Preparation method of amorphous nickel hydroxide material

Abstract

The invention discloses a preparation method of an amorphous nickel hydroxide material, which comprises the following steps: (1) adding nickel salt, urea and ammonium salt into ultrapure water, and stirring at room temperature to obtain a precursor solution; (2) transferring the precursor solution obtained in the step (1) into a hydrothermal reaction kettle with a polytetrafluoroethylene lining for hydrothermal reaction, and centrifugally drying to obtain a precursor powder material; and (3) putting the precursor powder material obtained in the step (2) into a tubular furnace, carrying out annealing treatment in an inert atmosphere, and carrying out centrifugal drying to obtain the amorphous nickel hydroxide material. The preparation method has the beneficial effects that the prepared amorphous nickel hydroxide material has the advantages of high selectivity, high activity, simplicity in preparation and low production cost; the preparation method disclosed by the invention is clear and simple, convenient to operate, high in controllability and low in device cost, and provides technical feasibility for industrial production and application.

Description

Technical Field

[0001] The invention relates to the technical field of material preparation, and in particular to a method for preparing an amorphous nickel hydroxide material. Background Art

[0002] As a green oxidant, hydrogen peroxide has a wide range of applications in medical disinfection, pulp bleaching, and chemical synthesis. The traditional anthraquinone oxidation method for preparing hydrogen peroxide in industry has problems such as high energy consumption and high pollution. However, electrocatalytic two-electron oxygen reduction is a technology for in-situ production of hydrogen peroxide, with only water as a byproduct. It is a green hydrogen peroxide production technology. However, electrocatalytic two-electron oxygen reduction cannot be applied on a large scale. The main obstacle is that the four-electron oxygen reduction pathway, as the thermodynamically preferred pathway, competes with the two-electron oxygen reduction pathway. Currently, it relies more on precious metal-based catalysts to improve the selectivity of the two-electron pathway of the reaction, which has a high industrial cost. In addition, the kinetic process of two-electron oxygen reduction also requires expensive precious metal-based catalysts to accelerate.

[0003] In recent years, transition metal oxide catalysts, i.e., nickel-based materials, have been developed to reduce production costs. Nickel-based materials have shown good development potential in the field of electrocatalysis due to their variable valence states, suitable energy band structures, high energy density, and moderate intermediate adsorption energy. Therefore, in order to take into account the activity, selectivity and cost issues of electrocatalyst materials, it is of great practical significance to develop a method for preparing amorphous nickel hydroxide materials. Summary of the invention

[0004] In order to solve the above problems, especially to address the deficiencies in the prior art, the present invention provides a method for preparing an amorphous nickel hydroxide material that can solve the above problems.

[0005] To achieve the above purpose, the present invention adopts the following technical means:

[0006] A method for preparing an amorphous nickel hydroxide material, the method comprising the following steps:

[0007] (1) Add nickel salt, urea and ammonium salt to ultrapure water and stir at room temperature to obtain a precursor solution;

[0008] (2) transferring the precursor solution obtained in step (1) into a hydrothermal reactor lined with polytetrafluoroethylene for hydrothermal reaction, and obtaining a precursor powder material after centrifugal drying;

[0009] (3) placing the precursor powder material obtained in step (2) in a tube furnace, performing annealing treatment in an inert atmosphere, and obtaining an amorphous nickel hydroxide material after centrifugal drying.

[0010] A further embodiment of the present invention is that the nickel salt in step (1) is nickel nitrate hexahydrate.

[0011] A further embodiment of the present invention is that the urea and the ammonium salt in step (1) are lattice structure regulators, and the ammonium salt is ammonium chloride or ammonium fluoride.

[0012] A further embodiment of the present invention is that the stirring time in step (1) is 30-60 min.

[0013] A further embodiment of the present invention is that the hydrothermal reaction temperature in step (2) is 135-140° C. and the reaction time is 8 hours.

[0014] A further embodiment of the present invention is that the inert atmosphere in step (3) is argon or helium.

[0015] A further solution of the present invention is that the annealing temperature in step (3) is 250° C., the heating rate is 1.4-5° C. / min, and the annealing time is 1 h.

[0016] A further embodiment of the present invention is that the drying temperature in step (2) and step (3) is 60-65° C. and the drying time is 12-24 hours.

[0017] Beneficial effects of the present invention:

[0018] 1. The amorphous nickel hydroxide material prepared by the present invention has excellent electrocatalytic performance. As an electrocatalyst for two-electron oxygen reduction to generate hydrogen peroxide, it has the advantages of high selectivity, high activity, simple preparation and low production cost.

[0019] 2. The preparation method of the present invention is clear and simple, easy to operate, highly controllable, and has low device cost, which provides technical feasibility for industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is an X-ray diffraction pattern of amorphous nickel hydroxide prepared by the method of the present invention;

[0021] Figure 2 is a linear voltammetric curve of amorphous nickel hydroxide prepared by the method of the present invention;

[0022] Figure 3 is a scanning electron microscope image of amorphous nickel hydroxide prepared by the method of the present invention;

[0023] Figure 4 It is a curve diagram of the number of transferred electrons in the process of electrocatalytic oxygen reduction of amorphous nickel hydroxide prepared by the method of the present invention;

[0024] Figure 5 It is a curve diagram of hydrogen peroxide yield of amorphous nickel hydroxide prepared by the method of the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example 1

[0027] A method for preparing an amorphous nickel hydroxide material, the method comprising the following steps:

[0028] Step 1: Weigh 1.1631 g nickel nitrate hexahydrate, 1.2012 g urea, and 0.2963 g ammonium chloride into a beaker, add 60 mL ultrapure water, place on a magnetic stirrer at 25°C, set the speed to 740 rpm, stir for 30 min, and dissolve to obtain a precursor solution.

[0029] Step 2: Transfer the precursor solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, then place the autoclave in an oven for hydrothermal reaction at 140°C for 8 hours. Transfer the system to a centrifuge tube, wash it several times with ultrapure water and ethanol, and dry it in an oven at 65°C for 12 hours to obtain a precursor powder material.

[0030] Step 3: Take 30 mg of the precursor powder material and place it in a porcelain ark. Place the porcelain ark in a tube furnace and anneal it at 250°C in an argon atmosphere for 1 hour at a heating rate of 1.4°C / min. The product is transferred to a centrifuge tube, washed several times by centrifugation with ultrapure water and ethanol, and then placed in a 65°C oven to dry for 12 hours to obtain an amorphous nickel hydroxide material, such as Figures 1 to 3 shown.

[0031] Example 2

[0032] A method for preparing an amorphous nickel hydroxide material, the method comprising the following steps:

[0033] Step 1: Weigh 1.1631 g nickel nitrate hexahydrate, 1.2012 g urea, and 0.2963 g ammonium chloride into a beaker, add 60 mL ultrapure water, place on a magnetic stirrer at 25°C, set the speed to 740 rpm, stir for 60 min, and dissolve to obtain a precursor solution.

[0034] Step 2: Transfer the precursor solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, then place the autoclave in an oven for hydrothermal reaction at 135°C for 8 hours. Transfer the system to a centrifuge tube, wash it several times with ultrapure water and ethanol, and dry it in an oven at 65°C for 12 hours to obtain a precursor powder material.

[0035] Step 3: Take 30 mg of the precursor powder material and place it in a porcelain ark. Place the porcelain ark in a tube furnace and anneal at 250°C in an argon atmosphere for 1 hour at a heating rate of 5°C / min. The product is transferred to a centrifuge tube, washed several times by centrifugation with ultrapure water and ethanol, and then placed in a 65°C oven to dry for 12 hours to obtain an amorphous nickel hydroxide material.

[0036] Example 3

[0037] A method for preparing an amorphous nickel hydroxide material, the method comprising the following steps:

[0038] Step 1: Weigh 1.1631 g nickel nitrate hexahydrate, 1.2012 g urea, and 0.2963 g ammonium fluoride into a beaker, add 60 mL ultrapure water, place on a magnetic stirrer at 25°C, set the speed to 740 rpm, stir for 30 min, and dissolve to obtain a precursor solution.

[0039] Step 2: Transfer the precursor solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, then place the autoclave in an oven for hydrothermal reaction at 140°C for 8 hours. Transfer the system to a centrifuge tube, wash it several times with ultrapure water and ethanol, and dry it in an oven at 65°C for 12 hours to obtain a precursor powder material.

[0040] Step 3: Take 30 mg of the precursor powder material and place it in a porcelain ark. Place the porcelain ark in a tube furnace and anneal it at 250°C in an argon atmosphere for 1 hour at a heating rate of 1.4°C / min. The product is transferred to a centrifuge tube, washed several times by centrifugation with ultrapure water and ethanol, and then placed in a 65°C oven to dry for 12 hours to obtain an amorphous nickel hydroxide material.

[0041] Example 4

[0042] A method for preparing an amorphous nickel hydroxide material, the method comprising the following steps:

[0043] Step 1: Weigh 1.1631 g nickel nitrate hexahydrate, 1.2012 g urea, and 0.2963 g ammonium fluoride into a beaker, add 60 mL ultrapure water, place on a magnetic stirrer at 25°C, set the speed to 740 rpm, stir for 60 min, and dissolve to obtain a precursor solution.

[0044] Step 2: Transfer the precursor solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, then place the autoclave in an oven for hydrothermal reaction at 135°C for 8 hours. Transfer the system to a centrifuge tube, wash it several times with ultrapure water and ethanol, and dry it in an oven at 65°C for 12 hours to obtain Ni(OH)x powder.

[0045] Step 3: Take 30 mg of Ni(OH)x powder and place it in a porcelain ark. Place the porcelain ark in a tube furnace and anneal it at 250°C in an argon atmosphere for 1 hour at a heating rate of 5°C / min. The product is transferred to a centrifuge tube, washed several times by centrifugation with ultrapure water and ethanol, and then placed in a 65°C oven to dry for 12 hours to obtain an amorphous nickel hydroxide material.

[0046] Example 5

[0047] A method for preparing an amorphous nickel hydroxide material, the method comprising the following steps:

[0048] Step 1: Weigh 1.1631 g nickel nitrate hexahydrate, 1.2012 g urea, 0.2963 g ammonium chloride, and 0.1 g XC-72R into a beaker, add 50 mL ultrapure water, place on a magnetic stirrer at 25° C., set the speed to 500 rpm, and stir for 45 min to obtain a precursor.

[0049] Step 2: Transfer the precursor solution to a 100 mL stainless steel autoclave lined with polytetrafluoroethylene, add 10 mL of ultrapure water during the process, and then place the autoclave in an oven for hydrothermal reaction at 140°C for 8 hours. Transfer the system to a centrifuge tube, wash it several times with ultrapure water and ethanol, and then dry it in a 65°C oven for 24 hours to obtain a precursor powder material.

[0050] Step 3: Take 30 mg of the precursor powder material and place it in a porcelain ark. Place the porcelain ark in a tube furnace and anneal it at 250°C in an argon atmosphere for 1 hour at a heating rate of 5°C / min. The product is transferred to a centrifuge tube, washed several times by centrifugation with ultrapure water and ethanol, and then placed in a 65°C oven to dry for 24 hours to obtain an amorphous nickel hydroxide material.

[0051] Example 6

[0052] like Figures 4 to 5 As shown, the amorphous nickel hydroxide material was subjected to electrocatalytic oxygen reduction tests and a series of characterizations:

[0053] Weigh 3 mg of catalyst using an electronic balance, disperse it in a mixed solution of isopropanol, water and Nafion, and ultrasonicate for 15-20 minutes to obtain a uniformly dispersed ink. Then take 5 μL of ink and spin-coat it on a ring-disk electrode, dry it naturally, and use it as a working electrode. The test system is a three-electrode system, the reference electrode is a saturated Ag / AgCl electrode, the auxiliary electrode is a platinum mesh electrode, and the working electrode is a rotating ring-disk electrode with ink added. The test environment is an O2-saturated 0.1M KOH solution, the potential scan range is 1.2-0.2V relative to the reversible hydrogen electrode, the potential scan rate is 5mV / s, and the rotation speed of the rotating ring-disk electrode is 1600rpm.

[0054] The structure of amorphous nickel hydroxide materials was characterized by XRD and SEM.

[0055] The examples given in the present invention are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here, and the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing an amorphous nickel hydroxide material, characterized in that: The method comprises the following steps: (1) Add nickel salt, urea and ammonium salt to ultrapure water and stir at room temperature to obtain a precursor solution; (2) transferring the precursor solution obtained in step (1) into a hydrothermal reactor lined with polytetrafluoroethylene for hydrothermal reaction, and obtaining a precursor powder material after centrifugal drying; (3) placing the precursor powder material obtained in step (2) in a tube furnace, performing annealing treatment in an inert atmosphere, and obtaining an amorphous nickel hydroxide material after centrifugal drying.

2. The method for preparing an amorphous nickel hydroxide material according to claim 1, characterized in that: The nickel salt in step (1) is nickel nitrate hexahydrate.

3. The method for preparing an amorphous nickel hydroxide material according to claim 2, characterized in that: The urea and ammonium salt in step (1) are lattice structure regulators, and the ammonium salt is ammonium chloride or ammonium fluoride.

4. The method for preparing an amorphous nickel hydroxide material according to claim 3, characterized in that: The stirring time in step (1) is 30-60 min.

5. The method for preparing an amorphous nickel hydroxide material according to claim 1, characterized in that: The hydrothermal reaction temperature in step (2) is 135-140° C., and the reaction time is 8 hours.

6. The method for preparing an amorphous nickel hydroxide material according to claim 1, characterized in that: The inert atmosphere in step (3) is argon or helium.

7. The method for preparing an amorphous nickel hydroxide material according to claim 6, characterized in that: The annealing temperature in step (3) is 250° C., the heating rate is 1.4-5° C. / min, and the annealing time is 1 h.

8. The method for preparing an amorphous nickel hydroxide material according to claim 1, characterized in that: The drying temperature in step (2) and step (3) is 60-65° C., and the drying time is 12-24 hours.

Images