A method for preparing porous silicon by magnesia thermal reduction

A technology of porous silicon and magnesium heating, applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the limitations of large-scale commercial application of porous silicon, the difficulty of mass preparation of porous silicon powder, and the limited thickness of porous silicon films, etc. problem, to achieve the effect of low cost, environmental friendliness and high luminous efficiency

Inactive Publication Date: 2011-11-30
TONGJI UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the thickness of the porous silicon film prepared by this method is limited, the mechanical strength is low, the pore size distribution is uneven, and the cost of raw materials is high, which is harmful to the environment.
In addition, due to

Method used

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  • A method for preparing porous silicon by magnesia thermal reduction
  • A method for preparing porous silicon by magnesia thermal reduction
  • A method for preparing porous silicon by magnesia thermal reduction

Examples

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Example Embodiment

[0018] Example 1

[0019] (1) At room temperature, mix SiO powder and magnesium powder at a molar ratio of 1:1 uniformly under the protection of argon, and put them in a tubular atmosphere furnace. Heat to 500°C in argon gas flow and react at a constant temperature for 6 hours, then naturally Cool to room temperature;

[0020] (2) Place the product obtained in hydrochloric acid with a concentration of 0.1 mol / L to fully soak for 24 hours to remove the magnesium oxide, and obtain a solid product after filtration, which is then fully washed with deionized water, and then fully washed with absolute ethanol, and dried Then, porous silicon powder was obtained. Its specific surface area is about 200 m 2 / g, the porosity is more than 90%. The microstructure and phase analysis are as follows figure 1 with figure 2 Shown. From figure 1 It can be seen that the product has a nanoporous structure with uniform pore size distribution. From figure 2 The XRD diffraction spectrum analysis o...

Example Embodiment

[0021] Example 2

[0022] (1) SiO 0.5 The molar ratio of powder and magnesium powder is 1:0.5, uniformly mixed under the protection of argon, and then placed in a tubular atmosphere furnace, heated to 450°C in argon flow, and reacted at a constant temperature for 12 hours, and then naturally cooled to room temperature;

[0023] (2) Place the obtained product in an ethanol solution of hydrochloric acid with a concentration of 6 mol / L to fully soak for 0.5 hours to remove the magnesium oxide, and obtain a solid product after filtration, which is then thoroughly washed with deionized water, and then fully washed with anhydrous ethanol. After washing and drying, porous silicon powder is obtained. Its specific surface area is about 210 m 2 / g, the porosity is more than 90%.

Example Embodiment

[0024] Example 3

[0025] (1) At room temperature, mix SiO powder and magnesium powder at a molar ratio of 1:1.5 uniformly under the protection of argon, then place them in a tubular atmosphere furnace, heat to 600°C in argon flow, and react at constant temperature for 4 hours, then naturally Cool to room temperature;

[0026] (2) Place the obtained product in dilute sulfuric acid with a concentration of 0.1 mol / L to fully soak for 24 hours to remove the magnesium oxide, and obtain a solid product after filtration. The solid product is then thoroughly washed with deionized water, then washed with acetone, and dried. Obtain porous silicon powder. Its specific surface area is about 180 m 2 / g, the porosity is about 80%.

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Abstract

The invention belongs to the synthesis field of porous silicon materials, and particularly relates to a method for preparing porous silicon by magnesiothermic reduction. The method comprises the following steps: carrying out magnesiothermic reduction reaction based on silicon oxide SiOx (x = 0.5-2) as a raw material to generate a mixture of silicon and magnesium oxide; and then selectively dissolving away magnesium oxide with an acid so as to ultimately obtain a self-supported porous silicon material. Compared with the previous conventional electrochemical anodic etching methods, the method provided by the invention has the advantages that the use of expensive monocrystal silicon wafers is avoided, but simple, easily available and low-cost silicon oxide is used as the raw material, thereby not only reducing the cost but also increasing the yield; and the method has the advantages of simple preparation process, environmental friendliness, high preparation efficiency and good repeatability, is more suitable for industrial production, and is expected to be widely applied in the fields of lithium ion secondary batteries, optical materials, biomedical devices, gas-sensitive devices, etc.

Description

technical field [0001] The invention belongs to the field of preparation of inorganic nanoporous materials, in particular to a method for preparing porous silicon by magnesia thermal reduction. Background technique [0002] As early as 1956, A. Uhlir Jr. and I. Uhlir of Bell Laboratories in the United States discovered that porous silicon could be formed by electrochemical corrosion of crystalline silicon in hydrofluoric acid. Until 1990, L. T. Canham of the British National Defense Research Institute further corroded porous silicon in hydrofluoric acid solution, and observed the remarkable visible light photoluminescence phenomenon at room temperature for the first time, which aroused extensive attention of researchers at home and abroad, thus opening up the A new field of research on silicon-based luminescent materials. As a new type of semiconductor material, porous silicon has the advantages of large specific surface area, high biological activity and unique photoelectr...

Claims

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Application Information

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IPC IPC(8): C01B33/023
Inventor 包志豪陈珂
Owner TONGJI UNIV
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