CN104043445A

CN104043445A - Visible light responsive photocatalyst Li2Zn2W2O9 and preparation method thereof

Info

Publication number: CN104043445A
Application number: CN201410237919.2A
Authority: CN
Inventors: 唐莹; 李洁; 方亮
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2014-06-02
Filing date: 2014-06-02
Publication date: 2014-09-17

Abstract

The invention discloses a visible light responsive photocatalyst Li2Zn2W2O9 and a preparation method thereof. The chemical composition formula of the photocatalyst is Li2Zn2W2O9. The invention also discloses a preparation method of the material. The photocatalyst obtained by the invention has the advantages of wide spectral response range, high light conversion efficiency, good stability and the like, and can decompose harmful chemical substances and organic biomasses and kill bacteria under visible light irradiation. In addition, the visible light responsive photocatalyst has the characteristics of simple preparation method, low synthesis temperature and low cost, thus being suitable for industrial production and application.

Description

Visible light-responded photocatalyst Li 2zn 2w 2o 9and preparation method thereof

Technical field

The present invention relates to a kind of visible light-responded photocatalyst Li ₂zn ₂w ₂o ₉and 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 and be realize sustainable development, improve people's living standard and safeguard national security in the urgent need to.

From phase late 1970s, people proposed to utilize in photochemical catalyst decomposition water and atmosphere in agricultural chemicals and the organic matter such as odorant, and application examples such as self-cleaning that scribble the surface of solids of photochemical catalyst.The principle of light-catalyzed reaction is that photochemical catalyst is after the photon having absorbed higher than its band-gap energy, hole and electronics have been generated, these holes and electronics carry out respectively oxidation reaction and reduction reaction, 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), utilized titanium dioxide to decompose organic matters such as the agricultural chemicals in water and in atmosphere and odorants, yet the band gap of titanium dioxide is 3.2eV, only under the ultraviolet irradiation shorter than 400nm, just can show activity, can only be indoor or have a local work of uviol lamp, almost can not utilize visible ray, this has limited the use of titanium dioxide optical catalyst greatly.

Consider the practicality of photochemical catalyst in decomposing harmful substances, utilizing sunshine is indispensable as light source.Irradiation is maximum near sunshine medium wavelength visible light intensity 500nm on earth's surface, wavelength is that the energy of the visible region of 400nm ~ 750nm is approximately 43% of sunshine gross energy, so for efficient utilization, the R and D of bismuth series photocatalyst have obtained a series of great achievements, and bismuthous compound is as BiVO ₄, Bi ₂moO ₆, Bi ₂mo ₂o ₉, Bi ₂mo ₃o ₁₂and Bi ₂wO ₄be reported in and under visible ray, there is good absorption.A series of niobiums (tantalum) hydrochlorate photochemical catalyst is because the photocatalytic activity having compared with high is widely studied.For example, 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 thering is good photocatalysis performance.

Although photocatalysis research has been carried out the several years, but at present report to have visible light-responded photochemical catalyst kind still very limited, still exist that light conversion efficiency is low, poor stability and the problem such as spectral response range is narrow, so research and develop the new visible light-responded high efficiency photocatalyst that has, be very necessary.We are to synthetic noval chemical compound Li in research ₂zn ₂w ₂o ₉carry out Photocatalytic Performance Study, found that Li ₂zn ₂w ₂o ₉band gap be 2.3eV, there is excellent visible light-responded photocatalysis performance.

Summary of the invention

The object of this invention is to provide a kind of visible light-responded photocatalyst Li that has ₂zn ₂w ₂o ₉and preparation method thereof.

The chemical composition general formula with visible light-responded photochemical catalyst the present invention relates to is: Li ₂zn ₂w ₂o ₉.

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, ZnO and WO ₃, by Li ₂zn ₂w ₂o ₉chemical formula weigh batching.

(2) raw material step (1) being prepared mixes, and puts into ball grinder, adds zirconia ball and distilled water, and ball milling 8 hours, is mixed and finely ground, and takes out and dries, and crosses 200 mesh sieves.

(3) powder step (2) being mixed is 620 ~ 640 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, average diameter of particles diminished, and lower than 2 μ m, obtains Li ₂zn ₂w ₂o ₉powder.

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

The specific embodiment

To be specifically described the present invention below:

1, the composite oxides in order to obtain using in the present invention, are first used solid-phase synthesis to prepare powder, the various oxides as raw material or carbonate measured than mixing according to target constitutional chemistry, more synthetic in air atmosphere under normal pressure.

2, in order effectively to 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.The oxide powder of preparing with solid-phase synthesis, its particle is compared with large and surface area is less, but can particle diameter be diminished by ball mill pulverizing means.

3, photocatalysis experiment of the present invention is usingd methyl orange as simulation organic pollution, and its concentration is 20mg/L; Photocatalyst Li ₂zn ₂w ₂o ₉addition be 1g/L; Light source is used the xenon lamp of 300W, and the vessel that reactive tank is used pyrex to make, obtain by wave filter the light that wavelength is greater than 420nm long wavelength, then irradiate photochemical catalyst; Catalysis time is set as 60 minutes.

Embodiment 1:

(3) powder step (2) being mixed is 620 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, average diameter of particles diminished, and lower than 2 μ m, obtains Li ₂zn ₂w ₂o ₉powder.

Prepared photochemical catalyst, is greater than at wavelength under the radiation of visible light of 420nm, methyl orange clearance is reached to 98.7% in 60 minutes.

Embodiment 2:

(3) powder step (2) being mixed is 630 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, average diameter of particles diminished, and lower than 2 μ m, obtains Li ₂zn ₂w ₂o ₉powder.

Prepared photochemical catalyst, is greater than at wavelength under the radiation of visible light of 420nm, methyl orange clearance is reached to 99.5% in 60 minutes.

Embodiment 3:

(3) powder step (2) being mixed is 640 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, average diameter of particles diminished, and lower than 2 μ m, obtains Li ₂zn ₂w ₂o ₉powder.

Prepared photochemical catalyst, is greater than at wavelength under the radiation of visible light of 420nm, and 60min reaches 98.4% to methyl orange clearance.

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

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 with the form of film.

Claims

1. a visible light-responded photochemical catalyst, is characterized in that the chemical constitution formula of described photochemical catalyst is: Li ₂zn ₂w ₂o ₉;

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

(1) by 99.9% analytically pure chemical raw material Li ₂cO ₃, ZnO and and WO ₃, by Li ₂zn ₂w ₂o ₉chemical formula weigh batching;

(2) raw material step (1) being prepared mixes, and puts into ball grinder, adds zirconia ball and distilled water, and ball milling 8 hours, is mixed and finely ground, and takes out and dries, and crosses 200 mesh sieves;

(3) powder step (2) being mixed is 620 ~ 640 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, makes average diameter of particles lower than 2 μ m, obtains Li ₂zn ₂w ₂o ₉powder.