CN104525208B - Visible light-responded photocatalyst Li Fe2b3o8and preparation method thereof - Google Patents

Abstract

The invention discloses the visible light responsive photocatalyst LiFe of a kind of high-efficient wide-frequency₂B₃O₈And preparation method thereof.The chemical constitution formula of this photochemical catalyst is LiFe₂B₃O₈.The invention also discloses the preparation method of above-mentioned material.The photochemical catalyst that the present invention obtains has the advantages such as spectral response range width, 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 industrial production and application.

Description

Visible light-responded photochemical catalystLiFe2B3O8And preparation method thereof

Technical field

The present invention relates to a kind of visible light-responded photocatalyst Li Fe₂B₃O₈And 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 photochemical catalyst decomposition water and the organic matter such as agricultural chemicals in air and odorant, and scribble the application example such as self-cleaning of the surface of solids of photochemical catalyst.The principle of light-catalyzed reaction be photochemical catalyst 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.Photochemical catalyst has many kinds, and the most most representative is titanium dioxide (TiO₂), utilize titanium dioxide that the organic matters such as the agricultural chemicals 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 photochemical catalyst practicality in decomposing harmful substances, it is indispensable for utilizing sunlight as light source.Irradiate the sunshine 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 sunshine 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 compound 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 photochemical catalyst 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, major part of exploring and develop to visible light-responded photochemical catalyst is the summary of experience drawn by great many of experiments at present, the most also cannot be from the structure of compound, composition, its photocatalysis performance is predicted in the physicochemical properties such as molecular weight, therefore at present report to have visible light-responded photochemical catalyst kind the most limited, and it is low to there is light conversion efficiency, synthesis difficulty, poor stability and the problem such as spectral response range is narrow, research and develop that new preparation method is simple and to have the visible light-responded high efficiency photocatalyst of wideband be that this area scientific and technical personnel thirst for solving always but are difficult to the difficult problem succeeded all the time, which greatly limits extensively application and the development of photochemical catalyst.We are to consisting of LiFe₂B₃O₈、LiBi₂B₃O₈、LiAl₂B₃O₈Sample carried out Photocatalytic Performance Study.Found that LiFe₂B₃O₈For semiconductor, band gap is 2.59eV, has the visible light-responded photocatalysis performance of excellence；LiBi₂B₃O₈Band gap width is more than 3.2eV, can only show activity under ultraviolet irradiation, and LiAl₂B₃O₈Sample is insulator, can not 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 Li Fe₂B₃O₈And preparation method thereof.

The chemical constitution formula with visible light-responded photochemical catalyst that the present invention relates to is: LiFe₂B₃O₈。

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

(1) by 99.9% analytically pure chemical raw material Li₂CO₃、Fe₂O₃And H₃BO₃Starting powder press LiFe₂B₃O₈Composition weigh dispensing.

(2) raw material mixing step (1) prepared, puts in ball grinder, adds zirconia ball and absolute ethyl alcohol, ball milling 8 hours, be mixed and finely ground, take out and dry, cross 200 mesh sieves.

(3) powder step (2) mixed is 700 ~ 750 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and makes average diameter of particles diminish, less than 2 μm, i.e. obtains LiFe₂B₃O₈Powder.

The spectral response range width of the photochemical catalyst 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 industrial production and application.

Detailed description of the invention

Present invention will be described in detail below:

1, in order to obtain the composite oxides used in the present invention, prepare powder first by solid-phase synthesis, i.e. various oxides or the carbonate as raw material is mixed according to target constitutional chemistry metering ratio, then synthesize in air atmosphere at ambient pressure.

2 in order to effectively utilize light, the size of the photochemical catalyst in the present invention preferably in micron level, even nano particle, and specific surface area is bigger.The oxide 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.

3, the photocatalysis experiment of the present invention is using methyl orange as simulation organic pollution, and its concentration is 20mg/L；Photocatalyst Li Fe₂B₃O₈Addition 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 photochemical catalyst；Catalysis time is set as 60 minutes.

Embodiment 1:

(1) by 99.9% analytically pure chemical raw material Li₂CO₃、Fe₂O₃And H₃BO₃Starting powder press LiFe₂B₃O₈Composition weigh dispensing.

(2) raw material mixing step (1) prepared, puts in ball grinder, adds zirconia ball and absolute ethyl alcohol, ball milling 8 hours, be mixed and finely ground, take out and dry, cross 200 mesh sieves.

(3) powder step (2) mixed is 700 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and makes average diameter of particles diminish, less than 2 μm, i.e. obtains LiFe₂B₃O₈Powder.

Prepared photochemical catalyst, under the wavelength radiation of visible light more than 420nm, reaches 97.7% to methyl orange clearance in 60 minutes.

Embodiment 2:

(1) by 99.9% analytically pure chemical raw material Li₂CO₃、Fe₂O₃And H₃BO₃Starting powder press LiFe₂B₃O₈Composition weigh dispensing.

(2) raw material mixing step (1) prepared, puts in ball grinder, adds zirconia ball and absolute ethyl alcohol, ball milling 8 hours, be mixed and finely ground, take out and dry, cross 200 mesh sieves.

(3) powder step (2) mixed is 730 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and makes average diameter of particles diminish, less than 2 μm, i.e. obtains LiFe₂B₃O₈Powder.

Prepared photochemical catalyst, under the wavelength radiation of visible light more than 420nm, reaches 98.9% to methyl orange clearance in 60 minutes.

Embodiment 3:

(1) by 99.9% analytically pure chemical raw material Li₂CO₃、Fe₂O₃And H₃BO₃Starting powder press LiFe₂B₃O₈Composition weigh dispensing.

(2) raw material mixing step (1) prepared, puts in ball grinder, adds zirconia ball and absolute ethyl alcohol, ball milling 8 hours, be mixed and finely ground, take out and dry, cross 200 mesh sieves.

(3) powder step (2) mixed is 750 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and makes average diameter of particles diminish, less than 2 μm, i.e. obtains LiFe₂B₃O₈Powder.

Prepared photochemical catalyst, under the wavelength radiation of visible light more than 420nm, 60min reaches 97.5% 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 photochemical catalyst can be carried on matrix surface in the form of a film.

Claims (1)

1. a visible light-responded photochemical catalyst, it is characterised in that the chemical constitution formula of described photochemical catalyst is LiFe₂B₃O₈；

The preparation method of described photochemical catalyst concretely comprises the following steps:

(1) by 99.9% analytically pure chemical raw material Li₂CO₃、Fe₂O₃And H₃BO₃Starting powder press LiFe₂B₃O₈Composition weigh dispensing；

(2) raw material mixing step (1) prepared, puts in ball grinder, adds zirconia ball and absolute ethyl alcohol, ball milling 8 hours, be mixed and finely ground, take out and dry, cross 200 mesh sieves；

(3) powder step (2) mixed is 700 ~ 750 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and makes average diameter of particles be less than 2 μm, i.e. obtains LiFe₂B₃O₈Powder.