WO2021022988A1

WO2021022988A1 - Co3o4/cumoo4 compound, preparation method therefor, and application thereof

Info

Publication number: WO2021022988A1
Application number: PCT/CN2020/102362
Authority: WO
Inventors: 李�浩; 卢东升; 廖锦云; 冯裕发; 王慧泽
Original assignee: 惠州学院
Priority date: 2019-08-07
Filing date: 2020-07-16
Publication date: 2021-02-11
Also published as: CN110586117B; CN110586117A

Abstract

Disclosed in the present invention is a Co₃O₄/CuMoO₄ compound. The compound is an urchin-like Co₃O₄/CuMoO₄ compound formed by nanorods. Also disclosed in the present invention a preparation method for the compound, comprising: (1) weighing cobalt nitrate, hexamethylene tetramine, and trisodium citrate and dissolving same in deionized water, and continuously stirring until complete dissolution; (2) transferring the solution to a reaction kettle; (3) performing suction filtration and water washing, and drying in a vacuum oven; (4) weighing a precipitate obtained in step (3) and dispersing same in water; (5) adding CuCl₂, stirring until complete dissolution, and then adding H₂MoO₄; (6) dissolving urea in water; (7) dropwise adding a urea solution to the solution and stirring; (8) transferring to the reaction kettle, cooling to room temperature after reaction is completed, collecting a precipitate, and vacuum-drying after washing several times; and (9) calcining the collected sample in a muffle furnace to obtain a product. According to the method, an urchin-like catalyst formed by assembling nanowires is successfully prepared by adjusting the doping amount of copper molybdate. The method is simple in synthetic process and cheap and easy-to-access in raw material, and the catalyst is unique and controllable in appearance and shows excellent catalytic activity in the field of catalysis of ammonia borane hydrolysis.

Description

A Co 3O 4/CuMoO 4 Complex and its preparation method and application

Technical field

The present invention relates to the technical field of catalyst synthesis, in particular to a Co ₃ O ₄ /CuMoO ₄ composite, a preparation method thereof and its application in hydrogen production.

Background technique

In response to the current energy crisis and ecological environmental protection, a series of studies have emerged, such as photoelectric catalytic hydrogen evolution, carbon dioxide electroreduction, oxygen reduction, and hydrogen evolution from chemical hydrides. Development has broad prospects. In these studies, catalysts are often needed to achieve a more ideal situation. For this reason, the design and synthesis of catalysts are particularly important. In various fields, precious metals show excellent activity, but due to objective factors such as higher cost and lower crust content, commercialization is not worth the loss, which limits its wide use. Therefore, the development of non-precious metal catalysts in transition metals has become the mainstream .

So far, the research on non-precious metal catalytic materials mainly includes sulfides, phosphides and oxides. Sulfides and phosphides, although a certain catalytic activity, there are security risks, such as Ashok K.Ganguli et al (Ashok K.Ganguli et al.Comparative Study of TiO 2 / CuS Core / Shell and Composite Nanostructures for Efficient in the manufacturing process Visible Light Photocatalysis, ACS Sustainable Chem. Eng. 2016, 4, 1487-1499) Hydrothermal synthesis to prepare sulfide, but sodium sulfide or thiourea is used as a sulfur source, the reaction is accompanied by the production of toxic gases of sulfur, which cannot be green production; .Chen et al.(Y.Chen et al.Ternary Ni-Co-P nanoparticles and their hybrids with graphene as noble-metal-free catalysts to boost the hydrolytic dehydrogenation of ammonia-borane, Energy Environ.Sci., 2017, 10, 1770-1776) Ni _2-x Co _x P catalyst was prepared by solid-phase reaction. Although good catalytic activity was achieved, in the preparation process, the sodium hypophosphite and hydroxide precursor were ground and directly heated to react. Sodium hypophosphite decomposes rapidly when heated above 200°C and emits spontaneously combustible toxic phosphine, which will explode when exposed to strong heat, and the preparation process is dangerous; therefore, the research on oxide catalysts is safer and more reliable. Various morphologies of oxides have been reported, but from the perspective of catalysis, a specific morphology with good dispersion and small size is more helpful to the progress of catalysis. No doubt nanowires are the most ideal morphology, such as Z.Ren (Z.Ren et al.Cu nanowires shelled with NiFe layered double hydroxide nanosheets as bifunctional electrocatalysts for overall water splitting, Energy Environ.Sci., 2017, 10, 1820-1827) reported core-shell nanowires, but the The method is based on copper foil, the use of the carrier makes the preparation process complicated; more interesting sea urchin-shaped has also been reported, such as J. Zhang et al. (J. Zhang et al. Morphological evolution of Fe doped sea urchin-shaped ZnO nanoparticles with Enhanced photocatalytic activity, J. Alloys Compound. 2017, 696, 639-647) Synthetic sea urchin-like Fe-doped ZnO catalyst, the use of surfactants and organic solvents in the preparation process are more expensive than pure aqueous solutions.

Summary of the invention

In view of the key problems of high preparation cost and cumbersome operation in the above preparation process, the present invention provides a Co ₃ O ₄ /CuMoO ₄ composite and a preparation method thereof. The method of the present invention is specifically adjusted by a two-step hydrothermal method. The added amount of copper molybdate successfully prepared a sea urchin-like catalyst assembled with nanowires. This method provides a simple and controllable technology for the synthesis of sea urchin-like materials, and at the same time, it is important to promote the low-cost mass production of materials. step.

To solve the above technical problems, the technical solution adopted by the present invention is:

The invention provides a Co ₃ O ₄ /CuMoO ₄ composite, a sea urchin-like Co ₃ O ₄ /CuMoO ₄ composite composed of nanorods.

The present invention also provides a method for preparing the aforementioned Co ₃ O ₄ /CuMoO ₄ composite, which includes the following steps:

(1). Dissolve cobalt nitrate, hexamethylenetetramine, and trisodium citrate in deionized water and continue stirring until dissolved. Among them, cobalt nitrate, hexamethylenetetramine, and trisodium citrate are charged The quantity ratio of the substances is 6:3:2;

(2) Transfer the above solution to the reaction kettle and react for a period of time at a certain temperature;

(3) Then, it is filtered and washed with water and dried in a vacuum oven;

(4) Disperse the precipitate in step (3) in water;

(5) Add CuCl _{2 and} stir to dissolve, and then add H ₂ MoO ₄ corresponding to the same substance;

(6) Dissolve urea in water;

(7) Add the urea solution dropwise to the above solution through the sealing funnel, and stir;

(8) Transfer to the reactor, react for a period of time at a certain temperature, cool to room temperature after the reaction, collect the precipitate, wash it several times and then vacuum dry;

(9) After calcining the collected samples in a muffle furnace for a period of time, the final catalyst Co ₃ O ₄ /CuMoO _{4 is obtained} .

Further, the amount of CuCl ₂ and urea fed is 1:10.

Preferably, the synthesis conditions of the cobalt precursor in step (2) are 95-110°C for 8-24 hours.

Preferably, the temperature of the vacuum oven in step (3) is 40-60°C, and the drying time is 3-6h.

Preferably, in step (8), the synthesis condition of Co ₃ O ₄ /CuMoO ₄ is 150-180° C. for 6-10 hours.

Preferably, in step (9), the muffle furnace temperature is 450-600°C for calcination for 2 to 4 hours, and the muffle furnace temperature rise rate is 2°C/min.

Preferably, the stirring time in step (7) is 30 minutes.

The invention also discloses the application of the Co ₃ O ₄ /CuMoO ₄ composite prepared by the above preparation method as a catalyst in the hydrolysis of ammonia borane.

The Co ₃ O ₄ /CuMoO ₄ composite provided by the present invention successfully prepares a sea urchin-like catalyst assembled with nanowires by a two-step hydrothermal method by adjusting the doping amount of copper molybdate. The method has a simple synthesis process. The raw materials are cheap and easy to obtain, and the morphology is unique and controllable, and it shows excellent catalytic activity in the field of catalyzing the hydrolysis of ammonia borane.

In summary, using the technical solution of the present invention has the following beneficial effects:

1. The process is simple, and the raw materials are cheap and easy to obtain;

2. The unique sea urchin-like catalyst prepared by the present invention has a novel method and only regulates the morphology by adjusting the doping amount of CuMoO ₄ ;

3. The synthesized Co ₃ O ₄ /CuMoO ₄ composite has the characteristics of sea urchin-like microstructure and is expected to be a highly active catalyst, such as showing superior catalytic activity in catalyzing the hydrolysis of ammonia borane to produce hydrogen.

Description of the drawings

Figure 1 is an SEM image of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention.

Figure 2 is a TEM image of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention.

3 is a BET test curve of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention.

FIG. 4 is an XRD test curve of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention.

5 is a test curve of the catalytic hydrogen production of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention.

detailed description

The invention provides a method for preparing a Co3O4/CuMoO4 composite, which specifically includes the following methods:

1, taken _{_{4.5mmol Co (NO 3) 2 ·}} 6H 2 O, 2.25mmol C 6 H 12 N 4, 1.5mmol Na 3 C 6 H 5 O 7 · 2H 2 O was dissolved in 35mL of deionized water, stirring was continued until dissolved ；

2. Transfer the above solution to a 100mL reactor and react at 95～110℃ for 8～24h;

3. Suction, filter and wash, dry in a vacuum oven at 40～60℃ for 3～6h;

4. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O;

5. Add CuCl ₂ (0.5-2mmol) and stir to dissolve, and then add H ₂ MoO _{4 of the} same amount respectively;

6. Dissolve urea (5-20mmol) in 40mL water;

7. Add the urea solution dropwise to the above solution through the sealing funnel, and stir for 30 min;

8. Transfer to a reaction kettle, react at 150-180°C for 6-10 hours, cool to room temperature after the reaction, collect the precipitate, wash it several times and then vacuum dry;

9. Calcining the collected samples in a muffle furnace at 450-600°C for 2 to 4 hours at a heating rate of 2°C/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ ;

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention, but it does not constitute a limitation to the protection scope of the present invention.

Example 1

1, taken _{_{4.5mmol Co (NO 3) 2 ·}} 6H 2 O, 2.25mmol C 6 H 12 N 4, 1.5mmol Na 3 C 6 H 5 O 7 · 2H 2 O was dissolved in 35mL of deionized water, stirring was continued until dissolved ; Transfer the above solution to a 100mL reactor, react at 100°C for 24h; filter and wash with suction, and dry in a vacuum oven at 40°C for 3h;

2. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O; add CuCl ₂ (0.5 mmol) and stir to dissolve, and then add the same amount of H ₂ MoO _{4 respectively} ; dissolve urea (5 mmol) in 40 mL Water, add the urea solution dropwise to the above solution through the sealing funnel, stir for 30min; transfer to the reactor, react at 160℃ for 8h, cool to room temperature after the reaction, collect the precipitate, wash several times and then vacuum dry; collect the sample Calcined in a muffle furnace at 500°C for 2h at a heating rate of 2°C/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ ;

data analysis:

1. SEM analysis

Figure 1 is an SEM image of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention. It can be seen from the scan that the Co ₃ O ₄ /CuMoO ₄ synthesized by hydrothermal method has a sea urchin-like appearance.

2. TEM test

Figure 2 is a TEM image of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention. The projection image can further confirm the sea urchin-like catalyst.

3. BET test

FIG. 3 is a nitrogen adsorption and desorption isotherm curve of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention.

4. XRD

Fig. 4 is an XRD test of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention. Marked in the figure are the characteristic peaks of CuMoO ₄ and Co ₃ O ₄ corresponding crystal planes.

5. Test of catalytic hydrogen production performance

Fig. 5 is a performance test of Co ₃ O ₄ /CuMoO ₄ prepared in Example 1 of the present invention as a catalyst to catalyze the hydrolysis of ammonia borane to produce hydrogen. The amount of NH ₃ BH ₃ is 3 mmol, NaOH 20 mmol, and the catalyst 10 mg. It is measured that Co ₃ O ₄ /CuMoO _{4 is} used as a catalyst to produce 121.5 mL of hydrogen per minute at 25°C.

Example 2

1, taken _{_{4.5mmol Co (NO 3) 2 ·}} 6H 2 O, 2.25mmol C 6 H 12 N 4, 1.5mmol Na 3 C 6 H 5 O 7 · 2H 2 O was dissolved in 35mL of deionized water, stirring was continued until dissolved ; Transfer the above solution to a 100mL reactor, react at 100°C for 8 hours; filter and wash with suction, and dry in a vacuum oven at 40°C for 3 hours;

Example 3

1, taken _{_{4.5mmol Co (NO 3) 2 ·}} 6H 2 O, 2.25mmol C 6 H 12 N 4, 1.5mmol Na 3 C 6 H 5 O 7 · 2H 2 O was dissolved in 35mL of deionized water, stirring was continued until dissolved ; Transfer the above solution to a 100mL reaction kettle, react at 110°C for 12h; filter and wash with suction, and dry in a vacuum oven at 40°C for 3h;

2. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O; add CuCl ₂ (0.5 mmol) and stir to dissolve, then add the same amount of H ₂ MoO _{4 respectively} ; dissolve urea (5 mmol) in 40 mL of water , The urea solution was added dropwise to the above solution through the sealing funnel, stirring for 30min; transferred to the reactor, reacted at 160℃ for 8h, after the reaction, cooled to room temperature, collected the precipitate, washed several times and dried in vacuum; Calcined in a muffle furnace at 500°C for 2h at a heating rate of 2°C/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ ;

Example 4

1, taken _{_{4.5mmol Co (NO 3) 2 ·}} 6H 2 O, 2.25mmol C 6 H 12 N 4, 1.5mmol Na 3 C 6 H 5 O 7 · 2H 2 O was dissolved in 35mL of deionized water, stirring was continued until dissolved ; Transfer the above solution to a 100mL reactor, react at 100°C for 24h; filter and wash with suction, and dry at 60°C in a vacuum oven for 6h;

Example 5

2. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O; add CuCl ₂ (0.5 mmol) and stir to dissolve, then add the same amount of H ₂ MoO _{4 respectively} ; dissolve urea (5 mmol) in 40 mL of water , The urea solution was added dropwise to the above solution through a liquid-sealed funnel, and stirred for 30 minutes; transferred to the reactor, reacted at 150°C for 10 hours, cooled to room temperature after the reaction, collected the precipitate, washed several times and then dried in vacuum; Calcined in a muffle furnace at 500°C for 2h at a heating rate of 2°C/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ ;

Example 6

2. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O; add CuCl ₂ (0.5 mmol) and stir to dissolve, then add the same amount of H ₂ MoO _{4 respectively} ; dissolve urea (5 mmol) in 40 mL of water , The urea solution was added dropwise to the above solution through a liquid-sealed funnel, and stirred for 30 minutes; transferred to the reactor, reacted at 180°C for 8 hours, cooled to room temperature after the reaction, collected the precipitate, washed several times and dried in vacuum; the sample was collected Calcined in a muffle furnace at 500°C for 2h at a heating rate of 2°C/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ ;

Example 7

2. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O; add CuCl ₂ (1 mmol) and stir to dissolve, then add the same amount of H ₂ MoO _{4 respectively} ; dissolve urea (10 mmol) in 40 mL of water, The urea solution was added dropwise to the above solution through a liquid-sealed funnel, and stirred for 30 minutes; transferred to a reactor, reacted at 160°C for 8 hours, cooled to room temperature after the reaction, collected the precipitate, washed several times and dried in vacuum; Calcined in a muffle furnace at 500°C for 2h at a heating rate of 2°C/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ ;

Example 8

2. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O; add CuCl ₂ ( ₂ mmol) and stir to dissolve, and then add the same amount of H ₂ MoO _{4 respectively} ; dissolve urea (20 mmol) in 40 mL of water, The urea solution was added dropwise to the above solution through a sealed liquid funnel, and stirred for 30 min; transferred to the reactor, reacted at 160°C for 8 hours, cooled to room temperature after the reaction, collected the precipitate, washed several times and then dried in vacuum; Calcined in a Furnace at 500℃ for 2h at a heating rate of 2℃/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ ;

Example 9

2. Weigh 90 mg of the above precipitate and disperse it in 40 mL of H ₂ O; add CuCl ₂ ( ₂ mmol) and stir to dissolve, then add the same amount of H ₂ MoO _{4 respectively} ; dissolve urea (20 mmol) in 40 mL of water , The urea solution was added dropwise to the above solution through the sealing funnel, stirring for 30min; transferred to the reactor, reacted at 160℃ for 8h, after the reaction, cooled to room temperature, collected the precipitate, washed several times and dried in vacuum; It was calcined in a muffle furnace at 600°C for 3 hours at a heating rate of 2°C/min to obtain the final catalyst Co ₃ O ₄ /CuMoO ₄ .

The above are the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also considered This is the protection scope of the present invention.

Claims

A Co 3 O 4 /CuMoO 4 composite, which is characterized in that: a sea urchin-like Co 3 O 4 /CuMoO 4 composite composed of nanorods.
A preparation method of Co 3 O 4 /CuMoO 4 composite, which is characterized in that it comprises the following steps:

(1). Dissolve cobalt nitrate, hexamethylenetetramine, and trisodium citrate in deionized water and continue stirring until dissolved. Among them, cobalt nitrate, hexamethylenetetramine, and trisodium citrate are charged The quantity ratio of the substances is 6:3:2;

(2) Transfer the above solution to the reaction kettle and react for a period of time at a certain temperature;

(3) Then, it is filtered and washed with water and dried in a vacuum oven;

(4) Disperse the precipitate in step (3) in water;

(5) Add CuCl 2 and stir to dissolve, and then add H 2 MoO 4 corresponding to the same substance;

(6) Dissolve urea in water;

(7) Add the urea solution dropwise to the above solution through the sealing funnel, and stir;

(8) Transfer to the reactor, react for a period of time at a certain temperature, cool to room temperature after the reaction, collect the precipitate, wash it several times and then vacuum dry;

(9) After calcining the collected samples in a muffle furnace for a period of time, the final catalyst Co 3 O 4 /CuMoO 4 is obtained .
The method for preparing the Co 3 O 4 /CuMoO 4 composite according to claim 2, wherein the amount of the CuCl 2 and urea is 1:10.
The preparation method of the Co 3 O 4 /CuMoO 4 composite according to claim 2, wherein the synthesis conditions of the cobalt precursor in step (2) are 95-110° C. for 8-24 hours.
The method for preparing the Co 3 O 4 /CuMoO 4 composite according to claim 2, wherein the temperature of the vacuum oven in step (3) is 40-60°C.
The method for preparing the Co 3 O 4 /CuMoO 4 composite according to claim 5, wherein the drying time in step (3) is 3 to 6 hours.
The preparation method of Co 3 O 4 /CuMoO 4 composite according to claim 2, characterized in that: in step (8), the synthesis condition of Co 3 O 4 /CuMoO 4 is 150-180° C. for 6-10 hours.
The method for preparing the Co 3 O 4 /CuMoO 4 composite according to claim 2, characterized in that: in step (9), the muffle furnace temperature is 450 to 600° C. for calcination for 2 to 4 hours.
The method for preparing the Co 3 O 4 /CuMoO 4 composite according to claim 8, wherein the temperature rise rate of the muffle furnace is 2° C./min.
An application of the Co 3 O 4 /CuMoO 4 composite according to any one of claims 1-9 as a catalyst in the hydrolysis of ammonia borane.