CN104368371B - Visible light-responded photocatalyst Sr3laSi3n7and preparation method thereof - Google Patents

Abstract

The invention discloses a kind of visible light-responded photocatalyst Sr₃LaSi₃N₇And preparation method thereof.The chemical constitution formula of this photocatalyst is Sr₃LaSi₃N₇.The invention also discloses the preparation method of above-mentioned material.The photocatalyst that the present invention obtains has the advantages such as spectral response range width, light conversion efficiency height and good stability and has decomposition harmful chemical, organic-biological matter and the effect of sterilization under visible light illumination.

Description

Visible light-responded photocatalystSr3LaSi3N7And preparation method thereof

Technical field

The present invention relates to a kind of visible light-responded photocatalyst Sr₃LaSi₃N₇And preparation method thereof, belong to inorganic field of photocatalytic material.

Background technology

Along with socioeconomic development, people increasingly pay close attention to for the energy and ecological environment, solve energy shortage and problem of environmental pollution be realize sustainable development, improve people's living standard and safeguard national security in the urgent need to.

From phase late 1970s, there has been proposed and utilize in photocatalyst decomposition water and the Organic substance such as pesticide in air and odorant, and scribble the application example such as self-cleaning of the surface of solids of photocatalyst.The principle of light-catalyzed reaction be photocatalyst after absorbing higher than the photon of its band-gap energy, generate hole and electronics, these holes and electronics carry out oxidation reaction and reduction reaction respectively, reach to decompose harmful chemical, organic-biological matter and the purpose of sterilization.Photocatalyst has many kinds, and the most most representative is titanium dioxide (TiO₂), utilize titanium dioxide that the Organic substances such as the pesticide in water and in air and odorant are decomposed, but the band gap of titanium dioxide is 3.2eV, under the ultraviolet irradiation shorter than 400nm, only just can show activity, can only be at indoor or the local work having uviol lamp, being little to utilize visible ray, this greatly limits the use of titanium dioxide optical catalyst.

In view of photocatalyst practicality in decomposing harmful substances, it is indispensable for utilizing sunlight as light source.Irradiate the sunlight medium wavelength maximum intensity of visible ray near 500nm to earth's surface, wavelength is that the energy of the visible region of 400nm ~ 750nm is about the 43% of sunlight gross energy, so in order to utilize efficiently, the R and D of bismuth series photocatalyst have been achieved for a series of great achievement, bismuthous complex such as BiVO₄、Bi₂MoO₆、Bi₂Mo₂O₉、Bi₂Mo₃O₁₂And Bi₂WO₄It is in the news and there is good absorption under visible light.A series of niobiums (tantalum) hydrochlorate photocatalyst is widely studied owing to having higher photocatalytic activity.Such as, niobate photocatalyst Pb₃Nb₄O₁₃、BiNbO₄And Bi₂MNbO₇(M=Al, Ga, In, Y, rare earth element and Fe) etc. and niobium potassium compound oxide photocatalyst such as KNbO₃、KNb₃O₈、K₄Nb₆O₁₇And K₆Nb_10.6O₃₀Deng all having preferable photocatalysis performance, but in visible-range, its intrinsic photocatalytic effect is the most weak or does not has activity.

Although photocatalysis research has been carried out the several years, but at present report to have visible light-responded photocatalyst kind the most limited, there are still that light conversion efficiency is low, poor stability and the problem such as spectral response range is narrow, so it is the most necessary for researching and developing the new visible light-responded high efficiency photocatalyst that has.We are to consisting of Sr₃LaSi₃N₇、Sr₃NdSi₃N₇、Sr₃SmSi₃N₇ 、Sr₃EuSi₃N₇Compound carried out Photocatalytic Performance Study, found that Sr₃LaSi₃N₇Band gap be 2.85eV, have excellence visible light-responded photocatalysis performance；And other sample is insulator, band gap width is both greater than 3.2eV, just can only can show activity under ultraviolet irradiation.

Summary of the invention

It is an object of the invention to provide and a kind of there is visible light-responded photocatalyst Sr₃LaSi₃N₇And preparation method thereof.

The chemical constitution formula with visible light-responded photocatalyst that the present invention relates to is: Sr₃LaSi₃N₇。

The preparation method of above-mentioned visible light-responded photocatalyst concretely comprises the following steps:

(1) be 99.9%(percentage by weight by purity) more than Sr₃N₂, LaN and Si₃N₄Starting powder press Sr₃LaSi₃N₇Composition weigh dispensing.

(2) step (1) raw material wet ball-milling is mixed 12 hours, ball-milling medium is dehydrated alcohol, is calcined 8 hours, naturally cools to room temperature after drying in 1300 ~ 1400 DEG C of nitrogen atmospheres, then being pulverized by ball mill makes average diameter of particles be less than 2 μm, i.e. obtains Sr₃LaSi₃N₇Powder.

The spectral response range width of the photocatalyst that the present invention obtains, light conversion efficiency height and good stability, there is decomposition harmful chemical, organic-biological matter and the effect of sterilization under visible light illumination；Additionally preparation method is simple, synthesis temperature is low, low cost, is suitable for commercial production and application.

Detailed description of the invention

Present invention will be described in detail below:

1 in order to effectively utilize light, the size of the photocatalyst in the present invention preferably in micron level, even nanoparticle, and specific surface area is bigger.The nitride powder prepared with solid-phase synthesis, its particle is relatively big and surface area is less, but can be by ball mill pulverizing means and make particle diameter diminish.

2, the photocatalysis experiment of the present invention is using methyl orange as simulation organic pollution, and its concentration is 20mg/L；Photocatalyst Sr₃LaSi₃N₇Addition be 1g/L；Light source uses the xenon lamp of 300W, and reactive tank uses the vessel that pyrex is made, and obtains the wavelength light more than 420nm by wave filter, then irradiates photocatalyst；Catalysis time is set as 120 minutes.

Embodiment 1:

(1) be 99.9%(percentage by weight by purity) more than Sr₃N₂, LaN and Si₃N₄Starting powder press Sr₃LaSi₃N₇Composition weigh dispensing.

(2) being mixed 12 hours by step (1) raw material wet ball-milling, ball-milling medium is dehydrated alcohol, is calcined 8 hours, naturally cools to room temperature after drying in 1300 DEG C of nitrogen atmospheres, is then pulverized by ball mill and makes average diameter of particles be less than 2 μm, i.e. obtains Sr₃LaSi₃N₇Powder.

Prepared photocatalyst, under the wavelength radiation of visible light more than 420nm, reaches 97.5% to methyl orange clearance in 120 minutes.

Embodiment 2:

(1) be 99.9%(percentage by weight by purity) more than Sr₃N₂, LaN and Si₃N₄Starting powder press Sr₃LaSi₃N₇Composition weigh dispensing.

(2) being mixed 12 hours by step (1) raw material wet ball-milling, ball-milling medium is dehydrated alcohol, is calcined 8 hours, naturally cools to room temperature after drying in 1350 DEG C of nitrogen atmospheres, is then pulverized by ball mill and makes average diameter of particles be less than 2 μm, i.e. obtains Sr₃LaSi₃N₇Powder.

Prepared photocatalyst, under the wavelength radiation of visible light more than 420nm, reaches 98.1% to methyl orange clearance in 120 minutes.

Embodiment 3:

1) be 99.9%(percentage by weight by purity) more than Sr₃N₂, LaN and Si₃N₄Starting powder press Sr₃LaSi₃N₇Composition weigh dispensing.

(2) being mixed 12 hours by step (1) raw material wet ball-milling, ball-milling medium is dehydrated alcohol, is calcined 8 hours, naturally cools to room temperature after drying in 1400 DEG C of nitrogen atmospheres, is then pulverized by ball mill and makes average diameter of particles be less than 2 μm, i.e. obtains Sr₃LaSi₃N₇Powder.

Prepared photocatalyst, under the wavelength radiation of visible light more than 420nm, 120min reaches 98.0% to methyl orange clearance.

The present invention is never limited to above example.The bound of each temperature, interval value can realize the present invention, embodiment numerous to list herein.

The made photocatalyst powder of above inventive embodiments can be carried on multiple matrix surface.Matrix can be glass, pottery, activated carbon or quartz sand etc., and photocatalyst can be carried on matrix surface in the form of a film.

Claims (1)

1. a visible light-responded photocatalyst, it is characterised in that the chemical constitution formula of described photocatalyst is Sr₃LaSi₃N₇；

The preparation method of described photocatalyst concretely comprises the following steps:

(1) be 99.9%(percentage by weight by purity) more than Sr₃N₂, LaN and Si₃N₄Starting powder press Sr₃LaSi₃N₇Composition weigh dispensing；

(2) step (1) raw material wet ball-milling is mixed 12 hours, ball-milling medium is dehydrated alcohol, is calcined 8 hours, naturally cools to room temperature after drying in 1300 ~ 1400 DEG C of nitrogen atmospheres, then being pulverized by ball mill makes average diameter of particles be less than 2 μm, i.e. obtains Sr₃LaSi₃N₇Powder.