CN111424289A - A kind of preparation method of bimetallic persulfide multifunctional catalyst and its application - Google Patents

Abstract

The invention relates to the technical fields of electrocatalysis ORR, OER and HER, and a preparation method of a bimetallic persulfide multifunctional catalyst. A vacuum high-frequency induction melting furnace is used to heat two of cobalt, iron, nickel and manganese together with aluminum. To the molten state, the alloy liquid is cooled in an inert gas atmosphere to form a rod-shaped alloy ingot, and then the single-roller chilling device is used to chill and rapidly solidify into a corresponding alloy strip; the obtained alloy strip is placed in an alkali. Dealloying treatment in neutral or neutral solution to obtain transition metal oxide or oxyhydroxide powder products; placed in a tubular annealing furnace, sulfur powder is placed upstream of the sample, driven by the airflow of a protective inert gas Under high temperature, the volatilized sulfur vapor and the dealloyed product are contacted and reacted at high temperature, and the bimetallic persulfide multifunctional catalyst is prepared after being lowered to room temperature.

Description

A kind of preparation method of bimetallic persulfide multifunctional catalyst and its application

technical field

The present invention relates to the technical field of electrocatalytic ORR, OER and HER.

Background technique

After human beings entered the industrial society, the demand for energy is increasing day by day, while the reserves of non-renewable resources such as coal, oil, and natural gas are limited on the earth, and the environmental pollution caused is irreversible. It can be seen that the development of green new energy has become the most urgent in today's society. need. In recent years, researchers have devoted themselves to the development of clean and efficient energy conversion systems, such as fuel cells, rechargeable metal-air batteries, and electrolysis of water to produce hydrogen and oxygen, as ideal substitutes for fossil fuels. Oxygen reduction reaction (ORR), oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are the three basic electrochemical reactions commonly involved in the above energy systems. High-performance electrocatalysts are often required for practical applications. Currently, noble metal Pt-based catalysts are widely used in ORR and HER processes, but they are expensive and have low OER activity; IrO ₂ /RuO ₂ has been shown to have excellent OER catalytic activity, but its ORR and HER performance is poor. For most catalysts, only single-function or dual-function activity can be achieved. For example, Fe _x Co _1-x P, AlNiP, and CuS belong to HER, OER, and ORR single-function catalysts, respectively, while MoO ₂ and CoFe/N-GCT are It belongs to HER-OER, OER-ORR bifunctional catalyst. Therefore, finding a trifunctional catalyst with high activity, low cost, and long-range stability is a difficult problem that must be overcome in self-powered water electrolysis systems.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: how to solve the problems in the background technology, and provide a preparation method of a bimetallic persulfide multifunctional catalyst.

The technical scheme adopted in the present invention is: a preparation method of a bimetallic persulfide multifunctional catalyst, which is carried out according to the following steps:

Step 1. Use a vacuum high-frequency induction melting furnace to heat two of cobalt, iron, nickel, and manganese together with aluminum to a molten state, wait for the alloy liquid to cool in an inert gas atmosphere to form a rod-shaped alloy ingot, and then use a single roll to chill The device chills and rapidly solidifies the strip into the corresponding alloy strip;

Step 2, placing the alloy strip obtained in step 1 in an alkaline or neutral solution for dealloying treatment, washing with ultrapure water for several times and drying to obtain a powdered product of transition metal oxide or oxyhydroxide;

Step 3: Place the dealloyed product obtained in Step 2 in a tubular annealing furnace, place the sulfur powder upstream of the sample, the distance between the two is 0.5~5cm, and the mass ratio of the sulfur powder to the dealloyed product is 1:1~20 : 1; the tubular annealing furnace is heated to 350~700℃, and the temperature is kept for 0.5~12h; driven by the airflow of the protective inert gas, the volatilized sulfur vapor contacts and reacts with the dealloyed product at high temperature, and the The bimetallic persulfide multifunctional catalyst was prepared by cooling down to room temperature.

As a preferred way: in step 1, the atomic percentage content of aluminum in the alloy strip is 70%-90%, and the atomic ratio of the remaining two metal elements is 1:29-29:1.

As a preferred way: in step 1, the width of the alloy strip is 1-5 mm, and the thickness is 10-60 μm.

As a kind of preferred way: the alkaline solution described in step 2 is a kind of in sodium hydroxide and potassium hydroxide, and the molar concentration is 1～10mol/L; The neutral solution is one in sodium chloride and potassium chloride species, the molar concentration is 1~10mol/L.

As a preferred way: the dealloying treatment time in step 2 is 2~48h.

As a preferred way: the heating rate in step 3 is 1~10°C/min, and the cooling rate is 1~5°C/min.

As a preferred way: in step 3, the protective gas is one of nitrogen and argon, and the flow rate is 100-1000 sccm.

An application of a bimetallic persulfide multifunctional catalyst, characterized in that: a three-electrode system is adopted, the bimetallic persulfide described in any one of claims 1-7 is used as a working electrode, a platinum wire is used as an auxiliary electrode, and the Ag/AgCl The electrode was used as a reference electrode for electrocatalytic ORR and OER tests.

An application of a bimetallic persulfide multifunctional catalyst, characterized in that: a three-electrode system is adopted, the bimetallic persulfide described in any one of claims 1-7 is used as a working electrode, a graphite rod is used as an auxiliary electrode, Ag/AgCl The electrode was used as a reference electrode for electrocatalytic HER testing.

The beneficial effects of the invention are as follows: the bimetallic persulfide multifunctional catalyst prepared by the invention adopts aluminum-based alloy as the master alloy, and its raw material sources are wide, the composition is adjustable, the designability is strong, and the price is low, which can greatly reduce the production cost. . The invention can flexibly control the composition, distribution and structure of the active phase according to the composition of the master alloy, the concentration of the etching solution and the dealloying time. The bimetallic persulfide prepared by the invention presents a micro/nano scale structure, which can greatly increase the reaction contact area of the electrode material and improve the utilization rate of the catalyst. The high-temperature vulcanization treatment involved in the present invention can not only maintain the original micro/nano structure, but also improve the crystallinity and stability of the material. The bimetallic persulfide in the present invention combines the electrocatalytic advantages of two monometallic sulfides, can produce beneficial synergistic effects, exhibits good electrocatalytic activity for ORR, OER and HER, and is expected to become a multifunctional catalyst.

Description of drawings

1 is a scanning electron microscope (SEM) photo of the cobalt iron persulfide multifunctional catalyst prepared in Example 1;

Fig. 2 is the X-ray diffraction (XRD) pattern of the cobalt iron persulfide multifunctional catalyst prepared in Example 1;

Fig. 3 is the electrocatalytic oxygen reduction polarization curve diagram of the cobalt iron persulfide multifunctional catalyst prepared in Example 1 in 0.1mol/L potassium hydroxide solution;

Fig. 4 is the electrocatalytic oxygen evolution polarization curve diagram of the cobalt iron persulfide multifunctional catalyst prepared in Example 1 in 0.1 mol/L potassium hydroxide solution;

Figure 5 is a graph of the electrocatalytic hydrogen evolution polarization curve of the cobalt iron persulfide multifunctional catalyst prepared in Example 1 in a 0.1 mol/L potassium hydroxide solution.

Detailed ways

The present invention will be described in further detail below with reference to specific embodiments and accompanying drawings.

Example 1

A preparation method of a cobalt iron persulfide multifunctional catalyst is carried out according to the following steps:

Step 1. Use a vacuum high-frequency induction melting furnace to heat cobalt, iron, and aluminum (atomic ratio of 5:5:90) to a molten state. After the alloy liquid is cooled to a rod-shaped alloy ingot in an argon atmosphere, a single roll is used. The chilling device blows it into an alloy strip with a width of 3mm and a thickness of 40μm;

In step 2, the cobalt-iron-aluminum alloy strip obtained in step 1 is placed in a sodium hydroxide solution with a molar concentration of 6 mol/L for dealloying treatment, the reaction time is 4h, and the ultrapure water is used for several times of washing and drying to obtain Cobalt iron oxide or oxyhydroxide;

Step 3. Place the cobalt iron oxide or oxyhydroxide obtained in step 2 in a tubular annealing furnace, place the sulfur powder upstream of the sample, the distance between the two is 2cm, and the mass ratio of the sulfur powder to the dealloyed product is 5:1 ; Raise the tubular annealing furnace to 400 °C at a heating rate of 5 °C/min, and keep it for 1 h; Driven by the flow of argon gas (flow rate of 600sccm), the sulfur vapor is contacted with cobalt iron oxide or oxyhydroxide at high temperature And the reaction occurs, and the tube furnace is cooled down to room temperature at a cooling rate of 2°C/min to prepare a cobalt iron persulfide multifunctional catalyst.

Through SEM observation, it was found that cobalt iron persulfide showed a nano-sheet cluster structure (see Figure 1); XRD analysis found that a large number of (CoFe)(S ₂ ) ₂ phases were formed on the electrode surface (see Figure 2); The electrode was used as the working electrode, the platinum wire was used as the auxiliary electrode, and the Ag/AgCl electrode was used as the reference electrode. The wave potential is 0.79V, see Figure 3) and OER activity (the required potential is 1.53V at a current density of 10mA/cm ² , see Figure 4), the smaller the absolute value of the difference between the two potentials, the better The charge-discharge process of the secondary metal-air battery; the electrode was used as the working electrode, the graphite rod was used as the auxiliary electrode, and the Ag/AgCl electrode was used as the reference electrode. The solution showed good electrocatalytic HER activity (the required potential was 161 mV at a current density of 10 mA/cm ² , see Figure 5), and the smaller the hydrogen evolution potential value, the more conducive to the realization of hydrogen production by electrolysis of water.

Example 2

A preparation method of a cobalt-nickel persulfide multifunctional catalyst is carried out according to the following steps:

Step 1. Use a vacuum high-frequency induction melting furnace to heat cobalt, nickel, and aluminum (atomic ratio of 5:10:85) to a molten state. After the alloy liquid is cooled to a rod-shaped alloy ingot in an argon atmosphere, a single roll is used. The chilling device blows it into an alloy strip with a width of 2mm and a thickness of 50μm;

In step 2, the cobalt-nickel-aluminum alloy strip obtained in step 1 is placed in a potassium hydroxide solution with a molar concentration of 3 mol/L for dealloying treatment, the reaction time is 10h, and the ultrapure water is used for several times of rinsing and drying to obtain Cobalt nickel oxide or oxyhydroxide;

Step 3. Place the cobalt-nickel oxide or oxyhydroxide obtained in step 2 in a tubular annealing furnace, place the sulfur powder upstream of the sample, the distance between the two is 1 cm, and the mass ratio of the sulfur powder to the dealloyed product is 3:1 ; Raise the tube annealing furnace to 450°C at a heating rate of 8°C/min, and keep it for 2h; Driven by the flow of nitrogen (flow rate of 500sccm), the sulfur vapor is contacted with cobalt nickel oxide or oxyhydroxide at high temperature and heated. After the reaction occurs, the tube furnace is lowered to room temperature at a cooling rate of 4° C./min to prepare a cobalt-nickel persulfide multifunctional catalyst.

Example 3

A preparation method of an iron-nickel persulfide multifunctional catalyst is carried out according to the following steps:

Step 1. Use a vacuum high-frequency induction melting furnace to heat iron, nickel, and aluminum (atomic ratio of 20:10:70) together to a molten state. After the alloy liquid is cooled to a rod-shaped alloy ingot in an argon atmosphere, a single roll is used. The chilling device blows it into an alloy strip with a width of 3mm and a thickness of 30μm;

In step 2, the iron-nickel-aluminum alloy strip obtained in step 1 is placed in a sodium chloride solution with a molar concentration of 8 mol/L for dealloying treatment, the reaction time is 36h, and the ultrapure water is used for several times of washing and drying to obtain Iron nickel oxide or oxyhydroxide;

Step 3. Place the iron-nickel oxide or oxyhydroxide obtained in step 2 in a tubular annealing furnace, place the sulfur powder upstream of the sample, the distance between the two is 3cm, and the mass ratio of the sulfur powder to the dealloyed product is 10:1 ; Raise the tubular annealing furnace to 500°C at a heating rate of 8°C/min, and keep it for 2h; Driven by the flow of argon gas (flow rate of 800sccm), the sulfur vapor contacts with iron-nickel oxide or oxyhydroxide at high temperature And the reaction occurs, and the tube furnace is cooled down to room temperature at a cooling rate of 4°C/min to prepare an iron-nickel persulfide multifunctional catalyst.

Example 4

A preparation method of a nickel-manganese persulfide multifunctional catalyst is carried out according to the following steps:

Step 1. Use a vacuum high-frequency induction melting furnace to heat nickel, manganese, and aluminum (atomic ratio of 7.5:7.5:85) to a molten state. After the alloy liquid is cooled to a rod-shaped alloy ingot in an argon atmosphere, a single roll is used. The chiller blows it into an alloy strip with a width of 3mm and a thickness of 60μm;

In step 2, the nickel-manganese-aluminum alloy strip obtained in step 1 is placed in a sodium hydroxide solution with a molar concentration of 2 mol/L for dealloying treatment, the reaction time is 24h, and the ultra-pure water is used for several times of washing and drying to obtain Nickel manganese oxide or oxyhydroxide;

Step 3. Place the nickel-manganese oxide or oxyhydroxide obtained in step 2 in a tubular annealing furnace, place the sulfur powder upstream of the sample, the distance between the two is 5cm, and the mass ratio of the sulfur powder to the dealloyed product is 8:1 ; Raise the tube annealing furnace to 600°C at a heating rate of 6°C/min, and keep it for 1 h; Driven by the flow of nitrogen (flow rate of 600sccm), the sulfur vapor is contacted with nickel manganese oxide or oxyhydroxide at high temperature and heated. After the reaction occurs, the tube furnace is cooled down to room temperature at a cooling rate of 3° C./min to prepare a nickel-manganese persulfide multifunctional catalyst.

The description of the above embodiments is only used to help understand the method of the present invention and its core idea; meanwhile, for those skilled in the art, according to the idea of the present invention, there will be changes in the specific implementation and application scope. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (9)

1. a preparation method of bimetallic persulfide multifunctional catalyst, is characterized in that: carry out according to the following steps Step 1. Use a vacuum high-frequency induction melting furnace to heat two of cobalt, iron, nickel, and manganese together with aluminum to a molten state, wait for the alloy liquid to cool to a rod-shaped alloy ingot in an inert gas atmosphere, and then use a single roll to chill The device blows it into the corresponding alloy strip; In step 2, the alloy strip obtained in step 1 is placed in an alkaline or neutral solution for dealloying treatment, rinsed with ultrapure water for several times, and then dried to obtain a powder sample of transition metal oxide or oxyhydroxide; Step 3: Place the dealloyed product obtained in Step 2 in a tubular annealing furnace, place the sulfur powder upstream of the sample, the distance between the two is 0.5~5cm, and the mass ratio of the sulfur powder to the dealloyed product is 1:1~20 : 1; the tubular annealing furnace is heated to 350~700°C, and the temperature is kept for 0.5~12h; driven by the airflow of the protective gas, the sulfur vapor and the dealloyed product are contacted and reacted at high temperature, and the double annealing product is prepared after being lowered to room temperature. Metal persulfide multifunctional catalysts. 2. the preparation method of a kind of bimetallic persulfide multifunctional catalyst as claimed in claim 1 is characterized in that: in step 1, the atomic percentage content of aluminum in the alloy strip is 70%～90%, and the remaining two The atomic ratio of metal elements is 1:29~29:1. 3 . The method for preparing a bimetallic persulfide multifunctional catalyst according to claim 1 , wherein in step 1, the alloy strip has a width of 1-5 mm and a thickness of 10-60 μm. 4 . 4. the preparation method of a kind of bimetallic persulfide multifunctional catalyst as claimed in claim 1, is characterized in that: the alkaline solution described in step 2 is a kind of in sodium hydroxide and potassium hydroxide, molar concentration It is 1~10mol/L; the neutral solution is one of sodium chloride and potassium chloride, and the molar concentration is 1~10mol/L. 5 . The preparation method of a bimetallic persulfide multifunctional catalyst according to claim 1 , wherein the dealloying treatment time in step 2 is 2 to 48 h. 6 . 6. the preparation method of a kind of bimetallic persulfide multifunctional catalyst as claimed in claim 1, is characterized in that: the rate of temperature rise described in step 3 is 1～10 ℃/min, and the rate of temperature drop is 1～5 ℃/min min. 7. The preparation method of a bimetallic persulfide multifunctional catalyst according to claim 1, wherein the protective gas in step 3 is one of nitrogen gas and argon gas, and the flow rate is 100～1000sccm. 8. the application of a kind of bimetallic persulfide multifunctional catalyst, it is characterized in that: adopt three-electrode system, with any described bimetallic persulfide of claim 1-7 as working electrode, platinum wire as auxiliary electrode, Ag /AgCl electrode was used as a reference electrode for electrocatalytic ORR and OER tests. 9. the application of a kind of bimetallic persulfide multifunctional catalyst, it is characterized in that: adopt three-electrode system, with any described bimetallic persulfide of claim 1-7 as working electrode, graphite rod as auxiliary electrode, Ag /AgCl electrode was used as a reference electrode for electrocatalytic HER test.

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