CN102910680A - Preparation method for preparing manganese dioxides in various crystal forms - Google Patents

Abstract

The invention discloses a preparation method for preparing manganese dioxides in various crystal forms, comprising the following steps of: with divalent manganese salt as a reducing agent and potassium permanganate as an oxidant, adjusting the ratio of raw materials, and reacting in a reaction kettle at 160 DEG C for 1-12h to synthesize both one-dimensional alpha-MnO2 nano fibers and beta-MnO2 nano bars and gamma-MnO2 flower-like structures. The preparation method is simple in preparation process and low in cost; and the product can be used for the research in fields such as super capacitor direction, catalysis and the like.

Description

A kind of preparation method who prepares different crystal forms Manganse Dioxide

Technical field

The present invention relates to a kind of preparation method of Manganse Dioxide, particularly a kind of preparation method of nano manganese dioxide with different crystal forms.

Background technology

Manganse Dioxide crystal aboundresources, cheap, form multiple crystalline structure so that [MnO6] is octahedra for basic, common are α, β, the γ type of chain or tunnel structure, the δ type of stratiform and the λ type of 3-D solid structure.Can obtain by changing preparation method, raw material and preparation condition the MnO of different crystal forms ₂, MnO ₂These character it is especially had broad application prospects at ultracapacitor at catalysis, electronics, pottery.

The common method for preparing Manganse Dioxide has, electrodip process, microemulsion method, hydrothermal method, oxidation reduction process etc.As, Deva raj etc. adopt microemulsion method to prepare α-MnO at J Solid State Electrochem magazine report ₂Vargas etc. are at the standby δ-MnO of the hot legal system of Journal of Power Sources magazine report water ₂, the above single crystal form of all only preparing.Report adopts under the oxidation reduction process room temperature and makes δ-MnO on the J.Phys.Chem.C magazines such as Ragupathy ₂, the δ-MnO that makes ₂Obtain α-MnO 600 ℃ of calcinings ₂The patent of Tsing-Hua University " a kind of method of synthetic different crystal form one-dimensional single crystal mangnesium dioxide nano wire " (CN1377832A), synthetic α, β manganese dioxide one-dimensional monocrystal nanowire under hydrothermal condition, above two kinds of methods exist respectively calcining temperature height and product that the shortcoming of one-dimensional single crystal nano wire is only arranged.

Summary of the invention

Purpose of the present invention, be for only prepare single crystal form, calcining temperature is high and product only has the problem of one-dimensional single crystal nano wire, provide a kind of by adjusting proportioning raw materials, in the situation that other conditionally completes are identical, prepared the α-MnO of existing one-dimentional structure ₂Nanofiber, β-MnO ₂Nanometer rod has again the δ-MnO of two-dirnentional structure (flower-like structure) ₂

The present invention is achieved by following technical solution.

A kind of preparation method who prepares different crystal forms Manganse Dioxide, the employing manganous salt is reductive agent, potassium permanganate is oxygenant, join respectively in the distilled water, stir and form homogeneous solution, the concentration of potassium permanganate solution is 0.1～0.27mol/L, and the concentration of manganese sulfate solution is 0.1～0.75mol/L; Potassium permanganate solution is dropwise joined in the manganous salt solution, mixing solutions is transferred in the reactor again, in 160 ℃ of reaction 1～12h, product is collected in cooling, uses respectively distilled water and washing with alcohol, makes α-MnO ₂, β-MnO ₂And δ-MnO ₂

When potassium permanganate and manganous salt mol ratio are 2:3～5:2, prepare one dimension α-MnO ₂Nanofiber;

When potassium permanganate and manganous salt mol ratio are 0.5:3～1:3, prepare one dimension β-MnO ₂Nanometer rod;

When potassium permanganate and manganous salt mol ratio are 3:1～6:1, prepare the two-dimentional δ-MnO of flower-like structure ₂

Described reductive agent manganous salt is manganous sulfate, manganous nitrate, manganese acetate and Manganous chloride tetrahydrate.

The invention has the beneficial effects as follows, the reaction raw materials of this reaction system only has two kinds, and is additive-free, and cost is low, and experimentation is simple.But in same system, only pass through to adjust both synthesizing one-dimensional α-MnO of proportioning raw materials ₂Nanofiber, β-MnO ₂Nanometer rod can be synthesized again the δ-MnO of two-dirnentional structure ₂Flower-like structure, the present invention can be widely used in the research in the fields such as ultracapacitor, catalysis.

Description of drawings

Fig. 1 is scanning electron microscope (SEM) figure of the embodiment of the invention 1 product;

Fig. 2 is X-ray diffraction (XRD) figure of the embodiment of the invention 1 product;

Fig. 3 is scanning electron microscope (SEM) figure of the embodiment of the invention 2 products;

Fig. 4 is X-ray diffraction (XRD) figure of the embodiment of the invention 2 products;

Fig. 5 is scanning electron microscope (SEM) figure of the embodiment of the invention 3 products;

Fig. 6 is X-ray diffraction (XRD) figure of the embodiment of the invention 3 products.

Embodiment

The present invention is raw materials used to be commercially available analytical reagent.

Embodiment 1

(1) take by weighing respectively the 608.4mg manganous sulfate, 379.2mg potassium permanganate is dissolved in 5mL and the 12mL distilled water, stir to form uniform solution;

(2) under the room temperature, under the condition that stirs, the potassium permanganate solution of step (1) dropwise is added in the manganese sulfate solution, stirs 30min;

(3) reaction solution in the step (2) is transferred in the reactor 160 ℃ of reaction 6h.After reaction finished, centrifugal collection product was used distilled water and washing with alcohol 5 times;

(4) with step (3) products obtained therefrom dry 8h under 100 ℃, namely make α-MnO ₂Nanofiber.

Above-mentioned gained sample is made electrode: press MnO ₂: the weight ratio of graphite: acetylene black: PTFE is that 70:12:12:6 takes by weighing 4 kinds of electrode materialss and mixes, and adds the 3mL dehydrated alcohol, ultra-sonic dispersion 10min.The slurry that mixes all is poured on the stainless steel plate, with slurry roll into uniformly, the thin slice of thickness between 100-200 μ m.Be that the mould stamp of 9mm is detained the circular electric pole piece from the thin slice of rolling with diameter, for subsequent use.The electrode slice that makes is put into vacuum drying oven, in the dry 8h of 120 ° of C.Take stainless (steel) wire as collector, electrode slice is pressed in oil press makes electrode on the collector, be used for measuring chemical property, pressure 15MPa.The electro-chemical test of electrode adopts three-electrode system, and Electrode is the MnO of preparation ₂Electrode is platinum filament to electrode, and reference electrode is saturated calomel electrode, and electrolytic solution is 1M Na ₂SO ₄Solution.Electro-chemical test is tested at the CHI660D electrochemical workstation, and the voltage range of test is-0.05-0.85V.

Fig. 1 is the SEM figure of gained nanofiber, and Fibre diameter is about 30-50nm, and length is about 1 μ m, and the XRD figure of Fig. 2 shows that products therefrom is α-MnO ₂

Embodiment 2

(1) take by weighing respectively the 405.6mg manganous sulfate, 126.4mg potassium permanganate is dissolved in 12mL and the 4mL distilled water, stir to form uniform solution;

(2) under the room temperature, under the condition that stirs, the potassium permanganate solution of step (1) dropwise is added in the manganese sulfate solution, stirs 30min.

(3) reaction solution in the step (2) is transferred in the reactor 160 ℃ of reaction 6h.After reaction finished, centrifugal collection product was used distilled water and washing with alcohol 6 times.

(4) with step (3) products obtained therefrom dry 8h under 100 ℃, namely make β-MnO ₂Nanometer rod.

Above-mentioned gained sample is made electrode: by weight MnO ₂: graphite: acetylene black: PTFE=70:12:12:6 takes by weighing 4 kinds of electrode materialss and mixes, and adds the 4mL dehydrated alcohol, ultra-sonic dispersion 10min.The slurry that mixes all is poured on the stainless steel plate, with slurry roll into uniformly, the thin slice of thickness between 100-200 μ m.Be that the mould stamp of 9mm is detained the circular electric pole piece from the thin slice of rolling with diameter, for subsequent use.The electrode slice that makes is put into vacuum drying oven, at the dry 8h of 120 ° of C.Take stainless (steel) wire as collector, electrode slice is pressed in oil press makes electrode on the collector, be used for measuring chemical property, pressure 15MPa.The electro-chemical test of electrode adopts three-electrode system, and Electrode is the MnO of preparation ₂Electrode is platinum filament to electrode, and reference electrode is saturated calomel electrode, and electrolytic solution is 1M Na ₂SO ₄Solution.Electro-chemical test is tested at the CHI660D electrochemical workstation, and the voltage range of test is-0.05-0.85V.

Fig. 3 is the SEM figure of gained nanometer rod, and diameter is about 0.5-1 μ m, about the thick 20nm of nanometer rod sheet.The XRD figure of Fig. 4 shows that products therefrom is β-MnO ₂

Embodiment 3

(1) take by weighing respectively the 113mg manganous sulfate, 632mg potassium permanganate is dissolved in 2mL and the 15mL distilled water, stir to form uniform solution;

(2) under the room temperature, under the condition that stirs, the potassium permanganate solution of step (1) dropwise is added in the manganese sulfate solution, stirs 30min.

(3) reaction solution in the step (2) is transferred in the reactor 160 ℃ of reaction 6h.After reaction finished, centrifugal collection product was used distilled water and washing with alcohol 7 times;

(4) with step (3) products obtained therefrom dry 8h under 100 ℃, namely make δ-MnO ₂Nanofiber.

Above-mentioned gained sample is made electrode: by weight MnO ₂: graphite: acetylene black: PTFE=70:12:12:6 takes by weighing 4 kinds of electrode materialss and mixes, and adds the 5mL dehydrated alcohol, ultra-sonic dispersion 10min.The slurry that mixes all is poured on the stainless steel plate, with slurry roll into uniformly, the thin slice of thickness between 100-200 μ m.Be that the mould stamp of 9mm is detained the circular electric pole piece from the thin slice of rolling with diameter, for subsequent use.The electrode slice that makes is put into vacuum drying oven, at the dry 8h of 120 ° of C.Take stainless (steel) wire as collector, electrode slice is pressed in oil press makes electrode on the collector, be used for measuring chemical property, pressure 15MPa.The electro-chemical test of electrode adopts three-electrode system, and Electrode is the MnO of preparation ₂Electrode is platinum filament to electrode, and reference electrode is saturated calomel electrode, and electrolytic solution is 1MNa ₂SO ₄Solution.Electro-chemical test is tested at the CHI660D electrochemical workstation, and the voltage range of test is-0.05-0.85V.

Fig. 5 is the SEM figure of gained nanofiber, and Fibre diameter is about 30-50nm, and length is about 1 μ m, and the XRD figure of Fig. 6 shows that products therefrom is δ-MnO ₂The chemical property that above-mentioned three embodiment record sees Table 1.

Table 1

	Embodiment 1 (α-MnO 2)	Embodiment 2 (β-MnO 2)	Embodiment 3 (δ-MnO 2)
				Than electric capacity (F/g) 1A/g	47	7.4	162

Claims (2)

1. preparation method who prepares different crystal forms Manganse Dioxide, the employing manganous salt is reductive agent, potassium permanganate is oxygenant, join respectively in the distilled water, stir and form homogeneous solution, the concentration of potassium permanganate solution is 0.1～0.27mol/L, and the concentration of manganese sulfate solution is 0.1～0.75mol/L; Potassium permanganate solution is dropwise joined in the manganous salt solution, mixing solutions is transferred in the reactor again, in 160 ℃ of reaction 1～12h, product is collected in cooling, uses respectively distilled water and washing with alcohol, makes α-MnO ₂, β-MnO ₂And δ-MnO ₂

When potassium permanganate and manganous salt mol ratio are 2:3～5:2, prepare one dimension α-MnO ₂Nanofiber;

When potassium permanganate and manganous salt mol ratio are 0.5:3～1:3, prepare one dimension β-MnO ₂Nanometer rod;

When potassium permanganate and manganous salt mol ratio are 3:1～6:1, prepare the two-dimentional δ-MnO of flower-like structure ₂

2. according to a kind of preparation method who prepares different crystal forms Manganse Dioxide of claim 1, it is characterized in that, described reductive agent manganous salt is manganous sulfate, manganous nitrate, manganese acetate and Manganous chloride tetrahydrate.

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