CN103157459A

CN103157459A - Visible-light-responsive vanadate photocatalyst LiMVO4 and preparation method thereof

Info

Publication number: CN103157459A
Application number: CN2013101106850A
Authority: CN
Inventors: 方亮; 韦珍海; 唐莹
Original assignee: Guilin University of Technology
Current assignee: Guilin University of Technology
Priority date: 2013-04-01
Filing date: 2013-04-01
Publication date: 2013-06-19

Abstract

The invention discloses a visible-light-responsive vanadate photocatalyst LiMVO4 and a preparation method thereof. The general formula of the chemical composition of the vanadate photocatalyst is LiMVO4, wherein M is Mg, Zn or Co. The invention also discloses a preparation method of the material. The preparation method disclosed by the invention is simple and low in cost; and the prepared photocatalyst has the advantages of excellent catalytic property and high stability, has the function of decomposing harmful chemical substances under visible light irradiation, and thus, has favorable application prospects.

Description

Visible light-responded vanadate photocatalyst Li MVO 4And preparation method thereof

Technical field

The present invention relates to a kind of visible light-responded vanadate photocatalyst Li MVO 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 the photon that has 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 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 water and the agricultural chemicals in atmosphere and the organic matters such as odorant decompose, yet the band gap of titanium dioxide is 3.2eV, only just can show activity under the ultraviolet irradiation shorter than 400nm, 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 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, bismuthous compound such as BiVO ₄, Bi ₂MoO ₆, Bi ₂Mo ₂O ₉, Bi ₂Mo ₃O ₁₂And Bi ₂WO ₄Be reported in and have good absorption under visible light.A series of niobiums (tantalum) hydrochlorate photochemical catalyst is widely studied owing to having higher photocatalytic activity.For example, niobate photocatalyst Pb ₃Nb ₄O ₁₃, BiNbO ₄And Bi ₂MNbO ₇(M=Al, Ga, In, Y, rare earth element and Fe) etc. and niobium potassium compound oxide photocatalyst such as KNbO ₃, KNb ₃O ₈, K ₄Nb ₆O ₁₇And K ₆Nb _10.6O ₃₀Deng all having photocatalysis performance preferably.

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, poor stability and the problem such as the spectrum respective range is narrow, be very necessary so research and develop the new visible light-responded high efficiency photocatalyst that has.Document [D. Capsoni, M. Bini, V. Massarotti, P. Mustarelli, F. Belotti, and P. Galinetto, Cation Distribution in LiMgVO ₄And LiZnVO ₄: Structural and Spectroscopic Study, J. Phys. Chem. B 2006,110:5409-5415] contain the serial vanadate LiMVO of lithium ₄Crystal structure and the spectral characteristic of (M=Zn or Mg) have also been introduced this compounds and have been had application prospect in fields such as electrochemistry, gas sensor, luminescent materials.Consider the research report that there is no at present relevant this compounds photocatalysis performance, we are to vanadate LiMVO ₄(M=Mg, Zn or Co) carried out Photocatalytic Performance Study, found that this compounds has excellent visible light-responded photocatalysis performance.

Summary of the invention

The purpose of this invention is to provide a kind of visible light-responded vanadate photocatalyst Li MVO that has ₄And preparation method thereof.

The chemical composition general formula with visible light-responded vanadate photochemical catalyst that the present invention relates to is: LiMVO ₄, wherein M is a kind of in Mg, Zn and Co.

Preparation method's concrete steps of above-mentioned visible light-responded vanadate photochemical catalyst are:

(1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, MO and V ₂O ₅, press LiMVO ₄The chemical formula weigh batching, wherein M is a kind of in Mg, Zn and Co.

(2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 8 hours mixes levigately, takes out oven dry, mistake 200 mesh sieves.

(3) powder that step (2) is mixed is 750 ~ 780 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by pulverizing means such as ball mills, particle diameter diminished, and lower than 2 μ m, namely obtains vanadate LiMVO 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, at first the composite oxides in order to obtain using in the present invention use solid-phase synthesis to prepare powder, namely as the various oxides of raw material or carbonate according to the metering of target constitutional chemistry than mixing, then synthesize 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.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; Vanadate photocatalyst Li MVO ₄Addition be 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 120 minutes.

Embodiment 1:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, MgO and V ₂O ₅, press LiMgVO 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 8 hours mixes levigately, takes out oven dry, mistake 200 mesh sieves.

3) powder that step (2) is mixed is 770 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, particle diameter diminished, and lower than 2 μ m, namely obtains vanadate LiMgVO ₄Powder.

Prepared photochemical catalyst under the radiation of visible light of wavelength greater than 420nm, reached 97.3% to the methyl orange clearance in 120 minutes.

Embodiment 2:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, CoO and V ₂O ₅, press LiCoVO ₄The chemical formula weigh batching.

3) powder that step (2) is mixed is 760 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, particle diameter diminished, and lower than 2 μ m, namely obtains vanadate LiCoVO ₄Powder.

Prepared photochemical catalyst under the radiation of visible light of wavelength greater than 420nm, reached 98.4% to the methyl orange clearance in 120 minutes.

Embodiment 3:

1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, ZnO and V ₂O ₅, press LiZnVO ₄The chemical formula weigh batching.

3) powder that step (2) is mixed is 750 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, particle diameter diminished, and lower than 2 μ m, namely obtains vanadate LiZnVO ₄Powder.

Prepared photochemical catalyst, under the radiation of visible light of wavelength greater than 420nm, 120min reaches 99.1% to the methyl orange clearance.

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

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 vanadate as the application of visible light-responded photochemical catalyst, is characterized in that the chemical composition general formula of described vanadate is: LiMVO ₄, wherein M is a kind of in Mg, Zn and Co;

Preparation method's concrete steps of described vanadate are:

(1) with 99.9% analytically pure chemical raw material Li ₂CO ₃, MO and V ₂O ₅, press LiMVO ₄The chemical formula weigh batching, wherein M is a kind of in Mg, Zn and Co;

(2) raw material that step (1) prepared mixes, and puts into ball grinder, adds zirconia ball and absolute ethyl alcohol, and ball milling 8 hours mixes levigately, takes out oven dry, mistake 200 mesh sieves;

(3) powder that step (2) is mixed is 750 ~ 780 ℃ of pre-burnings, and is incubated 6 hours, naturally cools to room temperature, then by ball mill pulverizing means, particle diameter diminished, and lower than 2 μ m, namely obtains vanadate LiMVO ₄Powder.