Use of layered mesoporous birnessite type MnO2 cellular nano-sphere

A birnessite, honeycomb-shaped technology applied in the field of catalysts for the complete catalytic oxidation of formaldehyde

Inactive Publication Date: 2008-07-02
TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So far, no Bir-type manganese oxides with controllable morphology have been prepared by redox at room temperature and neutral conditions.

Method used

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  • Use of layered mesoporous birnessite type MnO2 cellular nano-sphere
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  • Use of layered mesoporous birnessite type MnO2 cellular nano-sphere

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Take a certain amount of potassium permanganate with a purity of not less than 99.5% and dissolve it in 40-60 mL of distilled water, stir at room temperature for 15-30 minutes, and add 1 mL of oleic acid dropwise (the density of oleic acid is 0.891-0.899 g / mL, and the saponification value is not less than 3. The acid value is 190-200), the molar ratio of potassium permanganate / oleic acid is 1 / 10-3 / 10, and the stirring reaction is continued for not less than 5 hours. After reacting for a certain period of time until solid precipitates appear, separate at 4000 rpm for 10 to 15 minutes, then wash the sample with distilled water and ethanol, and repeat 3 to 5 times. The final sample was vacuum-dried at 50-70 degrees Celsius for more than 10 hours, and the obtained dark brown layered mesoporous birnessite-type MnO 2 Honeycomb nanospheres such as figure 1 shown in a and 1b. Take a small amount of dried sample and redisperse it in ethanol, ultrasonically disperse it under 1...

Embodiment 2

[0042] Prepare layered mesoporous birnessite type MnO according to the method of Example 1 2 Honeycomb hollow nanosphere structure. Take a certain amount of potassium permanganate with a purity of not less than 99.5% and dissolve it in 40-60 mL of distilled water, stir at room temperature for 15-30 minutes, and add 1 mL of oleic acid dropwise (the density of oleic acid is 0.891-0.899 g / mL, and the saponification value is not less than 3. The acid value is 190-200), the molar ratio of potassium permanganate / oleic acid is 1-2, and the stirring reaction is continued for not less than 5 hours. After reacting for a certain period of time, separate at 4000 r / min for 10-15 minutes, then wash the sample with distilled water and ethanol, and repeat 3-5 times. The final prepared samples were dispersed and dried in vacuum at 50-70 degrees Celsius for more than 10 hours, and the obtained dark brown layered mesoporous birnessite-type MnO 2 Honeycomb hollow nanospheres such as figure 1 ...

Embodiment 3

[0046] Get the layered mesoporous birnessite type MnO obtained in embodiment 1 and 2 2 Honeycomb nanospheres and honeycomb hollow nanospheres were degassed at 150 degrees Celsius respectively, and their nitrogen adsorption characteristics at -196 degrees Celsius were measured on a nitrogen adsorption-desorption analyzer (Quantachrome NOVA4200e, Quanta, USA). The experimental results are shown in the curve in Figure 3, which shows that the obtained layered mesoporous birnessite-type MnO 2 Honeycomb nanospheres and honeycomb hollow nanospheres have good gas adsorption properties. Figure 3a layered mesoporous birnessite-type MnO 2 Nitrogen adsorption-desorption isotherms and pore size distribution curves of honeycomb nanospheres; Figure 3b layered mesoporous birnessite-type MnO 2 Nitrogen adsorption-desorption isotherms and pore size distribution curves of honeycomb hollow nanospheres. The isotherm has a hysteresis loop, indicating that the as-prepared layered mesoporous bi...

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Abstract

The invention belongs to the technical field of nanophase material preparation, in particular to faviform nano-spheres of lamellar mesoporous birnessite-manganese-dioxides MnO2 type which are used as catalysts for catalyzing and oxidizing formaldehyde completely under high-efficiency low temperature. The invention takes inexpensive potassium permanganate and oleic acid as reagents with no need of acid or alkali processing, leads redox reaction of the reagents to take place in a neutral aqueous solution, and controls the molar ratio between the potassium permanganate and the oleic acid, thus respectively obtaining monodisperse-faviform nano-spheres and hollow nano-spheres of lamellar mesoporous birnessite-manganese-dioxides. The monodisperse-faviform nano-spheres and the hollow nano-spheres of lamellar mesoporous birnessite-manganese-dioxides of the invention have rich mesopores, bigger specific surface and mesopore capacity, and good structural stability, and can be taken as carriers of catalysts or sorbents, separation materials, magnetic materials, electrode materials of batteries, oxidation and degradation materials, desulfidation or air purification materials, especially as catalysts for catalyzing and oxidizing formaldehyde completely at low temperature.

Description

technical field [0001] The invention belongs to the technical field of nanomaterial preparation, in particular to the preparation of layered mesoporous birnessite type MnO 2 Honeycomb nanospheres serve as efficient catalysts for completely catalyzing the oxidation of formaldehyde at low temperature. Background technique [0002] Birnessite (hereinafter referred to as Bir) type manganese oxide (also known as birnessite, Na 4 mn 14 o 27 9H 2 O), which widely exists in soil and sediments in nature, is a kind of two-dimensional layered manganese oxide with a layer spacing of about 0.7nm (Y Ma, J Luo, S L Suib, Chem.Mater.1999, 11:1972 ; Q Feng, H Kanoh, K Ooi, J. Mater. Chem. 1999, 9: 319; Z H Liu, K Ooi, H Kanoh, et al. Langmuir, 2000, 16: 4154.). Its sheets are composed of manganese oxide octahedral MnO 6 It is composed of common edges, and the interlayer is filled by water molecules and metal ions. Every 6 manganese oxide octahedral MnO on the layer structure 6 There ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J23/34B01J35/04A61L9/00A61L101/02
Inventor 贺军辉陈洪敏
Owner TECHNICAL INST OF PHYSICS & CHEMISTRY - CHINESE ACAD OF SCI
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