material Co @ CoMoO in hoursxA composite material.
Comparative example 1
The comparative example prepares an electrocatalytic material, and the difference with the example 1 is that the electrocatalytic material is not coated with an elemental cobalt core, and the specific process comprises the following steps:
s1: 582.1mg of Co (NO)3)2·6H2O was dissolved in 120mL of deionized water to give solution A, and 83.9mg of Na was added2MoO4·2H2O was dissolved in 30mL of deionized water to give solution B. Respectively heating the solution A and the solution B to 80 ℃, soaking a piece of foamed nickel into the solution A for reaction for 10 minutes, then transferring the nanosheet array into the solution B for reaction for 10 minutes, naturally cooling to room temperature, taking out, sufficiently washing with deionized water, and drying in an oven at 70 ℃.
S2: placing the material prepared in S1 into a quartz boat, placing the quartz boat into a tube furnace, and introducing H2Heating to 450 ℃ at the heating rate of 5 ℃/min and maintaining the temperature at 450 ℃ for reacting for one hour under the atmosphere of hydrogen-argon mixed gas to obtain the electro-catalytic material CoMoO (modified alumina-based organic silica)x。
Test examples
For the electrocatalytic material Co @ CoMoO prepared in example 1xThe composite material was subjected to X-ray powder diffraction, and the results are shown in FIG. 1
As can be seen from FIG. 1, the material contains metal cobalt and CoMoO simultaneously4、Co2Mo3O8The signal peaks of the three phases show that the three phases exist simultaneously, and the method successfully synthesizes Co and CoMoOxA composite material.
To further observe the microstructure of the composite, the nanosheet arrays of example 1, both before and after hydrogenation, were subjected to electron microscopy and the results are shown in fig. 2, wherein (a) is a scanning electron micrograph of the nanosheet array before hydrogenation; (b) is a scanning electron microscope photograph of the nanosheet array after hydrogenation.
As can be seen from fig. 2, comparing the scanning electron microscope photographs before and after hydrogenation, it is demonstrated that the original nanosheet structure is retained while the nanosheets are reduced by the hydrogenation step.
To further verify that the electrocatalytic material prepared by the invention is Co @ CoMoOxComposite material, electrocatalytic material Co @ CoMoO prepared in example 1xThe composite was analyzed by transmission electron microscopy, and the results are shown in FIG. 3, in which (a) is a low-power transmission electron micrograph; (b) high power transmission electron microscope photograph.
As can be seen from FIG. 3, Co and CoMoOxThe composite material is CoMoOxThe microstructure of the Co nano-particles coated by the shell exists, and the dispersion degree of the nano-particles is better.
To further test the electrocatalytic properties of the electrocatalytic materials prepared according to the invention, the electrocatalytic material Co @ CoMoO prepared in example 1 was subjected toxComposite and electrocatalytic material CoMoO prepared in comparative example 1xCarrying out electrocatalysis performance test, and the specific process is as follows:
the obtained electrocatalytic material is used as a working electrode, a graphite rod is used as an auxiliary electrode, a mercury/mercury oxide electrode is used as a reference electrode, a three-electrode system is formed to test the hydrogen evolution reaction performance of the cathode of the catalyst, the electrolyte is 1mol/L potassium hydroxide water-soluble, a CHI760E electrochemical workstation is adopted, 100% of iR reduction is deducted, and the obtained LSV (Linear Sweep Voltammetry, LSV for short) curve is tested at the scanning speed of 0.005V/s. The results are shown in FIG. 4.
As can be seen from FIG. 4, at 10mA/cm2Current density of Co @ CoMoOxThe overpotential of (A) is only 56.2mV, which is much less than that of CoMoOxThe overpotential of 217.2mV is also superior to other reported CoMo oxide series catalysts.
To further test the impedance generated by the electrocatalytic material prepared according to the present invention, the electrocatalytic material Co @ CoMoO prepared in example 1 was subjected toxComposite and electrocatalytic material CoMoO prepared in comparative example 1xAnd (3) carrying out impedance spectrum test, which comprises the following specific processes:
the obtained electrocatalytic material is used as a working electrode, a graphite rod is used as an auxiliary electrode, a mercury/mercury oxide electrode is used as a reference electrode, a three-electrode system is formed to test the impedance of the catalyst, the electrolyte is 1mol/L potassium hydroxide water-soluble, and an EIS (Electrochemical impedance spectroscopy) curve obtained by 0.005V amplitude test is adopted in a range of 0.01Hz to 10000Hz under a potential of-1.15V by adopting a CHI760E Electrochemical workstation. The results are shown in FIG. 5.
As can be seen from FIG. 5, Co @ CoMoOxThe resistance of the composite material is obviously less than that of CoMoOxAnd the conductive performance is better.
To further test the stability of the electrocatalytic material prepared according to the present invention, the electrocatalytic material Co @ CoMoO prepared in example 1 was subjected toxThe composite material is subjected to stability test, and the specific process is as follows:
the obtained electrocatalytic material is used as a working electrode, a graphite rod is used as an auxiliary electrode, a mercury/mercury oxide electrode is used as a reference electrode to form a three-electrode system, an electrolyte is dissolved in 1mol/L potassium hydroxide, a CHI760E electrochemical workstation is adopted, and a chronopotentiometry method is used for testing Co @ CoMoOxStability of the composite. The results are shown in FIG. 6.
As can be seen from FIG. 6, the catalyst was at 10mA/cm2The overpotential of the catalyst is kept unchanged basically and the catalyst has excellent stability.
In order to further test the electrochemical performance of the electrocatalytic material prepared by the invention, the electrocatalytic material Co @ CoMoO prepared in examples 1-4 was subjected toxComposite and electrocatalytic material CoMoO prepared in comparative example 1xCarrying out electrochemical performance test, which comprises the following specific processes: an electrocatalytic material electrode, a mercury/mercury oxide electrode and a carbon rod are respectively used as a working electrode, a reference electrode and a counter electrode to form a three-electrode system, an electrolyte is a potassium hydroxide aqueous solution with the molar concentration of 1mol/L, a CHI760E electrochemical workstation is adopted, and an LSV (Linear scanning Voltammetry, LSV for short) curve obtained at the scanning rate of 0.005V/s is obtained at 10mAcm-2The overpotential at current density was used to compare catalytic performance and the results are shown in table 1.
TABLE 1
Comparative example 1
Example 1
Example 2
Example 3
Example 4
Example 5
Electric potential (mV)
217.2
56.2
71.2
94.2
121.2
183.2
From the overpotentials of comparative example 1 and examples 1 to 4, pure CoMoO was observedxThe material is 10mAcm-2The overpotential at current density was 217.2mV versus Co @ CoMoOxThe catalytic performance of the material is greatly improved, and the same current density is achieved under the potential of 56.2 mV. Illustrating the Co @ CoMoO prepared according to the inventionxThe nano-sheet array is a good hydrogen evolution electrocatalyst.
The embodiments of the present invention have been described in detail, but the present invention is not limited to the embodiments, and various changes can be made without departing from the gist of the present invention within the knowledge of those skilled in the art. Furthermore, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict.
