CN104437464A

CN104437464A - Visible-light-response photo-catalyst Li3Nb2B3O11 and preparation method thereof

Info

Publication number: CN104437464A
Application number: CN201410716949.1A
Authority: CN
Inventors: 方维双; 苏和平; 李洁
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2014-12-02
Filing date: 2014-12-02
Publication date: 2015-03-25

Abstract

The invention discloses a visible-light-response photo-catalyst Li3Nb2B3O11 and a preparation method thereof. The chemical composition formula of the photo-catalyst is Li3Nb2B3O11. The photo-catalyst has the advantages of being wide in spectral response range, high in light conversion efficiency, high in stability and the like. The photo-catalyst has the effects of decomposing harmful chemicals and organic biomass and sterilizing under irradiation of visible light; and in addition, the preparation method is simple, low in synthesis temperature, low in cost and suitable of industrial production and application.

Description

Visible light-responded photocatalyst Li 3nb 2b 3o 11and preparation method thereof

Technical field

The present invention relates to a kind of visible light-responded photocatalyst Li ₃nb ₂b ₃o ₁₁and preparation method thereof, belong to inorganic field of photocatalytic material.

Background technology

Along with socioeconomic development, people more and more 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 to 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 is that photochemical catalyst is after absorbing the photon higher than its band-gap energy, generate hole and electronics, these holes and electronics carry out oxidation reaction and reduction reaction respectively, reach the object of decomposing harmful chemical, organic-biological matter and sterilization.Photochemical catalyst has many kinds, and wherein most representative is titanium dioxide (TiO ₂), titanium dioxide has been utilized to decompose organic matters such as the agricultural chemicals in water and in air and odorants, but the band gap of titanium dioxide is 3.2eV, only under the ultraviolet irradiation shorter than 400nm, just activity can be shown, can only at indoor or the local work having uviol lamp, almost can not utilize visible ray, this limits the use of titanium dioxide optical catalyst greatly.

Consider the practicality of photochemical catalyst in decomposing harmful substances, utilize sunshine to be indispensable as light source.Irradiate maximum to sunshine medium wavelength intensity of visible ray near 500nm on earth's surface, wavelength is the energy of the visible region of 400nm ~ 750nm is approximately 43% of sunshine gross energy, so in order to efficient utilization, the R and D of bismuth series photocatalyst have achieved a series of great achievement, and bismuthous compound is as BiVO ₄, Bi ₂moO ₆, Bi ₂mo ₂o ₉, Bi ₂mo ₃o ₁₂and Bi ₂wO ₄be in the news and there is good absorption under visible light.A series of niobium (tantalum) hydrochlorate photochemical catalyst is widely studied owing to having higher photocatalytic activity.Such as, niobate photocatalyst Pb ₃nb ₄o ₁₃, BiNbO ₄and Bi ₂mNbO ₇(M=Al, Ga, In, Y, rare earth element and Fe) etc. with niobium potassium compound oxide photocatalyst as KNbO ₃, KNb ₃o ₈, K ₄nb ₆o ₁₇and K ₆nb _10.6o ₃₀deng all, there is good photocatalysis performance, but its intrinsic photocatalytic effect is very weak or do not have activity in visible-range.

Although photocatalysis research has carried out the several years, the current exploration to visible light-responded photochemical catalyst is the summary of experience drawn by great many of experiments with exploitation major part, in theory also cannot from the structure of compound, composition, the physicochemical properties such as molecular weight are predicted its photocatalysis performance, therefore at present report to have visible light-responded photochemical catalyst kind still very 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 that succeeds all the time, which greatly limits extensive use and the development of photochemical catalyst.We are to consisting of Li ₃nb ₂b ₃o ₁₁, Li ₃ta ₂b ₃o ₁₁, Li ₃v ₂b ₃o ₁₁sample carried out Photocatalytic Performance Study, found that Li ₃nb ₂b ₃o ₁₁for semiconductor, band gap is 2.58eV, has excellent visible light-responded photocatalysis performance; Li ₃ta ₂b ₃o ₁₁band gap width is greater than 3.2eV, can only show activity under ultraviolet irradiation; And Li ₃v ₂b ₃o ₁₁sample is insulator, can not show activity under ultraviolet irradiation.

Summary of the invention

The object of this invention is to provide and a kind of there is visible light-responded photocatalyst Li ₃nb ₂b ₃o ₁₁and preparation method thereof.

The chemical constitution formula with visible light-responded photochemical catalyst that the present invention relates to is: Li ₃nb ₂b ₃o ₁₁.

Preparation method's concrete steps of above-mentioned visible light-responded photochemical catalyst are:

(1) by 99.9% analytically pure chemical raw material Li ₂cO ₃, Nb ₂o ₅and H ₃bO ₃starting powder press Li ₃nb ₂b ₃o ₁₁composition weigh batching.

(2) raw material mixing step (1) prepared, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 8 hours, is mixed and finely ground, and takes out and dries, and crosses 200 mesh sieves.

(3) powder step (2) mixed 700 ~ 750 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and average diameter of particles is diminished, lower than 2 μm, namely obtain Li ₃nb ₂b ₃o ₁₁powder.

The spectral response range of the photochemical catalyst that the present invention obtains is wide, the high and good stability of light conversion efficiency, has the effect of decomposing harmful chemical, organic-biological matter and sterilization under visible light illumination; Preparation method is simple in addition, synthesis temperature is low, and cost is low, is applicable to industrial production and application.

Detailed description of the invention

To be specifically described the present invention below:

1, in order to obtain the composite oxides used in the present invention, first use solid-phase synthesis to prepare powder, namely using as the various oxide of raw material or carbonate according to the metering of target constitutional chemistry than mixing, then to synthesize in air atmosphere at ambient pressure.

2, in order to effectively utilize light, the size of the photochemical catalyst in the present invention is preferably in micron level, or even nano particle, and specific area is larger.With oxide powder prepared by solid-phase synthesis, its particle is comparatively large and surface area is less, but can pulverize means by ball mill makes particle diameter diminish.

3, photocatalysis experiment of the present invention is using methyl orange as simulation organic pollution, and its concentration is 20mg/L; Photocatalyst Li ₃nb ₂b ₃o ₁₁addition be 1g/L; Light source uses the xenon lamp of 300W, the vessel that reactive tank uses pyrex to make, and obtains the light that wavelength is greater than 420nm, then irradiate photochemical catalyst by wave filter; Catalysis time is set as 60 minutes.

Embodiment 1:

(3) powder step (2) mixed 700 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and average diameter of particles is diminished, lower than 2 μm, namely obtain Li ₃nb ₂b ₃o ₁₁powder.

Prepared photochemical catalyst, under being greater than the radiation of visible light of 420nm, reaches 97.6% to methyl orange clearance in 60 minutes at wavelength.

Embodiment 2:

(3) powder step (2) mixed 740 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and average diameter of particles is diminished, lower than 2 μm, namely obtain Li ₃nb ₂b ₃o ₁₁powder.

Prepared photochemical catalyst, under being greater than the radiation of visible light of 420nm, reaches 98.5% to methyl orange clearance in 60 minutes at wavelength.

Embodiment 3:

(3) powder step (2) mixed 750 DEG C of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, is then pulverized by ball mill and average diameter of particles is diminished, lower than 2 μm, namely obtain Li ₃nb ₂b ₃o ₁₁powder.

Prepared photochemical catalyst, be greater than the radiation of visible light of 420nm at wavelength under, 60min reaches 97.7% to methyl orange clearance.

The present invention is never limited to above embodiment.Bound, the interval value of each temperature can realize the present invention, do not enumerate embodiment at this.

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

Claims

1. a visible light-responded photochemical catalyst, is characterized in that the chemical constitution formula of described photochemical catalyst is Li ₃nb ₂b ₃o ₁₁;

Preparation method's concrete steps of described photochemical catalyst are:

(1) by 99.9% analytically pure chemical raw material Li ₂cO ₃, Nb ₂o ₅and H ₃bO ₃starting powder press Li ₃nb ₂b ₃o ₁₁composition weigh batching;

(2) raw material mixing step (1) prepared, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 8 hours, is mixed and finely ground, and takes out and dries, and crosses 200 mesh sieves;

(3) powder step (2) mixed 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 lower than 2 μm, namely obtain Li ₃nb ₂b ₃o ₁₁powder.