CN112694130A - alpha-MnO taking (211) crystal face as dominant crystal face2And preparation method and application thereof - Google Patents
alpha-MnO taking (211) crystal face as dominant crystal face2And preparation method and application thereof Download PDFInfo
- Publication number
- CN112694130A CN112694130A CN202011400017.8A CN202011400017A CN112694130A CN 112694130 A CN112694130 A CN 112694130A CN 202011400017 A CN202011400017 A CN 202011400017A CN 112694130 A CN112694130 A CN 112694130A
- Authority
- CN
- China
- Prior art keywords
- mno
- crystal face
- alpha
- crystal
- dominant
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000013078 crystal Substances 0.000 title claims abstract description 158
- 238000002360 preparation method Methods 0.000 title claims abstract description 48
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910001868 water Inorganic materials 0.000 claims abstract description 28
- 230000032683 aging Effects 0.000 claims abstract description 26
- 239000012855 volatile organic compound Substances 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 13
- 239000007790 solid phase Substances 0.000 claims description 29
- 239000008367 deionised water Substances 0.000 claims description 19
- 229910021641 deionized water Inorganic materials 0.000 claims description 19
- 239000012286 potassium permanganate Substances 0.000 claims description 18
- 239000007788 liquid Substances 0.000 claims description 17
- 238000000926 separation method Methods 0.000 claims description 17
- 238000001816 cooling Methods 0.000 claims description 16
- 238000001035 drying Methods 0.000 claims description 16
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 14
- 239000004202 carbamide Substances 0.000 claims description 14
- 238000003756 stirring Methods 0.000 claims description 12
- 230000003647 oxidation Effects 0.000 claims description 11
- 238000007254 oxidation reaction Methods 0.000 claims description 11
- 230000003197 catalytic effect Effects 0.000 claims description 10
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 claims description 8
- 229910052748 manganese Inorganic materials 0.000 claims description 8
- 239000011572 manganese Substances 0.000 claims description 8
- 238000005406 washing Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 238000003760 magnetic stirring Methods 0.000 claims description 2
- 238000010304 firing Methods 0.000 claims 1
- 230000000694 effects Effects 0.000 abstract description 14
- 229910003144 α-MnO2 Inorganic materials 0.000 abstract description 11
- 230000001590 oxidative effect Effects 0.000 abstract description 8
- 238000011031 large-scale manufacturing process Methods 0.000 abstract description 5
- 238000001556 precipitation Methods 0.000 abstract description 4
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 description 22
- 230000000052 comparative effect Effects 0.000 description 21
- 239000003054 catalyst Substances 0.000 description 14
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 8
- 229910002092 carbon dioxide Inorganic materials 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 6
- 238000001000 micrograph Methods 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 238000001354 calcination Methods 0.000 description 4
- 239000001569 carbon dioxide Substances 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 238000001027 hydrothermal synthesis Methods 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000004627 transmission electron microscopy Methods 0.000 description 4
- 238000003917 TEM image Methods 0.000 description 3
- 239000003463 adsorbent Substances 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 239000001294 propane Substances 0.000 description 3
- 238000000746 purification Methods 0.000 description 3
- 238000001878 scanning electron micrograph Methods 0.000 description 3
- 238000003775 Density Functional Theory Methods 0.000 description 2
- 238000003915 air pollution Methods 0.000 description 2
- 238000004364 calculation method Methods 0.000 description 2
- 238000007084 catalytic combustion reaction Methods 0.000 description 2
- 238000006555 catalytic reaction Methods 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 238000011156 evaluation Methods 0.000 description 2
- 239000008187 granular material Substances 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 238000000024 high-resolution transmission electron micrograph Methods 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Inorganic materials O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 description 2
- 239000002120 nanofilm Substances 0.000 description 2
- 230000009257 reactivity Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 238000007873 sieving Methods 0.000 description 2
- 230000010718 Oxidation Activity Effects 0.000 description 1
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000005119 centrifugation Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 229910001385 heavy metal Inorganic materials 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G45/00—Compounds of manganese
- C01G45/02—Oxides; Hydroxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8678—Removing components of undefined structure
- B01D53/8687—Organic components
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
- B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
- B01J23/32—Manganese, technetium or rhenium
- B01J23/34—Manganese
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2257/00—Components to be removed
- B01D2257/70—Organic compounds not provided for in groups B01D2257/00 - B01D2257/602
- B01D2257/708—Volatile organic compounds V.O.C.'s
Abstract
The invention relates to alpha-MnO with a (211) crystal face as a dominant crystal face2And preparation method and application thereof, the alpha-MnO2The area of the middle (211) crystal face accounts for 33.5-45.8% of the total crystal face area, and the preparation method adopts a uniform precipitation method, further limits the temperature of water bath aging to 88-92 ℃, and can prepare the alpha-MnO with the (211) crystal face as the dominant crystal face, which can be used for catalytically oxidizing volatile organic compounds2Not only has high activity of catalyzing and oxidizing volatile organic compounds, but also has CO2The preparation method has the advantages of high selectivity, simple operation, low cost and high reproducibility, and is suitable for large-scale production.
Description
Technical Field
The invention relates to the technical field of catalyst preparation and air pollution purification, in particular to alpha-MnO with a (211) crystal face as a dominant crystal face2And a preparation method and application thereof.
Background
Volatile Organic Compounds (VOCs) are one of the main causes of air pollution, and the large amount of Volatile Organic Compounds in the air can cause photochemical smog, severe haze and tropospheric ozone, which poses serious threats to human life health and environment. At present, the technology for reducing the emission of the VOCs is widely researched and explored, wherein the catalytic oxidation technology is one of the important research points. The catalytic oxidation technology can completely decompose the VOCs into harmless CO at low temperature (200-2And H2O, has the advantages of low energy consumption, high efficiency and low secondary pollution. The catalyst is the core of the catalytic oxidation technology, and the hot point in the research field of VOCs catalysis is to improve the low-temperature activity of the catalyst and reduce the cost of the catalyst.
The manganese oxide catalyst (MnOx) has rich natural resources, better oxidation capability and various crystal structures, wherein alpha-MnO is2Because of its outstanding oxidation activity, it is of interest to a wide range of researchers. According to the standard XRD pattern (JCPDS 44-0140) in the literature, alpha-MnO2The main crystal planes of (1), (200), (310), (211), etc. The method is reported to have abundant defect sites generated on the crystal face of a coordinating atom, which is beneficial to the catalytic reaction, so that the design and preparation of the alpha-MnO 2 with a high-activity crystal face as a dominant crystal face have important significance.
At present, some researchers adopt a hydrothermal method to prepare alpha-MnO with a (310) crystal face or a (100) crystal face as a dominant crystal face2. For example, CN103920449A discloses a self-assembled nano-film MnO for efficiently adsorbing heavy metals2Adsorbent and preparation method thereof, MnO2The adsorbent has a nano film hierarchical layered structure which is formed by self-assembling slices with the thickness of 2-3 nanometers and the size of 700 nanometers, wherein the slices are tetragonal crystal form alpha-MnO2The strongest three diffraction peaks appear in tetragonal alpha-MnO2The (200) crystal plane, (310) crystal plane and (211) crystal plane, and the preferred orientation of the (310) crystal plane is obvious. The MnO2The adsorbent can be used for removing heavy metal ions in an acidic medium, and has a wide application prospect.
CN111889099A discloses a catalyst for propane low-temperature catalytic combustion, a preparation method and application thereof, wherein the catalyst is alpha-MnO with oxygen vacancy concentration of 0.7-1.52(100) Crystal face, i.e. the catalyst is alpha-MnO with (100) crystal face as dominant crystal face2. The preparation method comprises the steps of taking manganese nitrate and potassium permanganate as raw materials, and obtaining alpha-MnO with oxygen vacancy concentration of 0.7-1.5 through hydrothermal reaction2(100) The catalyst is used for propane catalytic combustion and is completely oxidized into carbon dioxide, the propane is catalytically combusted and oxidized into carbon dioxide at low temperature, the combustion temperature is low, and the stability is high.
However, the above-mentioned technical solutions have the following problems: 1) preparation of alpha-MnO by hydrothermal method2The catalyst is expensive in equipment, high in energy consumption and low in yield, and is not beneficial to mass production; 2) alpha-MnO with different crystal planes as dominant crystal planes is not systematically investigated2The catalyst has different activity in the catalytic oxidation of VOCs, and does not disclose alpha-MnO taking a (211) crystal face as a dominant crystal face2Has more abundant defects and higher activity.
In view of the above, there is a need to develop an α -MnO having a (211) crystal plane as a dominant crystal plane2And a preparation method and application thereof.
Disclosure of Invention
In view of the problems in the prior art, the invention provides alpha-MnO with a (211) crystal plane as a dominant crystal plane2And preparation method and application thereof, the alpha-MnO2The area of the middle (211) crystal face accounts for 33.5-45.8% of the total crystal face area, and the preparation method adopts a uniform precipitation method, further limits the temperature of water bath aging to 88-92 ℃, and can prepare the alpha-MnO with the (211) crystal face as the dominant crystal face, which can be used for catalytically oxidizing volatile organic compounds2Not only has high activity of catalyzing and oxidizing volatile organic compounds, but also has CO2The preparation method has the advantages of high selectivity, simple operation, low cost and high reproducibility, and is suitable for large-scale production.
In order to achieve the purpose, the invention adopts the following technical scheme:
an object of the present invention is to providealpha-MnO taking (211) crystal face as dominant crystal face2The alpha-MnO of2The area of the middle (211) crystal plane accounts for 33.5-45.8% of the total area of the crystal planes.
The applicant calculates the oxygen vacancy generation energy E of each surface by a density functional theory, namely DFT theory for shortvoThe reactivity of surface oxygen is disclosed, which varies as follows: (211) crystal face (E)vo＝1.47eV)<(200) Crystal face (E)vo＝1.71eV)<(310) Crystal face (E)vo1.96 eV). Wherein E of the (211) surfacevoThe lowest value indicates that oxygen vacancies are easily formed on the surface, and the reactivity of oxygen is the strongest, which is consistent with the results of the activity test of the present invention, thus confirming that in alpha-MnO2The crystal (211) has more abundant defects than the (200) and (310) crystal planes, and the activity is higher. Therefore, α -MnO having (211) crystal plane as a dominant crystal plane was developed2Has very important significance.
As is well known to those skilled in the art, alpha-MnO2The crystal belongs to a tetragonal system, and will grow along the normal direction of the (001) crystal plane, as shown in fig. 13a and 13b, and the side surface includes the (211) crystal plane, the (200) crystal plane and the (310) crystal plane, and the area ratio of the three is 2:1: 1. Therefore, from the structural model, the calculation formula of the area of the (211) crystal plane occupying the total crystal plane area can be derived as: 0.5X 4ah/(4ah +2 a)2) H/(a +2 h). As shown in FIG. 14, the present invention counted α -MnO with (211) crystal plane as dominant crystal plane2Corresponding to 50 crystal grain sizes in the HRTEM image, the area ratio of the (211) crystal plane was calculated as h/(a +2h), and the calculation result was plotted as a bar graph shown in fig. 15, which shows that the area of the (211) crystal plane accounts for 33.5 to 45.8% of the total crystal plane area.
The second object of the present invention is to provide an α -MnO having a (211) crystal plane as a dominant crystal plane2The preparation method comprises the following steps:
(1) dissolving a manganese source in deionized water, adding urea, stirring, carrying out water bath aging at 88-92 ℃, and carrying out solid-liquid separation;
(2) will be described in detail(1) Washing, drying and roasting solid phases obtained by solid-liquid separation in sequence to obtain the alpha-MnO with the (211) crystal face as the dominant crystal face2。
Compared with a hydrothermal method, the preparation method has the advantages of simple operation, low cost, high reproducibility and the like, and is suitable for large-scale production; moreover, the applicant of the present invention has proved through a large number of experiments that the aging temperature of the water bath in the preparation method is corresponding to alpha-MnO2The type of the leading crystal face has key influence, the temperature of water bath aging is further limited to 88-92 ℃, and the alpha-MnO taking the (211) crystal face as the leading crystal face can be prepared2。
The temperature of the aging in the water bath in the preparation method of the present invention is 88 to 92 ℃, for example, 88 ℃, 88.5 ℃, 89 ℃, 89.5 ℃, 90 ℃, 90.5 ℃, 91 ℃, 91.5 ℃ or 92 ℃, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
As a preferable technical scheme of the invention, the manganese source in the step (1) is potassium permanganate.
Preferably, the mass ratio of the manganese source to the deionized water in step (1) is (0.10-0.15):1, such as 0.10:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, or 0.15:1, but not limited to the recited values, and other values not recited in this range are equally applicable.
Preferably, the mass ratio of the urea to the manganese source in step (1) is (0.6-1.0):1, such as 0.6:1, 0.7:1, 0.8:1, 0.9:1 or 1.0:1, but not limited to the recited values, and other values not recited within this range are equally applicable.
In a preferred embodiment of the present invention, the stirring time in step (1) is 2 to 4 hours, for example, 2 hours, 2.2 hours, 2.5 hours, 2.7 hours, 3 hours, 3.2 hours, 3.5 hours, 3.8 hours, or 4 hours, but is not limited to the above-mentioned values, and other values not shown in the above-mentioned range are also applicable.
Preferably, the stirring in step (1) is magnetic stirring.
It is worth noting that the same stirring operation was maintained during the ageing of the water bath described in step (1).
In a preferred embodiment of the present invention, the aging time of the water bath in step (1) is 12-48h, for example, 12h, 18h, 24h, 30h, 36h, 42h or 48h, but not limited to the above-mentioned values, and other values not listed in the above-mentioned range are also applicable.
As a preferable technical scheme of the invention, after the water bath aging in the step (1) and before the solid-liquid separation, air cooling is further included.
In the present invention, the air cooling means natural cooling to room temperature.
It should be noted that, in the preparation method of the present invention, the solid-liquid separation in step (1) is performed by a technique commonly used in the art, such as filtration, suction filtration, centrifugation, or sedimentation, but is not limited thereto, and those skilled in the art can make a reasonable choice according to the actual situation.
As a preferred technical scheme of the invention, the drying in the step (2) is carried out in an oven.
Preferably, the drying temperature in step (2) is 90-110 deg.C, such as 90 deg.C, 92 deg.C, 95 deg.C, 98 deg.C, 100 deg.C, 102 deg.C, 105 deg.C, 107 deg.C or 110 deg.C, but not limited to the recited values, and other values not recited in the range of values are also applicable.
Preferably, the drying time in step (2) is 12-24h, such as 12h, 14h, 15h, 16h, 18h, 20h, 22h or 24h, but not limited to the recited values, and other values not recited in the range of values are also applicable.
As a preferable embodiment of the present invention, the calcination in the step (2) is carried out in a muffle furnace.
Preferably, the calcination of step (2) is carried out under an air atmosphere.
Preferably, the temperature of the calcination in step (2) is 400-.
Preferably, the calcination time in step (2) is 2-5h, such as 2h, 2.5h, 3h, 3.5h, 4h, 4.5h or 5h, but not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, after the roasting in the step (2), air cooling is further included.
As a preferred technical scheme of the invention, the preparation method comprises the following steps:
(1) dissolving potassium permanganate into deionized water according to the mass ratio of (0.10-0.15) to 1 of potassium permanganate to deionized water, adding urea according to the mass ratio of (0.6-1.0) to 1 of urea to potassium permanganate, magnetically stirring for 2-4h, carrying out water bath aging at 88-92 ℃ for 12-48h, air cooling, and then carrying out solid-liquid separation;
(2) washing the solid phase obtained by the solid-liquid separation in the step (1) with deionized water, then placing the solid phase into an oven, drying the solid phase at 90-110 ℃ for 12-24h, then placing the dried solid phase into a muffle furnace, roasting the solid phase at 400-600 ℃ for 2-5h in the air atmosphere, and obtaining the alpha-MnO with the crystal face (211) as the dominant crystal face through air cooling2。
It is a further object of the present invention to provide α -MnO having a (211) crystal plane as a dominant crystal plane2The alpha-MnO taking the (211) crystal face as a dominant crystal face2For the catalytic oxidation of volatile organic compounds.
Compared with the prior art, the invention at least has the following beneficial effects:
(1) the invention relates to alpha-MnO taking a (211) crystal face as a dominant crystal face2Not only has high activity of catalyzing and oxidizing volatile organic compounds, but also has CO2The catalyst has the advantage of high selectivity, and can be used for catalytic oxidation of volatile organic compounds;
(2) the preparation method adopts a uniform precipitation method, further limits the temperature of water bath aging to 88-92 ℃, and can prepare the alpha-MnO with the crystal face (211) as the dominant crystal face for catalyzing and oxidizing the volatile organic compounds2The method has the advantages of simple operation, low cost, high reproducibility and the like, and is suitable for large-scale production.
Drawings
FIG. 1 shows the present invention[ alpha ] -MnO having (211) crystal plane as dominant crystal plane as described in example 12Scanning electron microscope images of;
FIG. 2 shows α -MnO having (211) crystal plane as dominant crystal plane according to example 1 of the present invention2Transmission electron microscopy images of;
FIG. 3 is a view showing α -MnO having a crystal plane (310) as a dominant crystal plane in comparative example 1 of the present invention2Scanning electron microscope images of;
FIG. 4 is a view showing α -MnO having a crystal plane of (310) as a dominant crystal plane in comparative example 1 of the present invention2Transmission electron microscopy images of;
FIG. 5 is a view showing α -MnO having a (200) crystal plane as a dominant crystal plane in comparative example 2 of the present invention2Scanning electron microscope images of;
FIG. 6 is a view showing α -MnO having a (200) crystal plane as a dominant crystal plane in comparative example 2 of the present invention2Transmission electron microscopy images of;
FIG. 7 is a view showing α -MnO having a (310) crystal plane as a dominant crystal plane in comparative example 3 of the present invention2Scanning electron microscope images of;
FIG. 8 is a view showing α -MnO having a crystal plane (310) as a dominant crystal plane in comparative example 3 of the present invention2Transmission electron microscopy images of; FIG. 9 shows α -MnO prepared in example 1 of the present invention and comparative examples 1-22The effect diagram of the conversion rate of the ethyl acetate when catalyzing the decomposition of the ethyl acetate;
FIG. 10 shows α -MnO prepared in example 1 of the present invention and comparative examples 1-22Effect diagram of carbon dioxide yield when catalyzing ethyl acetate decomposition;
FIG. 11 shows α -MnO prepared in examples 1-3 and comparative example 3 of the present invention2The effect diagram of the conversion rate of the ethyl acetate when catalyzing the decomposition of the ethyl acetate;
FIG. 12 shows α -MnO prepared in examples 1-3 and comparative example 3 of the present invention2Effect diagram of carbon dioxide yield when catalyzing ethyl acetate decomposition; FIG. 13a is an alpha-MnO of the present invention2A structural model schematic diagram of a crystal (tetragonal system);
FIG. 13a is an alpha-MnO of the present invention2A structural model schematic diagram of a crystal (tetragonal system);
FIG. 13b is an α -MnO of the present invention2A structural schematic diagram of a crystal (tetragonal system);
FIG. 14 is an exemplary HRTEM image of the present invention in which the area fraction of the (211) facets is counted and calculated;
fig. 15 is a bar graph corresponding to the statistical results of fig. 14.
Detailed Description
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.
To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:
example 1
This example provides an α -MnO with a (211) crystal plane as the dominant crystal plane2And a preparation method thereof, the preparation method comprises the following steps:
(1) dissolving potassium permanganate into deionized water according to the mass ratio of the potassium permanganate to the deionized water of 0.13:1, adding urea according to the mass ratio of the urea to the potassium permanganate of 0.8:1, magnetically stirring for 3 hours, carrying out water bath aging for 24 hours at 90 ℃, then carrying out air cooling, and then carrying out solid-liquid separation;
(2) washing the solid phase obtained by solid-liquid separation in the step (1) with deionized water, then placing the solid phase into a drying oven, drying the solid phase at 100 ℃ for 18h, then placing the dried solid phase into a muffle furnace, roasting the solid phase at 500 ℃ for 3h in an air atmosphere, and air-cooling the solid phase to obtain the alpha-MnO with the crystal face (211) as the dominant crystal face2The alpha-MnO of2The percentage of the area of the middle (211) crystal plane to the total area of the crystal planes meets the requirement of the range of 33.5-45.8%, a corresponding scanning electron microscope image is shown in figure 1, and a corresponding transmission electron microscope image is shown in figure 2.
Example 2
This example provides an α -MnO with a (211) crystal plane as the dominant crystal plane2And a preparation method thereof, wherein the preparation method is completely the same as the preparation method of the example 1 except that the aging time of the water bath in the step (1) is changed from '24 h' to '12 h'.
In this example, α -MnO having (211) crystal plane as dominant crystal plane was prepared2The alpha-MnO of2The area of the middle (211) crystal plane accounts for the total crystal plane areaThe percentage of (B) meets the requirement of the range of 33.5-45.8%.
Example 3
This example provides an α -MnO with a (211) crystal plane as the dominant crystal plane2And a preparation method thereof, wherein the preparation method is completely the same as the preparation method of the example 1 except that the aging time of the water bath in the step (1) is changed from '24 h' to '48 h'.
In this example, α -MnO having (211) crystal plane as dominant crystal plane was prepared2The alpha-MnO of2The percentage of the area of the middle (211) crystal plane in the total area of the crystal planes meets the requirement of the range of 33.5-45.8 percent.
Example 4
This example provides an α -MnO with a (211) crystal plane as the dominant crystal plane2And a preparation method thereof, the preparation method comprises the following steps:
(1) dissolving potassium permanganate into deionized water according to the mass ratio of the potassium permanganate to the deionized water of 0.10:1, adding urea according to the mass ratio of the urea to the potassium permanganate of 0.6:1, magnetically stirring for 2 hours, carrying out water bath aging for 36 hours at 88 ℃, then carrying out air cooling, and then carrying out solid-liquid separation;
(2) washing the solid phase obtained by solid-liquid separation in the step (1) with deionized water, then placing the solid phase into a drying oven, drying the solid phase for 24 hours at the temperature of 90 ℃, then placing the dried solid phase into a muffle furnace, roasting the solid phase for 5 hours at the temperature of 400 ℃ in the air atmosphere, and obtaining the alpha-MnO with the crystal face (211) as the dominant crystal face through air cooling2The alpha-MnO of2The percentage of the area of the middle (211) crystal plane in the total area of the crystal planes meets the requirement of the range of 33.5-45.8 percent.
Example 5
This example provides an α -MnO with a (211) crystal plane as the dominant crystal plane2And a preparation method thereof, the preparation method comprises the following steps:
(1) dissolving potassium permanganate into deionized water according to the mass ratio of the potassium permanganate to the deionized water of 0.15:1, adding urea according to the mass ratio of the urea to the potassium permanganate of 1.0:1, magnetically stirring for 4 hours, carrying out water bath aging for 18 hours at the temperature of 92 ℃, then carrying out air cooling, and then carrying out solid-liquid separation;
(2) washing the solid phase obtained by solid-liquid separation in the step (1) with deionized water, then placing the solid phase into a drying oven, drying the solid phase at 110 ℃ for 12h, then placing the dried solid phase into a muffle furnace, roasting the solid phase at 600 ℃ for 2h in an air atmosphere, and air-cooling the solid phase to obtain the alpha-MnO with the crystal face (211) as the dominant crystal face2The alpha-MnO of2The percentage of the area of the middle (211) crystal plane in the total area of the crystal planes meets the requirement of the range of 33.5-45.8 percent.
Comparative example 1
This comparative example provides an alpha-MnO2And a preparation method thereof, wherein the preparation method is completely the same as the preparation method described in the example 1 except that the temperature of the water bath aging in the step (1) is changed from '90 ℃ to' 80 ℃.
The alpha-MnO with the crystal face (310) as the dominant crystal face is prepared by the comparative example2The alpha-MnO of2The area of the medium (211) plane accounts for 30% or less of the total plane area, and fig. 3 shows a corresponding scanning electron micrograph, and fig. 4 shows a corresponding transmission electron micrograph.
Comparative example 2
This comparative example provides an alpha-MnO2And a preparation method thereof, wherein the preparation method is completely the same as the preparation method described in the example 1 except that the temperature of the water bath aging in the step (1) is changed from '90 ℃ to' 70 ℃.
The alpha-MnO with the (200) crystal face as the dominant crystal face is prepared by the comparative example2The alpha-MnO of2The area of the medium (211) plane accounts for 15% or less of the total plane area, and fig. 5 shows a corresponding scanning electron micrograph, and fig. 6 shows a corresponding transmission electron micrograph.
Comparative example 3
This comparative example provides an alpha-MnO2And a preparation method thereof, wherein the preparation method is completely the same as the preparation method of the example 1 except that the aging time of the water bath in the step (1) is changed from '24 h' to '6 h'.
The alpha-MnO with the crystal face (310) as the dominant crystal face is prepared by the comparative example2The alpha-MnO of2The area of the medium (211) plane accounts for 30% or less of the total plane area, and fig. 7 shows a corresponding scanning electron micrograph, and fig. 8 shows a corresponding transmission electron micrograph.
Performance testing
(i) alpha-MnO prepared in example 1 and comparative examples 1 and 22Sequentially tabletting, grinding and sieving, taking 40-60 mesh granules to evaluate the purification activity of the volatile organic compounds on a fixed bed reactor, wherein the evaluation conditions of the catalyst are as follows: the composition of the off-gas simulating the volatile organic compounds was 1000ppm, [ O ] ethyl acetate2]＝20％，N2As equilibrium gas, the total flow of gas is 300mL/min, and the reaction space velocity GHSV is 78000h-1. The conversion rate of ethyl acetate and CO were calculated by gas chromatography (Agilent-7980B, FID and TCD)2The yield, the specific test results are shown in fig. 9 and fig. 10, and it can be seen that the alpha-MnO with the crystal face (211) as the dominant crystal face, which can be used for catalytic oxidation of volatile organic compounds, can be prepared only by further limiting the temperature of the water bath aging to 88-92 ℃ in the preparation method of the invention2。
(ii) alpha-MnO prepared in examples 1-3 and comparative example 32Sequentially tabletting, grinding and sieving, taking 40-60-mesh granules to perform purification activity evaluation on the volatile organic compound on a fixed bed reactor, wherein the specific test method is consistent with the content, and the corresponding test results are shown in a figure 11 and a figure 12, and it can be seen that the time for water bath aging in the preparation method provided by the invention also needs to be limited, and only within 12-48h, the alpha-MnO which takes the (211) crystal face as the dominant crystal face and can be used for catalytically oxidizing the volatile organic compound can be further ensured to be prepared2。
In conclusion, the invention provides alpha-MnO with the (211) crystal plane as the dominant crystal plane2Not only has high activity of catalyzing and oxidizing volatile organic compounds, but also has CO2The catalyst has the advantage of high selectivity, and can be used for catalytic oxidation of volatile organic compounds; moreover, the preparation method adopts a uniform precipitation method, and can be prepared only by further limiting the temperature of water bath aging to 88-92 DEG CTo alpha-MnO taking (211) crystal face as dominant crystal face and capable of being used for catalytic oxidation of volatile organic compounds2The method has the advantages of simple operation, low cost, high reproducibility and the like, and is suitable for large-scale production.
The applicant declares that the present invention illustrates the detailed structural features of the present invention through the above embodiments, but the present invention is not limited to the above detailed structural features, that is, it does not mean that the present invention must be implemented depending on the above detailed structural features. It should be understood by those skilled in the art that any modifications of the present invention, equivalent substitutions of selected components of the present invention, additions of auxiliary components, selection of specific modes, etc., are within the scope and disclosure of the present invention.
The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.
It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.
In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.
Claims (10)
1. alpha-MnO taking (211) crystal face as dominant crystal face2Characterized in that the α -MnO is2The area of the middle (211) crystal plane accounts for 33.5-45.8% of the total area of the crystal planes.
2. alpha-MnO taking (211) crystal face as dominant crystal face according to claim 12The preparation method is characterized by comprising the following steps:
(1) dissolving a manganese source in deionized water, adding urea, stirring, carrying out water bath aging at 88-92 ℃, and carrying out solid-liquid separation;
(2) washing, drying and roasting the solid phase obtained by solid-liquid separation in the step (1) in sequence to obtain the alpha-MnO with the crystal face (211) as the dominant crystal face2。
3. The method according to claim 2, wherein the manganese source in step (1) is potassium permanganate;
preferably, the mass ratio of the manganese source to the deionized water in the step (1) is (0.10-0.15): 1;
preferably, the mass ratio of the urea to the manganese source in the step (1) is (0.6-1.0): 1.
4. The method according to claim 2 or 3, wherein the stirring time in step (1) is 2 to 4 hours;
preferably, the stirring in step (1) is magnetic stirring.
5. The method for preparing a water bath of any one of claims 2 to 4, wherein the aging time of the water bath in the step (1) is 12 to 48 hours.
6. The method according to any one of claims 2 to 5, wherein after the aging in the water bath in step (1) and before the solid-liquid separation, air cooling is further included.
7. The production method according to any one of claims 2 to 6, wherein the drying in step (2) is performed in an oven;
preferably, the temperature of the drying in the step (2) is 90-110 ℃;
preferably, the drying time in the step (2) is 12-24 h.
8. The production method according to any one of claims 2 to 7, wherein the firing of step (2) is performed in a muffle furnace;
preferably, the roasting of step (2) is carried out in an air atmosphere;
preferably, the roasting temperature in the step (2) is 400-600 ℃;
preferably, the roasting time of the step (2) is 2-5 h;
preferably, after the roasting in the step (2), air cooling is further included.
9. The method according to any one of claims 2 to 8, characterized by comprising the steps of:
(1) dissolving potassium permanganate into deionized water according to the mass ratio of (0.10-0.15) to 1 of potassium permanganate to deionized water, adding urea according to the mass ratio of (0.6-1.0) to 1 of urea to potassium permanganate, magnetically stirring for 2-4h, carrying out water bath aging at 88-92 ℃ for 12-48h, air cooling, and then carrying out solid-liquid separation;
(2) washing the solid phase obtained by the solid-liquid separation in the step (1) with deionized water, then placing the solid phase into an oven, drying the solid phase at 90-110 ℃ for 12-24h, then placing the dried solid phase into a muffle furnace, roasting the solid phase at 400-600 ℃ for 2-5h in the air atmosphere, and obtaining the alpha-MnO with the crystal face (211) as the dominant crystal face through air cooling2。
10. alpha-MnO taking (211) crystal face as dominant crystal face according to claim 12Characterized in that the alpha-MnO with the (211) crystal plane as the dominant crystal plane2For the catalytic oxidation of volatile organic compounds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011400017.8A CN112694130A (en) | 2020-12-02 | 2020-12-02 | alpha-MnO taking (211) crystal face as dominant crystal face2And preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011400017.8A CN112694130A (en) | 2020-12-02 | 2020-12-02 | alpha-MnO taking (211) crystal face as dominant crystal face2And preparation method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112694130A true CN112694130A (en) | 2021-04-23 |
Family
ID=75506265
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011400017.8A Pending CN112694130A (en) | 2020-12-02 | 2020-12-02 | alpha-MnO taking (211) crystal face as dominant crystal face2And preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112694130A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114392735A (en) * | 2022-02-08 | 2022-04-26 | 中国科学院城市环境研究所 | alpha-MnO2Catalyst, preparation method and application thereof |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108479762A (en) * | 2018-03-14 | 2018-09-04 | 中国科学院城市环境研究所 | A kind of manganese oxide catalyst and its preparation method and application |
| CN108686650A (en) * | 2018-05-16 | 2018-10-23 | 中国科学院城市环境研究所 | A kind of cryptomelane type manganese dioxide, preparation method and use |
| CN110240203A (en) * | 2019-06-04 | 2019-09-17 | 上海大学 | The preparation method and applications for the manganese oxide catalyst that hydrogen peroxide decomposes |
| WO2020041575A1 (en) * | 2018-08-22 | 2020-02-27 | The University Of North Carolina At Greensboro | Compositions and methods for enhancing electrocatalytic efficiencies |
| CN111889099A (en) * | 2020-05-21 | 2020-11-06 | 华中师范大学 | Catalyst for propane low-temperature catalytic combustion and preparation method and application thereof |
-
2020
- 2020-12-02 CN CN202011400017.8A patent/CN112694130A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108479762A (en) * | 2018-03-14 | 2018-09-04 | 中国科学院城市环境研究所 | A kind of manganese oxide catalyst and its preparation method and application |
| CN108686650A (en) * | 2018-05-16 | 2018-10-23 | 中国科学院城市环境研究所 | A kind of cryptomelane type manganese dioxide, preparation method and use |
| WO2020041575A1 (en) * | 2018-08-22 | 2020-02-27 | The University Of North Carolina At Greensboro | Compositions and methods for enhancing electrocatalytic efficiencies |
| CN110240203A (en) * | 2019-06-04 | 2019-09-17 | 上海大学 | The preparation method and applications for the manganese oxide catalyst that hydrogen peroxide decomposes |
| CN111889099A (en) * | 2020-05-21 | 2020-11-06 | 华中师范大学 | Catalyst for propane low-temperature catalytic combustion and preparation method and application thereof |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114392735A (en) * | 2022-02-08 | 2022-04-26 | 中国科学院城市环境研究所 | alpha-MnO2Catalyst, preparation method and application thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109762614B (en) | Cobaltosic oxide catalyst for methane catalytic combustion, preparation and application thereof | |
| CN107456964A (en) | For the extra specific surface area perovskite type composite oxide catalyst of hydrocarbon low-temperature oxidation and its preparation | |
| CN112551590B (en) | Synthesis of porous manganese dioxide and desulfurization application thereof | |
| CN111229238B (en) | Ordered porous perovskite catalyst for synergistically catalyzing and oxidizing NO and toluene and preparation method and application thereof | |
| JP2010099638A (en) | Catalyst, catalyst for purifying exhaust gas, and method for manufacturing the catalyst | |
| CN105903464A (en) | NO oxidation catalyst with wide activity temperature window and preparation method and application thereof | |
| Trivedi et al. | Design of active NiCo2O4‐δ spinel catalyst for abatement of CO‐CH4 emissions from CNG fueled vehicles | |
| CN114377679A (en) | Carbon dioxide capturing and converting integrated bifunctional catalyst, preparation method and application | |
| CN107233895B (en) | Oxidation catalyst for purifying motor vehicle tail gas and preparation method thereof | |
| CN112694130A (en) | alpha-MnO taking (211) crystal face as dominant crystal face2And preparation method and application thereof | |
| Zhao et al. | Unveiling a remarkable enhancement role by designing a confined structure Ho-TNTs@ Mn catalyst for low-temperature NH 3-SCR reaction | |
| CN113134352B (en) | Composite metal oxide catalyst for catalyzing direct decomposition of nitrogen oxide and preparation method thereof | |
| Xue et al. | Preparation, characterization and catalytic properties of yttrium-zirconium-pillared montmorillonite and their application in supported Ce catalysts | |
| CN114849698B (en) | Mesoporous Na-alpha-MnO 2 Catalyst, preparation method and application thereof | |
| CN110586118A (en) | Magnetic iron-based catalyst for selective catalytic reduction denitration and preparation method thereof | |
| CN114653356B (en) | Preparation method of lanthanum-doped cerium oxide catalyst material and formaldehyde-removing compound | |
| CN109647504A (en) | A kind of Mn for cement kiln containing tourmaline, Fe, Ce/Cu-SAPO-34 low-temperature denitration catalyst | |
| CN111514887A (en) | α -MnO with exposed specific crystal face2Alpha crystal form metal oxide catalyst and preparation method thereof | |
| CN114425365B (en) | Preparation method of defect-rich Mn-Co metal oxide catalyst | |
| CN116474842B (en) | Method for preparing metal-based small-pore molecular sieve by ion capturing method, and obtained product and application | |
| CN112844396B (en) | Copper/cerium lanthanum composite oxide nanorod catalyst, preparation method and application | |
| KR101625464B1 (en) | Method of preparing mesoporous silica catalyst having copper manganese complex oxide to remove carbon monoxide | |
| CN114870848B (en) | Tubular perovskite type composite oxide catalyst capable of reducing soot oxidation temperature of diesel engine | |
| CN114618475B (en) | Preparation method of flexible manganese-based catalyst for decomposing ozone | |
| CN102864003B (en) | Composite metal oxide oxygen carrier of a kind of chemical chain burning technology and its preparation method and application |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210423 |