High-entropy material with high photocatalytic hydrogen production performance as well as preparation method and application of high-entropy material

Abstract

The invention relates to the technical field of high-entropy materials, in particular to a high-entropy material with high photocatalytic hydrogen production performance and a preparation method and application thereof. According to the (TiMnCoNiCu) 3O4-TiO2 composite material prepared by the method, large crystal grains are broken and dispersed into small particles during reaction at a high temperature, the particles grow again and are reduced in size when heterojunction is formed, and due to the fact that the size of nano particles is small, photon-generated carriers are easily diffused to the surface, compounding of photo-generated electron-hole pairs is prevented, and therefore good photocatalytic activity is generated.

Description

Technical Field

[0001] The present invention relates to the technical field of high entropy materials, and in particular to a high entropy material with high photocatalytic hydrogen production performance, a preparation method and an application thereof. Background Art

[0002] In the exploration of sustainable development, photocatalytic technology has become one of the key ways to solve the energy crisis and environmental pollution problems because it can directly use solar energy for chemical reactions. Although traditional photocatalysts have achieved certain results, they still face many challenges in terms of efficiency, stability and cost. High entropy oxides (HEOs), as an emerging material design concept, are gradually entering the field of photocatalysis. With their unique composition and physical and chemical properties, they provide a new direction for the development of photocatalysts.

[0003] As a photocatalyst, the advantages of high entropy oxides are mainly reflected in the following aspects: First, the introduction of multi-metal elements provides HEOs with abundant active sites, which can effectively promote the separation and migration of photogenerated electrons and holes and improve the photocatalytic efficiency; second, the crystal structure of HEOs is relatively stable and can maintain the structure unchanged under various catalytic conditions, thereby extending the service life of the catalyst; in addition, by adjusting the composition and synthesis conditions of HEOs, the light absorption range, specific surface area and other properties can be optimized to further improve its photocatalytic performance. In recent years, researchers have conducted a lot of research on the photocatalytic properties of HEOs, not only making significant progress in photocatalytic degradation of pollutants and photocatalytic water decomposition to produce hydrogen, but also exploring its application potential in new reactions such as photocatalytic carbon dioxide reduction. In 2020, Edalati et al. first synthesized TiHfZrNbTaO through a series of methods including mechanical alloying, high pressure torsion (HPT), and high temperature oxidation. 11 Perovskite type (40% monoclinic + 60% orthorhombic) high entropy oxide. TiHfZrNbTaO 11 As a photocatalyst with a visible light absorption rate greater than that of the binary oxide in the Ti-Hf-Zr-Nb-Ta-O system, its main band gap is 2.9 eV, and it has good photocatalytic hydrogen production ability. The material was tested for three cycles, and the photocatalytic hydrogen production in the three cycles was quite similar, indicating that the oxide in this system has the potential for long-term photocatalytic activity.

[0004] The traditional method of preparing high entropy oxides may face problems such as high cost, complex preparation process, and low product purity. The solution combustion method uses the high temperature generated by the spontaneous combustion of combustible materials and metal nitrates in the solution to quickly synthesize high-purity spinel structure high entropy oxides, effectively improving the preparation efficiency and product uniformity. Single photocatalysts (such as TiO2) often have problems such as narrow light absorption range, high recombination rate of photogenerated electron-hole pairs, and low catalytic efficiency. By combining (TiMnCoNiCu)3O4 with TiO2, the light absorption range can be broadened, the separation efficiency of photogenerated carriers can be improved, and the photocatalytic performance can be significantly improved. The composite material shows higher activity in photocatalytic reactions, can more effectively degrade organic pollutants, decompose water to produce hydrogen, etc., and has broad application prospects.

[0005] The excellent photocatalytic performance makes this composite material have great application potential in environmental protection (such as wastewater treatment, air purification), energy conversion (such as photocatalytic water splitting to produce hydrogen, photocatalytic carbon dioxide reduction) and other fields. Therefore, the development of a high entropy material with high photocatalytic hydrogen production performance is very promising. Summary of the invention

[0006] The first aspect of the present invention provides a method for preparing a high entropy material having high photocatalytic hydrogen production performance, comprising the following steps:

[0007] S1. Weigh nitrate and dissolve it in deionized water, stirring to obtain a metal salt solution 1;

[0008] S2. dissolving tetrabutyl titanate in anhydrous ethanol to obtain solution 2;

[0009] S3. The metal salt solution 1 and solution 2 are mixed, heated to 70-85 ° C, kept warm for 10-60 minutes, glycine is added as a fuel and stirred continuously until it becomes a gel, and placed in an oven at 70-85 ° C for 10-20 hours to obtain a gel;

[0010] S4. The gel is placed in a heating furnace and calcined to obtain a nanomaterial, which is then ground to obtain a nanopowder;

[0011] S5. Mix the nanopowder and TiO2 and grind them. The ground powder is placed in a heating furnace for heating and heat preservation. The powder is then cooled to room temperature and taken out to obtain a high entropy material.

[0012] As a preferred embodiment, the nitrate includes Cu(NO3)3·3H2O, Mn(NO3)2·H2O, Co(NO3)2·6H2O, and Ni(NO3)2·6H2O, with a mass ratio of (1-2):(1-2):(1-2):(1-2).

[0013] Preferably, the mass ratio of Cu(NO3)3·3H2O, Mn(NO3)2·H2O, Co(NO3)2·6H2O, and Ni(NO3)2·6H2O is 1:1:1:1.

[0014] As a preferred embodiment, the mass ratio of the nitrate to deionized water is 1:(30-50), and / or the mass ratio of tetrabutyl titanate to anhydrous ethanol is 1:(20-50).

[0015] As a preferred embodiment, the mass ratio of the metal salt solution 1 to the solution 2 is 1:1.

[0016] As a preferred embodiment, the amount of glycine added is 1-3% of the total mass of the metal salt solution 1 and the solution 2.

[0017] As a preferred embodiment, the calcination time in S4 is 0.5-2 hours, and the calcination temperature is 700-800°C.

[0018] As a preferred embodiment, the nano powder is (TiMnCoNiCu)3O4.

[0019] As a preferred embodiment, the mass ratio of the nano powder to TiO2 is 1:(10-14).

[0020] As a preferred implementation, the heating and insulation time is 1-2 hours, the insulation temperature is 400-500°C, and the heating rate is 4-6°C / min.

[0021] The second aspect of the present invention provides a high entropy material with high photocatalytic hydrogen production performance, which is obtained according to the above-mentioned preparation method.

[0022] The third aspect of the present invention provides the use of the above-mentioned high entropy material as a catalyst in a photocatalytic reaction.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. When the (TiMnCoNiCu)3O4-TiO2 composite material prepared by the present invention reacts at high temperature, large grains break and shatter, and disperse into small particles. When a heterojunction is formed, the particles grow again and become smaller in size. Due to the small size of the nanoparticles, photogenerated carriers can easily diffuse to the surface, preventing the recombination of photogenerated electron-hole pairs, thereby producing good photocatalytic activity.

[0025] 2. The present invention determines the optimal composite ratio of nanopowder and TiO2, which can slow down the light shielding effect of TiO2 to the greatest extent, maintain a high photocatalytic reaction rate and the ability to separate photogenerated electrons and holes, and has a high photocatalytic hydrogen production performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The average hydrogen production rate of the high entropy materials prepared in Examples 1-3. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0028] Example 1

[0029] This embodiment provides a high entropy material with high photocatalytic hydrogen production performance, and a preparation method thereof comprises the following steps:

[0030] S1. Weigh Cu(NO3)3·3H2O, Mn(NO3)2·H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O (mass ratio of 1:1:1:1, total mass of 1 g) and dissolve in 30 g of deionized water, stirring to obtain a metal salt solution 1;

[0031] S2. Dissolve 1 g of tetrabutyl titanate in 30 g of anhydrous ethanol to obtain solution 2;

[0032] S3. 1 g of metal salt solution 1 was mixed with 1 g of solution 2, heated to 75 ° C, kept warm for 30 minutes, 1 wt% glycine was added as a fuel and stirred continuously until it became a gel, and placed in a 75 ° C oven for 12 hours to obtain a gel;

[0033] S4. The gel was placed in a heating furnace and calcined for 1 hour at a calcination temperature of 750°C to obtain (TiMnCoNiCu)3O4 nanomaterials, which were ground to obtain nanopowders;

[0034] S5. Mix and grind the nanopowder and TiO2 in a mass ratio of 1:10. Place the ground powder in a heating furnace and heat it for 1.5 hours at a temperature of 475°C and a heating rate of 5°C / min. Then cool it to room temperature and take it out to obtain a high entropy material.

[0035] Example 2

[0036] This embodiment provides a high entropy material with high photocatalytic hydrogen production performance, and a preparation method thereof comprises the following steps:

[0037] S1. Weigh Cu(NO3)3·3H2O, Mn(NO3)2·H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O (mass ratio of 1:1:1:1, total mass of 1 g) and dissolve in 30 g of deionized water, stirring to obtain a metal salt solution 1;

[0038] S2. Dissolve 1 g of tetrabutyl titanate in 30 g of anhydrous ethanol to obtain solution 2;

[0039] S3. 1 g of metal salt solution 1 was mixed with 30 g of solution 2, heated to 75 ° C, kept warm for 30 minutes, 1 wt% glycine was added as a fuel and stirred continuously until it was in a gel state, and placed in an oven at 75 ° C for 12 hours to obtain a gel;

[0040] S4. The gel was placed in a heating furnace and calcined for 1 hour at a calcination temperature of 750°C to obtain (TiMnCoNiCu)3O4 nanomaterials, which were ground to obtain nanopowders;

[0041] S5. Mix and grind the nanopowder and TiO2 in a mass ratio of 1:12. Place the ground powder in a heating furnace and heat it for 1.5 hours at a temperature of 475°C and a heating rate of 5°C / min. Then cool it to room temperature and take it out to obtain a high entropy material.

[0042] Example 3

[0043] This embodiment provides a high entropy material with high photocatalytic hydrogen production performance, and a preparation method thereof comprises the following steps:

[0044] S1. Weigh Cu(NO3)3·3H2O, Mn(NO3)2·H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O (mass ratio of 1:1:1:1, total mass of 1 g) and dissolve in 30 g of deionized water, stirring to obtain a metal salt solution 1;

[0045] S2. Dissolve 1 g of tetrabutyl titanate in 30 g of anhydrous ethanol to obtain solution 2;

[0046] S3. 1 g of metal salt solution 1 was mixed with 1 g of solution 2, heated to 75 ° C, kept warm for 30 minutes, 1 wt% glycine was added as a fuel and stirred continuously until it became a gel, and placed in a 75 ° C oven for 12 hours to obtain a gel;

[0047] S4. The gel was placed in a heating furnace and calcined for 1 hour at a calcination temperature of 750°C to obtain (TiMnCoNiCu)3O4 nanomaterials, which were ground to obtain nanopowders;

[0048] S5. Mix and grind the nanopowder and TiO2 in a mass ratio of 1:14. Place the ground powder in a heating furnace and heat it for 1.5 hours at a temperature of 475°C and a heating rate of 5°C / min. Then cool it to room temperature and take it out to obtain a high entropy material.

[0049] Performance Testing

[0050] The high entropy materials prepared in the above examples and comparative examples were tested for hydrogen production rate, and the results are shown in Table 1.

[0051] Table 1

[0052] Hydrogen production rate Example 1 <![CDATA[1145.3μmol·h -1 ·g -1 ]]> Example 2 <![CDATA[1225.5μmol·h -1 ·g -1 ]]> Example 3 <![CDATA[1114.3μmol·h -1 ·g -1 ]]>

[0053] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a high entropy material with high photocatalytic hydrogen production performance, characterized in that: The steps include: S1. Weigh nitrate and dissolve it in deionized water, stirring to obtain a metal salt solution 1; S2. dissolving tetrabutyl titanate in anhydrous ethanol to obtain solution 2; S3. The metal salt solution 1 and solution 2 are mixed, heated to 70-85 ° C, kept warm for 10-60 minutes, glycine is added as a fuel and stirred continuously until it becomes a gel, and placed in an oven at 70-85 ° C for 10-20 hours to obtain a gel; S4. The gel is placed in a heating furnace and calcined to obtain a nanomaterial, which is then ground to obtain a nanopowder; S5. Mix the nanopowder and TiO2 and grind them. The ground powder is placed in a heating furnace for heating and heat preservation. The powder is then cooled to room temperature and taken out to obtain a high entropy material.

2. The preparation method according to claim 1, characterized in that: The nitrate includes Cu(NO3)3·3H2O, Mn(NO3)2·H2O, Co(NO3)2·6H2O, Ni(NO3)2·6H2O, and the mass ratio is (1-2): (1-2): (1-2)：(1-2)。 3. The preparation method according to claim 2, characterized in that: The mass ratio of the nitrate to deionized water is 1:(30-50), and / or the mass ratio of tetrabutyl titanate to anhydrous ethanol is 1:(20-50).

4. The preparation method according to claim 3, characterized in that: The mass ratio of the metal salt solution 1 to the solution 2 is 1:

1.

5. The preparation method according to claim 4, characterized in that: The amount of glycine added is 1-3% of the total mass of the metal salt solution 1 and the solution 2.

6. The preparation method according to claim 5, characterized in that: The calcination time in S4 is 0.5-2 hours, and the calcination temperature is 700-800°C.

7. The preparation method according to claim 6, characterized in that: The mass ratio of the nano powder to TiO2 is 1:(10-14).

8. The preparation method according to claim 7, characterized in that: The heating and heat preservation time is 1-2 hours, the heat preservation temperature is 400-500° C., and the heating rate is 4-6° C. / min.

9. A high entropy material with high photocatalytic hydrogen production performance, characterized in that: Obtained according to the preparation method according to any one of claims 1 to 7.

10. Use of the high entropy material according to claim 9 as a catalyst in a photocatalytic reaction.

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