A method for preparing an integral ferrite nanowire composite catalyst

Abstract

This invention discloses a method for preparing a monolithic ferrite nanowire composite catalyst, belonging to the field of catalyst technology. The preparation steps are as follows: a highly conductive foamed metal is selected as the substrate for the monolithic catalyst; graphene is grown on the substrate by chemical vapor deposition; iron oxide nanoparticles are grown on the graphene protective layer using a hydrothermal method and used as the seed layer and tip discharge site for the growth of the ferrite photoelectric layer; ferrite nanowires are directionally grown by electrodeposition in a uniform rotating magnetic field environment; after electrodeposition, the ferrite composite catalyst is annealed at high temperature in air, finally generating the monolithic ferrite nanowire composite catalyst. This invention obtains a well-crystallized, neatly arranged, and directionally grown ferrite nanowire composite catalyst on a conductive metal substrate without using a template. Furthermore, the method is easy to operate, has good reproducibility, and the prepared monolithic catalyst has certain application prospects in the field of photocatalysis.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology and relates to a method for preparing a monolithic ferrite nanowire composite catalyst; specifically, it relates to a method for preparing a monolithic ferrite (XFe2O4, X=Zn,Cu,Ni,Co,Mn) nanowire composite catalyst on a conductive foam metal substrate by utilizing the negative magnetoresistance effect under a uniform rotating magnetic field. Background Technology

[0002] With the continuous enrichment of catalyst preparation techniques, various methods for preparing ferrite composite catalysts have emerged. Ferrites typically possess excellent band gap structures and exhibit ferromagnetic properties, showing great promise in fields such as electronics, magnetism, and photocatalysis. Meanwhile, ferrite nanowires, due to their unique structure, large specific surface area, and abundant surface active sites, are among the best choices for photoelectrophotocatalysts.

[0003] However, nanowires prepared by traditional hydrothermal methods are difficult to grow stably on substrates, exhibiting drawbacks such as easy detachment, low composite efficiency, and difficulty in recycling. Template electrodeposition can enable ferrite nanowires to grow firmly on substrates, but template electrodeposition for ferrite nanowire preparation is typically energy-intensive, and the prepared nanowires may suffer from adhesion problems, significantly reducing the specific surface area and active sites of the ferrite nanowire composite catalyst.

[0004] By utilizing the negative magnetoresistance effect of ferromagnetic and ferrite materials, electrodeposition is performed in a magnetic field. The interfacial charge transfer resistance of the ferromagnetic material is reduced, and the ferromagnetic material becomes a sharp discharge site. During the electrodeposition process, the ferrite continuously grows at the sharp discharge site, eventually forming nanowires. This efficient and directional electrodeposition method under a uniform rotating magnetic field provides a new approach for the preparation of ferrite nanowire composite catalysts. Summary of the Invention

[0005] Purpose of the Invention: The purpose of this invention is to provide a method for preparing a monolithic ferrite nanowire composite catalyst on a conductive foam metal substrate using the negative magnetoresistance effect under a uniform rotating magnetic field. Utilizing the negative magnetoresistance effect of the seed layer, electrodeposition is performed under a uniform rotating magnetic field, allowing ferrite to grow directionally on the surface of the seed layer, ultimately forming ferrite nanowires. Using this method, a well-crystallized, neatly arranged, and directionally grown ferrite nanowire composite catalyst can be obtained on a conductive substrate without the use of a template.

[0006] This invention utilizes the negative magnetoresistance effect to directionally electrodeposit ferrite nanowires under a rotating magnetic field, providing a new method for electrodepositing ferrite nanowires. Furthermore, the prepared monolithic catalyst shows promising applications in the field of photocatalysis. This method is easy to operate and has good reproducibility, providing a new approach for non-template-based growth of ferrite nanowires on metal substrates. The prepared catalyst also shows promising applications in the field of photocatalysis.

[0007] Technical solution: The present invention discloses a method for preparing a monolithic ferrite nanowire composite catalyst on a conductive foam metal substrate under a uniform rotating magnetic field by utilizing the negative magnetoresistance effect.

[0008] A seed layer with negative magnetoresistance effect is grown on a conductive foam metal substrate. Utilizing the negative magnetoresistance effect of the seed layer, ferrite nanowires are electrodeposited under a uniform rotating magnetic field, resulting in the directional growth of ferrite nanowires on the conductive foam metal substrate. This synthesizes a monolithic ferrite nanowire composite catalyst (using highly conductive foam metal as the substrate of the monolithic catalyst; graphene prepared by vapor deposition as a protective layer and conductive layer; and iron oxide nanoparticles grown by hydrothermal method as the seed layer and tip discharge sites for the growth of the ferrite photoelectric layer; due to the negative magnetoresistance effect of iron oxide, under rotating magnetic field conditions, the iron oxide particles become tip discharge sites, causing ferrite to tend to grow directionally at the iron oxide sites, ultimately forming a ferrite nanowire photoelectric layer. The catalyst is then annealed in an air atmosphere to obtain the monolithic ferrite nanowire composite catalyst).

[0009] Furthermore, the specific preparation steps are as follows:

[0010] Step (1): Select a highly conductive foamed metal material as the substrate for the monolithic catalyst;

[0011] Step (2): The substrate of the monolithic catalyst is pretreated to remove the surface oxide layer. It is then placed in a quartz tube, and a mixture of high-purity methane and hydrogen is introduced and sealed. A certain pressure is maintained, and chemical vapor deposition is performed at high temperature for a certain time to obtain a graphene conductive layer grown on the foam metal substrate.

[0012] Step (3): Add a certain amount of ferric nitrate nonahydrate, urea, polyvinyl alcohol and polyvinylpyrrolidone to deionized water to prepare a precursor solution. Transfer the foam metal substrate with graphene conductive layer along with the precursor solution to a high-pressure hydrothermal autoclave with a polytetrafluoroethylene liner and perform hydrothermal treatment at a constant temperature to obtain a composite catalyst loaded with iron oxide nanoparticles.

[0013] Step (4): Prepare an electrolyte by mixing a certain amount of ferric nitrate nonahydrate and metal nitrate deionized water, and adjust the pH to alkaline with potassium hydroxide.

[0014] The electrodeposition process uses a three-electrode system, with a foamed metal substrate as the cathode, a platinum sheet electrode as the anode, and a calomel electrode as the reference electrode, and the electrodeposition is carried out in a quartz electrolytic cell.

[0015] During the electrodeposition process, a uniform rotating magnetic field is applied outside the electrolytic cell, and the negative magnetoresistance effect is used to make ferrite nanowires grow directionally on iron oxide particles.

[0016] Step (5): Anneal the catalyst obtained after electrodeposition in a muffle furnace to finally produce an integral ferrite nanowire composite catalyst.

[0017] Furthermore, in step (1), the highly conductive foam metal material is a nickel and copper-based foam metal.

[0018] Furthermore, in step (2), the ratio of high-purity methane to hydrogen is 4:1 to 3:2; the pressure is 100 to 200 Pa; the reaction temperature is 800 to 1000 °C; and the deposition time is 30 to 90 min.

[0019] Furthermore, in step (3), the mass ratio of ferric nitrate nonahydrate to urea in each 100 mL precursor solution is 10:1 to 5:1, the mass ratio of polyvinyl alcohol to polyvinylpyrrolidone is 3:1 to 2:1, the constant temperature hydrothermal temperature is maintained at 160 to 200 °C, and the constant temperature hydrothermal time is 8 to 16 h.

[0020] Furthermore, in step (4), the metal nitrate is one of zinc nitrate hexahydrate, copper nitrate hexahydrate, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, and manganese nitrate hexahydrate.

[0021] Furthermore, in step (4), the mass ratio of ferric nitrate nonahydrate to metal nitrate in the electrolyte is 1:1 to 2:1, and potassium hydroxide is added to adjust the pH to 10 to 13.

[0022] Furthermore, in step (4), the current density of the electrodeposition is 2.5–5.0 mA / cm². 2 The electrodeposition time is 180–300 s.

[0023] Furthermore, in step (4), the rotational speed of the uniform rotating magnetic field is 500-1000 rpm, and the magnetic field strength is 1000-2000 Gs.

[0024] Furthermore, in step (5), the annealing temperature is 200-400°C and the annealing time is 3-5 hours.

[0025] Beneficial Effects: Compared with existing technologies, the present invention is characterized by providing a method for preparing monolithic ferrite nanowire composite catalysts on conductive foam metal substrates using the negative magnetoresistance effect under a uniform rotating magnetic field. This method is a novel approach that can obtain well-crystallized, neatly arranged, and directionally grown ferrite nanowire composite catalysts on conductive metal substrates without the use of templates. Furthermore, this method is easy to operate, has good reproducibility, and the prepared monolithic catalysts show promising applications in the field of photocatalysis. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating the operation of electrodepositing and directional growth of ferrite nanowires in a uniform rotating magnetic field in this invention.

[0027] Figure 2 This is a scanning electron microscope image of the foamed copper-based monolithic zinc ferrite nanowire composite catalyst prepared in Example 1 of this invention;

[0028] Figure 3 This is a scanning electron microscope image of the foamed nickel-based monolithic manganese ferrite nanowire composite catalyst prepared in Example 4 of the present invention. Detailed Implementation

[0029] To more clearly illustrate the technical solution of the present invention, the technical solution of the present invention will be further described in detail below with reference to the accompanying drawings;

[0030] The present invention discloses a method for preparing a monolithic ferrite (XFe2O4, X=Zn,Cu,Ni,Co,Mn) nanowire composite catalyst on a conductive foam metal substrate by utilizing the negative magnetoresistance effect under a uniform rotating magnetic field.

[0031] Highly conductive foamed metal is used as the substrate of the monolithic catalyst; graphene prepared by vapor deposition is used as a protective layer and a conductive layer; iron oxide nanoparticles grown by hydrothermal method are used as the seed layer and tip discharge sites for the growth of ferrite photoelectric layer; by utilizing the negative magnetoresistance effect of iron oxide, under the condition of rotating magnetic field, iron oxide particles will become tip discharge sites, thereby causing ferrite to tend to grow in a directional manner at iron oxide sites, and finally forming ferrite nanowire photoelectric layer. After annealing in air atmosphere, the monolithic ferrite nanowire composite catalyst is finally obtained.

[0032] The specific preparation steps are as follows:

[0033] 1. Select highly conductive foamed metal material as the substrate for the monolithic catalyst;

[0034] 2. The substrate of the monolithic catalyst is pretreated to remove the surface oxide layer. It is then placed in a quartz tube, and a mixture of high-purity methane and hydrogen is introduced and sealed. Under a certain pressure, chemical vapor deposition is carried out at a high temperature (200-400℃) for a certain period of time to obtain a graphene conductive layer grown on a foam metal substrate.

[0035] 3. A certain amount of ferric nitrate nonahydrate, urea, polyvinyl alcohol and polyvinylpyrrolidone were added to deionized water to prepare a precursor solution. The foam metal substrate with graphene conductive layer was transferred together with the precursor solution to a high-pressure hydrothermal autoclave with a polytetrafluoroethylene liner and hydrothermally heated at a constant temperature to obtain a composite catalyst loaded with iron oxide nanoparticles.

[0036] 4. Add a certain amount of ferric nitrate nonahydrate and metal nitrate to deionized water to prepare an electrolyte, and adjust the pH to alkaline with potassium hydroxide.

[0037] The electrodeposition process uses a three-electrode system, with a foamed metal substrate as the cathode, a platinum sheet electrode as the anode, and a calomel electrode as the reference electrode, and electrodeposition is carried out in a quartz electrolytic cell. During the electrodeposition process, a uniform rotating magnetic field is applied outside the electrolytic cell, and the negative magnetoresistance effect is used to make ferrite nanowires grow directionally on iron oxide particles.

[0038] 5. The catalyst obtained after electrodeposition is annealed in a muffle furnace to prepare an integral ferrite nanowire composite catalyst.

[0039] The conductive foam metal material used in this invention is a nickel- and copper-based foam metal.

[0040] The ratio of high-purity methane to hydrogen used in this invention is 4:1 to 3:2; the pressure is 100 to 200 Pa; the reaction temperature is 800 to 1000 °C; and the deposition time is 30 to 90 min.

[0041] In this invention, the mass ratio of ferric nitrate nonahydrate to urea in every 100 mL of precursor solution is 10:1 to 5:1, the mass ratio of polyvinyl alcohol to polyvinylpyrrolidone is 3:1 to 2:1, the constant temperature hydrothermal temperature is maintained at 160 to 200°C, and the constant temperature hydrothermal time is 8 to 16 h.

[0042] The metal nitrate used in this invention is one of zinc nitrate hexahydrate, copper nitrate hexahydrate, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, and manganese nitrate hexahydrate.

[0043] In this invention, the mass ratio of ferric nitrate nonahydrate to metallic nitrate in the electrolyte is 1:1 to 2:1, and potassium hydroxide is added to adjust the pH to 10 to 13.

[0044] The electrodeposition current density used in this invention is 2.5–5.0 mA / cm².2 The electrodeposition time is 180–300 s.

[0045] The uniform rotating magnetic field used in this invention has a rotational speed of 500-1000 rpm and a magnetic field strength of 1000-2000 Gs.

[0046] In this invention, the annealing temperature is 200–400°C, and the annealing time is 3–5 hours.

[0047] Example 1:

[0048] A 20*20*2mm copper foam substrate was pretreated by removing the surface oxide layer with 1M dilute hydrochloric acid, rinsing with deionized water, and drying under nitrogen for 12 hours. The oxide-free copper foam substrate was then placed in a quartz tube for chemical vapor deposition: a mixture of high-purity methane and hydrogen (4:1 concentration ratio) was introduced, the pressure was maintained at 150 Pa, and the reaction was carried out at 800℃ for 30 minutes to grow a graphene conductive layer on the surface of the copper foam substrate. In 100 mL of deionized water, 0.005 mol of ferric nitrate nonahydrate, 0.0005 mol of urea, 0.3 g of polyvinyl alcohol, and 0.1 g of polyvinylpyrrolidone were added. An iron oxide precursor solution was prepared, and a copper foam substrate with a graphene conductive layer was transferred along with the precursor solution to a high-pressure hydrothermal reactor lined with polytetrafluoroethylene. The mixture was hydrothermally heated at 160℃ for 10 hours to obtain a copper foam-based monolithic composite catalyst loaded with iron oxide nanoparticles. 0.01 mol of ferric nitrate nonahydrate and 0.005 mol of zinc nitrate hexahydrate were added to 100 mL of deionized water, and the pH was adjusted to 10 with 2M potassium hydroxide solution to prepare the electrolyte. A three-electrode system was used for electrodeposition, with the copper foam substrate as the cathode, a platinum sheet electrode as the anode, and a calomel electrode as the reference electrode. Electrodeposition was carried out in a quartz electrolytic cell at a current density of 3 mA / cm². 2 The electrodeposition time was 200 s. During the electrodeposition process, a uniform rotating magnetic field was applied outside the electrolytic cell at a rotation speed of 500 rpm and a magnetic field strength of 1200 Gs. Utilizing the negative magnetoresistance effect, zinc ferrite nanowires were directionally grown on the iron oxide particles. The monolithic catalyst obtained after electrodeposition was annealed in a muffle furnace at 250 °C for 3 h to obtain a copper-foamed monolithic zinc ferrite nanowire composite catalyst.

[0049] Example 2:

[0050] A 20*20*4mm nickel foam substrate was pretreated by removing the surface oxide layer with 1M dilute hydrochloric acid, rinsing with deionized water, and drying under nitrogen for 12 hours. The oxide-free nickel foam substrate was then placed in a quartz tube for chemical vapor deposition: a mixture of high-purity methane and hydrogen (4:1 concentration ratio) was introduced, the pressure was maintained at 200 Pa, and the reaction was carried out at 800℃ for 50 minutes to grow a graphene conductive layer on the surface of the nickel foam substrate. In 100 mL of deionized water, 0.005 mol of ferric nitrate nonahydrate, 0.001 mol of urea, 0.6 g of polyvinyl alcohol, and 0.2 g of polyvinylpyrrolidone were added. An iron oxide precursor solution was prepared, and a nickel foam substrate with a graphene conductive layer was transferred along with the precursor solution to a high-pressure hydrothermal reactor lined with polytetrafluoroethylene. The mixture was hydrothermally heated at 180℃ for 12 hours to obtain a monolithic nickel foam composite catalyst loaded with iron oxide nanoparticles. 0.02 mol of ferric nitrate nonahydrate and 0.01 mol of copper nitrate hexahydrate were added to 100 mL of deionized water, and the pH was adjusted to 10 with 2M potassium hydroxide solution to prepare the electrolyte. A three-electrode system was used for electrodeposition, with the nickel foam substrate as the cathode, a platinum sheet electrode as the anode, and a calomel electrode as the reference electrode. Electrodeposition was carried out in a quartz electrolytic cell at a current density of 3 mA / cm². 2 The electrodeposition time was 250 s. During the electrodeposition process, a uniform rotating magnetic field was applied outside the electrolytic cell. The magnetic field speed was 800 rpm and the magnetic field strength was 1500 Gs. Copper ferrite nanowires were directionally grown on iron oxide particles by utilizing the negative magnetoresistance effect. The monolithic catalyst obtained after electrodeposition was annealed in a muffle furnace at 300 °C for 4 h to obtain a nickel foam substrate monolithic copper ferrite nanowire composite catalyst.

[0051] Example 3:

[0052] A 30*30*4mm copper foam substrate was pretreated by removing the surface oxide layer with 1M dilute hydrochloric acid, rinsing with deionized water, and drying under nitrogen for 12 hours. The oxide-removed copper foam substrate was then placed in a quartz tube for chemical vapor deposition: a mixture of high-purity methane and hydrogen (methane to hydrogen concentration ratio 3:2) was introduced, the pressure was maintained at 100 Pa, and the reaction was carried out at 1000℃ for 80 minutes to grow a graphene conductive layer on the surface of the copper foam substrate. In 100 mL of deionized water, 0.008 mol of ferric nitrate nonahydrate, 0.0016 mol of urea, 0.6 g of polyvinyl alcohol, and 0.3 g of polyvinylpyrrolidone were added. Ketones were prepared into an iron oxide precursor solution. A copper foam substrate with a graphene conductive layer was transferred along with the precursor solution to a high-pressure hydrothermal reactor lined with polytetrafluoroethylene (PTFE). The mixture was hydrothermally heated at 180°C for 15 hours to obtain a monolithic copper foam composite catalyst loaded with iron oxide nanoparticles. 0.02 mol of ferric nitrate nonahydrate and 0.02 mol of cobalt nitrate hexahydrate were added to 100 mL of deionized water, and the pH was adjusted to 12 with 2M potassium hydroxide solution to prepare the electrolyte. A three-electrode system was used for electrodeposition: the copper foam substrate as the cathode, a platinum sheet electrode as the anode, and a calomel electrode as the reference electrode. Electrodeposition was carried out in a quartz electrolytic cell at a current density of 5 mA / cm². 2 The electrodeposition time was 300 s. During the electrodeposition process, a uniform rotating magnetic field was applied outside the electrolytic cell. The magnetic field speed was 800 rpm and the magnetic field strength was 1500 Gs. Cobalt ferrite nanowires were directionally grown on iron oxide particles by utilizing the negative magnetoresistance effect. The monolithic catalyst obtained after electrodeposition was annealed in a muffle furnace at 250 °C for 3 h to obtain a copper foam substrate monolithic cobalt ferrite nanowire composite catalyst.

[0053] Example 4:

[0054] A 20*20*2mm nickel foam substrate was pretreated by removing the surface oxide layer with 1M dilute hydrochloric acid, washing with deionized water, and drying under nitrogen for 12 hours. The oxide-removed nickel foam substrate was then placed in a quartz tube for chemical vapor deposition: a mixture of high-purity methane and hydrogen (4:1 concentration ratio) was introduced, the pressure was maintained at 200 Pa, and the reaction was carried out at 800℃ for 70 minutes to grow a graphene conductive layer on the nickel foam substrate surface. In 100 mL of deionized water, 0.004 mol of ferric nitrate nonahydrate, 0.0004 mol of urea, 0.6 g of polyvinyl alcohol, and 0.2 g of polyvinylpyrrolidone were added. An iron oxide precursor solution was prepared, and a nickel foam substrate with a graphene conductive layer was transferred along with the precursor solution to a high-pressure hydrothermal reactor lined with polytetrafluoroethylene. The mixture was hydrothermally heated at 160℃ for 10 hours to obtain a monolithic nickel foam composite catalyst loaded with iron oxide nanoparticles. 0.06 mol of ferric nitrate nonahydrate and 0.03 mol of manganese nitrate hexahydrate were added to 100 mL of deionized water, and the pH was adjusted to 12 with 2M potassium hydroxide solution to prepare the electrolyte. A three-electrode system was used for electrodeposition, with the nickel foam substrate as the cathode, a platinum sheet electrode as the anode, and a calomel electrode as the reference electrode. Electrodeposition was carried out in a quartz electrolytic cell at a current density of 2.5 mA / cm². 2 The electrodeposition time was 300 s. During the electrodeposition process, a uniform rotating magnetic field was applied outside the electrolytic cell. The magnetic field speed was 1000 rpm and the magnetic field strength was 2000 Gs. Manganese ferrite nanowires were directionally grown on iron oxide particles by utilizing the negative magnetoresistance effect. The monolithic catalyst obtained after electrodeposition was annealed in a muffle furnace at 300 °C for 4 h to obtain a foamed nickel substrate monolithic manganese ferrite nanowire composite catalyst.

[0055] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a monolithic ferrite nanowire composite catalyst, characterized in that, The substrate of the monolithic catalyst is a highly conductive foam metal, the protective layer and conductive layer are graphene prepared by vapor deposition, and the seed layer and tip discharge site for the growth of the ferrite photoelectric layer are iron oxide nanoparticles grown by hydrothermal method. Due to the negative magnetoresistance effect of iron oxide, under the condition of a rotating magnetic field, iron oxide particles will become sharp discharge sites, which makes ferrite tend to grow in a directional manner at the iron oxide sites to form a ferrite nanowire photoelectric layer. After annealing in an air atmosphere, an integral ferrite nanowire composite catalyst is finally obtained. The preparation steps are as follows: Step (1): Select a highly conductive foamed metal material as the substrate for the monolithic catalyst; The highly conductive foamed metal material is a nickel-based or copper-based foamed metal; Step (2): The substrate of the monolithic catalyst is pretreated to remove the surface oxide layer. It is then placed in a quartz tube, and a mixture of high-purity methane and hydrogen is introduced. The tube is then sealed and pressure is maintained. Chemical vapor deposition is performed at high temperature for a certain period of time to obtain a graphene conductive layer grown on the foam metal substrate. The ratio of high-purity methane to hydrogen is 4:1 to 3:2; the pressure is 100 to 200 Pa; the vapor deposition temperature is 800 to 1000°C; and the deposition time is 30 to 90 min. Step (3): Add a certain amount of ferric nitrate nonahydrate, urea, polyvinyl alcohol and polyvinylpyrrolidone to deionized water to prepare a precursor solution; The foam metal substrate with the graphene conductive layer grown on it, along with the prepared precursor solution, is then transferred to a high-pressure hydrothermal reactor lined with polytetrafluoroethylene and subjected to constant-temperature hydrothermal treatment to obtain a composite catalyst loaded with iron oxide nanoparticles. In the prepared precursor solution, the mass ratio of ferric nitrate nonahydrate to urea per 100 mL is 10:1 to 5:

1. The mass ratio of polyvinyl alcohol to polyvinylpyrrolidone contained is 3:1 to 2:1; In addition, the temperature of the constant temperature hydrothermal reactor in the high-pressure hydrothermal reactor is maintained at 160~200 °C, and the constant temperature hydrothermal time is 8~16 hours; Step (4): Add a certain amount of ferric nitrate nonahydrate and metal nitrate to deionized water to prepare an electrolyte, and use potassium hydroxide to adjust its pH value to alkaline. The electrodeposition process uses a three-electrode system, with a foamed metal substrate as the cathode, a platinum sheet electrode as the anode, and a calomel electrode as the reference electrode, and electrodeposition is carried out in a quartz electrolytic cell. During the electrodeposition process, a uniform rotating magnetic field is applied outside the electrolytic cell, and the negative magnetoresistance effect is used to make ferrite nanowires grow directionally on iron oxide particles. The metal nitrate is one of zinc nitrate hexahydrate, copper nitrate hexahydrate, nickel nitrate hexahydrate, cobalt nitrate hexahydrate, and manganese nitrate hexahydrate; The mass ratio of ferric nitrate nonahydrate to metal nitrate in the prepared electrolyte is 1:1 to 2:1, and the pH value is adjusted to 10 to 13 by adding potassium hydroxide. The uniform rotating magnetic field has a rotational speed of 500~1000 rpm and a magnetic field strength of 1000~2000 Gs; Step (5): Anneal the catalyst obtained after electrodeposition in a muffle furnace to finally produce an integral ferrite nanowire composite catalyst; The annealing temperature is 200~400 °C, and the annealing time is 3~5 h.

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