CN102600828B - Visible light responded composite oxide photocatalyst LiBiTiO4 and its preparation method - Google Patents

Abstract

The invention discloses a visible light responded composite oxide photocatalyst LiBiTiO4 and its preparation method. The composite oxide photocatalyst has a chemical composition formula as: LiBiTiO4. And the preparation method comprises: 1) weighing and burdening the 99.9% analytically pure chemical raw materials Li2CO3, Bi2O3 and TiO2 according to chemical formula LiBiTiO4; 2) mixing the raw materials well burdened in step (1), and putting the mixture into a ball milling pot, adding a zirconia ball and anhydrous ethanol, conducting ball milling for 12 hours for mixing and grinding, then taking out of the mixture, drying it, and sieving it through a sieve of 200 meshes; and 3) presintering the powder obtained in step (2) at a temperature of 800-950DEG C, and conducting heat preservation for 8-10 hours, and leaving the powder to cool naturally to room temperature, then decreasing the particle diameter to less than 2 micrometers through the ball mill and other crushing means, thus obtaining the composite oxide photocatalyst LiBiTiO4 powder. The preparation method of the invention is characterized by simplicity and low cost. The prepared photocatalyst has excellent catalytic performance, and has the effects of harmful chemical substance and organic biomass decomposition as well as sterilization under irradiation of visible lights.

Description

Visible light-responded composite oxide photocatalyst Li BiTiO 4And preparation method thereof

Technical field

The present invention relates to a kind of visible light-responded composite oxide photocatalyst Li BiTiO ₄And 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 the 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 having absorbed the photon that is 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 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 the organic matters such as 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 earth's surface, wavelength is that the energy of the visible region of 400nm～750nm approximately is 43% of sunshine gross energy, so in order to utilize efficiently solar spectrum, searching has the attention that visible light-responded photochemical catalyst has caused people.

Catalysis material is having important application prospect 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, 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.

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, exist still that light conversion efficiency is low, the problem such as poor stability and spectrum respective range are narrow, be 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 compound oxide photocatalyst with and preparation method thereof.

A kind of visible light-responded compound oxide photocatalyst that has provided by the invention is characterized in that the chemical constitution formula of described compound oxide photocatalyst is: LiBiTiO ₄

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

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, Bi ₂O ₃And TiO ₂, press LiBiTiO ₄The chemical formula weigh batching;

2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 12 hours mixes levigately, takes out oven dry, 200 mesh sieves;

3) with step (2) gained powder 800～950 ℃ of pre-burnings, and the insulation 8-10 hour, naturally cool to room temperature, then by pulverizing means such as ball mills particle diameter is diminished, be lower than 2 μ m, can obtain composite oxide photocatalyst Li BiTiO ₄Powder.

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

The specific embodiment

The below will be specifically described the present invention:

1, in order to obtain employed composite oxides among the present invention, at first use solid-phase synthesis to prepare powder, namely various oxides or carbonate as raw material are measured than mixing according to the target constitutional chemistry, 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 larger.With the oxide powder of solid-phase synthesis preparation, its particle is large 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 wavelength greater than 420nm long wavelength's light by wave filter, then shine photochemical catalyst; Catalysis time is set as 120min.

Embodiment 1:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, Bi ₂O ₃And TiO ₂, press LiBiTiO ₄The chemical formula weigh batching;

2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 12 hours mixes levigately, takes out oven dry, 200 mesh sieves.

3) with step (2) gained powder 800 ℃ of pre-burnings, and be incubated 10 hours, naturally cool to room temperature, then pulverize by ball mill particle diameter diminished, be lower than 2 μ m, can obtain composite oxide photocatalyst Li BiTiO ₄Powder.

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

Embodiment 2:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, Bi ₂O ₃And TiO ₂, press LiBiTiO ₄The chemical formula weigh batching;

2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 12 hours mixes levigately, takes out oven dry, 200 mesh sieves.

3) with step (2) gained powder 850 ℃ of pre-burnings, and be incubated 10 hours, naturally cool to room temperature, then pulverize by ball mill particle diameter diminished, be lower than 2 μ m, can obtain composite oxide photocatalyst Li BiTiO ₄Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 98.8% to the methyl orange clearance.

Embodiment 3:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, Bi ₂O ₃And TiO ₂, press LiBiTiO ₄The chemical formula weigh batching;

2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 12 hours mixes levigately, takes out oven dry, 200 mesh sieves.

3) with step (2) gained powder 900 ℃ of pre-burnings, and be incubated 9 hours, naturally cool to room temperature, then pulverize by ball mill particle diameter diminished, be lower than 2 μ m, can obtain composite oxide photocatalyst Li BiTiO ₄Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 99.3% to the methyl orange clearance.

Embodiment 4:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, Bi ₂O ₃And TiO ₂, press LiBiTiO ₄The chemical formula weigh batching;

2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 12 hours mixes levigately, takes out oven dry, 200 mesh sieves.

3) with step (2) gained powder 950 ℃ of pre-burnings, and be incubated 8 hours, naturally cool to room temperature, then pulverize by ball mill particle diameter diminished, be lower than 2 μ m, can obtain composite oxide photocatalyst Li BiTiO ₄Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 98.9% to the methyl orange clearance.

The present invention never is limited to above embodiment.Have element such as Zr with Ti analog structure and chemical property, Sn etc. also can make the photochemical catalyst with analogous crystalline structure of the present invention and performance.Bound, the interval value of the technological parameter of each raw material (such as temperature, time etc.) can both realize the present invention, do not enumerate one by one embodiment 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 constitution formula of described composite oxides is: LiBiTiO as the application of visible light-responded photochemical catalyst ₄

Preparation method's step of described composite oxides is:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, Bi ₂O ₃And TiO ₂, press LiBiTiO ₄The chemical formula weigh batching;

2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 12 hours mixes levigately, takes out oven dry, 200 mesh sieves;

3) with step (2) gained powder 800～950 ℃ of pre-burnings, and the insulation 8-10 hour, naturally cool to room temperature, then by pulverizing means such as ball mills particle diameter is diminished, be lower than 2 μ m, can obtain composite oxides LiBiTiO ₄Powder.