CN102228830B - Visible light responding composite oxide photocatalyst LiWNb1-xTaxO6 and preparation method thereof - Google Patents

Abstract

The invention discloses a visible light responding composite oxide photocatalyst LiWNb1-xTaxO6 and a preparation method thereof. The general formula of chemical composition of the composite oxide photocatalyst is LiWNb1-xTaxO6, wherein x is no less than 0 and no more than 1. The preparation method comprises the following steps: weighing and preparing chemical raw materials Li2CO3, WO3, Nb2O5 and Ta2O5 which are an analytical purity of 99.9% according to the chemical formula LiWNb1-xTaxO6, wherein x is no less than 0 and no more than 1; mixing the weighed raw materials, putting the mixture into a ball milling jar, adding zirconia balls and anhydrous ethanol, carrying out ball milling for 12 hours to grind the mixture into fine powder, drying the powder and sieving the powder with a 200 mesh sieve; pre-burning uniformly mixed powder at a temperature of 800 to 920 DEG C, keeping the powder at the temperature for 8 to 10 hours, naturally cooling the powder to room temperature and diminishing particle diameter of the powder by crushing means like a ball mill to less than 2 mu m so as to obtain composite oxide photocatalyst LiWNb1-xTaxO6 powder. According to the invention, the preparation method is simple and the cost is low; the prepared photocatalyst has excellent catalysis performance, can decompose harmful chemicals under irradiation of visible light, shows good stability and has a good application prospect.

Description

Visible light responded composite oxide photocatalyst LiWNb 1-xTa xO 6And preparation method

Technical field

The present invention relates to a kind of visible light responded composite oxide photocatalyst LiWNb _1-xTa _xO ₆(0≤x≤1) and preparation method thereof belongs to inorganic field of photocatalytic material.

Background technology

Along with The development in society and economy, people more and more pay close attention to for the energy and ecological environment, solve energy shortage and problem of environmental pollution and be to realize sustainable development, raising people's living standard and pressing for of safeguarding national security.

From phase late 1970s, people proposed to utilize in the photochemical catalyst decomposition water with atmosphere in organic matters such as agricultural chemicals and 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 having absorbed the photon that is higher than its band-gap energy; Hole and electronics have been generated; These holes and electronics carry out oxidation reaction and reduction reaction respectively, reach the purpose 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 in the water with atmosphere in organic matters such as agricultural chemicals and odorant decompose; 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 the local work of uviol lamp arranged; Almost can not utilize visible light, 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 the face of land; Wavelength is that the energy of the visible region of 400nm-750nm approximately is 43% of a sunshine gross energy; So in order to utilize solar spectrum efficiently, searching has the attention that visible light-responded photochemical catalyst has caused people.

Catalysis material is having important application prospects aspect the solution energy and the environmental problem.In the last few years; Photochemical catalyst has caused countries in the world scientist's concern; Many famous research institutions and enterprise drop into the research that huge fund is engaged in photochemical catalyst mechanism and application in succession, and photochemical catalyst has begun to get in many fields such as antibiotic, deodorization, antifouling and water treatments to be applied the stage.Some scientists think that because photochemical catalyst has good depollution of environment effect, along with going deep into of various countries' research work, this new material will become one of 21 century brand-new material product the most likely.

Though photocatalysis research has been carried out the several years; But at present report to have visible light-responded photochemical catalyst kind still very limited; Problem such as exist still that light conversion efficiency is low, poor stability and spectrum respective range are narrow is very necessary so research and develop the new visible light-responded high efficiency photocatalyst that has.

Summary of the invention

The purpose of this invention is to provide a kind of have visible light responded composite oxide photocatalyst with and preparation method thereof.

A kind of visible light responded composite oxide photocatalyst that has provided by the invention is characterized in that the chemical composition general formula of said compound oxide photocatalyst is: LiWNb _1-xTa _xO ₆, 0≤x≤1.

The preparation method of above-mentioned visible light responded composite oxide photocatalyst, carry out according to the following steps:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, WO ₃, Nb ₂O ₅And Ta ₂O ₅, press LiWNb _1-xTa _xO ₆Chemical formula weigh batching, wherein 0≤x≤1;

2) step (1) confected materials is mixed, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 12h mixes levigately, takes out oven dry, 200 mesh sieves;

3) powder that step (2) is mixed is 800-920 ℃ of pre-burning, and insulation 8-10h, naturally cools to room temperature, through pulverizing means such as ball mills particle diameter is diminished then, is lower than 2 μ m, can obtain composite oxide photocatalyst Li WNb _1-xT _xO ₆Powder.

Preparation method of the present invention is simple, cost is low, and the photochemical catalyst of preparation has excellent catalytic performance, under radiation of visible light, has the effect of decomposing harmful chemical, organic-biological matter and sterilization.

The specific embodiment

To specify the present invention below:

1, in order to obtain employed composite oxides among the present invention, at first use solid-phase synthesis to prepare powder, promptly mix various oxides or carbonate according to target composition stoichiometric proportion as raw material, synthetic in air atmosphere under normal pressure again.

2, in order effectively to utilize light, the size of the photochemical catalyst among the present invention is preferably in micron level, or even nano particle, and specific area is bigger.With the oxide powder of solid-phase synthesis preparation, its particle is big and surface area is less, but can particle diameter diminished through pulverizing means such as ball mills.

3, as the simulation organic pollution, its concentration is 20mg/L with methyl orange in photocatalysis experiment of the present invention; The addition of bismuth-system compound oxide photocatalyst is 1g/L; Light source uses the xenon lamp of 300W, and the vessel that reactive tank uses pyrex to process obtain the light of wavelength greater than 420nm long wavelength, irradiates light catalyst then through wave filter; The catalysis time set is 120min.

Embodiment

Serve as that the basis is elaborated to the present invention with concrete practical operation example below.

Embodiment 1:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, WO ₃And Nb ₂O ₅, press LiWNbO ₆The chemical formula weigh batching;

2) confected materials is mixed, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 12h mixes levigately, takes out oven dry, 200 mesh sieves;

3) the above-mentioned powder that mixes is 800 ℃ of pre-burnings, and insulation 8h, naturally cools to room temperature, through pulverizing means such as ball mills particle diameter diminished then, is lower than 2 μ m, can obtain composite oxide photocatalyst Li WNbO ₆Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 96.9% to the methyl orange clearance.

Embodiment 2:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, WO ₃And Ta ₂O ₅, press LiWTaO ₆The chemical formula weigh batching;

2) confected materials is mixed, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 12h mixes levigately, takes out oven dry, 200 mesh sieves;

3) the above-mentioned powder that mixes is 920 ℃ of pre-burnings, and insulation 10h, naturally cools to room temperature, through pulverizing means such as ball mills particle diameter diminished then, is lower than 2 μ m, can obtain composite oxide photocatalyst Li WTaO ₆Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 97.9% to the methyl orange clearance.

Embodiment 3:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, WO ₃, Nb ₂O ₅, Ta ₂O ₅, press LiWNb _0.5Ta _0.5O ₆The chemical formula weigh batching;

2) confected materials is mixed, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 12h mixes levigately, takes out oven dry, 200 mesh sieves;

3) the above-mentioned powder that mixes is 900 ℃ of pre-burnings, and insulation 9h, naturally cools to room temperature, through pulverizing means such as ball mills particle diameter diminished then, is lower than 2 μ m, can obtain composite oxide photocatalyst Li WNb _0.5Ta _0.5O ₆Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 98.6% to the methyl orange clearance.

Embodiment 4:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, WO ₃, Nb ₂O ₅, Ta ₂O ₅, press LiWNb _0.7Ta _0.3O ₆The chemical formula weigh batching.

2) chemical raw material for preparing is mixed, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 12h mixes levigately, takes out oven dry, 200 mesh sieves.

3) the above-mentioned powder that mixes is 880 ℃ of pre-burnings, and insulation 9h, naturally cools to room temperature, pulverizes through ball mill then particle diameter is diminished, and is lower than 2 μ m, can obtain composite oxide photocatalyst Li WNb _0.7Ta _0.3O ₆Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 98.6% to the methyl orange clearance.

Embodiment 5:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, WO ₃, Nb ₂O ₅, Ta ₂O ₅, press LiWNb _0.2Ta _0.8O ₆The chemical formula weigh batching.

2) chemical raw material for preparing is mixed, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 12h mixes levigately, takes out oven dry, 200 mesh sieves.

3) the above-mentioned powder that mixes is 910 ℃ of pre-burnings, and insulation 9h, naturally cools to room temperature, pulverizes through ball mill then particle diameter is diminished, and is lower than 2 μ m, can obtain composite oxide photocatalyst Li WNb _0.2Ta _0.8O ₆Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 98.3% to the methyl orange clearance.

The present invention never is limited to above embodiment.Have and Nb, the element of Ta analog structure and chemical property such as V, Sb etc. also can make the photochemical catalyst with analogous crystalline structure of the present invention and performance.The bound of each raw material, interval value, and the bound of technological parameter (like temperature, time etc.), interval value can both realize the present invention, do not enumerate embodiment one by one at this.

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

Claims (1)

1. composite oxides is characterized in that the chemical composition general formula of said composite oxides is: LiWNb in visible light-responded Application in Photocatalysis _1-xTa _xO ₆, 0≤x≤1 wherein;

Preparation method's step of described composite oxides is:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, WO ₃, Nb ₂O ₅And Ta ₂O ₅, press LiWNb _1-xTa _xO ₆, chemical formula weigh batching, wherein 0≤x≤1;

2) step (1) confected materials is mixed, put into ball grinder, add zirconia ball and absolute ethyl alcohol, ball milling 12h mixes levigately, takes out oven dry, 200 mesh sieves;

3) powder that step (2) is mixed is 800-920 ℃ of pre-burning, and insulation 8-10h, naturally cools to room temperature, through ball mill pulverizing means particle diameter is diminished then, is lower than 2 μ m, can obtain composite oxide photocatalyst Li WNb _1-xTa _xO ₆Powder.