Method for preparing porous silicon

Abstract

The invention relates to a method for preparing porous silicon. The method comprises the following steps of: (1) calcining a molecular sieve at high temperature and removing a template agent or deposited carbon; (2) diffusing the metal ions of the powder of the molecular sieve after being calcined and the elemental particles of metal into the molecular sieve under a vacuum condition by adopting a chemical gas / solid-phase reaction method and also reacting with the molecular sieve; and (3) taking out black solid after finishing the reaction in the step (2) from a reactor, washing repeatedly, filtering for several times and finally, drying so as to obtain a gray powder body, i.e. the porous silicon. Compared with the prior art, the reaction temperature can be lowered to a very large extent according to the method for preparing the porous silicon. The method for preparing the porous silicon has the advantage that a by-product can be removed very easily. Meanwhile, a silicon source material used by the reaction is expanded from pure silicon zeolite to a commercialized silicon-aluminum molecular sieve, the process is simple, and the operability is strong. The obtained porous silicon has the structural characteristic of a multi-stage pore taking a meso pore as a main part and has the advantages of very large specific surface area (which is not smaller than 420cm2 / g) and the like.

Description

technical field [0001] The invention relates to a method for preparing porous silicon powder by using molecular sieve, in particular to a method for preparing porous silicon powder by reducing molecular sieve by sodium thermal method. Background technique [0002] Porous silicon powder, as a high porosity semiconductor material, has unique photoelectric properties and has a wide range of uses in the field of traditional electronic devices. In addition, due to its large specific surface area, high lithium storage capacity and good biological activity, porous silicon also has good application prospects in the fields of sensor devices, emerging energy and biomedicine, and has gradually become a hot spot in the field of material science in recent years. . At present, the commonly used porous silicon preparation methods are mainly chemical etching and electrochemical anodic etching. The porous silicon prepared by the chemical corrosion method has limited thickness, poor uniform...

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Problems solved by technology

However, the use of magnesia thermal method also has certain limitations. First, the reaction temperature must be controlled above 630°C, and the magnesium and SiO 2 It is easy to generate by-products such as magnesium silicate that are difficult to remove, which will affect the purification of porous silicon; in addition, the main body of silicon source used in the reaction is often limited to pure silica zeolite, and silica-alumina molecular sieve is used as the template main body to react with metal magnesium , it is easy to form magnesium aluminum silicate gel that is difficult to remove, and generally should not be used in the reduction of magnesia thermal method

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