CN101773823A - Visible light responded composite oxide photocatalyst BaLi2Nb2-xTaxO9 and preparation method thereof - Google Patents

Abstract

The invention discloses a visible light responded composite oxide photocatalyst. The chemical general formula of the composite oxide photocatalyst is BaLi2Nb2-xTaxO9, wherein x is more than or equal to 0 and less than or equal to 2. The preparation method comprises the followings steps: 1) weighing and preparing 99.9 percent of analytical-purity chemical raw materials, namely BaCO3, Li2CO3, Nb2O5 and Ta2O5 according to the chemical formula of BaLi2Nb2-xTaxO9, wherein x is more than or equal to 0 and less than or equal to 2; 2) mixing the prepared raw materials, putting the mixture into a mill pot, adding zirconia balls and absolute ethyl alcohol, performing ball milling for 12 hours, mixing, grinding, taking out, drying, and sieving with a 200-mesh sieve; and 3) presintering the powder obtained in the step 2) at the temperature of between 700 and 1,000 DEG C, preserving the heat for 8 to 10 hours, naturally cooling to room temperature, and grinding to make particles smaller, namely about 2 mu m. The preparation method has the advantages of simpleness and low cost; the prepared photocatalyst has good catalytic performance, has the effect of decomposing harmful chemical substances under the radiation of visible light, and has high stability.

Description

Visible light responded composite oxide photocatalyst Ba 3Li 2Nb 2-xTa xO 9And preparation method

Technical field

The present invention relates to a kind of visible light responded composite oxide photocatalyst Ba ₃Li ₂Nb _2-xTa _xO ₉And preparation method thereof.

Background technology

Environmental pollution is the problem that countries in the world are extremely paid close attention to, and has caused drinking water source, the industry water source quality of people's lives constantly to descend, and causes atmosphere pollution constantly to aggravate, and causes the continuous destruction of ecological environment, and human existence is constituted a serious threat.In order to address these problems, people control by the whole bag of tricks and curb environmental pollution.

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.At present, the photochemical catalyst that uses is mainly titanium dioxide, 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 almost can not utilize visible light indoor or the local work of uviol lamp is arranged, 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.At present report to have visible light-responded photochemical catalyst kind still very limited, 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 composite oxide photocatalyst with and preparation method thereof.

The chemical composition general formula of visible light responded composite oxide photocatalyst provided by the invention is: Ba ₃Li ₂Nb _2-xTa _xO ₉, 0≤x≤2 wherein.

Above-mentioned visible light responded composite oxide photocatalyst Ba ₃Li ₂Nb _2-xTa _xO ₉The preparation method, concrete steps are:

1) with 99.9% analytically pure chemical raw material BaCO ₃, Li ₂CO ₃, Nb ₂O ₅And Ta ₂O ₅, press Ba ₃Li ₂Nb _2-xTa _xO ₉Chemical 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 700-1000 ℃ 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 Ba ₃Li ₂Nb _2-xTa _xO ₉Powder.

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, prepare powder, promptly various oxides or carbonate as raw material are mixed according to target composition stoichiometric proportion by solid-phase synthesis, 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; Composite oxide photocatalyst Ba ₃Li ₂Nb _2-xTa _xO ₉Addition be 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 1:

1) with 99.9% analytically pure chemical raw material BaCO ₃, Li ₂CO ₃And Nb ₂O ₅, press Ba ₃Li ₂Nb ₂O ₉The 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 700 ℃ 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 Ba ₃Li ₂Nb ₂O ₉Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 99% to the methyl orange clearance.

Embodiment 2:

1) with 99.9% analytically pure chemical raw material BaCO ₃, Li ₂CO ₃, Nb ₂O ₅And Ta ₂O ₅, press Ba ₃Li ₂Nb _1.5Ta _0.5O ₉The 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 880 ℃ 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 Ba ₃Li ₂Nb _1.5Ta _0.5O ₉Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 98.5% to the methyl orange clearance.

Embodiment 3:

1) with 99.9% analytically pure chemical raw material BaCO ₃, Li ₂CO ₃, Nb ₂O ₅And Ta ₂O ₅, press Ba ₃Li ₂NbTaO ₉The 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 930 ℃ 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 Ba ₃Li ₂NbTaO ₉Powder.

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

Embodiment 4:

1) with 99.9% analytically pure chemical raw material BaCO ₃, Li ₂CO ₃, Nb ₂O ₅And Ta ₂O ₅, press Ba ₃Li ₂Nb _0.5Ta _1.5O ₉The 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 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 Ba ₃Li ₂Nb _0.5Ta _1.5O ₉Powder.

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

Embodiment 5:

1) with 99.9% analytically pure chemical raw material BaCO ₃, Li ₂CO ₃And Ta ₂O ₅, press Ba ₃Li ₂Ta ₂O ₉The 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 1000 ℃ 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 Ba ₃Li ₂Ta ₂O ₉Powder.

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, as Mo, 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 bound, the interval value of technological parameter (as temperature, time, pH value etc.) 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. a visible light responded composite oxide photocatalyst is characterized in that the chemical composition general formula of compound oxide photocatalyst is: Ba ₃Li ₂Nb _2-xTa _xO ₉, 0≤x≤2 wherein.

2. the preparation method of compound oxide photocatalyst according to claim 1 is characterized in that concrete steps are:

1) with 99.9% analytically pure chemical raw material BaCO ₃, Li ₂CO ₃, Nb ₂O ₅And Ta ₂O ₅, press Ba ₃Li ₂Nb _2-xTa _xO ₉Chemical 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 700-1000 ℃ of pre-burning, and insulation 8-10h naturally cools to room temperature, pulverizes then particle diameter is diminished, and reaches about 2 μ m, can obtain composite oxide photocatalyst Ba ₃Li ₂Nb _2-xTa _xO ₉Powder.