Nickel phosphide nanoflower catalyst loaded with ultrafine CeO2 nanoparticles, preparation method and application

Abstract

The application relates to the preparation of nanomaterials and the field of energy catalysis, and provides a phosphide nickel nanoflower catalyst loaded with superfine CeO2 nanoparticles, a preparation method and application. The nanoflower catalyst is composed of Ni2P nanosheets with a thickness of about 3.6 nm, and the nanoflower is uniformly loaded with superfine CeO2 nanoparticles with a particle size of 5.5 nm. A non-ionic surfactant P123 is dissolved in acetone, and is poured into a solvent in a stirring state. Cerium nitrate and nickel acetate are added. Hexamethylenetetramine is added, the mixed solution is transferred to a reaction kettle after being fully stirred, is taken out after being reacted in a reaction oven, is centrifuged, washed and freeze-dried to obtain a powder sample. Sodium hypophosphite is put into a quartz tube furnace for phosphorization treatment to obtain the catalyst X-CeO2 / Ni2P. The preparation method is simple, raw materials are cheap and easy to obtain, and the catalyst can be prepared in a large amount. The catalyst is widely applied to electrocatalytic water decomposition, oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), organic catalytic reaction and zinc air battery catalytic reaction.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preparation of nanomaterials and energy catalysis, in particular, to a kind of supported ultrafine CeO2 Nanoparticle nickel phosphide nanoflower catalyst and its preparation method. BACKGROUND

[0002] Two-dimensional nanomaterials generally have high surface area and obvious edge effect, and their unique structure endows them with various extraordinary physical and chemical properties, which can provide sufficient reaction sites for catalysis. Transition metal phosphides (TMPs) are attracting much attention due to their high abundance, low cost and abundant active sites. The adjustable component structure, unique metal-like physical and chemical properties and stable structure of TMPs, especially the two-dimensional nanosheets formed by TMPs, have great potential in improving catalytic activity and are widely used in energy storage, electrochemistry, catalysis and other aspects. Currently, TMPs have become one of the research hotspots in the field of energy catalysis. However, TMPs also have the disadvantages of poor dispersity, low specific surface area and limited electronic structure, which leads to slow reaction kinetics, low catalytic activity and poor durability in water electrolysis. SUMMARY

[0003] In view of the above-mentioned deficiencies in the prior art, the present application provides a kind of supported ultrafine CeO2 Nanoparticle nickel phosphide nanoflower catalyst and its preparation method, which has simple preparation method, cheap and easily available raw materials and wide application.

[0004] The technical scheme adopted by the present application is as follows:

[0005] In a first aspect, a kind of supported ultrafine CeO2 Nanoparticle nickel phosphide nanoflower catalyst is provided, and the nanoflower catalyst is composed of Ni2P nanosheet with a thickness of about 3.6 nm, with a diameter of 280-300 nm. The nanoflower uniformly loads ultrafine CeO2 Nanoparticle with a particle size of 5.5-6.0 nm.

[0006] In a second aspect, a kind of supported ultrafine CeO2 Nanoparticle nickel phosphide nanoflower catalyst preparation method is provided, and the preparation method comprises the following steps:

[0007] Dissolve 0.4 g of non-ionic surfactant P123 in 6 g of acetone, pour into solvents under stirring, solvents are 24 ml of ethylene glycol and 30 ml of water, uniformly mix, then add cerium nitrate and nickel acetate with a molar ratio of 0.05-0.25, add hexamethylenetetramine, the molar ratio of nickel acetate to hexamethylenetetramine is 1, after sufficient stirring, transfer the mixed solution to a reaction kettle, and place it in a reaction oven for constant temperature at 150 DEG C for 2 hours, after the reaction is completed, remove it, centrifuge, wash, and freeze-dry to obtain a powder sample of pre-catalyst X-CeO2 / Ni(OH)2 (X = 0.05, 0.10, 0.15, 0.20, 0.25), and place the pre-catalyst X-CeO2 / Ni(OH)2 and sodium hypophosphite into a quartz tube furnace, and carry out phosphating treatment at 300 DEG C for 2 hours, the mass ratio of pre-catalyst X-CeO2 / Ni(OH)2 to sodium hypophosphite can be 1:5, to obtain catalyst X-CeO2 / Ni2P (X = 0.05, 0.10, 0.15, 0.20, 0.25).

[0008] The transition metal phosphide nanoflower catalyst loaded with superfine CeO2 nanoparticles prepared by the above method is a nanosheet with a relatively thin morphology, and the metal is highly uniformly distributed.

[0009] In a third aspect, a preparation method of a nickel phosphide nanoflower catalyst loaded with superfine CeO2 nanoparticles is provided.

[0010] The molar ratio of cerium nitrate to nickel acetate is 0.15.

[0011] In a fourth aspect, a preparation method of a nickel phosphide nanoflower catalyst loaded with superfine CeO2 nanoparticles is provided.

[0012] During the constant temperature at 150 DEG C for 2 hours, the self-supporting carrier can be added to enable the catalyst to grow in situ on the self-supporting carrier to become a self-supporting electrode.

[0013] In a fifth aspect, a preparation method of a nickel phosphide nanoflower catalyst loaded with superfine CeO2 nanoparticles is provided, and the self-supporting carrier includes but is not limited to carbon cloth, foam metal, TiO2, and FTO.

[0014] In a sixth aspect, a nickel phosphide nanoflower catalyst loaded with superfine CeO2 nanoparticles is provided, and the catalyst is applied to electrocatalytic water splitting, oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), organic catalytic reaction, zinc air battery catalytic reaction, and energy devices.

[0015] The beneficial effects of the present application relative to the prior art are as follows:

[0016] The application has the following beneficial effects:

[0017] (1) The CeO2 / Ni2P catalyst with unique nanoflower morphology is synthesized in situ by a template method.

[0018] (2) The nanoflower catalyst prepared by the application is composed of Ni2P nanosheets with a thickness of about 3.6 nm, and the diameter is 280-300 nm, and the nanoflower uniformly loads superfine CeO2 nanoparticles with a particle size of 5.5-6.0 nm.

[0019] (3) The nanoflower catalyst prepared by the application can be grown in situ on a self-supporting carrier and used as a self-supporting electrode.

[0020] (4) The preparation method used by the application is simple, and the raw materials are cheap and easy to obtain, and can be prepared in large quantities.

[0021] (6) The 0.15 CeO2 / Ni2P catalyst prepared by the application shows excellent OER catalytic performance. In a classic three-electrode system with an electrolyte of 1.0M KOH, the sample on a glassy carbon electrode only needs an overpotential of 250 mV to reach a current density of 10 mA·cm -2 .

[0022] (7) The self-supporting electrode 0.15 CeO2 / Ni2P / NF prepared by the application only needs 290 mV to drive a current density of 100 mA·cm -2 ; the 0.15 CeO2 / Ni2P / NF has good stability, and after electrolysis at a current density of 1000 mA·cm -2 for 12 h, the catalytic performance only decreases by 6.9%.

[0023] (8) The X CeO2 / Ni2P catalyst prepared by the application has various applications in the field of energy catalysis, and can be used for reactions such as HER, CO2RR and organic catalysis. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is an optical photo of 0.15 CeO2 / Ni2P in the embodiment of the application;

[0025] Figure 2 is an X-ray powder diffraction pattern of 0.15 CeO2 / Ni2P in the embodiment of the application;

[0026] Figure 3 is a scanning electron microscope image of 0.15 CeO2 / Ni2P in the embodiment of the application;

[0027] Figure 4 Transmission electron microscope image of 0.15 CeO2 / Ni2P in the embodiment of the present application;

[0028] Figure 5 Transmission electron microscope image of 0.15 CeO2 / Ni2P in the embodiment of the present application;

[0029] Figure 6 OER linear sweep voltammetry curve of 0.15 CeO2 / Ni2P on glassy carbon electrode in the embodiment of the present application;

[0030] Figure 7 77 K nitrogen adsorption-desorption isotherm of 0.15 CeO2 / Ni2P in the embodiment of the present application;

[0031] Figure 8 X-ray photoelectron spectroscopy of 0.15 CeO2 / Ni2P in the embodiment of the present application;

[0032] Figure 9 Scanning electron microscope image of 0.15 CeO2 / Ni2P and NF composite self-supporting electrode in the embodiment of the present application;

[0033] Figure 10 Scanning electron microscope image of 0.15 CeO2 / Ni2P and NF composite self-supporting electrode in the embodiment of the present application;

[0034] Figure 11 OER linear sweep voltammetry curve of 0.15 CeO2 / Ni2P and NF composite self-supporting electrode in the embodiment of the present application;

[0035] Figure 12 OER constant voltage electrolysis of 0.15 CeO2 / Ni2P and NF composite self-supporting electrode under different current densities in the embodiment of the present application. DETAILED DESCRIPTION

[0036] The present application is described in detail below with reference to the accompanying drawings and embodiments:

[0037] High valence metal doping, organic molecule enhancement, heterostructure design and lattice strain engineering strategies can help to adjust the adsorption strength of metal active centers and reaction intermediates, thereby improving the electrocatalytic oxygen evolution performance of transition metal compounds. The variable valence metal cerium (Ce) with higher valence and redox characteristics can provide new possibilities for electron rearrangement of TMPs. For example, the unique outer electron configuration, superior oxygen storage capacity and flexible and variable element valence of CeO2 are conducive to electron transfer, which not only can promote the formation of more oxygen vacancies, but also can create opportunities for strong electronic interaction in complex heterojunction interfaces, and is a good electrocatalytic promoter. Therefore, by synergizing TMPs with CeO2, it is expected to adjust the electronic structure of the material and add more active sites, effectively improve the electrocatalytic performance of TMPs, and has unparalleled practical significance for promoting the industrial production of energy catalysis field.

[0038] In a first aspect, a nickel phosphide nanoflower catalyst loaded with ultrafine CeO2 nanoparticles is provided, the nanoflower catalyst being composed of Ni2P nanosheets with a thickness of about 3.6 nm, and the nanoflower having a diameter of 280-300 nm, and the nanoflower uniformly loaded with ultrafine CeO2 nanoparticles with a particle size of 5.5-6.0 nm.

[0039] In a second aspect, a preparation method of a nickel phosphide nanoflower catalyst loaded with ultrafine CeO2 nanoparticles is provided, the preparation method comprising the following steps:

[0040] 0.4 g of non-ionic surfactant P123 is dissolved in 6 g of acetone, and solvents are sequentially poured in a stirred state, the solvents being 24 ml of ethylene glycol and 30 ml of water, and after uniform mixing, cerium nitrate with a molar ratio of 0.05-0.25 and nickel acetate are added therein; hexamethylenetetramine is added, and the molar ratio of nickel acetate to hexamethylenetetramine is 1; after sufficient stirring, the mixed solution is transferred to a reaction kettle and placed in a reaction oven for constant temperature at 150℃ for 2 hours; after the reaction is completed, it is taken out, centrifuged, washed, and freeze-dried to obtain a powder sample of pre-catalyst X-CeO2 / Ni(OH)2 (X = 0.05, 0.10, 0.15, 0.20, 0.25); the pre-catalyst X-CeO2 / Ni(OH)2 and sodium hypophosphite are placed in a quartz tube furnace, and phosphating treatment is carried out at 300℃ for 2 hours, and the mass ratio of pre-catalyst X-CeO2 / Ni(OH)2 to sodium hypophosphite can be 1:5, to obtain catalyst X-CeO2 / Ni2P (X = 0.05, 0.10, 0.15, 0.20, 0.25).

[0041] The transition metal phosphide nanoflower catalyst loaded with ultrafine CeO2 nanoparticles prepared by the above method is a relatively thin nanosheet in morphology, and the metal is highly uniformly distributed.

[0042] In a third aspect, a preparation method of a self-supported electrode loaded with superfine CeO2 nanoparticles and phosphorus nickel nanoflower catalyst is provided,

[0043] The molar ratio of the cerium nitrate to the nickel acetate is 0.15.

[0044] In a fourth aspect, a preparation method of a self-supported electrode loaded with superfine CeO2 nanoparticles and phosphorus nickel nanoflower catalyst is provided,

[0045] During the constant temperature of 150 DEG C for 2 hours, the self-supported carrier can be added to enable the catalyst to grow in situ on the self-supported carrier, thereby becoming a self-supported electrode.

[0046] In a fifth aspect, a preparation method of a self-supported electrode loaded with superfine CeO2 nanoparticles and phosphorus nickel nanoflower catalyst is provided, and the self-supported carrier includes but is not limited to carbon cloth, foam metal, TiO2 and FTO.

[0047] In a sixth aspect, a self-supported electrode loaded with superfine CeO2 nanoparticles and phosphorus nickel nanoflower catalyst is provided, and the self-supported electrode is applied to electrocatalytic water splitting, oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), organic catalytic reaction, zinc air battery catalytic reaction and energy device.

[0048] On one hand, the synergistic effect between metal elements significantly improves the electron transmission efficiency; on the other hand, the high orbital electrons of the metal elements interact with surface anions, which can affect the binding energy of the adsorbed oxygen intermediate, and is a good electrocatalytic promoter.

[0049] The self-supported electrode loaded with superfine CeO2 nanoparticles and phosphorus nickel nanoflower catalyst and the preparation method thereof have the following beneficial effects:

[0050] (1) The CeO2 / Ni2P catalyst with unique nanoflower morphology is synthesized in situ by a template method for the first time.

[0051] (2) The nanoflower catalyst prepared by the method is composed of Ni2P nanosheets with a thickness of about 3.6 nm, and the diameter is 280-300 nm, and the nanoflower uniformly loads superfine CeO2 nanoparticles with a particle size of 5.5-6.0 nm.

[0052] (3) The nanoflower catalyst prepared by the method can grow in situ on the self-supported carrier and be used as a self-supported electrode.

[0053] (4) The preparation method used in the application is simple, the raw materials are cheap and easy to obtain, and the nanoflower catalyst can be prepared in large quantities.

[0054] (6) The 0.15 CeO2 / Ni2P catalyst prepared by the method has excellent OER catalytic performance; in a classic three-electrode system with an electrolyte of 1.0 M KOH, the sample on a glassy carbon electrode can reach a current density of 10 mA·cm -2 at an overpotential of only 250 mV.

[0055] (7) The self-supporting electrode 0.15 CeO2 / Ni2P / NF prepared by the method can be driven at a current density of 100 mA·cm -2 at an overpotential of only 290 mV; the 0.15 CeO2 / Ni2P / NF has good stability, and after electrolysis at a current density of 1000 mA·cm -2 for 12 h, the catalytic performance is only reduced by 6.9%.

[0056] (8) The X CeO2 / Ni2P catalyst prepared by the method has various applications in the field of energy catalysis, and can be used in reactions such as HER, CO2RR and organic catalysis.

[0057] Example 1: Preparation of 0.15 CeO2 / Ni2P:

[0058] The non-ionic surfactant P123 (0.4 g) was dissolved in acetone (6 g), and then poured into ethylene glycol (24 ml) and water (30 ml) respectively, and stirred uniformly. Then cerium nitrate and nickel acetate tetrahydrate were added in a molar ratio of 0.15, and then hexamethylenetetramine was added, and after stirring, it was transferred to a reaction kettle and placed in a reaction oven at 150 DEG C for 2 hours. After the reaction, it was taken out, centrifuged, washed and freeze-dried. The freeze-dried powder sample and sodium hypophosphite were placed in a quartz tube furnace and phosphorized at 300 DEG C for 2 hours to obtain the catalyst 0.15 CeO2 / Ni2P. The optical photograph of the 0.15 CeO2 / Ni2P sample is shown in Figure 1 ; the X-ray powder diffraction pattern is shown in Figure 2 ; the scanning electron microscope image is shown in Figure 3 ; the transmission electron microscope image is shown in Figure 4 ; the OER linear sweep voltammetry curve on a glassy carbon electrode is shown in Figure 5 ; the 77 K nitrogen adsorption-desorption isotherm graph is shown in Figure 6 ; the X-ray photoelectron spectroscopy graph is shown in Figure 7 ; the scanning electron microscope image of the self-supporting electrode is shown in Figure 8 ; the OER linear sweep voltammetry curve of the self-supporting electrode is shown in Figure 9 ; and the constant voltage electrolysis graph of the self-supporting electrode is shown in Figure 10 .

[0059] Example 2: Electrocatalytic OER performance test of 0.15 CeO2 / Ni2P:

[0060] The electrocatalytic OER performance test of the 0.15 CeO2 / Ni2P obtained in Example 1 was conducted using a conventional three-electrode system on an electrochemical workstation (CHI760E, Shanghai Chenhua). A 1.0 M KOH solution was used as the electrolyte, a platinum sheet electrode as the counter electrode, and a Hg / HgO electrode as the reference electrode. 2 mg of 0.15 CeO2 / Ni2P and 1 mg of acetylene black were dispersed in a mixed solution of 300 μL isopropanol and 25 μL Nafion, sonicated for half an hour, and then drop-coated onto a glassy carbon electrode, which was then allowed to air dry to serve as the working electrode. Figure 5 It can be seen from this that 0.15 CeO2 / Ni2P drives 10 mA·cm -2 The current density overpotential required is only 250 mV. Figure 9 The OER linear sweep voltammetry curves for the self-supporting electrode synthesized in situ on NF show that 0.15 CeO2 / Ni2P / NF requires only 290 mV to drive the electrode at 100 mA·cm⁻¹. -2 The current density. Furthermore, 0.15 CeO2 / Ni2P / NF exhibits good stability, such as... Figure 10 As shown, at 1000 mA·cm -2 After electrolysis at the specified current density for 12 hours, the catalytic performance decreased by only 6.9%.

[0061] This invention utilizes a simple hydrothermal growth and template conversion strategy to obtain a heterostructure catalyst with Ni2P nanoflowers as a support and ultrafine CeO2 nanoparticles loaded on it.

[0062] The preparation method of this invention is simple, low-cost, highly operable, and suitable for large-scale production. The catalyst produced by this method has potential commercial applications in the field of energy catalysis and can be used in electrocatalytic water splitting, oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), organic catalysis, and metal-air batteries. The electrocatalytic oxygen evolution reaction (OER) is the rate-determining step in electrocatalytic water splitting and also an important half-reaction in rechargeable metal-air batteries. Commonly used OER electrocatalysts are mostly oxides of precious metals, which are expensive and difficult to apply industrially.

[0063] This invention synthesizes inexpensive, highly active, stable, and readily available non-precious metal-based catalysts.

[0064] The catalyst material prepared by this invention is widely available, inexpensive and readily available, and possesses both high electrocatalytic oxygen evolution activity and stability, thus having great potential for industrial application.

[0065] The above merely describes preferred embodiments of the present application, and is not intended to limit the structure of the present application in any form. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application are within the technical solution range of the present application.

Claims

1. A method for preparing a nickel phosphide nanoflower catalyst loaded with ultrafine CeO2 nanoparticles, the nanoflower catalyst being composed of Ni2P nanosheets with a thickness of 3.6 nm and a diameter of 280-300 nm, the nanoflower being uniformly loaded with ultrafine CeO2 nanoparticles with a particle size of 5.5-6.0 nm, characterized in that, The preparation method comprises the following steps: Dissolve 0.4 g of non-ionic surfactant P123 in 6 g of acetone, pour in solvents in a stirred state, the solvents are 24 ml of ethylene glycol and 30 ml of water, uniformly mix, then add cerium nitrate and nickel acetate; add hexamethylenetetramine, the molar ratio of nickel acetate to hexamethylenetetramine is 1; after sufficient stirring, transfer the mixed solution to a reaction kettle, and place it in a reaction oven for constant temperature at 150 DEG C for 2 hours; after the reaction is completed, remove it, centrifuge, wash, and freeze-dry to obtain a powder sample of pre-catalyst X-CeO2 / Ni(OH)2; X = 0.05, 0.10, 0.15, 0.20, 0.25; place the pre-catalyst X-CeO2 / Ni(OH)2 and sodium hypophosphite in a quartz tube furnace, and perform phosphating treatment at 300 DEG C for 2 hours, the mass ratio of pre-catalyst X-CeO2 / Ni(OH)2 to sodium hypophosphite is 1:5, to obtain catalyst X-CeO2 / Ni2P; X = 0.05, 0.10, 0.15, 0.20, 0.25; X refers to the molar ratio of cerium nitrate to nickel acetate put in when the pre-catalyst is synthesized.

2. The preparation method of the nickel phosphide nanoflower catalyst loaded with superfine CeO2 nanoparticles according to claim 1, characterized in that: The molar ratio of cerium nitrate to nickel acetate is 0.

15.

3. The preparation method of the nickel phosphide nanoflower catalyst loaded with superfine CeO2 nanoparticles according to claim 1, characterized in that: During the constant temperature at 150 DEG C for 2 hours, the addition of a self-supporting carrier can enable the catalyst to grow in situ on the self-supporting carrier, becoming a self-supporting electrode.

4. The method for preparing the nickel phosphide nanoflower catalyst loaded with ultrafine CeO2 nanoparticles according to claim 3, characterized in that: The self-supporting carrier comprises carbon cloth, foam metal, TiO2, and FTO.

5. The use of the catalyst prepared according to the method of claim 1, characterized in that: It is applied to electrocatalytic water splitting, oxygen reduction reaction, carbon dioxide reduction reaction, organic catalytic reaction, and zinc air battery catalytic reaction.

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