CN114592209B

CN114592209B - Catalyst, and large-scale preparation method and application thereof

Info

Publication number: CN114592209B
Application number: CN202210359971.XA
Authority: CN
Inventors: 吕瑞涛; 周灵犀; 黄正宏; 康飞宇
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2022-04-06
Filing date: 2022-04-06
Publication date: 2024-01-26
Anticipated expiration: 2042-04-06
Also published as: CN114592209A

Abstract

The invention discloses a catalyst, a large-scale preparation method and application thereof. The catalyst comprises: the base body is foam ferronickel; a carrier on the surface of the substrate, the carrier comprising a plurality of substructures, the substructures being composed of a plurality of nanoplatelets and the substructures being in a patterned shape, wherein the nanoplatelets comprise nickel iron oxyhydroxide; catalyst particles supported on the surface of the nanoplatelets. Therefore, the carrier foam nickel-iron matrix has better supporting performance, so that the catalyst has good structural stability; the carrier is positioned on the surface of the foam ferronickel matrix, and the nano-sheet structure enables the carrier to have higher specific surface area, which is beneficial to improving the contact area during the catalytic reaction, and further improving the catalytic performance of the catalyst; the catalyst particles are loaded on the nano-sheet, and have stronger interaction with the carrier, so that the catalytic performance of the catalyst can be further improved.

Description

Catalyst, and large-scale preparation method and application thereof

Technical Field

The invention relates to the technical field of electrocatalysis, in particular to a catalyst and a large-scale preparation method and application thereof.

Background

With the increasing prominence of energy and environmental problems, the development of new energy sources that are economical, clean and renewable, instead of fossil energy sources, is an urgent task in the scientific research field. Hydrogen is used as an energy carrier of zero carbon, is ideal clean secondary energy, and has the advantages of high combustion heat value, no pollution of combustion products and the like; water is one of the most abundant resources on earth, and electrocatalytic water splitting technology driven by electric energy is considered as an ideal way for green hydrogen production. Electrocatalytic water decomposition is the conversion of water to hydrogen (H) by cathodic Hydrogen Evolution (HER) and anodic Oxygen Evolution (OER) ₂ ) And oxygen (O) ₂ ) Is a process of (2). The OER reaction is more complex than HER, the slow kinetics of the processThe sign reduces the efficiency of the overall electrolysis process. Generally, an electrocatalyst is added to the reaction system to increase the rate of oxygen generation by electrocatalytically decomposing water, and materials based on ruthenium (Ru) and iridium (Ir) oxides are currently considered to be catalysts with highest oxygen activity by electrocatalytically decomposing water, but large-scale commercial application of the materials is limited due to scarce and expensive noble metal reserves. Therefore, development of a catalyst with low price and excellent performance is needed, and improvement of the intrinsic catalytic activity of the catalyst while reducing the consumption of noble metals is needed to promote development of the water electrolysis technology.

Supported metal catalysts (Supported Metal Catalyst, SMC) are a type of catalyst which is common in chemical production and are widely focused by researchers as a material with excellent performance. On the one hand, the utilization rate of noble metal can be improved by dispersing the noble metal active center on the carrier with large specific surface area, so that the consumption of noble metal catalyst is saved. On the other hand, strong Metal-Support interactions (SMSI) in SMC can prevent Metal site agglomeration (Metal particle agglomeration) and optimize its electronic structure, thereby improving its catalytic activity in both spatial and electronic structures.

Noble metals Ru and Ir based SMC have been reported to exhibit higher OER catalytic activity, however, the synthesis process is generally complex, including steps such as carrier synthesis (typically hydrothermal and co-precipitation) and metal loading (typically impregnation and heat treatment). The separation and synthesis of the carrier and the metal not only increases the preparation cost of the catalyst, but also importantly weakens the interaction between the metal and the carrier, so that the metal active center is easy to dissolve out in the electrolysis process. Therefore, most reported evaluation of the electrochemical activity and stability of SMCs as OER electrodes is usually performed at a low current density [ ] <50mAcm ^-2 ) Under the condition of not meeting the industrial standard of the electrocatalytic OER technology (current density is that>500mAcm ^-2 At the time of overpotential<300 mV). Therefore, there is a need to provide a supported metal catalyst with strong metal-carrier interactions to meet OER industrial application requirements, and to develop a scalable preparation method to obtain a supported catalyst with strong metal-carrier interactionsA metal catalyst.

Disclosure of Invention

The present invention aims to at least partially alleviate or solve at least one of the above mentioned problems. In view of this, in one aspect of the present invention, the present invention provides a catalyst comprising: the base body is foam ferronickel; a carrier on the surface of the substrate, the carrier comprising a plurality of substructures, the substructures being composed of a plurality of nanoplatelets and the substructures being in a patterned shape, wherein the nanoplatelets comprise nickel iron oxyhydroxide; catalyst particles supported on the surface of the nanoplatelets. Therefore, the carrier foam nickel-iron matrix has better supporting performance, so that the catalyst has good structural stability; the carrier is positioned on the surface of the foam ferronickel matrix, and the nano-sheet structure enables the carrier to have higher specific surface area, which is beneficial to improving the contact area during the catalytic reaction, and further improving the catalytic performance of the catalyst; the catalyst particles are loaded on the nano-sheet, and have stronger interaction with the carrier, so that the catalytic performance of the catalyst can be further improved.

According to an embodiment of the invention, the catalyst particles are ruthenium nanoparticles. Thus, the catalytic performance of the catalyst is further improved.

According to an embodiment of the present invention, the mass ratio of the catalyst particles to the carrier is 1:9 to 11. Therefore, the catalyst particles and the carrier have proper mass ratio, and the catalyst particles have higher loading capacity, which is beneficial to further improving the catalytic performance of the catalyst.

According to an embodiment of the invention, the catalyst fulfils at least one of the following conditions: the nanoplatelets have a first end disposed proximate to the substrate and a second end disposed distal to the substrate, the nanoplatelets having a width that decreases progressively in a direction along the first end toward the second end; the average length of the nano-sheets is 300-500 nm; the average particle diameter of the catalyst particles is 1.5-3.5 nm; the thickness of the matrix is 0.5-1.2 mm; the pore density of the matrix is 90-100 ppi; the mass ratio of the matrix to the carrier is 10-30: 1. thereby, it is advantageous to further improve the performance of the catalyst.

In another aspect of the invention, the invention provides a process for the preparation of the aforementioned catalyst on a large scale, said process comprising: providing a substrate; etching the substrate to obtain an etched substrate; and mixing the etching substrate, the catalyst precursor and the chlorine source solution, stirring and reacting to obtain the catalyst. Therefore, the in-situ growth of the carrier and the reduction loading of the metal nano particles can be realized by a simple method, the self-supporting loaded metal catalyst is obtained in one step, and the self-supporting loaded metal catalyst is applied to oxygen evolution reaction in electrocatalytic water decomposition; the method has the advantages of simple operation steps, mild reaction conditions, short synthesis period, low preparation cost and mass production; and the obtained self-supporting electrode has good effect of catalyzing water to decompose and separate out oxygen.

According to an embodiment of the invention, the method fulfils at least one of the following conditions: the catalyst precursor comprises at least one of ruthenium trichloride, potassium ruthenate chloride, ammonium ruthenate chloride and ruthenium carbonyl chloride; the chlorine source solution comprises at least one of sodium chloride aqueous solution, potassium chloride aqueous solution, magnesium chloride solution and natural seawater; the molar concentration of the chlorine source solution is 1-15 mmol/L; the temperature of stirring is 10-40 ℃ and the time is 5-60 min.

According to the embodiment of the invention, an acid solution is adopted for etching, and the acid solution comprises at least one of hydrochloric acid and nitric acid; optionally, the concentration of the acid solution is 1mol/L to 6mol/L. Therefore, the substrate is etched by using the acid solution, so that defects can be generated on the surface of the substrate, and the in-situ growth of the carrier is facilitated.

According to an embodiment of the invention, mixing the etching substrate, the catalyst precursor and the chlorine source comprises: first mixing the catalyst precursor and the chlorine source solution to obtain a precursor solution; the etched substrate is placed in the precursor solution.

According to an embodiment of the invention, the method fulfils at least one of the following conditions: in the precursor solution, the molar concentration of ruthenium element is 5-15 mmol/L; the pH value of the precursor solution is 1.5-6.0; the ratio of the volume of the etching matrix to the volume of the precursor solution is 1-8: 10.

In a further aspect of the invention, the invention proposes the use of the catalyst as described above or of a catalyst prepared by the process as described above in electrocatalysis.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

fig. 1 a shows a schematic structural view of a catalyst according to an embodiment of the present invention, and fig. 1 b and c show partial schematic structural views of the catalyst;

fig. 2 a shows a schematic structural view of a substrate according to an embodiment of the present invention, and fig. 2 b shows a schematic structural view of a portion of the substrate;

FIG. 3 is a diagram showing a physical view of a substrate used for preparing a catalyst according to an embodiment of the present invention, and FIG. 3 is a diagram showing a physical view of a catalyst prepared using the substrate;

FIG. 4 shows a flow chart of a method of preparing a catalyst according to one embodiment of the invention;

FIG. 5 shows an SEM image of the catalyst of example 1;

FIG. 6 shows a TEM image of the catalyst of example 1;

fig. 7 shows a and b TEM images of the catalyst of example 1;

FIG. 8, panel a, shows the XRD pattern of the bulk catalyst of example 1, where Ni#87-0712 is the standard XRD pattern for nickel, fe ₇ Ni ₃ #65-7251 is the standard XRD spectrum of nickel-iron alloy; FIG. 8 b shows the XRD pattern of the powder after ultrasonic stripping of the catalyst of example 1, where NiFeOOH#14-0556 is the standard XRD pattern of iron nickel oxyhydroxide, ni (OH) ₂ #38-0715 is a standard XRD pattern for nickel hydroxide;

fig. 9 a shows a graph of a contact angle test of the substrate (nickel iron foam) used in example 1 with water in air, fig. 9 b shows a graph of a contact angle test of the catalyst (ruthenium/nickel iron oxyhydroxide) used in example 1 with water in air, fig. 9 c shows a graph of a contact angle test of the substrate (nickel iron foam) used in fig. 1 with gas in water, and fig. 9 d shows a graph of a contact angle test of the catalyst (ruthenium/nickel iron oxyhydroxide) used in example 1 with gas in water;

FIG. 10 shows the voltammetric characteristic curves obtained by testing at a scan rate of 10mv/s with the catalysts of example 1, comparative examples 1 to 4 as working electrodes;

FIG. 11 shows the Tafil slope of the working electrode for the catalysts of example 1, comparative examples 1-4 calculated from the voltammetric characteristic curves obtained by testing the catalysts of example 1, comparative examples 1-4 at a scan rate of 10 mv/s;

FIG. 12 shows the overpotential-time curves (voltage-time curves) of the catalyst of example 1 tested using chronopotentiometry;

FIG. 13 shows voltammogram curves measured with the catalysts of example 1, example 2, comparative example 4 and comparative example 5 as working electrodes and 1.0mol/L of a potassium hydroxide seawater solution as electrolyte;

FIG. 14 shows an SEM image of the catalyst of comparative example 1;

FIG. 15 shows an SEM image of the catalyst of comparative example 2;

fig. 16 shows an SEM image of the catalyst of comparative example 3.

Reference numerals illustrate:

100: a base; 200: a carrier; 210: a substructure; 211: a nanosheet; a: a first end; b: a second end; 300: catalyst particles.

Detailed Description

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

In one aspect of the present invention, the present invention provides a catalyst, referring to a, b, and c in fig. 1, the catalyst includes a substrate 100, a support 200, and catalyst particles 300.

According to the embodiment of the present invention, the substrate 100 is nickel foam, and the structure of the substrate 100 can be referred to as a diagram a in fig. 2, it can be seen that the nickel foam is a porous support structure, and a diagram b in fig. 2 is an enlarged view of the surface structure of the nickel foam, and it can be seen that the surface of the nickel foam is relatively smooth, and the surface does not have a carrier or catalyst particles. The foam nickel-iron structure is used as a matrix of the catalyst, can provide good supporting effect for a catalyst carrier and catalyst particles, and is convenient for forming a self-supporting catalyst subsequently. It should be noted that, according to some embodiments of the present invention, the foam ferronickel may include nickel and ferronickel alloy, and the content ratio of nickel and ferronickel alloy is not particularly limited in the present invention, so long as the nickel oxyhydroxide carrier can be generated by a subsequent reaction.

According to some embodiments of the present invention, the thickness of the substrate 100 may be 0.5mm to 1.2mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, etc., so that the foamed nickel iron substrate with the above thickness may have a good supporting effect, and may improve the structural stability of the catalyst as a whole, and the thickness of the prepared catalyst may not be too large, so that the catalyst may be used in electrocatalysis. According to some embodiments of the invention, the thickness of the substrate may be 1.0mm, thereby further contributing to the overall performance of the catalyst.

According to some embodiments of the invention, the matrix 100 may have a pore density of 90 to 100ppi (number of pores per inch), for example 90ppi, 92ppi, 95ppi, 98ppi, 100ppi, whereby the matrix may have a pore density within the above-mentioned range so that the matrix may not only provide more sites for carrier growth, but may also maintain good support. According to some embodiments of the present invention, the pore density of the matrix 100 may be 95ppi, whereby the overall performance of the catalyst may be further improved.

In the present invention, the shape and size of the substrate 100 are not particularly limited, and those skilled in the art may set and select according to actual needs, for example, the shape of the substrate 100 may be rectangular (as shown in a diagram of fig. 3), pentagonal, hexagonal, circular, etc. According to an embodiment of the present invention, the shape of the substrate 100 may be rectangular, and the size of the rectangular substrate may be set to 10mm×10mm, 20mm×20mm, 30mm×30mm, 40mm×40mm, 50mm×50mm, etc., according to actual needs.

According to an embodiment of the present invention, referring to fig. 1, where the carrier 200 is located on the surface of the substrate 100, and referring to fig. 1, the specific structure of the carrier 200 may refer to fig. b, where the carrier 200 includes a plurality of substructures 210, the substructures 210 are composed of a plurality of nano-sheets 211, and the substructures 210 have a patterned shape, and in some embodiments, the patterned shape may be a structure similar to a three-dimensional flower shape as shown in fig. 1, where one nano-sheet 211 corresponds to a petal, and the nano-sheet 211 includes nickel iron oxyhydroxide; referring to fig. 1 c, the catalyst further includes catalyst particles 300, and the catalyst particles 300 are supported on the surface of the nanoplatelets 211. The foam ferronickel matrix can provide good supporting effect for the catalyst carrier and the catalyst particles; the substructure is composed of a plurality of nano-sheets, so that the carrier has a larger specific surface area, the loading capacity of catalyst particles is improved, the carrier (comprising ferronickel oxyhydroxide) can be formed by in-situ growth of ferronickel foam, the binding force between the carrier and a matrix is stronger, and the structural stability of the catalyst is improved; in addition, the catalyst particles are uniformly loaded on the surface of the nano sheet and have stronger interaction force with the carrier, so that the catalyst can keep higher catalytic activity and stability in the electrocatalytic process.

According to the embodiment of the invention, the specific shape of the patterned shape is not particularly required, and can be flexibly set by a person skilled in the art according to actual reaction conditions. In some embodiments, referring to B and c of fig. 1, the patterned shape may be a flower-like structure, and referring to c of fig. 1, the nano-sheet 211 has a first end a and a second end B, the first end a is disposed close to the substrate, the second end B is disposed away from the substrate, and the width of the nano-sheet 211 is gradually reduced in a direction along the first end a toward the second end B, so that the nano-sheet has a tapered structure, thereby facilitating improvement of the gas-repellent property of the carrier, while oxygen is generated in the anodic oxygen evolution reaction, and the carrier has good gas-repellent property, facilitating rapid separation of oxygen, and thus facilitating reaction of electrocatalytically decomposing water into oxygen.

According to an embodiment of the present invention, the average length of the nanoplatelets 211 may be 300nm to 500nm, for example, 300nm, 350nm, 400nm, 450nm, 500nm, etc., whereby the nanoplatelets have a suitable length, which is advantageous for maintaining the stability of the neutron structure of the carrier. According to some embodiments of the present invention, the average length of the nanoplatelets 211 may be 350nm to 380nm, for example, 350nm, 360nm, 370nm, 380nm, etc., thereby further improving the stability of the neutron structure of the carrier. It should be noted that the average length of the nanoplatelets 211 can be understood as an average distance between the first end a and the second end B of the nanoplatelets 211.

According to an embodiment of the present invention, the catalyst particles 300 may be ruthenium nanoparticles, which have high catalytic activity in the anodic oxygen evolution reaction, and thus, the use of ruthenium nanoparticles as the catalyst particles is advantageous for further improving the catalytic activity of the catalyst.

According to an embodiment of the present invention, the average particle diameter of the catalyst particles 300 may be 1.5nm to 3.5nm, for example, 1.5nm, 2nm, 2.5nm, 3nm, 3.5nm, etc., and thus the catalyst particles have a smaller particle diameter, and accordingly, the catalyst particles have a larger specific surface area, thereby being advantageous for improving the catalytic activity of the catalyst particles, and the particle diameter of the catalyst particles is also not easy to agglomerate in the above range, and can maintain good catalytic activity during the electrocatalytic process. According to some embodiments of the present invention, the average particle diameter of the catalyst particles 300 may be 1.5nm to 2nm, for example, may be 1.5nm, 1.6nm, 1.7nm, 1.8nm, 1.9nm, 2nm, etc., thereby facilitating further improvement of the catalytic activity and stability of the catalyst.

According to an embodiment of the present invention, the mass ratio of the catalyst particles 300 to the carrier 200 may be 1:9 to 11, for example, may be 1:9. 1:9.5, 1:10. 1:10.5, 1:11, etc., whereby the catalyst particles and the carrier have a proper mass ratio, and the catalyst particles can more sufficiently exert their catalytic action, thereby contributing to the improvement of the catalytic performance of the catalyst. According to some embodiments of the invention, the mass ratio of the catalyst particles 300 to the support 200 may be 1:10, thereby, the catalytic performance of the catalyst can be more favorably improved.

According to an embodiment of the present invention, the mass ratio of the substrate 100 to the carrier 200 may be 10 to 30:1, for example, the mass ratio of the substrate 100 and the carrier 200 may be 10: 1. 20: 1. 30:1, etc., whereby the mass ratio of the support and the matrix is appropriate, more advantageous for improving the overall performance of the catalyst.

In another aspect of the invention, the invention provides a method for the large-scale preparation of the catalyst described above, with reference to fig. 4, comprising the steps of:

s100: a substrate is provided.

In this step, a substrate 100 is provided, wherein the substrate 100 is nickel foam iron, a carrier is formed on the surface of the substrate by self-growth through a subsequent reaction, and catalyst particles are supported on the surface of the carrier. The foam ferronickel is used as a matrix, and simultaneously provides a nickel source and an iron source for the growth of a carrier (comprising the hydroxyl ferronickel oxide), thereby being beneficial to reducing the production cost. The three-dimensional skeleton of the foam ferronickel can provide a larger space for the growth of a carrier (comprising ferronickel oxyhydroxide), is beneficial to the growth of the ferronickel oxyhydroxide, and meanwhile, the large space of the three-dimensional skeleton is beneficial to the transmission of ions, electrons and the like.

According to an embodiment of the present invention, the thickness of the substrate 100 may be 0.5mm to 1.2mm, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, etc., whereby the foamed nickel iron substrate has a large thickness and hardness, and may be directly used as a self-supporting electrode.

According to an embodiment of the present invention, the pore density of the matrix 100 may be 90ppi to 100ppi (the number of pores per inch), for example, 90ppi, 92ppi, 95ppi, 98ppi, 100ppi, thereby facilitating in-situ growth of the support, and the catalyst prepared using the matrix is more advantageous for ion and electron transport when used for the electrocatalytic reaction, thereby promoting the electrocatalytic reaction.

The shape and size of the substrate 100 are described above, and will not be described again here.

S200: and etching the substrate to obtain an etched substrate.

In this step, the substrate 100 is etched, resulting in an etched substrate. According to an embodiment of the present invention, the etching is performed using an acid solution, wherein the acid solution includes at least one of hydrochloric acid and nitric acid, and for example, the acid solution may be hydrochloric acid, nitric acid, or a mixed solution of hydrochloric acid and nitric acid.

According to some embodiments of the present invention, the concentration of the acid solution used for etching may be 1mol/L to 6mol/L, for example, 1mol/L, 3mol/L, 5mol/L, 6mol/L, etc., and the acid solution with the above concentration may remove impurities such as oxide, hydroxide, etc. on the surface of the substrate, and may generate defects on the surface of the substrate, so as to facilitate in-situ growth of the subsequent carrier. According to some embodiments of the present invention, the concentration of the acid solution used for etching may be 3mol/L to 4mol/L, for example, 3mol/L, 3.2mol/L, 3.5mol/L, 3.7mol/L, 4mol/L, etc., thereby further facilitating in-situ growth of the subsequent carrier.

According to an embodiment of the present invention, the volume ratio of the substrate 100 and the acid solution may be 1: 1-30, for example, the volume of the substrate 100 and the acid solution may be 1: 1. 1: 5. 1: 10. 1: 15. 1: 20. 1: 25. 1:30, etc., thereby facilitating etching of the substrate. According to an embodiment of the present invention, the volume ratio of the substrate 100 and the acid solution may be 1:5 to 10, for example, may be 1: 5. 1: 6. 1: 7. 1: 8. 1: 9. 1:10, etc., thereby facilitating more etching of the substrate and further facilitating in situ growth of subsequent carriers.

According to the embodiment of the invention, the substrate 100 can be soaked in an acid solution for etching, so that the substrate is more beneficial to being etched effectively, and the method is simple and easy to operate, and is beneficial to shortening the preparation time. The etching mode can be selected by a person skilled in the art according to actual needs, so long as impurities on the surface of the substrate can be removed and defects are formed on the surface of the substrate so as to facilitate in-situ growth of the subsequent carrier.

According to some embodiments of the present invention, the etching temperature may be 10 ℃ to 40 ℃, for example, 10 ℃, 15 ℃, 20 ℃, 22 ℃, 25 ℃, 28 ℃, 30 ℃, 35 ℃, 40 ℃, etc., so that the etching temperature does not need to provide excessive energy, which is beneficial to saving the preparation cost; and the etching of the substrate can be completed in a short time.

According to the embodiment of the invention, the etching time can be 5-30 min, for example, 5min, 8min, 10min, 12min, 13min, 15min, 18min, 20min, 25min, 30min and the like, so that the substrate can be etched in a shorter time.

According to other embodiments of the present invention, after the substrate is etched, the substrate may also be washed to remove residual acid and other impurities from the surface, facilitating subsequent in situ growth of the carrier. According to some embodiments of the present invention, after etching the substrate, the substrate may be washed with water (e.g., ultrapure water), acetone, and absolute ethanol in this order, the substrate may be washed with water, impurities such as acids and inorganic substances (inorganic substances including oxides, hydroxides, etc.) remaining on the surface of the substrate may be removed, the substrate may be washed with acetone, organic impurities (including grease, etc.) on the surface of the substrate may be removed, and the substrate may be washed with absolute ethanol, which is advantageous for removing acetone remaining on the surface of the substrate, while the absolute ethanol may be easily volatilized.

In the present invention, the amount of water, acetone, and absolute ethanol used in washing the substrate is not particularly limited, as long as the object of removing impurities on the surface of the substrate by washing can be achieved. According to some embodiments of the invention, the volume of water, acetone, absolute ethanol may be 50mL to 150mL, for example, 50mL, 60mL, 80mL, 100mL, 120mL, 130mL, 150mL, etc.

According to some embodiments of the present invention, the time for washing the substrate with water, the time for washing the substrate with acetone, and the time for washing the substrate with absolute ethanol may be 5 to 15 minutes, for example, may be 5 minutes, 8 minutes, 10 minutes, 12 minutes, 15 minutes, etc., independently of each other, and thus, the washing may remove impurities from the surface of the substrate.

According to other embodiments of the present invention, the washing of the substrate may be performed under ultrasonic conditions, and the specific power of the ultrasonic wave is not particularly limited in the present invention, so long as the purpose of removing impurities from the surface of the substrate can be achieved. According to some specific embodiments of the present invention, the power of the ultrasound may be 600W, 800W, 900W, 1100W, 1300W, 1500W, etc., and the time of the ultrasound may be 1min to 5min, for example, 1min, 2min, 3min, 4min, 5min, etc., so that the time for washing the substrate may be further shortened by using the ultrasound-assisted method, and effective removal of impurities on the surface of the substrate may be achieved.

S300: and mixing the etching substrate, the catalyst precursor and the chlorine source solution, stirring and reacting to obtain the catalyst.

After the etching substrate is obtained, the etching substrate, the catalyst precursor and the chlorine source solution are mixed and then stirred and reacted to obtain the catalyst, and a physical diagram of the prepared catalyst can be referred to as a b diagram in fig. 3.

According to an embodiment of the present invention, mixing an etching substrate, a catalyst precursor, and a chlorine source comprises the steps of:

s310: and carrying out first mixing on the catalyst precursor and the chlorine source solution to obtain a precursor solution.

In step S310, the catalyst precursor and the chlorine source solution are first mixed to obtain a precursor solution. The first mixing method is not particularly limited as long as the catalyst precursor and the chlorine source solution can be uniformly mixed, and for example, the catalyst precursor may be added to the chlorine source solution and stirred.

According to an embodiment of the present invention, the catalyst precursor may include at least one of ruthenium trichloride, potassium ruthenate, ammonium ruthenate, ruthenium carbonyl chloride, etc., that is, one or more of ruthenium trichloride, potassium ruthenate, ammonium ruthenate, and ruthenium carbonyl chloride may be included in the catalyst precursor, whereby the catalyst precursor may generate catalyst particles (i.e., ruthenium nanoparticles) during a subsequent reaction.

According to the embodiment of the invention, the chlorine source solution can comprise at least one of sodium chloride aqueous solution, potassium chloride aqueous solution, magnesium chloride solution, natural seawater and the like, namely, the chlorine source solution can comprise one or more of sodium chloride aqueous solution, potassium chloride aqueous solution, magnesium chloride solution and natural seawater, so that the chlorine source solution can provide chloride ions for subsequent reactions, and the chloride ions can accelerate corrosion of a matrix to form a nickel iron oxyhydroxide corrosion layer, and further promote generation of subsequent catalyst particles. The natural seawater in the invention can only contain a certain concentration of chloride ions, and according to a specific embodiment of the invention, the natural seawater can be obtained from yellow sea (120 DEG E,35 DEG N, namely 120 DEG east longitude and 35 DEG North latitude), and the water taking time is 2021 and 2 months.

According to the embodiment of the invention, the molar concentration of the chlorine source solution can be 1 mmol/L-15 mmol/L, for example, 1mmol/L, 3mmol/L, 5mmol/L, 8mmol/L, 10mmol/L, 15mmol/L and the like, so that the chlorine source solution with the concentration has a proper molar concentration, thereby being beneficial to further promoting the generation of the iron nickel oxyhydroxide corrosion layer and further promoting the generation of subsequent catalyst particles.

According to the embodiment of the invention, the molar concentration of the ruthenium element in the precursor solution can be 5 mmol/L-15 mmol/L, for example, 5mmol/L, 8mmol/L, 10mmol/L, 12mmol/L, 15mmol/L and the like, and the ruthenium ion can accelerate the corrosion of ferronickel, so that the generation of a nickel oxyhydroxide corrosion layer is promoted, and the generation of subsequent catalyst particles is facilitated.

According to an embodiment of the present invention, the pH of the precursor solution may be 1.5 to 6.0, for example, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, etc., and thus, the pH of the precursor solution is within the above range, which is advantageous for the growth of the nickel oxyhydroxide carrier.

S320: the etched substrate is placed in a precursor solution.

After the precursor solution is obtained, the etched substrate is placed in the precursor solution. According to some embodiments of the invention, the ratio of the volume of the etched substrate to the volume of the precursor solution may be 1 to 8:10, for example, may be 1: 10. 2: 10. 3: 10. 4: 10. 5: 10. 6: 10. 7: 10. 8:10, etc., thereby facilitating in situ growth of subsequent supports and generation of catalyst particles.

After placing the etched substrate in the precursor solution, stirring is performed to react the reactants to obtain the catalyst. According to an embodiment of the present invention, the temperature of the stirring may be 10 to 40 ℃, for example, 10 ℃, 15 ℃, 20 ℃, 22 ℃, 25 ℃, 28 ℃, 30 ℃, 35 ℃, 40 ℃, etc., whereby no additional energy need be provided at the time of stirring, and the above temperature is also advantageous for in-situ growth of the carrier and generation of the catalyst particles. According to the embodiment of the invention, the stirring time can be 5-60 min, for example, 5min, 10min, 12min, 13min, 15min, 30min, 50min, 60min and the like, so that the reaction of reactants is facilitated, and the catalytic performance of the catalyst is further improved.

The process of forming the catalyst particles and the support of the present invention is specifically described below: and mixing the etching substrate, the catalyst precursor and the chlorine source solution, stirring, wherein in the stirring process, ruthenium ions and chloride ions can accelerate the corrosion of the foam ferronickel substrate, form a ferronickel oxyhydroxide corrosion layer and perform oxidation reduction reaction with the ruthenium ions, and trivalent ruthenium ions are reduced to obtain zero-valent ruthenium nano particles and are loaded on the ferronickel oxyhydroxide nano sheets. The chemical reaction occurring during stirring is shown in formulas 1 to 5:

2Ru ³⁺ +Fe→2Ru ²⁺ +Fe ²⁺ formula 1;

Ru ²⁺ +Ni→Ru+Ni ²⁺ formula 2;

4Fe ²⁺ +2H ₂ O+O ₂ →4Fe ³⁺ +4OH ^- formula 3;

2Fe ³⁺ +Ni→Ni ²⁺ +2Fe ²⁺ formula 4;

Ni ²⁺ +Fe ³⁺ +xOH ^- →FeNi(OH) _x +O ₂ →Ni _1-x Fe _x OOH formula 5.

Wherein, in formula 5, 0< x <1.

It should be noted that, during the above reaction, an intermediate nickel hydroxide may be generated, and a part of nickel hydroxide may remain due to insufficient reaction, etc., and in some embodiments of the present invention, the carrier may include both iron nickel oxyhydroxide and a part of nickel hydroxide, but the catalyst may not have significant adverse effects on the performance, and when the catalyst is used in the electrocatalytic oxygen evolution reaction, the nickel hydroxide may continuously react with the iron element in the matrix to generate the iron nickel oxyhydroxide.

According to an embodiment of the present invention, after mixing and stirring the etching substrate, the catalyst precursor, and the chlorine source solution, it may further include: and (3) carrying out solid-liquid separation on the reaction product obtained by stirring, and washing and drying the solid obtained by separation in sequence to obtain the catalyst.

In the present invention, the specific mode of performing the solid-liquid separation is not particularly limited, and those skilled in the art can select according to actual needs, as long as the solid-liquid separation can be achieved.

According to an embodiment of the present invention, washing the separated solid includes sequentially performing water washing and absolute ethanol washing, wherein the number of times of water washing and absolute ethanol washing may be 2 to 4 times each independently, whereby impurities on the surface of the solid may be removed.

According to an embodiment of the present invention, after washing the separated solid, the solid may be dried, and the vacuum degree of drying may be 80kPa to 130kPa, preferably 85kPa to 100kPa, the drying temperature may be 50 ℃ to 80 ℃, preferably 60 ℃ to 70 ℃, and the drying time may be 5h to 7h, preferably 5.5h to 6h. Through the drying process, the moisture and absolute ethyl alcohol remained on the solid surface can be removed more rapidly.

The schematic structural diagram of the catalyst prepared by the preparation method provided by the invention can refer to the a diagram, the b diagram and the c diagram in fig. 1, foamed ferronickel is taken as a matrix, a carrier 200 (comprising ferronickel oxyhydroxide) is positioned on the surface of the matrix 100, the carrier 200 comprises a plurality of substructures 210, the substructures 210 are in a flower shape, the substructures 210 are uniformly distributed on the surface of the matrix 100, and catalyst particles 300 are loaded on nano sheets 211 of the substructures 210; the ferronickel oxyhydroxide nano-sheets form a three-dimensional flower-shaped structure, so that the loading area of ruthenium nano-particles can be increased, the surface characteristics of super-hydrophilicity and super-hydrophobicity are presented, the diffusion of electrolyte and the transmission of gas are facilitated, and the catalytic performance of the catalyst on the anode oxygen evolution reaction is improved. The invention adopts a one-step stirring method to reduce trivalent ruthenium ions into zero-valent ruthenium, the foam ferronickel matrix is oxidized and simultaneously self-grows into hydroxyl ferronickel oxide nano-sheets on the surface of the foam ferronickel matrix, the nano-sheets are used as carriers of catalyst particles, and the zero-valent ruthenium is loaded on the surface of the nano-sheets; the preparation method takes the foam ferronickel as a matrix, and the foam ferronickel can be used as a nickel source and an iron source at the same time, thereby being beneficial to reducing the production cost; the self-supporting supported metal catalyst of the ruthenium-loaded ferronickel oxyhydroxide nano array is synthesized by stirring at room temperature in one step, the process is simple and easy to operate, and the method can be used for large-scale preparation and production of the self-supporting supported metal catalyst; in the catalyst prepared by the method, the carrier and the catalyst particles have stronger interaction, living sites are not easy to dissolve out when the catalyst is used for electrocatalysis, the catalyst can keep higher catalytic activity, the catalyst particles are not easy to agglomerate, and the catalyst has good catalytic stability.

The length of the nanosheets, the particle size of the ruthenium nanoparticles, the mass ratio of the catalyst particles to the support, etc. are all described in detail above, and are not described in detail herein.

In a further aspect of the invention, the invention proposes the use of the catalyst as described above or of a catalyst prepared by the process as described above in electrocatalysis. The catalyst takes foam ferronickel as a matrix, has good self-supporting performance, has excellent electrocatalytic performance under the combined action of the ferronickel oxyhydroxide nano-sheet carrier and the catalyst particle ruthenium nano-particles, can accelerate the reaction speed of electrolytic water to generate oxygen, and has good stability.

According to some embodiments of the invention, the catalyst may act as an electrocatalytic electrode, catalyzing an alkaline oxygen evolution reaction, or catalyzing an electrolysis reaction of alkaline seawater.

According to the embodiment of the invention, the catalyst is used as an electrocatalytic electrode, and the catalyst can perform high-efficiency electrocatalytic under alkaline conditions for a long time.

The invention is illustrated below by means of specific examples, which are given for illustrative purposes only and do not limit the scope of the invention in any way, as will be understood by those skilled in the art. In addition, in the examples below, materials and equipment used are commercially available unless otherwise specified. If in the following examples specific treatment conditions and treatment methods are not explicitly described, the treatment may be performed using conditions and methods well known in the art.

Example 1

The foam ferronickel with the thickness of 1.0mm is cut into a rectangle with the thickness of 10mm multiplied by 10mm, then soaked in 30mL of hydrochloric acid with the molar concentration of 3mol/L, and etched for 15min at 25 ℃.

And (3) ultrasonically washing the etched foam ferronickel for 4min under the condition of 1000W by using 80mL of ultrapure water until the washing liquid is neutral, and then sequentially ultrasonically washing the foam ferronickel for 15min by using the ultrapure water, acetone and absolute ethyl alcohol respectively to obtain the etched foam ferronickel.

Dissolving ruthenium trichloride and sodium chloride in water to obtain a mixed solution (precursor solution) of ruthenium trichloride (15 mmol/L) and sodium chloride (5 mmol/L), wherein the pH value of the mixed solution is 2.39; placing etching foam ferronickel into 10mL of mixed solution, stirring for 15min at 25 ℃, carrying out solid-liquid separation after the reaction is completed, washing the solid obtained by the solid-liquid separation with ultrapure water and absolute ethyl alcohol for 3 times in sequence, and drying the washed solid for 6h under the conditions of 85kPa of vacuum degree and 60 ℃ to obtain the self-supporting supported metal catalyst.

Example 2

Unlike example 1, the sodium chloride solution was replaced with natural seawater taken from yellow sea (120 ° E,35 ° N, i.e. 120 degrees east longitude, 35 degrees north latitude) for a water intake time of 2021 months, the remainder being the same as example 1.

Example 3

The procedure was repeated in example 1, except that the stirring time was 30 minutes.

Example 4

Unlike example 1, the concentration of sodium chloride in the precursor solution was 10mmol/L, and the remainder was the same as example 1.

Comparative example 1

Except for the difference from example 1, ruthenium trichloride was not added, and the rest was the same as example 1.

Comparative example 2

Unlike example 1, the substrate was foam iron, and the rest was the same as example 1.

Comparative example 3

Unlike example 1, the substrate was nickel foam, and the remainder was the same as example 1.

Comparative example 4

280. Mu.L of ethanol, 20. Mu.L of naphthol, 70. Mu.L of deionized water and 50mg of RuO having a particle size of less than 1. Mu.m ₂ Mixing to obtain ruthenium dioxide dispersion; 60 mu L of the ruthenium dioxide dispersion was dropped onto a rectangular foam nickel iron surface having a thickness of 1mm and a size of 10 mm. Times.10 mm (length. Times.width) at a dropping rate of 5 drops/min, and dried at 60℃for 6 hours to obtain a ruthenium dioxide/foam nickel iron electrode.

Comparative example 5

280. Mu.L of ethanol, 20. Mu.L of naphthol, 70. Mu.L of deionized water and 50mg of IrO having a particle size of less than 1. Mu.m ₂ Mixing to obtain iridium dioxide dispersion liquid; 60 mu L of the iridium dioxide dispersion was dropped onto a rectangular foam nickel iron surface having a thickness of 1mm and a size of 10 mm. Times.10 mm (length. Times.width) at a dropping rate of 5 drops/min, and dried at 60℃for 6 hours to obtain an iridium dioxide/foam nickel iron electrode.

Scanning Electron Microscopy (SEM) detection is performed on the catalyst prepared in example 1 to obtain an SEM image, as shown in FIG. 5. As can be seen from fig. 5, the catalyst carrier exhibits a three-dimensional flower-like structure composed of a plurality of nano-sheets, and the tips of the nano-sheets are tapered.

The catalyst prepared in example 1 was subjected to transmission electron microscopy to obtain TEM images at different magnifications, as shown in fig. 6 and 7. As can be seen from fig. 6, the flower-like structure is composed of a plurality of nano-sheets. As can be seen from the graph a in fig. 7, the carrier of the catalyst comprises nickel iron oxyhydroxide and nickel hydroxide, and as can be seen from the graphs a and b in fig. 7, the catalyst comprises ruthenium nanoparticles uniformly dispersed therein, and the particle diameter of the ruthenium nanoparticles is about 2nm. As can be seen from fig. 6 and 7, ruthenium nanoparticles are uniformly dispersed on the surface of the iron-nickel oxyhydroxide nanoplatelet support.

In the present invention, XRD spectra were also obtained by performing XRD detection on the powder obtained by subjecting the catalyst of example 1 to ultrasonic separation and the bulk catalyst, respectively, as shown in FIG. 8, wherein Ni#87-0712 is a standard XRD spectrum of nickel, fe ₇ Ni ₃ #65-7251 is the standard XRD spectrum of the nickel-iron alloy, and NiFeOOH #14-0556 is the standard XRD spectrum of nickel-iron oxyhydroxide, ni (OH) ₂ #38-0715 is the standard XRD pattern for nickel hydroxide. Wherein, the graph a in FIG. 8 is an XRD spectrum of a bulk catalyst, and the bulk catalyst has a main structure of foam ferronickel, including a part of ferronickel alloy and a part of nickel, and it should be noted that Fe ₇ Ni ₃ The diffraction peak of (2) is located between 40 degrees and 45 degrees, and coincides with one diffraction peak of nickel. The graph b in fig. 8 shows the XRD spectrum of the powder obtained after the ultrasonic separation of the catalyst, and it can be seen from this graph that the catalyst prepared in example 1 contains iron nickel oxyhydroxide and nickel hydroxide, and no significant diffraction peak appears in the XRD spectrum due to the smaller particles of Ru. The inventor finds that when the catalyst is used for the electrocatalytic anode oxygen evolution reaction, nickel hydroxide can continuously react with a foam ferronickel matrix to generate ferronickel oxyhydroxide, so that the catalytic performance of the catalyst is further improved.

The surface contact angle test was performed on the catalyst prepared in example 1 and the foam nickel iron matrix used in example 1, to obtain a contact angle picture, as shown in fig. 9. Wherein, graph a and graph b in fig. 9 are respectively contact angle test graphs of foam nickel iron matrix and catalyst (ruthenium/hydroxyl nickel iron oxide) with water in air, the smaller the contact angle, the better the wettability of the material is proved, therefore, the catalyst prepared in example 1 has super hydrophilicity. Graph c and graph d in fig. 9 are graphs for contact angle test of foam nickel iron matrix and catalyst (ruthenium/nickel iron oxyhydroxide) with gas in water, respectively, and the larger the contact angle, the better the gas-repellent ability of the material was demonstrated, and therefore, the catalyst prepared in example 1 has super-gas-repellent properties compared to the foam nickel iron matrix. Because the process of the electrocatalytic anode oxygen evolution relates to the mass transfer process of a solid-liquid-gas three-phase interface, the reactant is in a liquid state and the product is in a gas state, the catalyst has super-hydrophilicity and super-hydrophobicity, is favorable for full contact between the catalyst and the reactant and rapid separation of the product in the oxygen evolution process, and can promote the water electrocatalytic decomposition reaction.

Electrochemical tests were carried out using a workstation of a typical three-electrode configuration (graphite rod as counter electrode, mercury/oxidized mercury electrode as reference electrode, samples of examples 1, comparative examples 1-4 as working electrode) with 1.0mol/L aqueous potassium hydroxide as electrolyte; the voltammetric characteristic curve obtained at a scan rate of 10mv/s is shown in FIG. 10. The tafel slopes of the respective voltammetric characteristic curves were calculated from the voltammetric characteristic curves in fig. 10, and the results are shown in fig. 11. As can be seen from FIG. 10, electrocatalytic electrolysis was carried out using the catalyst provided in example 1 of the present invention as an electrode at 10mA cm ^-2 The lowest overpotential at the current density of (a) is only 215mV (the overpotential is 10 mAcm) ^-2 The difference between the voltage at the current density of (2) and 1.23V), while the maximum current density that can be achieved by the catalyst of example 1 is greater than 500mAcm ^-2 And at 500mA cm ^-2 The overpotential at the current density was 285mV (the overpotential was 500 mAcm) ^-2 The difference between the voltage at the current density and 1.23V). Therefore, the catalyst provided by the invention has good electrocatalytic oxygen evolution performance. As can be seen from FIG. 11, the Tafil slope of the electrode using the catalyst of example 1 of the present invention was only 46.8mV dec ^-1 The catalyst provided by the invention has excellent dynamic performance and higher electrocatalytic reaction rate.

As can be seen from the voltammetric characteristic curves in fig. 10, the samples in comparative examples 1 to 4 were relatively poor in electrocatalytic performance with respect to the sample in example 1. In comparative example 1, the substrate is foamed nickel iron, the reaction of formula 3 to formula 5 can be performed in a synergistic manner during stirring, the substrate corrodes faster, and after stirring for 15min, the substrate surface can also grow a nickel iron oxyhydroxide nano-sheet structure, as shown in fig. 14, the test result shows that the nickel iron oxyhydroxide nano-sheet can also play a certain role in electrocatalysis for oxygen evolution reaction, but since the precursor of ruthenium is not added in comparative example 1, ruthenium nano-particles are not generated after reaction, so that the catalytic performance of the sample of comparative example 1 is poor compared with that of the sample of example 1. Comparative example 2 and comparative example 3 used foam iron and foam nickel as substrates, respectively, there was no synergy of nickel and iron during the reaction, the corrosion rate of the substrates was relatively slow, and the corrosion rate of iron was somewhat faster than that of nickel, so that stirring for 15min in comparative example 2 could form a rudiment of nano-sheet array, refer to fig. 15, but did not generate a complete three-dimensional flower-like nano-sheet structure, and thus, although the precursor of ruthenium was added in comparative example 2, the support structure did not provide a relatively large specific surface area for the catalyst particles, resulting in relatively poor catalytic performance of the catalyst sample in comparative example 2; whereas the SEM image of the catalyst in comparative example 3 is shown in fig. 16, the nano-sheet structure is not formed on the surface of the foamed nickel substrate due to the slow corrosion rate of nickel, resulting in poor catalytic performance of the catalyst sample of comparative example 3. In comparative example 4, the catalyst sample was prepared by using foamed nickel iron as a substrate and supporting ruthenium dioxide on the substrate, the catalyst carrier was not formed by in-situ growth in comparative example 4, and the interaction force between ruthenium dioxide and the substrate was relatively weak, so that the catalyst sample (ruthenium dioxide/foamed nickel iron electrode) in comparative example 4 was also poor in catalytic performance.

The electrolyte was 1.0mol/L aqueous potassium hydroxide solution, and a typical three-electrode configuration (graphite rod as counter electrode, mercuryMercury oxide electrode as reference electrode and catalyst of example 1 as working electrode), wherein the catalyst has a test area of 1.0cm ² . The method of timing-potential is selected, the current value is set to be 100mA, and the current density is set to be 100mA cm ^-2 A timed potential test was performed to obtain an overpotential-time curve as shown in fig. 12. As can be seen from fig. 12, the continuous electrolysis time of the catalyst under the high current density can exceed 400 hours, and the voltage can still be kept stable, which proves that the catalyst provided by the invention has excellent electrocatalytic activity and stability.

Electrochemical measurements were performed using a workstation of a typical three electrode configuration (graphite rod as counter electrode, mercury/oxidized mercury electrode as reference electrode, and the composites of example 1, example 2, comparative example 4 and comparative example 5 as working electrode) with 1.0mol/L potassium hydroxide seawater as electrolyte; the voltammetric characteristic curve obtained at a scan rate of 10mv/s is shown in FIG. 13. As can be seen from FIG. 13, the catalyst provided by the present invention was used as an electrode for electrocatalytic alkaline electrolysis of seawater, and the catalyst in example 1 was used at 100mA cm ^-2 The lowest overpotential at the current density of (2) is only 270mV, and the maximum current density of the catalyst is more than 1000mAcm ^-2 And at 500mA cm ^-2 The overpotential at the current density is only 330mV, and the catalyst in the embodiment 2 also has better electrocatalytic performance, which shows that the catalyst provided by the invention has good electrocatalytic seawater decomposition performance. It should be noted that the seawater used in this test was also the natural seawater mentioned above.

The catalysts prepared in example 3 and example 4 in the present invention have similar performances to those of the catalyst prepared in example 1, and also have good catalytic activity and catalytic stability.

In the description of the present invention, the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present invention.

In the description of the present specification, reference to the terms "one embodiment," "some embodiments," "some particular embodiments," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims

1. A method for the large-scale preparation of a catalyst, comprising:

providing a matrix, wherein the matrix is foam ferronickel;

etching the substrate to obtain an etched substrate;

mixing the etching substrate, the catalyst precursor and the chlorine source solution, stirring and reacting to obtain a catalyst;

wherein the temperature of stirring is 10-40 ℃ and the time is 5-60 min;

the catalyst comprises:

a base;

a carrier on the surface of the substrate, the carrier comprising a plurality of substructures, the substructures being comprised of a plurality of nanoplatelets, the nanoplatelets comprising iron nickel oxyhydroxide;

catalyst particles supported on the surface of the nanoplatelets.

2. The method of claim 1, wherein at least one of the following conditions is satisfied:

the catalyst precursor comprises at least one of ruthenium trichloride, potassium ruthenate chloride, ammonium ruthenate chloride and ruthenium carbonyl chloride;

The chlorine source solution comprises at least one of sodium chloride aqueous solution, potassium chloride aqueous solution, magnesium chloride solution and natural seawater;

the molar concentration of the chlorine source solution is 1 mmol/L-15 mmol/L.

3. The method of claim 1, wherein the etching employs an acid solution comprising at least one of hydrochloric acid and nitric acid;

optionally, the concentration of the acid solution is 1mol/L to 6mol/L.

4. A method according to any one of claims 1 to 3, wherein mixing the etching substrate, catalyst precursor and chlorine source comprises:

first mixing the catalyst precursor and the chlorine source solution to obtain a precursor solution;

the etched substrate is placed in the precursor solution.

5. The method of claim 4, wherein at least one of the following conditions is satisfied:

in the precursor solution, the molar concentration of ruthenium element is 5 mmol/L-15 mmol/L;

the pH value of the precursor solution is 1.5-6.0;

the ratio of the volume of the etching matrix to the volume of the precursor solution is 1-8: 10.

6. a catalyst prepared by the method of any one of claims 1 to 5, comprising:

The base body is foam ferronickel;

a carrier on the surface of the substrate, the carrier comprising a plurality of substructures, the substructures being composed of a plurality of nanoplatelets and the substructures being in a patterned shape, wherein the nanoplatelets comprise nickel iron oxyhydroxide;

catalyst particles supported on the surface of the nanoplatelets.

7. The catalyst of claim 6, wherein the catalyst particles are ruthenium nanoparticles.

8. The catalyst according to claim 6 or 7, characterized in that the mass ratio of the catalyst particles to the support is 1:9 to 11.

9. The catalyst according to claim 6 or 7, characterized in that at least one of the following conditions is fulfilled:

the nanoplatelets have a first end disposed proximate to the substrate and a second end disposed distal to the substrate, the nanoplatelets having a width that decreases progressively in a direction along the first end toward the second end;

the average length of the nano-sheets is 300 nm-500 nm;

the average particle diameter of the catalyst particles is 1.5 nm-3.5 nm;

the thickness of the matrix is 0.5 mm-1.2 mm;

The pore density of the matrix is 90 ppi-100 ppi;

the mass ratio of the matrix to the carrier is 10-30: 1.

10. use of the catalyst of any one of claims 6 to 9 or prepared by the method of any one of claims 1 to 5 in electrocatalysis.

11. Use of the catalyst of any one of claims 6 to 9 or prepared by the method of any one of claims 1 to 5 in electrocatalysis wherein the electrolyte is alkaline seawater.