CN116103690A - Preparation method of self-supporting efficient difunctional electrocatalyst - Google Patents

Preparation method of self-supporting efficient difunctional electrocatalyst Download PDF

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CN116103690A
CN116103690A CN202310184562.5A CN202310184562A CN116103690A CN 116103690 A CN116103690 A CN 116103690A CN 202310184562 A CN202310184562 A CN 202310184562A CN 116103690 A CN116103690 A CN 116103690A
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self
supporting
preparing
carbon cloth
precursor
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郑晓航
叶振宇
闫耀天
王佩稼
钟文杰
顿量
王宏达
隋解和
蔡伟
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Harbin Institute of Technology
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Harbin Institute of Technology
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    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/02—Hydrogen or oxygen
    • C25B1/04—Hydrogen or oxygen by electrolysis of water
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
    • C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
    • C25B11/065—Carbon

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  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
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  • Inorganic Chemistry (AREA)
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Abstract

The invention discloses a preparation method of a self-supporting efficient difunctional electrocatalyst, and relates to a preparation method of a difunctional electrocatalyst. Solves the problems of complex preparation process and poor full-water decomposition performance of the existing transition metal-based catalyst. The preparation method comprises the following steps: 1. preparing a precursor by a hydrothermal method; 2. phosphating the precursor by a chemical vapor deposition method; the invention is used for preparing the self-supporting high-efficiency difunctional electrocatalyst.

Description

Preparation method of self-supporting efficient difunctional electrocatalyst
Technical Field
The invention relates to a preparation method of a bifunctional electrocatalyst.
Background
The hydrogen energy is regarded as the cleanest energy with the most development potential in the 21 st century, and has the characteristics of convenient storage and transportation, various utilization ways, high utilization rate, wide sources and the like. Compared with greenhouse gases generated by fossil energy combustion, the hydrogen combustion product is water, clean and pollution-free. Promoting the development of hydrogen energy industry and popularizing the use of hydrogen energy, and is important to realizing the aim of carbon neutralization. Currently, hydrogen is produced industrially mainly by reforming fossil energy, and a large amount of greenhouse gas emissions are associated with the process, which is contrary to the aim of reducing carbon emissions.
The hydrogen prepared by utilizing the electrolytic water reaction has the advantages of rich raw material reserve, clean and pollution-free preparation process, high preparation efficiency, no site limitation and the like, and is a future development trend of the hydrogen energy industry. At present, most of catalysts used for preparing hydrogen by industrial water electrolysis are noble metal catalysts, and the catalysts have excellent performance but high price and are difficult to popularize on a large scale. It is therefore a key issue to find a catalyst with good catalytic performance and low cost. In recent years, catalysts such as transition metal-based oxides, hydroxides, phosphides, sulfides have been attracting attention from researchers. However, the catalyst prepared at present has complex preparation process, and has excellent performance only in hydrogen evolution or oxygen evolution single-side reaction, and poor performance when being used for full water decomposition reaction. Therefore, it is necessary to design a bifunctional electrocatalyst with simple and controllable preparation process for full water decomposition.
Disclosure of Invention
The invention aims to solve the problems of complex preparation process and poor full-water decomposition performance of the existing transition metal-based catalyst, and further provides a preparation method of the self-supporting efficient double-function electrocatalyst.
The preparation method of the self-supporting high-efficiency bifunctional electrocatalyst comprises the following steps:
1. preparing a precursor by a hydrothermal method:
(1) dissolving nickel nitrate hexahydrate, ferric nitrate nonahydrate, ammonium fluoride and urea in deionized water, and stirring at room temperature to obtain a mixed solution;
the mole ratio of the nickel nitrate hexahydrate to the ferric nitrate nonahydrate is 1 (0.5-2); the mol ratio of the nickel nitrate hexahydrate to the ammonium fluoride is 1 (3-5); the mol ratio of the nickel nitrate hexahydrate to the urea is 1 (8-12);
(2) immersing the carbon cloth in the mixed solution, and then placing the carbon cloth in a high-pressure reaction kettle for high-temperature reaction;
(3) after the reaction is finished, cooling the high-pressure reaction kettle to room temperature, taking out the carbon cloth, and cleaning and drying to obtain the carbon cloth growing with the ferronickel precursor;
2. phosphating the precursor by chemical vapor deposition:
placing carbon cloth growing with a ferronickel precursor and sodium hypophosphite monohydrate in a tube furnace, placing sodium hypophosphite monohydrate in the gas upstream of the tube furnace, placing carbon growing with the ferronickel precursor in the gas downstream, introducing protective gas, preserving heat for 30-60 min at 300-450 ℃, and then naturally cooling to room temperature to obtain the self-supporting high-efficiency bifunctional electrocatalyst.
The beneficial effects of the invention are as follows:
1. the raw materials used in the invention are transition metals, so that the cost is low; the preparation process used in the preparation is relatively simple and controllable, and is suitable for large-scale production.
2. The nickel iron phosphide obtained by the invention uniformly grows on the carbon cloth substrate without using an extra binder, and has good catalytic activity under alkaline conditions, namely hydrogen evolution reaction and oxygen evolution reaction, and the current density is 10mA/cm 2 The overpotential was 94mV (hydrogen evolution) and 236mV (oxygen evolution), respectively. When the double-electrode full water decomposition device is used for double-electrode full water decomposition, the current density is 10mA/cm 2 Only a decomposition voltage of 1.59V is required.
Drawings
FIG. 1 is a scanning electron microscope image of a nickel phosphide ferroelectric catalyst grown on a carbon cloth prepared in example one;
FIG. 2 is an X-ray diffraction pattern of a nickel phosphide ferroelectric catalyst grown on a carbon cloth prepared in accordance with example one;
FIG. 3 is a graph showing the polarization of hydrogen evolution of a nickel phosphide ferroelectric catalyst grown on carbon cloth prepared in example one;
FIG. 4 is a graph showing oxygen evolution polarization of a nickel phosphide ferroelectric catalyst grown on carbon cloth prepared in example one;
fig. 5 is a graph showing the total water splitting profile of a nickel phosphide ferroelectric catalyst grown on a carbon cloth prepared in example one.
Detailed Description
The first embodiment is as follows: the preparation method of the self-supporting efficient bifunctional electrocatalyst comprises the following steps:
1. preparing a precursor by a hydrothermal method:
(1) dissolving nickel nitrate hexahydrate, ferric nitrate nonahydrate, ammonium fluoride and urea in deionized water, and stirring at room temperature to obtain a mixed solution;
the mole ratio of the nickel nitrate hexahydrate to the ferric nitrate nonahydrate is 1 (0.5-2); the mol ratio of the nickel nitrate hexahydrate to the ammonium fluoride is 1 (3-5); the mol ratio of the nickel nitrate hexahydrate to the urea is 1 (8-12);
(2) immersing the carbon cloth in the mixed solution, and then placing the carbon cloth in a high-pressure reaction kettle for high-temperature reaction;
(3) after the reaction is finished, cooling the high-pressure reaction kettle to room temperature, taking out the carbon cloth, and cleaning and drying to obtain the carbon cloth growing with the ferronickel precursor;
2. phosphating the precursor by chemical vapor deposition:
placing carbon cloth growing with a ferronickel precursor and sodium hypophosphite monohydrate in a tube furnace, placing sodium hypophosphite monohydrate in the gas upstream of the tube furnace, placing carbon growing with the ferronickel precursor in the gas downstream, introducing protective gas, preserving heat for 30-60 min at 300-450 ℃, and then naturally cooling to room temperature to obtain the self-supporting high-efficiency bifunctional electrocatalyst.
The beneficial effects of this concrete implementation are:
1. the raw materials used in the specific embodiment are transition metals, so that the cost is low; the preparation process used in the preparation is relatively simple and controllable, and is suitable for large-scale production.
2. The nickel iron phosphide obtained by the specific embodiment uniformly grows on the carbon cloth substrate without using an additional binder, and has good catalytic activity under alkaline conditions, namely hydrogen evolution reaction and oxygen evolution reaction, and the current density is 10mA/cm 2 The overpotential was 94mV (hydrogen evolution) and 236mV (oxygen evolution), respectively. When the double-electrode full water decomposition device is used for double-electrode full water decomposition, the current density is 10mA/cm 2 Only a decomposition voltage of 1.59V is required.
The second embodiment is as follows: the first difference between this embodiment and the specific embodiment is that: the volume ratio of the total mole number of the nickel nitrate hexahydrate, the ferric nitrate nonahydrate, the ammonium fluoride and the urea in the step one (1) to the deionized water is 1mmol (1-5) mL. The other is the same as in the first embodiment.
And a third specific embodiment: this embodiment differs from one or both of the embodiments in that: the high-temperature reaction in the step (2) is specifically carried out for 4 to 10 hours under the condition that the reaction temperature is 100 to 150 ℃. The other is the same as the first or second embodiment.
The specific embodiment IV is as follows: this embodiment differs from one of the first to third embodiments in that: the size of the carbon cloth in the step one (2) is 1cm multiplied by 1cm to 2cm multiplied by 4cm. The other embodiments are the same as those of the first to third embodiments.
Fifth embodiment: this embodiment differs from one to four embodiments in that: the washing and drying in the step one (3) is specifically to use deionized water and ethanol to wash for 0.5 to 2 minutes respectively, and then dry for 20 to 24 hours at room temperature. The other embodiments are the same as those of the first to fourth embodiments.
Specific embodiment six: this embodiment differs from one of the first to fifth embodiments in that: and in the second step, the distance between the sodium hypophosphite monohydrate and the carbon cloth growing with the ferronickel precursor is 1 cm-5 cm. The other embodiments are the same as those of the first to fifth embodiments.
Seventh embodiment: this embodiment differs from one of the first to sixth embodiments in that: and in the second step, the shielding gas is introduced at the gas flow rate of 50-150 sccm. The other embodiments are the same as those of the first to sixth embodiments.
Eighth embodiment: this embodiment differs from one of the first to seventh embodiments in that: and step two, wherein the protective gas is argon. The other is the same as in embodiments one to seven.
Detailed description nine: this embodiment differs from one to eight of the embodiments in that: and in the second step, the mass ratio of the carbon cloth growing with the nickel-iron precursor to the sodium hypophosphite monohydrate is 1 (1-3). The others are the same as in embodiments one to eight.
Detailed description ten: this embodiment differs from one of the embodiments one to nine in that: in the second step, the temperature is raised to 300 ℃ to 450 ℃ at a heating rate of 10 ℃/min to 15 ℃/min. The others are the same as in embodiments one to nine.
The following examples are used to verify the benefits of the present invention:
embodiment one:
the preparation method of the self-supporting high-efficiency bifunctional electrocatalyst comprises the following steps:
1. preparing a precursor by a hydrothermal method:
(1) dissolving nickel nitrate hexahydrate, ferric nitrate nonahydrate, ammonium fluoride and urea in deionized water, and stirring at room temperature to obtain a mixed solution;
the molar ratio of the nickel nitrate hexahydrate to the ferric nitrate nonahydrate is 1:1; the molar ratio of the nickel nitrate hexahydrate to the ammonium fluoride is 1:4; the molar ratio of the nickel nitrate hexahydrate to the urea is 1:10; the volume ratio of the total mole number of the nickel nitrate hexahydrate, the ferric nitrate nonahydrate, the ammonium fluoride and the urea to the deionized water is 1 mmol/3 mL;
(2) immersing the carbon cloth in the mixed solution, and then placing the carbon cloth in a high-pressure reaction kettle to react for 6 hours under the condition that the reaction temperature is 120 ℃;
(3) after the reaction is finished, cooling the high-pressure reaction kettle to room temperature, taking out the carbon cloth, and cleaning and drying to obtain the carbon cloth growing with the ferronickel precursor;
2. phosphating the precursor by chemical vapor deposition:
placing carbon cloth growing with a ferronickel precursor and sodium hypophosphite monohydrate in a tube furnace, placing sodium hypophosphite monohydrate in the gas upstream of the tube furnace, placing carbon growing with the ferronickel precursor in the gas downstream, introducing protective gas at the gas flow of 100sccm, heating to 350 ℃ at the heating rate of 10 ℃/min, preserving heat for 30min at the temperature of 350 ℃, and naturally cooling to room temperature to obtain the nickel phosphide ferroelectric catalyst growing on the carbon cloth.
The carbon cloth in the step (2) has the size of 2cm multiplied by 2cm.
The washing and drying in the step one (3) is specifically to wash for 1min with deionized water and ethanol respectively, and then dry for 24h at room temperature.
The distance between the sodium hypophosphite monohydrate and the carbon cloth growing with the ferronickel precursor in the second step is 2cm.
And step two, wherein the protective gas is argon.
And in the second step, the mass ratio of the carbon cloth growing with the nickel-iron precursor to the sodium hypophosphite monohydrate is 1:2.
FIG. 1 is a scanning electron microscope image of a nickel phosphide ferroelectric catalyst grown on a carbon cloth prepared in example one; as can be seen from the figure, the catalyst is mostly irregular nano particles with the diameter of 100nm to 800nm and is uniformly distributed on the carbon cloth.
FIG. 2 is an X-ray diffraction pattern of a nickel phosphide ferroelectric catalyst grown on a carbon cloth prepared in accordance with example one; from the figure, the catalyst phase is nickel iron phosphide, i.e. Ni 2 P-FeP。
Using a three-electrode test system, using KOH solution with the concentration of 1mol/L as electrolyte, and controlling the current density to be 10mA/cm 2 Under the conditions of (1), hydrogen evolution, oxygen evolution reaction and total water decomposition are carried out on the nickel phosphide ferroelectric catalyst which is prepared in the first embodiment and grows on the carbon cloth; FIG. 3 is a graph showing the polarization of hydrogen evolution of a nickel phosphide ferroelectric catalyst grown on carbon cloth prepared in example one; FIG. 4 is a real viewThe oxygen evolution polarization curve graph of the nickel phosphide ferroelectric catalyst growing on the carbon cloth prepared in the first embodiment; the hydrogen evolution and oxygen evolution overpotential were 94mV and 236mV, respectively. FIG. 5 is a graph showing the total water splitting profile of a nickel phosphide ferroelectric catalyst grown on a carbon cloth prepared in example one; as can be seen, in the double electrode test, only 1.59V is needed to reach 10mA/cm 2 Is used for the current density of the battery. Compared with the existing transition metal catalytic electrode, the material prepared in the first embodiment has excellent catalytic activity, and meanwhile, the preparation cost is low, and the preparation process is simple.

Claims (10)

1. The preparation method of the self-supporting efficient bifunctional electrocatalyst is characterized by comprising the following steps of:
1. preparing a precursor by a hydrothermal method:
(1) dissolving nickel nitrate hexahydrate, ferric nitrate nonahydrate, ammonium fluoride and urea in deionized water, and stirring at room temperature to obtain a mixed solution;
the mole ratio of the nickel nitrate hexahydrate to the ferric nitrate nonahydrate is 1 (0.5-2); the mol ratio of the nickel nitrate hexahydrate to the ammonium fluoride is 1 (3-5); the mol ratio of the nickel nitrate hexahydrate to the urea is 1 (8-12);
(2) immersing the carbon cloth in the mixed solution, and then placing the carbon cloth in a high-pressure reaction kettle for high-temperature reaction;
(3) after the reaction is finished, cooling the high-pressure reaction kettle to room temperature, taking out the carbon cloth, and cleaning and drying to obtain the carbon cloth growing with the ferronickel precursor;
2. phosphating the precursor by chemical vapor deposition:
placing carbon cloth growing with a ferronickel precursor and sodium hypophosphite monohydrate in a tube furnace, placing sodium hypophosphite monohydrate in the gas upstream of the tube furnace, placing carbon growing with the ferronickel precursor in the gas downstream, introducing protective gas, preserving heat for 30-60 min at 300-450 ℃, and then naturally cooling to room temperature to obtain the self-supporting high-efficiency bifunctional electrocatalyst.
2. The method for preparing the self-supporting efficient bifunctional electrocatalyst according to claim 1, wherein the volume ratio of the total mole number of nickel nitrate hexahydrate, iron nitrate nonahydrate, ammonium fluoride and urea in step one (1) to deionized water is 1mmol (1-5) mL.
3. The method for preparing a self-supporting and efficient bifunctional electrocatalyst according to claim 2, wherein the high-temperature reaction in step one (2) is specifically performed at a reaction temperature of 100 ℃ to 150 ℃ for 4h to 10h.
4. The method for preparing a self-supporting and efficient bifunctional electrocatalyst according to claim 1, wherein the carbon cloth in step one (2) has a size of 1cm×1cm to 2cm×4cm.
5. The method for preparing the self-supporting efficient bifunctional electrocatalyst according to claim 1, wherein the washing and drying in step one (3) is specifically performed by washing with deionized water and ethanol for 0.5min to 2min, respectively, and then drying at room temperature for 20h to 24h.
6. The method for preparing a self-supporting and efficient bifunctional electrocatalyst according to claim 1, wherein the distance between the sodium hypophosphite monohydrate and the carbon cloth grown with the nickel-iron precursor in the second step is 1cm to 5cm.
7. The method for preparing a self-supporting and efficient bifunctional electrocatalyst according to claim 1, wherein in the second step, a shielding gas is introduced at a gas flow rate of 50sccm to 150 sccm.
8. The method for preparing a self-supporting and efficient bifunctional electrocatalyst according to claim 7, wherein the shielding gas in the second step is argon.
9. The method for preparing the self-supporting efficient bifunctional electrocatalyst according to claim 6, wherein the mass ratio of the carbon cloth grown with the nickel-iron precursor to sodium hypophosphite monohydrate in the second step is 1 (1-3).
10. The method for preparing the self-supporting and efficient bifunctional electrocatalyst according to claim 1, wherein in the second step, the temperature is raised to 300 ℃ to 450 ℃ at a temperature raising rate of 10 ℃/min to 15 ℃/min.
CN202310184562.5A 2023-03-01 2023-03-01 Preparation method of self-supporting efficient difunctional electrocatalyst Pending CN116103690A (en)

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