CN103611559A

CN103611559A - Bi2WO6-SrTaO2N composite photocatalyst and preparation method thereof

Info

Publication number: CN103611559A
Application number: CN201310644514.6A
Authority: CN
Inventors: 吕华; 刘玉民; 汤海波; 李紫金; 李爽; 丁志伟
Original assignee: Henan Normal University
Current assignee: Henan Normal University
Priority date: 2013-12-05
Filing date: 2013-12-05
Publication date: 2014-03-05
Anticipated expiration: 2033-12-05
Also published as: CN103611559B

Abstract

The invention discloses a Bi2WO6-SrTaO2N composite photocatalyst and a preparation method thereof, belonging to the field of inorganic functional materials. The technical scheme is as follows: the Bi2WO6-SrTaO2N composite photocatalyst is compounded from Bi2WO6 powder and SrTaO2N powder in a mole ratio of (5-15):1. The invention also discloses a preparation method of the Bi2WO6-SrTaO2N composite photocatalyst. Compared with the prior art, the Bi2WO6-SrTaO2N composite photocatalyst has the following advantages: the compounding of the Bi2WO6 and SrTaO2N can greatly widen the spectral response range of the Bi2WO6, so that the Bi2WO6 has favorable absorptivity in the visible light region, thereby enhancing the utilization ratio of solar energy; the compounding of the Bi2WO6 and SrTaO2N can effectively reduce the compound probability between photogenerated electrons and holes, and enhance the photocatalytic activity of the Bi2WO6; and the preparation method of the Bi2WO6-SrTaO2N composite photocatalyst is simple and easy to control.

Description

A kind of Bi 2wO 6-SrTaO 2n composite photo-catalyst and preparation method thereof

Technical field

The invention belongs to inorganic environment-friendly catalysis material technical field, be specifically related to a kind of Bi ₂wO ₆-SrTaO ₂n composite photo-catalyst and preparation method thereof.

Background technology

Utilize solar energy photocatalytic decomposing organic matter to become the important means that solves environmental pollution, but traditional catalysis material is as TiO ₂, ZnO etc. can only absorb ultraviolet light, spectral response range is narrow, has limited their practical application.Therefore, the visible light catalyst of the efficient response of design becomes photocatalysis science and pollutes and control one of great research topic facing.Bi ₂wO ₆be a kind of novel visible light-responded catalysis material that has, its energy gap is 2.8 eV, can absorbing wavelength be less than the visible ray of 442 nm, is a kind of high performance visible-light photocatalysis material that has.Yet, Bi ₂wO ₆the hole producing after photochemical catalyst optical excitation and the probability of electron recombination are high, and quantum effect is low, and photocatalytic activity is low.Therefore, improve the Focal point and difficult point that its photo-quantum efficiency and photocatalytic activity become the research of photocatalysis subject.

SrTaO ₂n is a kind of transition metal oxynitride, and because divalence oxygen element part is replaced by the less trivalent nitrogen element of electronegativity, metal cation is more or less reduced, and crystal structure changes, SrTaO ₂optical, electrical, magnetic that N thereby performance make new advances, mechanical property.Research shows, SrTaO ₂the energy gap of N is 2.2 eV, and energy absorbing wavelength is less than the visible ray of 563 nm, is a kind of catalysis material with visible light-responded ability.In order to improve Bi ₂wO ₆photo-quantum efficiency, by itself and the SrTaO with ideal bandgap ₂n is mutually compound, utilizes two kinds of energy level differences between semiconductor can make the photoproduction son that dams be injected on another kind of semi-conductive energy level by a kind of energy level of semiconductive particles, makes electric charge effectively separated, is to improve Bi ₂wO ₆the effective way of solar energy utilization ratio and photo-quantum efficiency.Bi ₂wO ₆the conduction band potential E of photochemical catalyst _cB=0.46 eV, valence band electromotive force E _vB=3.26 eV, and SrTaO ₂the conduction band potential E of N photochemical catalyst _cB=-0.71 eV, valence band electromotive force E _vB=1.49 eV.At Bi ₂wO ₆-SrTaO ₂in N composite semiconductor, SrTaO ₂the conduction band potential of N is more negative, and light induced electron is easily from the low SrTaO of energy level ₂n conduction band moves to the Bi that energy level is high ₂wO ₆on conduction band; Meanwhile, Bi ₂wO ₆valence band electromotive force corrigendum, photohole is easily from the high Bi of energy level ₂wO ₆valence band moves to the SrTaO that energy level is low ₂in N valence band, thereby the separative efficiency of raising photogenerated charge has been expanded Bi ₂wO ₆spectral response range.

Summary of the invention

The technical problem that the present invention solves has been to provide the Bi that a kind of photo-quantum efficiency is high, photocatalytic activity is good ₂wO ₆-SrTaO ₂n composite photo-catalyst.

Another technical problem that the present invention solves has been to provide a kind of simple to operate and Bi of being easy to control ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst.

Technical scheme of the present invention is: a kind of Bi ₂wO ₆-SrTaO ₂n composite photo-catalyst, it is characterized in that by Bi ₂wO ₆with SrTaO ₂compound and the Bi that forms of N powder ₂wO ₆-SrTaO ₂n composite photo-catalyst, wherein Bi ₂wO ₆with SrTaO ₂the mol ratio of N is 5-15:1.

Bi of the present invention ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst, it is characterized in that comprising the following steps: (1) by tantalum pentoxide, strontium carbonate and acetone in molar ratio the ratio of 1:2:15 join in agate mortar and to grind evenly, then sample is evenly laid on corundum boat, pack in tube-type atmosphere furnace, under ammonia atmosphere, 1000 ℃ of calcinings obtain SrTaO for 20 hours ₂n powder; (2) preparation bismuth citrate solution, under the condition stirring by the SrTaO of step (1) gained ₂n powder and sodium citrate solution join must mixed solution A, wherein bismuth citrate and the SrTaO adding in bismuth citrate solution ₂the mol ratio of N powder is 10-30:1, and bismuth citrate is 1:1 with the mol ratio of the natrium citricum adding; (3) preparation sodium tungstate solution, in joining mixed solution A by sodium tungstate solution, the condition stirring obtains mixed solution B, wherein in mixed solution A, bismuth citrate is 2:1 with the mol ratio of the sodium tungstate adding, then mixed solution B is kept in the water-bath of 80 ℃ 24 hours obtaining to wet gel, wet gel is dried to obtain xerogel through 110 ℃; (4) step (3) gained xerogel is transferred in Muffle furnace and after 2-12 hour, obtained having the Bi that has high catalytic activity 450-600 ℃ of maintenance ₂wO ₆-SrTaO ₂n composite photo-catalyst.

Bi of the present invention ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst, is characterized in that: in described step (2), the molar concentration of bismuth citrate solution is 0.1-0.5mol/L.Bi of the present invention ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst, is characterized in that: in described step (2), the molar concentration of sodium citrate solution is 0.5mol/L.Bi of the present invention ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst, is characterized in that: in described step (3), the molar concentration of sodium tungstate solution is 0.1-0.5mol/L.

The present invention compared with prior art has following remarkable advantage: 1, Bi ₂wO ₆with SrTaO ₂the compound of N can have been widened Bi greatly ₂wO ₆spectral response range, make Bi ₂wO ₆in visible region, there is good absorption, improved the utilization rate of solar energy; 2, Bi ₂wO ₆with SrTaO ₂the compound probability of recombination that can effectively reduce light induced electron and hole of N, improves Bi ₂wO ₆photocatalytic activity; 3, Bi of the present invention ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst is simple, is easy to control.

Accompanying drawing explanation

Fig. 1 is under 300W xenon lamp irradiates, the Bi of the embodiment of the present invention 1 preparation ₂wO ₆-SrTaO ₂n photochemical catalyst and pure Bi ₂wO ₆light is urged the correlation curve figure (operating condition: the amount of catalyst: 1 g/L of agent to rhodamine B degraded situation; The concentration of rhodamine B: 5 mg/L).

The specific embodiment:

Below in conjunction with embodiment, further describe the present invention.Be noted that the present invention is not limited to following each embodiment.

Embodiment 1

(1) tantalum pentoxide, strontium carbonate and the acetone that amount of substance is respectively to 0.0005mol, 0.001mol, 0.075mol joins in agate mortar and grinds evenly, then sample is evenly laid on corundum boat, pack in tube-type atmosphere furnace, under ammonia atmosphere, 1000 ℃ of calcinings obtain SrTaO for 20 hours ₂n powder;

(2) the preparation molar concentration bismuth citrate solution 100mL that is 0.1mol/L, the sodium citrate solution 20mL that preparation molar concentration is 0.5mol/L, under stirring condition by step (1) gained SrTaO ₂the sodium citrate solution of N powder and preparation joins in bismuth citrate solution to obtain mixed solution A;

(3) the sodium tungstate solution 50mL that preparation molar concentration is 0.1mol/L, in joining mixed solution A by sodium tungstate solution, stirring condition obtains mixed solution B, then mixed solution B is kept in the water-bath of 80 ℃ 24 hours obtaining to wet gel, wet gel is dried to obtain xerogel through 110 ℃;

(4) step (3) gained xerogel is transferred in Muffle furnace and after 12 hours, obtained having the Bi that has high catalytic activity 450 ℃ of maintenances ₂wO ₆-SrTaO ₂n composite photocatalyst.

Embodiment 2

(2) the preparation molar concentration bismuth citrate solution 100mL that is 0.2mol/L, the sodium citrate solution 40mL that preparation molar concentration is 0.5mol/L, under the condition stirring by step (1) gained SrTaO ₂the sodium citrate solution of N powder and preparation joins in bismuth citrate solution to obtain mixed solution A;

(3) the sodium tungstate solution 50mL that preparation molar concentration is 0.2mol/L, in joining mixed solution A by sodium tungstate solution, stirring condition obtains mixed solution B, then mixed solution B is kept in the water-bath of 80 ℃ 24 hours obtaining to wet gel, wet gel is dried to obtain xerogel through 110 ℃;

(4) step (3) gained xerogel is transferred in Muffle furnace and after 6 hours, obtained having the Bi that has high catalytic activity 500 ℃ of maintenances ₂wO ₆-SrTaO ₂n composite photocatalyst.

Embodiment 3

(2) the preparation molar concentration bismuth citrate solution 60mL that is 0.5mol/L, the sodium citrate solution 60mL that preparation molar concentration is 0.5mol/L, under stirring condition by step (1) gained SrTaO ₂the sodium citrate solution of N powder and preparation joins in bismuth citrate solution to obtain mixed solution A;

(3) the sodium tungstate solution 30mL that preparation molar concentration is 0.5mol/L, in joining mixed solution A by sodium tungstate solution, stirring condition obtains mixed solution B, then mixed solution B is kept in the water-bath of 80 ℃ 24 hours obtaining to wet gel, wet gel is dried to obtain xerogel through 110 ℃;

(4) step (3) gained xerogel is transferred in Muffle furnace and after 2 hours, obtained having the Bi that has high catalytic activity 600 ℃ of maintenances ₂wO ₆-SrTaO ₂n composite photocatalyst.

Above embodiment has described basic principle of the present invention, principal character and advantage.The technical staff of the industry should understand; the present invention is not restricted to the described embodiments; that in above-described embodiment and description, describes just illustrates principle of the present invention; do not departing under the scope of the principle of the invention; the present invention also has various changes and modifications, and these changes and improvements all fall in the scope of protection of the invention.

Claims

1. a Bi ₂wO ₆-SrTaO ₂n composite photo-catalyst, it is characterized in that by Bi ₂wO ₆with SrTaO ₂compound and the Bi that forms of N powder ₂wO ₆-SrTaO ₂n composite photo-catalyst, wherein Bi ₂wO ₆with SrTaO ₂the mol ratio of N is 5-15:1.

2. the Bi described in a claim 1 ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst, it is characterized in that comprising the following steps: (1) by tantalum pentoxide, strontium carbonate and acetone in molar ratio the ratio of 1:2:15 join in agate mortar and to grind evenly, then sample is evenly laid on corundum boat, pack in tube-type atmosphere furnace, under ammonia atmosphere, 1000 ℃ of calcinings obtain SrTaO for 20 hours ₂n powder; (2) preparation bismuth citrate solution, under the condition stirring by the SrTaO of step (1) gained ₂n powder and sodium citrate solution join must mixed solution A, wherein bismuth citrate and the SrTaO adding in bismuth citrate solution ₂the mol ratio of N powder is 10-30:1, and bismuth citrate is 1:1 with the mol ratio of the natrium citricum adding; (3) preparation sodium tungstate solution, in joining mixed solution A by sodium tungstate solution, the condition stirring obtains mixed solution B, wherein in mixed solution A, bismuth citrate is 2:1 with the mol ratio of the sodium tungstate adding, then mixed solution B is kept in the water-bath of 80 ℃ 24 hours obtaining to wet gel, wet gel is dried to obtain xerogel through 110 ℃; (4) step (3) gained xerogel is transferred in Muffle furnace and after 2-12 hour, obtained having the Bi that has high catalytic activity 450-600 ℃ of maintenance ₂wO ₆-SrTaO ₂n composite photo-catalyst.

3. Bi according to claim 2 ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst, is characterized in that: in described step (2), the molar concentration of bismuth citrate solution is 0.1-0.5mol/L.

4. Bi according to claim 2 ₂wO ₆-SrTaO ₂the preparation method of N composite photo-catalyst, is characterized in that: in described step (2), the molar concentration of sodium citrate solution is 0.5mol/L.

5. Bi according to claim 2 ₂wO ₆the preparation method of-SrTaO2N composite photo-catalyst, is characterized in that: in described step (3), the molar concentration of sodium tungstate solution is 0.1-0.5mol/L.