NiO hollow microspheres with OER electrocatalytic activity and preparation method thereof

Abstract

The application discloses a kind of NiO hollow microspheres with OER electrocatalytic activity, which is prepared by Mist-CVD method and the average diameter is less than 1.5 µm. The application also discloses a preparation method of the NiO hollow microspheres with OER electrocatalytic activity. The nickel salt and ethanolamine complexing agent (ETA) are dissolved in deionized water to prepare a mixed precursor solution, and the Mist-CVD method is used for preparation to obtain the NiO hollow microspheres with OER electrocatalytic activity. The NiO hollow microspheres with OER electrocatalytic activity and the preparation method thereof use nickel salt and ethanolamine complexing agent (ETA) as mixed precursors, and the Mist-CVD method is used to prepare the NiO hollow microspheres with high OER activity. This method has the advantages of simple process, low raw material cost, mass production, and relatively friendly to the environment.

Description

Technical Field

[0001] This invention belongs to the field of OER electrocatalyst preparation technology, specifically, it relates to a NiO hollow microsphere with OER electrocatalytic activity and its preparation method. Background Technology

[0002] In today's energy structure, fossil fuels, primarily oil and natural gas, still dominate. The overuse of fossil fuels has led to a series of environmental problems, such as the greenhouse effect and acid rain. This urgently necessitates the search for a renewable energy source. Hydrogen is well-known as a renewable energy source. It possesses advantages such as being renewable, pollution-free, and having a high calorific value, making it a promising alternative to fossil fuels. Currently, published methods for producing hydrogen can be divided into two main categories: non-renewable hydrogen production technologies and renewable hydrogen production technologies. Non-renewable technologies include petroleum cracking, ammonia decomposition, and methanol decomposition; renewable technologies include water electrolysis, thermal cycle hydrogen production, and biomass hydrogen production. Water electrolysis, due to its advantages of low cost, high hydrogen purity, readily available raw materials, and no environmental pollution, has become one of the most promising hydrogen production technologies for industrial production.

[0003] However, water electrolysis also presents several challenges. Firstly, due to internal resistance in the reaction system and reaction resistance during Faraday electron transport, the actual overpotential (reaction barrier) is higher than the theoretical overpotential (1.23V). Secondly, water electrolysis involves two half-reactions; the oxygen evolution reaction (OER) at the anode, involving four electrons, has greater resistance than the hydrogen evolution reaction (HER) at the cathode. Therefore, an electrocatalyst is needed in the electrolysis system. Currently known electrocatalysts include noble metal oxides such as IrO2 and RuO2, but their high price and scarcity on Earth limit their commercial application. NiO, due to its low price, abundant resources, and high activity, is considered an effective electrocatalyst.

[0004] However, NiO materials also suffer from problems such as few active sites and poor conductivity. Currently, four solutions have been reported: 1) introducing defects, 2) introducing conductive materials, 3) preparing heterostructures, and 4) geometric structure manipulation. It is worth noting that hollow microsphere structures can increase the permeability between the electrolyte and active materials, which is beneficial for both Faraday electron transport and non-Faraday mass transfer processes, making it an effective modification method. Currently, the raw materials used in traditional CVD technology for preparing NiO powder are nickel-ceramic and nickel acetylacetonate, which are much more expensive than nickel chloride, nickel sulfate, and ethanolamine. Furthermore, traditional CVD equipment is complex, unsuitable for continuous production, and the OER performance of the prepared NiO powder is generally poor, limiting its commercial application prospects. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for preparing NiO hollow microspheres with OER electrocatalytic activity that is low in cost and suitable for mass production.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0007] A method for preparing NiO hollow microspheres with OER electrocatalytic activity includes the following steps:

[0008] To prepare the precursor solution, nickel salt is dissolved in deionized water to form a solution with a concentration of 30-70 g / L. Then, ethanolamine complexing agent is added, with a complexing molar ratio of ethanolamine complexing agent to nickel salt of 2-4:1. The mixture is stirred thoroughly to ensure complete complexation, thereby obtaining the precursor solution.

[0009] The reaction environment is constructed by sequentially connecting the reaction vessel, the tubular furnace, and the powder collection tank. The reaction vessel is also connected to a diaphragm pump and a cooling circulating water system. An ultrasonic atomizer is installed inside the reaction vessel.

[0010] The temperature is increased by heating the tube furnace to raise the temperature of its reaction zone to the reaction temperature;

[0011] Atomization: Add the precursor solution to the reaction vessel, and then turn on the ultrasonic nebulizer to atomize the precursor solution into micron-sized droplets.

[0012] The reaction proceeds by using a diaphragm pump to supply a strong airflow into the reaction vessel, which carries small droplets to the reaction zone of the tube furnace. Under the influence of the reaction temperature, NiO hollow microsphere powder is formed.

[0013] Powder collection: The formed NiO hollow microsphere powder is carried into the powder collection tank by a strong airflow for powder collection and falls into deionized water for water-soluble reaction. The reaction takes 3~12 hours to obtain a powder suspension.

[0014] Post-processing involves centrifuging, washing, and drying the powder suspension, followed by grinding to obtain NiO hollow microspheres with OER electrocatalytic activity.

[0015] The thorough stirring is carried out using magnetic stirring for 20-60 minutes; the reaction temperature is 600-1000℃; and the flow rate of the strong airflow is 50-200 sccm.

[0016] Specifically, in the reaction environment construction step, the air outlet of the powder collection tank is connected to the tail gas treatment channel for treating the gas after the reaction, and the cooling circulating water system is used to cool the reaction tank, with the temperature of the cooling circulating water being 5~10℃.

[0017] Furthermore, in the atomization step, the precursor solution added to the reaction vessel completely immerses the ultrasonic atomizer.

[0018] Specifically, the post-processing steps include the following steps:

[0019] Centrifugation: Pour the powder suspension into a centrifuge tube, balance it, and place it in a refrigerated centrifuge for centrifugation. After centrifugation for 30 minutes, discard the supernatant, and then repeat the balancing and centrifugation until the powder suspension is completely centrifuged to obtain the centrifuged product.

[0020] Washing: Add ethanol or deionized water to the centrifuge tube containing the centrifuged product, then place it in an ultrasonic machine for ultrasonication until the centrifuged product in the centrifuge tube is completely dissolved. Then balance and centrifuge to obtain the washed product.

[0021] Drying: After the washing product is placed into the crucible, it is placed in a vacuum drying oven. After the washing product is completely dried, the crucible is removed. The crucible contains the dried product.

[0022] Grinding: Grind the dried product until it forms a fine powder, thus obtaining NiO hollow microspheres with OER electrocatalytic activity.

[0023] Preferably, the nickel salt includes at least one of nickel chloride, nickel sulfate, and nickel nitrate.

[0024] A NiO hollow microsphere with OER electrocatalytic activity was prepared by the method described above, which belongs to the Mist-CVD method.

[0025] Specifically, the average diameter of the NiO hollow microspheres with OER electrocatalytic activity is less than 1.5µm.

[0026] This invention has the following beneficial effects: By adding a certain molar proportion of ETA complexing agent to a nickel salt solution of a certain concentration and thoroughly mixing it as a mixed precursor, hollow spheres are prepared using the Mist-CVD method. The principle of preparing hollow spheres by the Mist-CVD method is that during the drying process of a single droplet, the solvent in the droplet continuously evaporates. Due to the decomposition of the precursor at high temperature, single nanoparticles are generated, and the particles are formed on the surface of the droplet, eventually forming hollow spheres. Therefore, the Mist-CVD method is an effective method for preparing hollow microspheres. Generally, nickel salts with strong ionization characteristics have the disadvantage of high decomposition temperature. However, in aqueous solution, strongly ionized nickel salts can form a tight bond with metal ion complexing agents due to the presence of coordination bonds. Therefore, by complexing them, their decomposition temperature is reduced, thereby achieving the purpose of producing NiO hollow microspheres with OER electrocatalytic activity. This method has the advantages of simple process, low raw material cost, mass production capability, and relative environmental friendliness. Attached Figure Description

[0027] Figure 1 The images show a TEM image (left) and a high-resolution image (right) of the product obtained in Example 1 of this invention.

[0028] Figure 2 SEM image of the product obtained in Example 2 of this invention.

[0029] Figure 3 The image shows the XRD pattern of the product obtained in Example 2 of this invention. Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings.

[0031] An embodiment of the present invention provides a method for preparing NiO hollow microspheres with OER electrocatalytic activity, which includes the following steps:

[0032] For precursor solution preparation, 12g of nickel chloride hexahydrate (NiCl2•6H2O) with a purity of 99% and a molecular weight of 237.69 was dissolved in 350ml of deionized water to form a solution. The solution was placed in a beaker and stirred in a magnetic stirrer until the nickel chloride hexahydrate was completely dissolved in the deionized water. Then, according to the molar ratio of ethanolamine complexing agent to nickel salt of 4:1, 12.33ml of ethanolamine solution with a purity of 99% and a molecular weight of 61.08 was measured and added to the beaker. Deionized water was then added again until the total volume of the solution in the beaker was 400ml. The beaker was then stirred in a magnetic stirrer for 20min to ensure that the two were fully complexed, resulting in a precursor solution with a nickel chloride concentration of 30g / L and a molar ratio of ETA to nickel chloride hexahydrate of 4:1.

[0033] The reaction environment is constructed by sequentially connecting the reaction vessel, tubular furnace, and powder collection tank. The reaction vessel is also connected to a diaphragm pump and a cooling circulating water system. An ultrasonic atomizer is installed inside the reaction vessel. In this step, the air outlet of the powder collection tank is connected to a tail gas treatment channel to treat the gas after the reaction. The cooling circulating water system is used to cool the reaction vessel, and the temperature of the cooling circulating water is 5°C.

[0034] The temperature is increased by heating the tube furnace to raise the temperature of its reaction zone to the reaction temperature, which is 600°C.

[0035] Atomization: A precursor solution is added to the reaction vessel, and then the ultrasonic atomizer is turned on to atomize the precursor solution into micron-sized droplets; in this step, the precursor solution added to the reaction vessel completely immerses the ultrasonic atomizer.

[0036] The reaction is carried out by a strong airflow into the reaction vessel through a diaphragm pump, which carries small droplets to the reaction zone of the tube furnace. Under the action of the reaction temperature, NiO hollow microsphere powder is formed; the flow rate of the strong airflow is 50 sccm.

[0037] Powder collection: The formed NiO hollow microsphere powder is carried into the powder collection tank by a strong air flow for powder collection and falls into deionized water for water-soluble reaction. The reaction is carried out for 3 hours to obtain a powder suspension.

[0038] Post-processing involves centrifuging, washing, and drying the powder suspension, followed by grinding to obtain NiO hollow microspheres with OER electrocatalytic activity. Specifically, this step includes the following steps: centrifugation: the powder suspension is poured into a centrifuge tube, balanced, and then centrifuged in a refrigerated centrifuge for 30 minutes. The supernatant is discarded, and the process is repeated until the powder suspension is completely centrifuged to obtain the centrifuged product; washing: ethanol or deionized water is added to the centrifuge tube containing the centrifuged product, and then the tube is sonicated until the centrifuged product is completely dissolved. The tube is then balanced and centrifuged to obtain the washed product; drying: the washed product is transferred to a crucible and placed in a vacuum drying oven. After the washed product is completely dried, the crucible is removed, and the dried product is removed; grinding: the dried product is ground until it forms a fine powder, thus obtaining NiO hollow microspheres with OER electrocatalytic activity.

[0039] The lattice fringes of the obtained NiO hollow microspheres with OER electrocatalytic activity were measured using TEM imaging and HRTEM imaging. Figure 1 (Left) It can be seen that the powder does indeed have a hollow structure, and the particle size is around 1µm; from Figure 1 (Right) It can be seen that the lattice fringe spacing of this hollow microsphere is 0.241 Å, which corresponds to the (111) crystal plane of NiO, thus confirming that it is a NiO hollow sphere.

[0040] Example 2 of this invention discloses a method for preparing NiO hollow microspheres with OER electrocatalytic activity, which includes the following steps:

[0041] For precursor solution preparation, 20g of nickel chloride hexahydrate (NiCl2•6H2O) with a purity of 99% and a molecular weight of 237.69 was dissolved in 350ml of deionized water to form a solution. The solution was placed in a beaker and stirred in a magnetic stirrer until the nickel chloride hexahydrate was completely dissolved in the deionized water. Then, according to the molar ratio of ethanolamine complexing agent to nickel salt of 4:1, 20.55ml of ethanolamine solution with a purity of 99% and a molecular weight of 61.08 was measured and added to the beaker. Deionized water was then added again until the total volume of the solution in the beaker was 400ml. The beaker was then stirred in a magnetic stirrer for 20min to ensure that the two were fully complexed, resulting in a precursor solution with a nickel chloride concentration of 50g / L and a molar ratio of ETA to nickel chloride hexahydrate of 4:1.

[0042] The reaction environment is constructed by sequentially connecting the reaction vessel, tubular furnace, and powder collection tank. The reaction vessel is also connected to a diaphragm pump and a cooling circulating water system. An ultrasonic atomizer is installed inside the reaction vessel. In this step, the air outlet of the powder collection tank is connected to a tail gas treatment channel for treating the gas after the reaction. The cooling circulating water system is used to cool the reaction vessel, and the temperature of the cooling circulating water is 10°C.

[0043] The temperature is increased by heating the tube furnace to raise the temperature of its reaction zone to the reaction temperature, which is 1000°C.

[0044] Atomization: A precursor solution is added to the reaction vessel, and then the ultrasonic atomizer is turned on to atomize the precursor solution into micron-sized droplets; in this step, the precursor solution added to the reaction vessel completely immerses the ultrasonic atomizer.

[0045] The reaction is carried out by a strong airflow into the reaction vessel through a diaphragm pump, which carries small droplets to the reaction zone of the tube furnace. Under the action of the reaction temperature, NiO hollow microsphere powder is formed; the flow rate of the strong airflow is 150 sccm.

[0046] Powder collection: The formed NiO hollow microsphere powder is carried into the powder collection tank by a strong air flow for powder collection and falls into deionized water for water-soluble reaction. The reaction is carried out for 3 hours to obtain a powder suspension.

[0047] Post-processing involves centrifuging, washing, and drying the powder suspension, followed by grinding to obtain NiO hollow microspheres with OER electrocatalytic activity. Specifically, this step includes the following steps: centrifugation: the powder suspension is poured into a centrifuge tube, balanced, and then centrifuged in a refrigerated centrifuge for 30 minutes. The supernatant is discarded, and the process is repeated until the powder suspension is completely centrifuged to obtain the centrifuged product; washing: ethanol or deionized water is added to the centrifuge tube containing the centrifuged product, and then the tube is sonicated until the centrifuged product is completely dissolved. The tube is then balanced and centrifuged to obtain the washed product; drying: the washed product is transferred to a crucible and placed in a vacuum drying oven. After the washed product is completely dried, the crucible is removed, and the dried product is removed; grinding: the dried product is ground until it forms a fine powder, thus obtaining NiO hollow microspheres with OER electrocatalytic activity.

[0048] The obtained NiO hollow microspheres with OER electrocatalytic activity were subjected to SEM imaging and XRD characterization. Figure 2 It can be seen that the hollow microsphere powder has good dispersibility, and the measured average particle size is 1.08 µm; from Figure 3 It can be seen that the hollow microsphere powder is NiO and has good crystallinity.

[0049] Example 3 of the present invention discloses a method for preparing NiO hollow microspheres with OER electrocatalytic activity, which includes the following steps:

[0050] For precursor solution preparation, 12g of nickel chloride hexahydrate (NiCl2•6H2O) with a purity of 99% and a molecular weight of 237.69 was dissolved in 350ml of deionized water to form a solution with a concentration of 34g / L. The solution was placed in a beaker and stirred in a magnetic stirrer until the nickel chloride hexahydrate was completely dissolved in the deionized water. Then, according to the molar ratio of ethanolamine complexing agent to nickel salt of 2:1, 10.28ml of ethanolamine solution with a purity of 99% and a molecular weight of 61.08 was measured and added to the beaker. Deionized water was then added again until the total volume of the solution in the beaker was 400ml. The beaker was then stirred in a magnetic stirrer for 20min to ensure that the two were fully complexed, resulting in a precursor solution with a nickel chloride concentration of 50g / L and a molar ratio of ETA to nickel chloride hexahydrate of 2:1.

[0051] The reaction environment is constructed by sequentially connecting the reaction vessel, tubular furnace, and powder collection tank. The reaction vessel is also connected to a diaphragm pump and a cooling circulating water system. An ultrasonic atomizer is installed inside the reaction vessel. In this step, the air outlet of the powder collection tank is connected to a tail gas treatment channel for treating the gas after the reaction. The cooling circulating water system is used to cool the reaction vessel, and the temperature of the cooling circulating water is 10°C.

[0052] The temperature is increased by heating the tube furnace to raise the temperature of its reaction zone to the reaction temperature, which is 800°C.

[0053] Atomization: A precursor solution is added to the reaction vessel, and then the ultrasonic atomizer is turned on to atomize the precursor solution into micron-sized droplets; in this step, the precursor solution added to the reaction vessel completely immerses the ultrasonic atomizer.

[0054] The reaction is carried out by a strong airflow into the reaction vessel through a diaphragm pump, which carries small droplets to the reaction zone of the tube furnace. Under the action of the reaction temperature, NiO hollow microsphere powder is formed; the flow rate of the strong airflow is 100 sccm.

[0055] Powder collection: The formed NiO hollow microsphere powder is carried into the powder collection tank by a strong air flow for powder collection and falls into deionized water for water-soluble reaction. The reaction is carried out for 3 hours to obtain a powder suspension.

[0056] Post-processing involves centrifuging, washing, and drying the powder suspension, followed by grinding to obtain NiO hollow microspheres with OER electrocatalytic activity. Specifically, this step includes the following steps: centrifugation: the powder suspension is poured into a centrifuge tube, balanced, and then centrifuged in a refrigerated centrifuge for 30 minutes. The supernatant is discarded, and the process is repeated until the powder suspension is completely centrifuged to obtain the centrifuged product; washing: ethanol or deionized water is added to the centrifuge tube containing the centrifuged product, and then the tube is sonicated until the centrifuged product is completely dissolved. The tube is then balanced and centrifuged to obtain the washed product; drying: the washed product is transferred to a crucible and placed in a vacuum drying oven. After the washed product is completely dried, the crucible is removed, and the dried product is removed; grinding: the dried product is ground until it forms a fine powder, thus obtaining NiO hollow microspheres with OER electrocatalytic activity.

[0057] The obtained NiO hollow microspheres with OER electrocatalytic activity had an average particle size of 0.81 µm and good crystallinity.

[0058] Example 4 of the present invention discloses a method for preparing NiO hollow microspheres with OER electrocatalytic activity, which includes the following steps:

[0059] For precursor solution preparation, 28g of nickel sulfate hexahydrate (NiSO4•6H2O) with a purity of 99% and a molecular weight of 262.85 was dissolved in 350ml of deionized water to form a solution with a concentration of 34g / L. The solution was placed in a beaker and stirred in a magnetic stirrer until the nickel chloride hexahydrate was completely dissolved in the deionized water. Then, according to the molar ratio of ethanolamine complexing agent to nickel salt of 2:1, 14.4ml of ethanolamine solution with a purity of 99% and a molecular weight of 61.08 was measured and added to the beaker. Deionized water was then added again until the total volume of the solution in the beaker was 400ml. The beaker was then stirred in a magnetic stirrer for 20min to ensure that the two were fully complexed, resulting in a precursor solution with a nickel chloride concentration of 70g / L and a molar ratio of ETA to nickel chloride hexahydrate of 2:1.

[0060] The reaction environment is constructed by sequentially connecting the reaction vessel, tubular furnace, and powder collection tank. The reaction vessel is also connected to a diaphragm pump and a cooling circulating water system. An ultrasonic atomizer is installed inside the reaction vessel. In this step, the air outlet of the powder collection tank is connected to a tail gas treatment channel to treat the gas after the reaction. The cooling circulating water system is used to cool the reaction vessel, and the temperature of the cooling circulating water is 5°C.

[0061] The temperature is increased by heating the tube furnace to raise the temperature of its reaction zone to the reaction temperature, which is 600°C.

[0062] Atomization: A precursor solution is added to the reaction vessel, and then the ultrasonic atomizer is turned on to atomize the precursor solution into micron-sized droplets; in this step, the precursor solution added to the reaction vessel completely immerses the ultrasonic atomizer.

[0063] The reaction is carried out by a strong airflow into the reaction vessel through a diaphragm pump, which carries small droplets to the reaction zone of the tube furnace. Under the action of the reaction temperature, NiO hollow microsphere powder is formed; the flow rate of the strong airflow is 200 sccm.

[0064] Powder collection: The formed NiO hollow microsphere powder is carried into the powder collection tank by a strong air flow for powder collection and falls into deionized water for water-soluble reaction. The reaction is carried out for 3 hours to obtain a powder suspension.

[0065] Post-processing involves centrifuging, washing, and drying the powder suspension, followed by grinding to obtain NiO hollow microspheres with OER electrocatalytic activity. Specifically, this step includes the following steps: centrifugation: the powder suspension is poured into a centrifuge tube, balanced, and then centrifuged in a refrigerated centrifuge for 30 minutes. The supernatant is discarded, and the process is repeated until the powder suspension is completely centrifuged to obtain the centrifuged product; washing: ethanol or deionized water is added to the centrifuge tube containing the centrifuged product, and then the tube is sonicated until the centrifuged product is completely dissolved. The tube is then balanced and centrifuged to obtain the washed product; drying: the washed product is transferred to a crucible and placed in a vacuum drying oven. After the washed product is completely dried, the crucible is removed, and the dried product is removed; grinding: the dried product is ground until it forms a fine powder, thus obtaining NiO hollow microspheres with OER electrocatalytic activity.

[0066] The obtained NiO hollow microspheres with OER electrocatalytic activity had an average particle size of 0.92 µm and good crystallinity.

[0067] The OER electrocatalytically active NiO hollow microspheres from Examples 1-3 were compared with the currently recognized best-performing IrO2 and RuO2, as well as with commercial nano-NiO powder (50 nm, 99.9%). OER oxygen evolution tests were performed using a CorrTest electrochemical workstation (CS235OH, Wuhan) with a three-electrode system. Three samples were dispersed in a mixture containing 375 μL H2O and 125 μL anhydrous ethanol, respectively. 50 μL of Nafion was added as a binder (to increase the bond between the powder and the glassy carbon electrode). The mixture was ultrasonically dispersed for 3 days. 5 μL of the catalyst-containing dispersion was dropped onto a polished glassy carbon electrode (GCE, diameter: 3 mm, area: 0.0706 cm2) and allowed to air dry at room temperature in the dark for 1 day. The catalyst-added glassy carbon electrode served as the working electrode, the graphite electrode as the counter electrode, the Hg / HgO electrode as the reference electrode, and 1.0 M KOH solution as the electrolyte. The overpotential and Tafel slope at a current density of 10 mA / cm² were obtained from the OER oxygen evolution test, as shown in the table below.

[0068] As can be seen from the table above, the NiO hollow microsphere electrocatalyst obtained in this invention, compared with the currently recognized best-performing OER point catalysts IrO2 and RuO2, and with commercial nano-NiO powder (50nm, 99.9%), shows that its overall performance is significantly better than that of commercial nano-NiO powder. Its overpotential is higher than that of IrO2 and RuO2, but its Tafel slope is significantly lower. Overall, its oxygen evolution performance is close to that of IrO2 and RuO2, thus possessing high practical value. Furthermore, it has low preparation cost and can be mass-produced, effectively reducing the preparation cost of OER electrocatalysts.

[0069] This application employs Mist-CVD technology and the addition of ethanolamine complexing agent. Compared to traditional CVD technology, Mist-CVD technology offers advantages such as simpler preparation methods and lower production costs. This technology is conventionally used for thin film preparation, but there is currently no literature documenting its application in powder preparation. Furthermore, the use of inexpensive nickel salts with strong ionization properties generally results in excessively high decomposition temperatures. This application incorporates ethanolamine, a complexing agent with excellent complexing effects and low cost. Moreover, compared to conventional complexing agents such as phenanthroline, ethanolamine has advantages such as shorter carbon chains, resulting in nickel oxide powders with lower carbon content and higher phase purity. Therefore, the addition of ethanolamine complexing agent is an effective improvement measure and can effectively reduce the decomposition temperature of nickel salts with strong ionization properties.

[0070] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the inventive concept, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing NiO hollow microspheres with OER electrocatalytic activity, characterized in that, The method comprises the following steps: Preparation of a precursor solution, a nickel salt is dissolved in deionized water to form a solution with a concentration of 30-70 g / L, then an ethanolamine complexing agent is added, the complexing molar ratio of the ethanolamine complexing agent to the nickel salt is 2-4:1, the solution is fully stirred to fully complex the two, and a precursor solution is obtained; Construction of a reaction environment, a reaction tank, a tube furnace, and a powder collection tank are connected in sequence to construct a reaction environment, the reaction tank is also connected with a diaphragm pump and a cooling circulating water system, and the reaction tank is provided with an ultrasonic atomizer; Heating, the tube furnace is heated to raise the temperature of the reaction zone to a reaction temperature; Atomization, the precursor solution is added to the reaction tank, and then the ultrasonic atomizer is started to atomize the precursor solution, so that the precursor solution is atomized into micron-sized small droplets; Reaction, a strong air flow is input into the reaction tank by the diaphragm pump to drive the small droplets to the reaction zone of the tube furnace, under the action of the reaction temperature, NiO hollow microsphere powder is formed; Powder collection, the formed NiO hollow microsphere powder is driven into the powder collection tank by the strong air flow, and then falls into deionized water to perform a water-soluble reaction, the reaction is performed for 3-12 hours to obtain a powder suspension; Post-processing, after centrifugation, washing, and drying of the powder suspension, the powder is ground to obtain OER electrocatalytic activity NiO hollow microspheres; The sufficient stirring is performed by magnetic stirring, and the stirring time is 20-60 min; the reaction temperature is 600-1000℃; and the flow rate of the strong air flow is 50-200 sccm.

2. The method for preparing NiO hollow microspheres with OER electrocatalytic activity according to claim 1, characterized in that: In the reaction environment construction step, an air outlet of the powder collection tank is connected with an exhaust treatment channel for treating the gas after the reaction, and the cooling circulating water system is used to cool the reaction tank, and the temperature of the cooling circulating water is 5-10℃.

3. The method for preparing NiO hollow microspheres with OER electrocatalytic activity according to claim 1, characterized in that: In the atomization step, the precursor solution added to the reaction tank fully soaks the ultrasonic atomizer. 4.The method of claim 1, wherein the method comprises: The post-processing step comprises the following steps: Centrifugation, the powder suspension is poured into a centrifuge tube, and after balancing, the centrifuge tube is placed in a refrigerated centrifuge for centrifugation, the supernatant is poured out after centrifugation for 30 min, then the balancing and centrifugation are repeated until the centrifugation of the powder suspension is completed, and a centrifuged product is obtained; Washing, ethanol or deionized water is added to the centrifuge tube carrying the centrifuged product, then the centrifuge tube is placed in an ultrasonic machine for ultrasonic treatment until the centrifuged product in the centrifuge tube is completely melted, then the balancing and centrifugation are performed to obtain a washed product; Drying, the washed product is introduced into a crucible, and then the crucible is placed in a vacuum drying oven, the washed product is completely dried, the crucible is taken out, and the dried product is carried in the crucible; Grinding, the dried product is ground until the dried product forms a fine powder, and OER electrocatalytic activity NiO hollow microspheres are obtained.

5. The method of claim 1-4, wherein the method is characterized by: The nickel salt comprises at least one of nickel chloride, nickel sulfate, and nickel nitrate.

6. NiO hollow microspheres having OER electrocatalytic activity, characterized in that: The preparation method is a Mist-CVD method.

7. The NiO hollow microspheres having OER electrocatalytic activity according to claim 6, characterized by: The average diameter of the OER electrocatalytic activity NiO hollow microspheres is less than 1.5 µm.

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