Manganese-based high-entropy oxide and preparation method and application thereof

Abstract

The application discloses a manganese-based high-entropy oxide and a preparation method and application thereof, and belongs to the technical field of photo-thermal catalysis. The preparation method of the manganese-based high-entropy oxide comprises the following steps: S1, manganese salt, iron salt, cobalt salt, nickel salt and copper salt are mixed, and then glucose and ammonium nitrate are added and ground to obtain a precursor; S2, the precursor is calcined at 700-900 DEG C to obtain the manganese-based high-entropy oxide. The application further provides a manganese-based high-entropy oxide prepared by the above preparation method. The application further provides application of the manganese-based high-entropy oxide prepared by the above preparation method or the above manganese-based high-entropy oxide in photo-thermal catalysis of VOCs. The manganese-based high-entropy oxide prepared by the preparation method has improved ability and effect of photo-thermal catalytic degradation of VOCs pollutants.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photo-thermal catalysis, and particularly relates to a manganese-based high-entropy oxide as well as a preparation method and application thereof. BACKGROUND

[0002] The massive emission of volatile organic compounds (VOCs) can cause serious environmental pollution and harm the health of residents. Photo-thermal catalytic purification technology is expected to realize the governance and purification of VOCs by using solar energy, and is a low-energy VOCs end treatment technology. The manganese oxide (MnOx) based catalyst shows good low-temperature activity, but it is difficult to withstand the high-temperature environment under the condition of flying temperature, and will be phase changed and deactivated at 400 DEG C. Therefore, scholars compound manganese oxide on inert carriers such as SiO2 and Al2O3 to improve its stability, but these methods all reduce the light response ability of photo-thermal catalysts, resulting in the reduction of photo-thermal catalytic VOCs activity. SUMMARY

[0003] The present application aims to overcome the above technical deficiencies, and provides a manganese-based high-entropy oxide as well as a preparation method and application thereof, which solves the technical problem of the reduction of photo-thermal catalytic VOCs activity of the photo-thermal catalyst in the prior art.

[0004] To achieve the above technical purpose, the technical scheme of the present application provides a preparation method of a manganese-based high-entropy oxide, comprising the following steps:

[0005] S1, mixing manganese salt, iron salt, cobalt salt, nickel salt and copper salt, and then adding glucose and ammonium nitrate to grind to obtain a precursor, wherein glucose is used as a reducing agent and ammonium nitrate is used as an oxidizing agent;

[0006] S2, calcining the precursor at 700-900 DEG C to obtain the manganese-based high-entropy oxide.

[0007] In some embodiments, in step S1, the manganese salt is manganese nitrate tetrahydrate, the iron salt is iron nitrate nonahydrate, the cobalt salt is cobalt nitrate hexahydrate, the nickel salt is nickel nitrate hexahydrate, and the copper salt is copper nitrate trihydrate.

[0008] In some embodiments, in step S1, the total amount of the manganese salt, the iron salt, the cobalt salt, the nickel salt and the copper salt is in a molar ratio of 1:(10-20):(15-30) to glucose and ammonium nitrate.

[0009] In some embodiments, in step S1, the mass ratio of the manganese nitrate tetrahydrate, the iron nitrate nonahydrate, the cobalt nitrate hexahydrate, the nickel nitrate hexahydrate and the copper nitrate trihydrate is 0.04:(0.05-0.06):(0.06-0.07):(0.05-0.06):(0.05-0.06).

[0010] In some embodiments, in step S1, the grinding time is 5-10 min.

[0011] In some embodiments, in step S2, the calcination time is 10-30 min.

[0012] In addition, the application also provides a manganese-based high-entropy oxide prepared by the above preparation method.

[0013] In some embodiments, the micro-morphology of the manganese-based high-entropy oxide is corallike.

[0014] In addition, the application also provides a manganese-based high-entropy oxide prepared by the above preparation method or the application of the above manganese-based high-entropy oxide in the photocatalytic VOCs.

[0015] In some embodiments, the VOCs are toluene, and the temperature of the photocatalysis is above 70℃.

[0016] Compared with the prior art, the application has the following beneficial effects: the preparation method of the manganese-based high-entropy oxide provided by the application includes the following steps: mixing manganese salt, iron salt, cobalt salt, nickel salt and copper salt, and then adding glucose and ammonium nitrate to grind to obtain a precursor; and calcining the precursor at 700-900℃ to obtain the manganese-based high-entropy oxide. The manganese-based high-entropy oxide improves the light response ability and stability of the manganese-based high-entropy oxide under the synergistic action of various elements, thereby improving the ability and effect of the photocatalytic degradation of VOCs pollutants. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 The XRD image of the Mn x Fe y Co z Ni m Cu n O2 catalyst prepared for the application example 1.

[0018] Figure 2 The scanning electron microscope image of the Mn x Fe y Co z Ni m Cu n O2 catalyst prepared for the application example 1.

[0019] Figure 3 Cr prepared for Inventive Example 4 q Mn x Fe y Co z Ni m Cu n SEM images of O2catalysts.

[0020] Figure 4 Mn prepared for Inventive Example 1 x Fe y Co z Ni m Cu n Photocatalytic toluene activity plots of Mn O2catalysts prepared for Inventive Example 1 and Comparative Examples 1-4.

[0021] Figure 5 Mn prepared for Inventive Example 1 x Fe y Co z Ni m Cu n Photocatalytic toluene stability plots of Mn O2catalysts prepared for Inventive Example 1 and Comparative Example 1.

[0022] Figure 6 Mn prepared for Inventive Example 1 x Fe y Co z Ni m Cu n Surface temperature change plots of Mn O2catalysts prepared for Inventive Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0023] In the following description, reference is made to the accompanying drawings which form a part hereof, and in which are shown by way of illustration specific embodiments in which reference numerals are used to describe the components of the application. It is to be understood that other specific arrangements can be utilized and that structural, logical and other operational changes can be made without departing from the scope of the present application. The following description is, therefore, not to be taken in a limited sense. The same reference numerals in different drawings represent the same or similar elements and features.

[0024] If there are similar descriptions of "first / second" in the application file, the following explanations are added. In the following description, the terms "first\second\third" referred to are only to distinguish similar objects, and do not represent a specific order or sequence of the objects. Understandably, "first\second\third" can be interchanged in a specific order or sequence as allowed, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0025] The term "and / or" in the embodiments only describes the association relationship of the associated objects, and indicates that there can be three relationships, for example, object A and / or object B, which can represent three cases of the existence of object A alone, the existence of object A and object B together, and the existence of object B alone.

[0026] The specific embodiment provides a preparation method of a manganese-based high-entropy oxide, comprising the following steps:

[0027] S1, mixing manganese salt, iron salt, cobalt salt, nickel salt and copper salt, then adding glucose and ammonium nitrate and grinding for 5-10 min to obtain a precursor; the manganese salt is manganese nitrate tetrahydrate, the iron salt is iron nitrate nonahydrate, the cobalt salt is cobalt nitrate hexahydrate, the nickel salt is nickel nitrate hexahydrate, and the copper salt is copper nitrate trihydrate; the total amount of the manganese salt, the iron salt, the cobalt salt, the nickel salt and the copper salt is in a molar ratio of 1:(10-20):(15-30) to glucose and ammonium nitrate; the mass ratio of the manganese nitrate tetrahydrate, the iron nitrate nonahydrate, the cobalt nitrate hexahydrate, the nickel nitrate hexahydrate and the copper nitrate trihydrate is 0.04:(0.05-0.06):(0.06-0.07):(0.05-0.06):(0.05-0.06);

[0028] S2, calcining the precursor at 700-900 DEG C for 10-30 min to obtain the manganese-based high-entropy oxide.

[0029] The specific embodiment also provides a manganese-based high-entropy oxide prepared by the above preparation method; further, the micro-morphology of the manganese-based high-entropy oxide is corallike.

[0030] In addition, the specific embodiment also provides the manganese-based high-entropy oxide prepared by the above preparation method or the application of the above manganese-based high-entropy oxide in the photocatalytic VOCs.

[0031] In some embodiments, the VOCs are toluene, and the temperature of the photocatalysis is above 70 DEG C.

[0032] The inventive concept of the application is that: a manganese-based high-entropy oxide is constructed by a plurality of elements, due to the different atomic radii and binding energies of the plurality of elements, the high-entropy material exhibits severe lattice distortion and hysteresis spreading effect, which can resist atomic migration and phase change of metal oxides at high temperature. And the high-entropy oxide composed of a plurality of elements can reduce the band gap structure of manganese oxide, and further improve its light absorption and light response ability. Therefore, it is expected to construct a high-stable, strong light response Mn-based high-entropy oxide by high-entropy strategy, and to give it excellent and stable photocatalytic VOCs purification ability.

[0033] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application. It should be noted that x, y, z, m and n in the following examples represent numbers greater than 0.

[0034] Example 1

[0035] The present example proposes a manganese-based high-entropy oxide, which is prepared by the following steps:

[0036] S1, uniformly mix raw materials manganese nitrate tetrahydrate 0.04 g, iron nitrate nonahydrate 0.05 g, cobalt nitrate hexahydrate 0.06 g, nickel nitrate hexahydrate 0.06 g, and copper nitrate trihydrate 0.05 g, then add glucose 0.4 g and ammonium nitrate 0.6 g, and grind for 5 min until uniform, to obtain a precursor powder;

[0037] S12, place the precursor powder in a muffle furnace and calcine at 900℃ for 30 min, to obtain the coral-shaped manganese-based high-entropy oxide Mn x Fe y Co z Ni m Cu n O2 photo-thermal catalytic material.

[0038] From Figure 1 It can be seen that the micro-morphology of the photo-thermal catalytic material prepared in the present example is coral-shaped. Figure 2 It is shown that the present example successfully prepared the Mn x Fe y Co z Ni m Cu n O2 photo-thermal catalytic material.

[0039] Example 2

[0040] The present example proposes a manganese-based high-entropy oxide, which is prepared by the following steps:

[0041] S1, uniformly mix raw materials manganese nitrate tetrahydrate 0.04 g, iron nitrate nonahydrate 0.05 g, cobalt nitrate hexahydrate 0.06 g, nickel nitrate hexahydrate 0.06 g, and copper nitrate trihydrate 0.05 g, then add a small amount of glucose 0.5 g and ammonium nitrate 0.6 g, and grind for 8 min until uniform, to obtain a precursor powder;

[0042] S2, place the precursor powder in a muffle furnace and calcine at 800℃ for 30 min, to obtain the coral-shaped manganese-based high-entropy oxide Mn x Fe y Co zNi m Cu n O2 photo-thermal catalytic material.

[0043] Example 3

[0044] This example proposes a manganese-based high-entropy oxide, which is prepared by the following steps:

[0045] S1, uniformly mix raw materials manganese nitrate tetrahydrate 0.04 g, iron nitrate nonahydrate 0.05 g, cobalt nitrate hexahydrate 0.06 g, nickel nitrate hexahydrate 0.06 g, and copper nitrate trihydrate 0.05 g, then add a small amount of glucose 0.5 g and ammonium nitrate 0.8 g, and grind for 10 min until uniform, to obtain a precursor powder;

[0046] S2, place the precursor powder in a muffle furnace and calcine at 700℃ for 60 min, to obtain a coral-shaped manganese-based high-entropy oxide Mn x Fe y Co z Ni m Cu n O2 photo-thermal catalytic material.

[0047] Comparative Example 1

[0048] This comparative example proposes a catalyst, which is prepared by the following steps:

[0049] S1, place raw material manganese nitrate tetrahydrate 0.04 g in a mortar, then add a small amount of glucose 0.12 g and ammonium nitrate 0.21 g, and grind for 5 min until uniform, to obtain a precursor powder;

[0050] S2, place the precursor powder in a muffle furnace and calcine at 900℃ for 30 min, to obtain a manganese oxide photo-thermal catalytic material.

[0051] Comparative Example 2

[0052] This comparative example proposes a manganese-based high-entropy oxide, which is prepared by the following steps:

[0053] S1, uniformly mix raw materials iron nitrate nonahydrate 0.09 g, cobalt nitrate hexahydrate 0.08 g, and copper nitrate trihydrate 0.08 g, then add a small amount of glucose 0.4 g and ammonium nitrate 0.6 g, and grind for 5 min until uniform, to obtain a precursor powder;

[0054] S2, place the precursor powder in a muffle furnace and calcine at 900℃ for 30 min, to obtain Fe y Co z Cu n O2 photo-thermal catalytic material.

[0055] Comparative Example 3

[0056] The present example proposes a manganese-based high-entropy oxide, which is prepared by the following steps:

[0057] S1, uniformly mix raw materials iron nitrate nine hydrate 0.06 g, cobalt nitrate six hydrate 0.07 g, nickel nitrate six hydrate 0.07 g, copper nitrate three hydrate 0.06 g, continue to add a small amount of glucose 0.4 g, ammonium nitrate 0.6 g, and grind for 5 min until uniform, to obtain a precursor powder;

[0058] S1, place the precursor powder in a muffle furnace and calcine at 900℃ for 30 min, to obtain a manganese-based high-entropy oxide Fe y Co z Ni m Cu n O2 photo-thermal catalytic material.

[0059] Example 4

[0060] The present example proposes a manganese-based high-entropy oxide, which is prepared by the following steps:

[0061] S1, uniformly mix raw materials chromium nitrate nine hydrate 0.03 g, manganese nitrate four hydrate 0.03 g, iron nitrate nine hydrate 0.045 g, cobalt nitrate six hydrate 0.054 g, nickel nitrate six hydrate 0.056 g, copper nitrate three hydrate 0.041 g, continue to add a small amount of glucose 0.4 g, ammonium nitrate 0.6 g, and grind for 5 min until uniform, to obtain a precursor powder;

[0062] S2, place the precursor powder in a muffle furnace and calcine at 900℃ for 30 min, to obtain a coral-shaped manganese-based high-entropy oxide Cr q Mn x Fe y Co z Ni m Cu n O2 photo-thermal catalytic material. Figure 3 It can be seen that the morphology of the material is coral-shaped.

[0063] The photo-thermal performance test of the catalyst was carried out in a self-made quartz reaction device. A power-adjustable xenon lamp (800w) was used as a simulated sunlight light source to initiate propylene oxidation. The composition of the reaction gas was 800ppm C3H6, 12% O2 and N2 balance, and the total flow rate was set to 100mL / min. The composition of the tail gas of the catalytic reaction was monitored in real time online by a gas chromatograph (GC-9790) of Taizhou Fulide Company. The instrument setting conditions of the GC were: N2 as the carrier gas, hydrogen flame ionization detector (FID) was used, and the column oven temperature was 70℃. Figure 4 It can be seen that, Figure 4 Mnx Fe y Co z Ni m Cu n The removal rate of toluene of the Mn

[0064] The stability test needs to be tested for 15 hours under 6 solar intensities, the components of the reaction gas are 800ppm C3H6, 12% O2 and N2 balance, and the total flow is set to 100mL / min. Figure 5 It can be seen that the Mn x Fe y Co z Ni m Cu n The conversion rate of the Mn

[0065] The temperature of the surface of the catalyst is obtained by a thermocouple in contact with the catalyst. Figure 6 It can be seen that the Mn x Fe y Co z Ni m Cu n The Mn

[0066] Other beneficial effects:

[0067] The Mn x Fe y Co z Ni m Cu n O2 catalyst prepared by the Maillard reaction based on the high-entropy strategy presents a coral shape, different atomic radii and binding energies of multiple elements, improves the light response ability and stability of the photo-thermal material, and thus improves the ability and effect of degrading pollutants.

[0068] The Mn x Fe y Coz Ni m Cu n O2 material can realize complete degradation of part of VOCs by using sunlight, and can reduce the energy consumption of VOCs end treatment.

[0069] The manganese-based high-entropy oxide Mn x Fe y Co z Ni m Cu n The preparation method of the O2 material is simple and fast.

[0070] The product is applied to solar photothermal degradation of pollutants, has wide application prospect in the field of low-energy-consumption environmental protection technology, and can be produced on a large scale.

[0071] The specific embodiments of the application described above do not constitute a limitation on the scope of protection of the application. Any various other corresponding changes and modifications made according to the technical concept of the application shall be included in the scope of protection of the claims of the application.

Claims

1. The application of a manganese-based high-entropy oxide in photothermal catalysis of VOCs, characterized in that, The manganese-based high-entropy oxide is prepared by the following steps: S1. Mix manganese salt, iron salt, cobalt salt, nickel salt and copper salt, then add glucose and ammonium nitrate and grind to obtain the precursor; S2. The precursor is calcined at 700~900℃ to obtain the manganese-based high-entropy oxide; In step S1, the total amount of manganese salt, iron salt, cobalt salt, nickel salt, and copper salt is used in a molar ratio of glucose and ammonium nitrate of 1:(10-20):(15-30); the manganese salt is manganese nitrate tetrahydrate, the iron salt is ferric nitrate nonahydrate, the cobalt salt is cobalt nitrate hexahydrate, the nickel salt is nickel nitrate hexahydrate, and the copper salt is copper nitrate trihydrate. The mass ratio of the manganese nitrate tetrahydrate, the ferric nitrate nonahydrate, the cobalt nitrate hexahydrate, the nickel nitrate hexahydrate, and the copper nitrate trihydrate is 0.04:(0.05-0.06):(0.06-0.07):(0.05-0.06):(0.05-0.06).

2. The application according to claim 1, characterized in that, In step S1, the grinding time is 5-10 minutes.

3. The application according to claim 1, characterized in that, In step S2, the calcination time is 10-30 minutes.

4. The application according to claim 1, characterized in that, The microstructure of the manganese-based high-entropy oxide is coral-like.

5. The application according to claim 1, characterized in that, The VOCs are toluene, and the temperature of the photothermal catalysis is above 70°C.

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