CN101757905B - Visible light responding composite oxide photocatalyst Li6Ti5Nb2-xTaxO18 and preparation method - Google Patents

Abstract

The invention discloses a visible light responding composite oxide photocatalyst Li6Ti5Nb2-xTaxO18 and a preparation method. The method comprises the following steps: 1) weighing and batching 99.9% of the analytically pure chemical materials such as Li2CO3, TiO2, Nb2O5 and Ta2O5 according to the chemical formula Li6Ti5Nb2-xTaxO18; 2) mixing the batched materials, placing the materials into a ball milling pot, adding zirconia balls and absolute ethyl alcohol, carrying out ball milling for 12h, mixing and levigating the materials, taking out and drying the materials and sieving the materials with 200-mesh sieves; and 3) preburning the powder obtained in the step 2) at 950-1150 DEG C, preserving heat for 8-10h, naturally cooling the powder to the room temperature and then ensuring the diameter of the particles to be around 2mu m by grinding, thus obtaining the composite oxide photocatalyst Li6Ti5Nb2-xTaxO18 powder. The method is simple and low in cost. The prepared photocatalyst has excellent catalytic performance and has the effect of decomposing harmful chemicals and organic biomass and the effect of sterilization under the irradiation of the visible light.

Description

Visible light responded composite oxide photocatalyst Li 6Ti 5Nb 2-xTa xO 18And preparation method

Technical field

The present invention relates to a kind of visible light responded composite oxide photocatalyst Li ₆Ti ₅Nb _2-xTa _xO ₁₈And preparation method thereof, belong 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, improve 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 and atmosphere in agricultural chemicals and 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 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 and the agricultural chemicals in the atmosphere and organic matters such as odorant decompose, yet the band gap of titanium dioxide is 3.2eV, only under than the short ultraviolet irradiation of 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 near sunshine medium wavelength visible light intensity maximum 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 enter the stage of applying in many fields such as antibiotic, deodorization, antifouling and water treatments.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 most promising brand-new material product of 21 century.

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 described compound oxide photocatalyst is: Li ₆Ti ₅Nb _2-xTa _xO ₁₈, 0≤x≤2 wherein.

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, TiO ₂, Nb ₂O ₅And Ta ₂O ₅, press Li ₆Ti ₅Nb _2-xTa _xO ₁₈The 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) with step (2) gained powder 950-1150 ℃ of pre-burning, and the insulation 8-10h, naturally cool to room temperature, by pulverizing means such as ball mills particle diameter is diminished then, reach about 2 μ m, can obtain composite oxide photocatalyst Li ₆Ti ₅Nb _2-xTa _xO ₁₈Powder.

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

The specific embodiment

To be specifically described 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 various oxides or carbonate as raw material are mixed according to target composition stoichiometric proportion, 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 be diminished by 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 make obtain the light of wavelength greater than 420nm long wavelength, irradiates light catalyst then by wave filter; The catalysis time set is 120min.

Embodiment

Serve as that the present invention is described in detail on the basis with concrete practical operation example below.

Embodiment 1:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, TiO ₂And Nb ₂O ₅, press Li ₆Ti ₅Nb ₂O ₁₈The 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) with step (2) gained powder 950 ℃ of pre-burnings, and insulation 10h naturally cools to room temperature, pulverizes by ball mill then particle diameter is diminished, and reaches about 2 μ m, can obtain composite oxide photocatalyst Li ₆Ti ₅Nb ₂O ₁₈Powder.

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

Embodiment 2:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, TiO ₂, Nb ₂O ₅And Ta ₂O ₅, press Li ₆Ti ₅Nb _1.5Ta _0.5O ₁₈The 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) with step (2) gained powder 1020 ℃ of pre-burnings, and insulation 10h naturally cools to room temperature, pulverizes by ball mill then particle diameter is diminished, and reaches about 2 μ m, can obtain composite oxide photocatalyst Li ₆Ti ₅Nb _1.5Ta _0.5O ₁₈Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 98.1% to the methyl orange clearance.

Embodiment 3:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, TiO ₂, Nb ₂O ₅And Ta ₂O ₅, press Li ₆Ti ₅NbTaO ₁₈The 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) with step (2) gained powder 1070 ℃ of pre-burnings, and insulation 9h naturally cools to room temperature, pulverizes by ball mill then particle diameter is diminished, and reaches about 2 μ m, can obtain composite oxide photocatalyst Li ₆Ti ₅NbTaO ₁₈Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 97.6% to the methyl orange clearance.

Embodiment 4:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, TiO ₂, Nb ₂O ₅And Ta ₂O ₅, press Li ₆Ti ₅Nb _0.8Ta _1.2O ₁₈The 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) with step (2) gained powder 1120 ℃ of pre-burnings, and insulation 8h naturally cools to room temperature, pulverizes by ball mill then particle diameter is diminished, and reaches about 2 μ m, can obtain composite oxide photocatalyst Li ₆Ti ₅Nb _0.8Ta _1.2O ₁₈Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 97.2% to the methyl orange clearance.

Embodiment 5:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, TiO ₂And Ta ₂O ₅, press Li ₆Ti ₅Ta ₂O ₁₈The 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 8-10h mixes levigately, takes out oven dry, 200 mesh sieves.

3) with step (2) gained powder 1150 ℃ of pre-burnings, and insulation 8h naturally cools to room temperature, pulverizes by ball mill then particle diameter is diminished, and reaches about 2 μ m, can obtain composite oxide photocatalyst Li ₆Ti ₅Ta ₂O ₁₈Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 96.8% 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 (as 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 (2)

1. one kind has visible light responded composite oxide photocatalyst, it is characterized in that the chemical composition general formula of described compound oxide photocatalyst is: Li ₆Ti ₅Nb _2-xTa _xO ₁₈, 0≤x≤2 wherein.

2. the preparation method with visible light responded composite oxide photocatalyst as claimed in claim 1 is characterized in that concrete steps are:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, TiO ₂, Nb ₂O ₅And Ta ₂O ₅, press Li ₆Ti ₅Nb _2-xTa _xO ₁₈Chemical formula weigh batching, wherein 0≤x≤2;

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) with step (2) gained powder 950-1150 ℃ of pre-burning, and insulation 8-10h naturally cools to room temperature, pulverizes then particle diameter is diminished, and reaches 2 μ m, can obtain composite oxide photocatalyst Li ₆Ti ₅Nb _2-xTa _xO ₁₈Powder.