A ternary cadmium-based inverse perovskite nitride for photo-thermal catalytic dehydrogenation of methanol and a preparation method and application thereof

Abstract

The application discloses a ternary cadmium-based anti-perovskite nitride for photo-thermal catalytic methanol dehydrogenation and a preparation method and application thereof. First, a hydroxide precursor containing cadmium and nickel elements is prepared through a hydrothermal method, and then the hydroxide precursor is subjected to a nitriding treatment under high temperature by using ammonia to obtain the ternary cadmium-based anti-perovskite nitride CdNNi3. The CdNNi3 material prepared by the method has the advantages of excellent thermal stability, full-solar spectrum absorption and strong photo-thermal conversion capacity due to the formation of a cubic phase crystal type. The ternary cadmium-based anti-perovskite nitride CdNNi3 provided by the application has excellent photo-thermal catalytic methanol dehydrogenation performance, and high hydrogen production activity and cycle stability are achieved under sunlight. The ternary cadmium-based anti-perovskite nitride disclosed by the application has the advantages of simple preparation method, wide raw material source and low price, and is suitable for large-scale production; as a photo-thermal catalyst, the application can expand the application of the ternary cadmium-based anti-perovskite nitride in alcohol hydrogen production driven by solar energy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photo-thermal catalytic materials, in particular to a ternary cadmium-based anti-perovskite nitride and a preparation method and application thereof. BACKGROUND

[0002] In recent years, in order to reduce carbon emissions and achieve the goal of carbon peak and carbon neutralization as soon as possible, the development and utilization of clean energy has attracted widespread attention. Among them, hydrogen energy, as a clean, efficient and renewable energy, stands out among many environmentally friendly new energy sources and has been widely used in proton exchange membrane fuel cells. It is a promising form of clean energy utilization and is known as "energy currency". However, there is almost no hydrogen available directly from nature, and because hydrogen has strong diffusivity, explosiveness and flammability, its large-scale application is limited. Therefore, efficient production and high-density safe storage of hydrogen have become very important research topics.

[0003] In addition to traditional high-pressure hydrogen storage methods, the use of liquid substances that exist stably at room temperature and pressure and have high mass / volume hydrogen storage density can achieve efficient and safe storage of hydrogen. Further, in-situ production of the required hydrogen from stable liquid hydrogen storage substances through low-temperature and efficient catalytic reactions is expected to overcome the above-mentioned hydrogen production and storage problems. Compared with gasoline and metal hydrides, methanol has the advantages of no sulfur, no strong C-C bond, high hydrogen-carbon ratio, low hydrogen production temperature, etc., and is considered to be a very promising organic liquid hydrogen storage material with high hydrogen storage density. More importantly, methanol is liquid at room temperature and pressure, safe and inexpensive, easy to obtain from biomass, and completely biodegradable, and is also an important bulk chemical. Methanol can produce hydrogen through different reaction processes, such as direct decomposition dehydrogenation, steam reforming, partial oxidation reforming, etc.

[0004] Among them, methanol direct dehydrogenation is recognized as the simplest method for hydrogen production because it does not require any additional reactants such as water and oxygen. More importantly, methanol direct dehydrogenation has the advantages of convenient operation, simple equipment and low cost. Therefore, it can be used for large-scale production of hydrogen fuel and in-situ hydrogen supply for portable fuel cells, and has important practical application prospects.

[0005] Currently applied in the field of direct dehydrogenation of methanol catalysts mainly have two categories. One is the noble metal catalyst, among which Pd-based catalysts are most widely used. This part of the catalyst has high activity and stability, and is suitable for direct dehydrogenation of methanol at high temperature, but the high price of noble metal limits its application in actual production. The other is non-noble metal catalyst, among which two kinds of catalysts are most widely used. One is copper-based catalyst, among which Cu / ZnO, Cu / ZnO / Al2O3 and Cu / ZnO / ZrO2 are the most studied. The second is nickel-based metal catalyst. Studies have shown that Ni can catalyze hydrogenation and dehydrogenation, and has catalytic activity for C-C bond, O-H bond and C-H bond rupture. For example, Ni / Al2O3 is widely used in alcohol dehydrogenation reaction. Although non-noble metal catalysts have high activity and high selectivity, they are also criticized by researchers because of their flammability, sintering and poor stability. Therefore, based on previous research and the current problems of direct dehydrogenation of methanol, developing a new type of catalyst with high activity, high stability and low cost has become a key problem in the field of methanol to hydrogen.

[0006] In recent years, anti-perovskite nitride ANM3 has gradually entered people's field of vision as an electronic-inverted perovskite derivative. It inherits the flexible chemical composition characteristics of perovskite oxides and halides, and A and M sites can be occupied by suitable metal elements while maintaining the crystal structure, which makes this kind of material have the advantages of flexible structure and adjustable physical and chemical properties. As early as 2019, researchers reported a CuNNi3 type electrocatalytic oxygen evolution material with an anti-perovskite structure and its preparation method (CN 109786770 A). The anti-perovskite electrocatalytic oxygen evolution material synthesized has good oxygen evolution electrocatalytic activity and stability, and can be applied to water electrolysis and reversible metal-air batteries. In 2022, researchers also reported an anti-perovskite nitride three-dimensional self-supporting electrode material for nitrate reduction to ammonia and its preparation method and application (CN114672822 A). The new anti-perovskite CuNCo3 disclosed in the invention has good electrical conductivity and active area, and has good current density, faradic efficiency and ammonia yield in the nitrate reduction reaction. In addition, researchers have also reported an anti-perovskite material with room temperature magnetic refrigeration performance and its preparation method and application. The preparation method provided by the invention is simple to operate and low in cost. The prepared Sn 1-x NFe 3+xCN 114823022 A has room temperature magnetic refrigeration capacity and high refrigeration performance. However, current research on anti-perovskite nitrides mainly focuses on electrocatalysis and room temperature magnetic refrigeration, and the physical and chemical properties of the material, such as wide solar spectrum absorption, strong light-heat conversion ability, surface rich in metal cation characteristics and high thermal stability, have not been deeply explored and used in the field of photo-thermal catalysis. Therefore, finding a new type of anti-perovskite nitride is a new idea for developing low-cost, high-activity and high-stability photo-thermal catalytic methanol dehydrogenation materials. This is not only the first time that anti-perovskite nitride is applied in photo-thermal catalytic hydrogen production reaction, but also has very important significance for early realization of carbon peak and carbon neutral, alleviating the current severe energy shortage and promoting the development of hydrogen fuel. SUMMARY

[0007] In view of the problems existing in the current photo-thermal catalytic methanol dehydrogenation catalyst, the purpose of the present application is to provide a ternary cadmium-based anti-perovskite nitride for photo-thermal catalytic methanol dehydrogenation, its preparation method and application. The anti-perovskite nitride CdNNi3 is first applied in the photo-thermal catalytic methanol dehydrogenation reaction.

[0008] The primary object of the present document is to propose a ternary cadmium-based anti-perovskite nitride with the chemical formula CdNNi3, which has a cubic crystal phase.

[0009] Another object of the present document is the application of the above-mentioned ternary cadmium-based anti-perovskite nitride in photo-thermal catalytic methanol dehydrogenation.

[0010] In order to achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0011] The preparation method of the ternary cadmium-based anti-perovskite of the present application comprises: adding water-soluble nickel salt, cadmium salt and hexamethylenetetramine into ultrapure water in proportion, stirring thoroughly at room temperature to obtain a clear mixed solution, transferring the solution into a high-pressure reaction kettle for hydrothermal reaction, and after the hydrothermal reaction, centrifuging, washing and drying the obtained solid, placing it in a tube furnace, and nitriding under an ammonia atmosphere for a certain period of time to obtain the anti-perovskite nitride CdNNi3 photo-thermal catalytic material.

[0012] The present application provides a ternary cadmium-based anti-perovskite nitride for photo-thermal catalytic methanol dehydrogenation and its preparation method, the specific steps are as follows:

[0013] (1) Dissolve nickel salt, cadmium salt and hexamethylenetetramine in ultrapure water, stir thoroughly at room temperature, and obtain a clear mixed solution.

[0014] (2) Transfer the above-mentioned mixed solution into a reaction kettle, and place it in an oven. After hydrothermal reaction, centrifuging, washing and drying can obtain the cadmium-based anti-perovskite double-metal hydroxide precursor material.

[0015] (3) placing the above-mentioned double-metal hydroxide precursor material in a tube furnace, and obtaining the ternary cadmium-based inverse perovskite nitride after nitriding for a certain time under ammonia atmosphere.

[0016] Further, the nickel salt in step (1) includes one of nickel nitrate, nickel acetate and nickel chloride.

[0017] Further, the cadmium salt in step (1) includes one of nickel nitrate, nickel acetate and nickel chloride.

[0018] Further, the molar ratio of the nickel salt, the cadmium salt and the hexamethylenetetramine in step (1) is (2-4) : 1 : (7-10), and the stirring rate is 300-900 r / min.

[0019] Further, the hydrothermal reaction time in step (2) is 500-800 min, and the hydrothermal temperature is 110-160 ℃.

[0020] Further, the solvent for washing and drying in step (2) is ethanol and water, the drying temperature is 60-80 ℃, and the drying time is 12-24 h.

[0021] Further, the ammonia purity in step (3) is ≥98 wt%, the ammonia flow rate is 10-60 mL / min, the nitriding treatment temperature is 400-600 o C, and the nitriding treatment time is 4-8 h.

[0022] The ternary cadmium-based inverse perovskite nitride CdNNi3 photo-thermal catalytic material can be prepared by the above-mentioned preparation method.

[0023] The application provides application of the above-mentioned ternary cadmium-based inverse perovskite nitride in a photo-thermal catalytic methanol dehydrogenation reaction for preparing hydrogen.

[0024] Further, the catalytic condition in the photo-thermal catalytic methanol dehydrogenation reaction is as follows: a static kettle type photo-reactor is used, a xenon lamp is used as the light source, the light intensity is 16-26 kW / m 2 , the reaction temperature is 300-400 ℃, and the catalyst dosage is 5-20 mg.

[0025] When the light intensity is 26 kW / m 2 , the reaction temperature has reached 300-400 ℃, and the light intensity of a conventional photo-catalysis is only 1-2 kW / m 2 . The application belongs to the field of photo-thermal catalysis.

[0026] Compared with the prior art, the application has the following beneficial effects:

[0027] (1) The application provides a preparation method of a ternary cadmium-based anti-perovskite nitride CdNNi3, which is simple, has easily available raw materials, low cost and good reproducibility, and has the advantages of excellent thermal stability, full-solar spectrum absorption and strong light-heat conversion capacity.

[0028] (2) The prepared ternary cadmium-based anti-perovskite nitride CdNNi3 is applied to a photo-thermal catalytic methanol dehydrogenation reaction, and under sunlight, high hydrogen production activity and cycle stability are achieved, which can expand the application of the anti-perovskite nitride in the field of solar-driven alcohol hydrogen production.

[0029] In order to more clearly illustrate the content of the application and the implementation of the technical solutions, the following will be introduced in combination with the drawings and the corresponding preferred embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 Figure 1 is a scanning electron microscope (SEM) image of the ternary cadmium-based anti-perovskite nitride CdNNi3 prepared in Example 1.

[0031] Figure 2 Figure 2 is an X-ray diffraction (XRD) image of the ternary cadmium-based anti-perovskite nitride CdNNi3 prepared in Example 1 and the material after being placed in air for 60 days.

[0032] Figure 3 Figure 3 is an X-ray photoelectron spectroscopy (XPS) image of the ternary cadmium-based anti-perovskite nitride CdNNi3 prepared in Example 1.

[0033] Figure 4 Figure 4 is an ultraviolet absorption spectrum image of the ternary cadmium-based anti-perovskite nitride CdNNi3 prepared in Example 1.

[0034] Figure 5 Figure 5 is the hydrogen production performance of the ternary cadmium-based anti-perovskite nitride CdNNi3 prepared in Example 1 under different light intensities when applied to a photo-thermal catalytic methanol dehydrogenation reaction.

[0035] Figure 6 Figure 6 is the cycle hydrogen production performance of the ternary cadmium-based anti-perovskite nitride CdNNi3 prepared in Example 1 when applied to a photo-thermal catalytic methanol dehydrogenation reaction. DETAILED DESCRIPTION

[0036] In order to make the purpose, features and advantages of the application more obvious and easy to understand, the technical solutions in the embodiments of the application are described clearly and completely, obviously, the following described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0037] Example 1

[0038] A preparation method of a ternary cadmium-based inverse perovskite CdNNi3, comprising the following steps:

[0039] Step (1), first accurately take 3 mmol of nickel nitrate hexahydrate, 1 mmol of cadmium nitrate tetrahydrate and 8 mmol of hexamethylenetetramine, then add 70 ml of water, stir at a speed of 600 r / min for 30 min at room temperature, and fully mix and dissolve.

[0040] Step (2), after stirring, the obtained mixed solution is transferred to a high-pressure reaction kettle, and is placed in an oven, and is hydrothermally reacted at 120 DEG C for 720 min, after the hydrothermal reaction is completed, is washed with ethanol and water for 3 times respectively, and is dried in a 60 DEG C oven for 12 hours to obtain a cadmium-based inverse perovskite double-metal hydroxide precursor.

[0041] Step (3), the above double-metal hydroxide precursor is placed in a tube furnace, air in the tube furnace is extracted by a vacuum pump, then argon is introduced to normal pressure, after repeated extraction and washing for three times, high-purity ammonia gas is introduced, the ammonia gas flow rate is adjusted to 60 ml / min, the temperature is raised to 600 DEG C at a temperature raising rate of 10 DEG C / min and is maintained for 6 h, and after calcination, the ternary cadmium-based inverse perovskite nitride is obtained.

[0042] Example 2

[0043] A preparation method of a ternary cadmium-based inverse perovskite CdNNi3, comprising the following steps:

[0044] Step (1), first accurately take 3 mmol of nickel nitrate hexahydrate, 1 mmol of cadmium nitrate tetrahydrate and 8 mmol of hexamethylenetetramine, then add 70 ml of water, stir at a speed of 600 r / min for 30 min at room temperature, and fully mix and dissolve.

[0045] Step (2), after stirring, the obtained mixed solution is transferred to a high-pressure reaction kettle, and is placed in an oven, and is hydrothermally reacted at 120 DEG C for 720 min, after the hydrothermal reaction is completed, is washed with ethanol and water for 3 times respectively, and is dried in a 60 DEG C oven for 12 hours to obtain a cadmium-based inverse perovskite double-metal hydroxide precursor.

[0046] Step (3), the above double-metal hydroxide precursor is placed in a tube furnace, air in the tube furnace is extracted by a vacuum pump, then argon is introduced to normal pressure, after repeated extraction and washing for three times, high-purity ammonia gas is introduced, the ammonia gas flow rate is adjusted to 60 ml / min, the temperature is raised to 600 DEG C at a temperature raising rate of 10 DEG C / min and is maintained for 6 h, and after calcination, the ternary cadmium-based inverse perovskite nitride is obtained.

[0047] Example 3

[0048] A preparation method of a ternary cadmium-based inverse perovskite CdNNi3, comprising the following steps:

[0049] Step (1), first accurately take 6 mmol of nickel nitrate hexahydrate, 2 mmol of cadmium nitrate tetrahydrate and 16 mmol of hexamethylenetetramine, then add 70 ml of water, stir at a speed of 600 r / min for 30 min at room temperature, and fully mix and dissolve.

[0050] Step (2), after stirring, the obtained mixed solution is transferred to a high-pressure reaction kettle, and is placed in an oven, and is subjected to hydrothermal reaction at 120 DEG C for 720 min, after the hydrothermal reaction is completed, is washed with ethanol and water for 3 times respectively, and is dried in a 60 DEG C oven for 12 hours to obtain a cadmium-based inverse perovskite double-metal hydroxide precursor.

[0051] Step (3), the above double-metal hydroxide precursor is placed in a tube furnace, air in the tube furnace is extracted by a vacuum pump, then argon is introduced to normal pressure, after repeated extraction and washing for three times, high-purity ammonia gas is introduced, the ammonia gas flow rate is adjusted to 60 ml / min, the temperature is raised to 600 DEG C at a temperature raising rate of 10 DEG C / min and is maintained for 6 h, and after calcination, the ternary cadmium-based inverse perovskite nitride is obtained.

[0052] Example 4

[0053] A preparation method of a ternary cadmium-based inverse perovskite CdNNi3, comprising the following steps:

[0054] Step (1), first accurately take 3 mmol of nickel nitrate hexahydrate, 1 mmol of cadmium nitrate tetrahydrate and 8 mmol of hexamethylenetetramine, then add 70 ml of water, stir at a speed of 600 r / min for 30 min at room temperature, and fully mix and dissolve.

[0055] Step (2), after stirring, the obtained mixed solution is transferred to a high-pressure reaction kettle, and is placed in an oven, and is subjected to hydrothermal reaction at 120 DEG C for 720 min, after the hydrothermal reaction is completed, is washed with ethanol and water for 3 times respectively, and is dried in a 60 DEG C oven for 12 hours to obtain a cadmium-based inverse perovskite double-metal hydroxide precursor.

[0056] Step (3), the above double-metal hydroxide precursor is placed in a tube furnace, air in the tube furnace is extracted by a vacuum pump, then argon is introduced to normal pressure, after repeated extraction and washing for three times, high-purity ammonia gas is introduced, the ammonia gas flow rate is adjusted to 60 ml / min, the temperature is raised to 600 DEG C at a temperature raising rate of 10 DEG C / min and is maintained for 6 h, and after calcination, the ternary cadmium-based inverse perovskite nitride is obtained.

[0057] The SEM image of the ternary cadmium-based anti-perovskite nitride CdNNi3 obtained in Example 1 is shown below. Figure 1 As shown, the sample is a sheet-like structure composed of hundreds of nanoparticles with a size between 100 and 200 nm.

[0058] X-ray diffraction tests of the ternary cadmium-based anti-perovskite nitride CdNNi3 obtained in Examples 1, 2, 3, and 4 showed the same results. Taking the XRD of Example 1 as an example ( Figure 2 The CdNNi3 prepared by the above method exhibited good crystallinity, and its XRD pattern remained essentially unchanged after 60 days of exposure to air, indicating good stability. We also tested the X-ray photoelectron spectrum of CdNNi3, as shown below. Figure 3 As shown, the main peak of Cd 3d in CdNNi3 can be decomposed into Cd 3 / 2 and Cd 5 / 2 The values ​​are located at 414.3 eV and 404.5 eV respectively, while Ni is mainly in the form of Ni. 2+ and Ni 0 The existence of this ternary cadmium-based anti-perovskite nitride, CdNNi3, was further confirmed by XRD and XPS tests.

[0059] The UV absorption spectrum of the ternary cadmium-based anti-perovskite nitride CdNNi3 obtained in Example 1 is shown below. Figure 4 As shown, CdNNi3 exhibits good absorption across the entire spectrum, demonstrating excellent photothermal properties.

[0060] The ternary cadmium-based anti-perovskite nitride CdNNi3 obtained in Example 1 was applied to the photothermal catalytic methanol dehydrogenation reaction. A static batch photoreactor was used. 5 mg of catalyst was weighed onto a reaction vessel, and the hydrogen production rate of the catalytic methanol dehydrogenation reaction under different light intensities was tested. Figure 5 It can be seen that the hydrogen production rate gradually increases with increasing light intensity. When the light intensity is 26 solar rays, the hydrogen production rate of CdNNi3 can reach 1085 mmol / g / h, demonstrating excellent photothermal catalytic methanol dehydrogenation performance. Furthermore, we tested the cycling performance of CdNNi3, from... Figure 6 The results show that CdNNi3 can still maintain good hydrogen production performance after five cycles, indicating that it has good stability as a photothermal catalyst in the methanol dehydrogenation reaction.

[0061] Finally, it should be noted that the above-described embodiments are merely used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features thereof can be replaced equivalently; and these modifications or replacements do not cause the essential nature of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. Application of ternary cadmium-based anti-perovskite nitride CdNNi3 in the preparation of hydrogen by photo-thermal catalytic dehydrogenation of methanol, characterized in that, The catalytic conditions are: static kettle type photo-reactor is used, the light source is xenon lamp, the light intensity is 16-26 kW / m 2 , the reaction temperature is 300-400℃, and the catalyst CdNNi3 dosage is 5-20 mg. The preparation method of the ternary cadmium-based anti-perovskite nitride CdNNi3 comprises the following steps: S1. Add nickel salt, cadmium salt and hexamethylenetetramine into ultrapure water, and fully stir at room temperature to obtain a mixed solution; S2. Transfer the mixed solution obtained in S1 into a high-pressure reaction kettle and place it in an oven, and perform hydrothermal reaction at a certain temperature range for a period of time, and then wash and dry to obtain a ternary cadmium-based anti-perovskite nitride double-metal hydroxide precursor material; S3. Place the double-metal hydroxide precursor material obtained in S2 in a tube furnace, and perform nitrogenization treatment under the atmosphere of ammonia gas with a certain flow rate to obtain the ternary cadmium-based anti-perovskite nitride; The nickel salt in step S1 comprises one of nickel nitrate, nickel acetate and nickel chloride; the cadmium salt comprises one of cadmium nitrate, cadmium acetate and cadmium chloride; the molar ratio of the nickel salt, the cadmium salt and the hexamethylenetetramine is (2-4) : 1 : (7-10), and the stirring rate is 300-900 r / min; The hydrothermal reaction time in step S2 is 500-800 min, and the hydrothermal temperature is 110-160 o C; The purity of ammonia gas in step S3 is ≥98 wt%, the ammonia gas flow rate is 10-60 mL / min; the nitriding treatment temperature is 400-600 o C, and the nitriding treatment time is 4-8 h.

2. Use according to claim 1, characterized in that, The solvents used for washing in step S2 are ethanol and water, respectively, and the drying temperature is 60-80 o C, and the drying time is 12-24 h.

Images