Cerium dioxide and nickel oxide heterojunction stacked nanoflower preparation method

Abstract

The invention relates to a preparation method of stacked nanoflowers of cerium dioxide and nickel oxide heterojunction. The invention aims to solve the problems of few active sites and weak ion capture ability of the existing nickel oxide, and provides a preparation method for improving the capacitive deionization performance of a nickel-based catalyst. According to the method, nickel acetate, cerium chloride, porous carbon, urea and ammonium fluoride serve as raw materials, a hydrothermal method and a calcination method are adopted, the stacked nanoflowers loaded on the porous carbon are prepared, and the preparation method is provided for improving the capacitive deionization performance of an existing nickel-based catalyst.

Description

Technical Field

[0001] The invention relates to preparation of stacked nanoflowers of cerium dioxide and nickel oxide heterojunctions. Background Art

[0002] Capacitive deionization is based on the principle of supercapacitors. Salt ions in the aqueous solution migrate and are electrostatically adsorbed on the electrodes, thereby achieving efficient desalination. Due to its environmental sustainability, economic feasibility, and ability to operate efficiently under mild conditions, it has broad application prospects in the field of seawater desalination. The core of capacitive deionization is the electrode material. Nickel oxide has become one of the electrode materials that has attracted much attention in the field of electrochemistry due to its high catalytic activity and environmental protection. However, nickel oxide has few electrochemical active sites and its ability to capture ions still needs to be improved. The stacked nanoflowers of cerium dioxide and nickel oxide heterojunctions loaded on porous carbon prepared by hydrothermal method provide more active sites for electrode materials. At the same time, by introducing cerium in high-order orbits, the energy level of the electrode material is closer to the Fermi level, thereby enhancing its adsorption energy and further improving the ion capture ability. This has important research significance for the development of high-performance seawater desalination electrode materials. Summary of the invention

[0003] The purpose of the present invention is to overcome the problem of nickel oxide having few electrochemical active sites and weak ion capture ability, and to provide a simple and quick preparation method.

[0004] The preparation method of the stacked nanoflower of the heterojunction of cerium dioxide and nickel oxide of the present invention is completed by the following steps: (1) dissolving nickel acetate and cerium chloride in two portions of deionized water respectively, and then dripping the cerium chloride aqueous solution into the stirred nickel acetate aqueous solution drop by drop; (2) adding porous carbon to the solution of step (1) and continuing stirring; (3) transferring the solution of step (2) to a 100 ml reactor for hydrothermal reaction, cooling to room temperature after the reaction is complete, centrifuging, washing and drying to obtain cerium-containing nickel hydroxide nanosheets; (4) 200 mg of the cerium-containing nickel hydroxide nanosheets obtained in step (3) are placed in a muffle furnace for calcination to obtain stacked nanoflowers of cerium dioxide and nickel oxide heterojunction supported on porous carbon, which is a capacitor deionization electrode material.

[0005] In the step (1), the masses of nickel acetate and cerium chloride are 300-350 mg and 10-15 mg respectively, the volumes of the two portions of deionized water are 20-30 ml, and the stirring time is 10-20 minutes; In the step (2), the mass of the porous carbon is 300-350 mg, and the stirring time is 30-60 minutes; In step (3), the reaction temperature is 180-200 degrees Celsius, the hydrothermal time is 8-12 hours, and the drying condition is 50-80 degrees Celsius for 10-20 hours; In the step (4), the calcination temperature is 300-400 degrees Celsius and the calcination time is 2-5 hours.

[0006] Compared with the prior art, the beneficial effects of the present invention are: the present invention prepares a stacked nanoflower capacitor deionization electrode material of a cerium dioxide and nickel oxide heterojunction, the material preparation process is simple and efficient, and an electrode material with more active sites can be synthesized, and the prepared material has excellent desalination performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 This is a scanning electron microscope image of the stacked nanoflowers of the heterojunction of cerium dioxide and nickel oxide in Example 1; Figure 2 This is a diagram showing nitrogen absorption and desorption of stacked nanoflowers of cerium dioxide and nickel oxide heterojunctions in Example 1; Figure 3 The cyclic voltammetry curve of the stacked nanoflowers of the heterojunction of cerium dioxide and nickel oxide in Example 1; Figure 4 This is a constant current charge and discharge diagram of the stacked nanoflowers of the heterojunction of cerium dioxide and nickel oxide in Example 1; DETAILED DESCRIPTION

[0008] The technical solution of the present invention is not limited to the specific implementation modes listed below. The specific implementation modes listed below are only used to illustrate the present invention and are not limited to the technical solution described in the embodiments of the present invention. It should be understood by those skilled in the art that the present invention can still be modified or replaced by equivalents to achieve the same technical effects. As long as the use requirements are met, they are within the protection scope of the present invention.

[0009] The preparation method of a stacked nanoflower of a cerium dioxide and nickel oxide heterojunction in this embodiment is completed by the following steps: (1) 0.3110 g of nickel acetate was dissolved in 25 ml of deionized water, and 0.0120 g of cerium chloride was dissolved in 25 ml of deionized water. The obtained cerium chloride solution was added dropwise to the nickel acetate solution and stirred for 15 minutes; (2) adding 0.3230 g of porous carbon to the solution of step (1) and continuing stirring for 30 minutes; (3) transferring the solution of step (2) into a 100 ml reaction kettle, hydrothermally heating the solution at 200 degrees Celsius for 12 hours, cooling the solution to room temperature, centrifugally washing the solution, and drying the solution at 70 degrees Celsius for 12 hours to obtain cerium-containing nickel hydroxide nanosheets; (4) 0.2 g of the cerium-containing nickel hydroxide nanosheets prepared in step (3) was placed in a muffle furnace and calcined at 350 degrees Celsius for 2 hours to obtain stacked nanoflowers of cerium dioxide and nickel oxide heterojunction supported on porous carbon, which is a capacitor deionization electrode material.

[0010] The present invention will be further described below in conjunction with the accompanying drawings and embodiments: Figure 1 This is a scanning electron microscope image of the stacked nanoflower of the heterojunction of cerium dioxide and nickel oxide in Example 1. The heterojunction of cerium dioxide and nickel oxide presents a flower-like structure of stacked nanosheets.

[0011] Figure 2 The figure shows the nitrogen absorption and desorption of the stacked nanoflowers of the heterojunction of cerium dioxide and nickel oxide in Example 1. The material exhibits a higher specific surface area.

[0012] Figure 3 This is a cyclic voltammetry curve of the stacked nanoflower of the heterojunction of cerium dioxide and nickel oxide in Example 1. As the scan rate increases, the shape of the cyclic voltammetry curve is not obviously distorted, indicating that the material has good rate performance.

[0013] Figure 4 This is a constant current charge and discharge diagram of the stacked nanoflowers of the heterojunction of cerium dioxide and nickel oxide in Example 1. Under different current densities, the electrode material maintains an approximately symmetrical triangular shape, confirming the excellent reversibility of the electrode material.

Claims

1. A method for preparing a stacked nanoflower of a cerium dioxide and nickel oxide heterojunction is completed by the following steps: (1) dissolving nickel acetate and cerium chloride in two portions of deionized water respectively, and then dripping the cerium chloride aqueous solution into the stirred nickel acetate aqueous solution drop by drop; (2) adding porous carbon to the solution of step (1) and continuing stirring; (3) transferring the solution of step (2) to a 100 ml reactor for hydrothermal reaction, cooling to room temperature after the reaction is complete, centrifuging, washing and drying to obtain cerium-containing nickel hydroxide nanosheets; (4) 200 mg of the cerium-containing nickel hydroxide nanosheets obtained in step (3) are placed in a muffle furnace for calcination to obtain stacked nanoflowers of cerium dioxide and nickel oxide heterojunction supported on porous carbon, which is a capacitor deionization electrode material.

2. The method for preparing a stacked nanoflower of a heterojunction of cerium dioxide and nickel oxide according to claim 1, characterized in that: In the step (1), the masses of nickel acetate and cerium chloride are 300-350 mg and 10-15 mg respectively, the volumes of the two portions of deionized water are both 20-30 ml, and the stirring time is 10-20 minutes.

3. The method for preparing a stacked nanoflower of a heterojunction of cerium dioxide and nickel oxide according to claim 1, characterized in that: In the step (2), the mass of the porous carbon is 300-350 mg, and the stirring time is 30-60 minutes.

4. The method for preparing a stacked nanoflower of a heterojunction of cerium dioxide and nickel oxide according to claim 1, characterized in that: In the step (3), the reaction temperature is 180-200 degrees Celsius, the hydrothermal time is 8-12 hours, and the drying condition is 50-80 degrees Celsius for 10-20 hours.

5. The method for preparing a stacked nanoflower of a heterojunction of cerium dioxide and nickel oxide according to claim 1, characterized in that: In the step (4), the calcination temperature is 300-400 degrees Celsius and the calcination time is 2-5 hours.

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