CN106031869A - A BiVO4/TiO2 composite nanorod having visible light activity, and preparation and applications thereof - Google Patents

Abstract

A BiVO4/TiO2 composite nanorod having visible light activity is disclosed and is a light-yellow nanometer composite prepared by subjecting a TiO2 nanorod and BiVO4 in a mass ratio of 1:0.25-0.75 to a hydrothermal reaction. A preparing method of the composite nanorod mainly includes preparing the TiO2 nanorod and the BiVO4 into suspension, performing the hydrothermal reaction at 120-200 DEG C for 12-36 h, repeatedly washing the precipitate, drying, calcinating the dried precipitate at 500 DEG C for 3-8 h to obtain a light-yellow powdered compound that is the composite nanorod. Applications of the composite nanorod for catalytic degradation of pollutants are also provided. The composite nanorod is high in specific surface area and high in adsorbability. Compared with titanium oxide nanorods in the prior art, the composite nanorod has better visible light adsorbability and has a greatly improved capability of photocatalytic oxidation degradation of organic pollutants. The preparing method is simple, easy to operate and suitable for industrial production.

Description

A kind of BiVO with visible light activity4/TiO2Composite nanorod and preparation and application

Technical field

The present invention relates to a kind of semiconductor light-catalyst for curbing environmental pollution and preparation and application.

Background technology

Along with making constant progress of human society, energy crisis and environmental problem have been that the 21 century mankind have to face Two severe challenges, the most effectively controlling and administering various chemical pollutant to the pollution of environment is that environment comprehensive is controlled Emphasis in reason.In recent years, Photocatalytic Oxidation With Semiconductors technology, as one of high-level oxidation technology, just by domestic Outer scholar's is widely studied, and this technology can be degraded using solar energy as the energy pollutant in environment, effectively Utilize solar energy, reduce the utilization of energy of people.

Photocatalytic Oxidation With Semiconductors technology starts from Japanese Scientists Fujishima and Honda and finds the TiO by photoirradiation₂ Single Crystalline Electrodes can be by H₂O decomposes, and utilizes TiO₂Semiconductor light-catalyst just converts light energy into electric energy and chemical energy Become the study hotspot of field of semiconductor photocatalyst.At present, TiO₂Semiconductor light-catalyst primarily can be used for degraded to be had The aspects such as organic pollutants, deodorization, sterilization, automatically cleaning.But, Detitanium-ore-type TiO₂Energy gap be 3.2eV, Its excitation wavelength is 387.5nm, belongs to the ultraviolet light range in sunlight.And for solar energy, its main energetic collection In in the visible-range of 400～600nm, this considerably reduce TiO₂The efficiency of semiconductor light-catalyst, therefore, How to realize TiO₂The visible light activity of semiconductor light-catalyst, efficiently utilizing the visible ray in sunlight is TiO₂Half One of key content of conductor photocatalyst research.

TiO₂Nanometer rods, although there is bigger specific surface area, thus there is stronger absorption property, contribute to into one Step improves TiO₂Photocatalysis performance, but, photo-generated carrier than graininess be easier to from ion internal migration to surface, Thus improve the separation efficiency of photo-generate electron-hole.

Summary of the invention

It is an object of the invention to provide one and can be effectively improved TiO₂Response to visible ray, reduces light induced electron-sky Being combined of cave, improves a kind of BiVO with visible light activity to organic pollutant degradation ability₄/TiO₂Composite Nano Rod and preparation and application.The present invention is mainly by improving preparation method synthesis semiconductor catalyst BiVO₄/TiO₂Compound Nanometer rods, this BiVO₄/TiO₂Composite nanorod can be effectively improved the light degradation ability to organic pollution.

One, BiVO₄/TiO₂Composite nanorod is by TiO₂Nanometer rods and BiVO₄1:0.25 in mass ratio～0.75 warp The light yellow nanocomposite that hydro-thermal reaction obtains.

Two, BiVO₄/TiO₂The preparation method of composite nanorod is specific as follows:

1, by TiO₂Nanometer rods and BiVO₄1:0.25 in mass ratio～0.75 and water mix in suspension, add water Quality is 43:1 with the mass ratio of BiVO4, best ultrasonic disperse 15～60min；

2, the suspension of step 1 is moved in the reactor of inner liner polytetrafluoroethylene, 1.32～1.59atm, 120～ Hydro-thermal reaction 12～36h at 200 DEG C, after reaction terminates, natural cooling；

3, the precipitate that separating step 2 obtains, cleans repeatedly by precipitate deionized water and dehydrated alcohol, and It is dried at 60 DEG C, obtains amorphous BiVO₄/TiO₂；

4, by dried amorphous BiVO₄/TiO₂It is warming up to 500 DEG C with 10 DEG C/min, calcines at 500 DEG C 3～8h, the light yellow powder material obtained is BiVO₄/TiO₂Composite nanorod.

The present invention uses narrow-band semiconductor BiVO₄And TiO₂Compound, the BiVO of preparation₄/TiO₂Composite Nano bar BiVO in material₄With TiO₂Between formed heterojunction structure, beneficially TiO₂Extend to visible ray, simultaneously by controlling water Thermal response time and hydrothermal temperature, form the Rod-like shape of bigger serface so that the material of preparation has relatively The absorption degradation of big specific surface area, beneficially pollutant.

The BiVO with visible light activity of the present invention₄/TiO₂Composite nanorod, can answer as catalyzing and degrading pollutant With, the concrete practice is as follows: by BiVO₄/TiO₂Composite nanorod puts into reactor, by noble gas with flow velocity 20～ 100ml/min is passed through reactor purging to system stability, by pollutant with flow velocity 1～10 μ L/h be passed through reactor 10～ After 60min, inlet, outlet is closed, keep reactor to seal, reactor is placed in dark-state and makes the pollutant of gas phase exist BiVO₄/TiO₂Composite nanorod solid state surface absorption 0.5～3h, is then turned on xenon lamp and carries out light-catalyzed reaction, and 4～6h Rear closedown xenon lamp.Described pollutant are benzene, toluene, ethylbenzene and formaldehyde etc..

The present invention compared with prior art has the advantage that

①BiVO₄/TiO₂The specific surface area of composite nanorod is big, high adsorption capacity；

②BiVO₄/TiO₂Composite nanorod, compared with titanium dioxide nano-rod of the prior art, has the most visible Absorbing properties, improves a lot to photocatalytic oxidation degradation organic pollution；

③BiVO₄/TiO₂The preparation method of composite nanorod is fairly simple, it is easy to operation, is suitable to commercial production.

Accompanying drawing explanation

Fig. 1 is the BiVO in embodiment 1₄/TiO₂The scanning electron microscope (SEM) photograph that composite nanorod amplification is 30000 times.

Fig. 2 is the BiVO in embodiment 1₄/TiO₂Composite nanorod and/TiO₂Nanometer rods UV-Vis DRS figure.

Fig. 3 is the BiVO in embodiment 1₄/TiO₂Composite nanorod and TiO of the prior art₂Nanometer rods photocatalysis Degraded degradation of toluene figure.

Detailed description of the invention

Following non-limiting example can make those of ordinary skill in the art that the present invention be more fully understood, but not with Any mode limits the present invention.

Embodiment 1

①TiO₂The preparation of nanometer rods:

By 3g TiO₂Powder is dissolved in 10M NaOH 100mL solution, is creamy white after stirring 30min under room temperature Liquid, is transferred to this solution in the 120mL autoclave of inner liner polytetrafluoroethylene, hydro-thermal reaction 48 at 180 DEG C H, naturally cools to room temperature.It is centrifuged and collects bottom white depositions, use 1M HNO successively₃, deionized water, Ethanol purge sample, after making solution be neutrality, by sample in 80 DEG C of drying baker dried, be ground to fine particle.

②BiVO₄/TiO₂The preparation of composite nanorod:

By 0.09g NH₄VO₃Join in 5.15mL deionized water, form NH₄VO₃Solution, heats in a water bath And it is continuously stirred；Another by 0.37g Bi (NO₃)₃·5H₂O joins in 5.15mL deionized water, forms bismuth salt molten Liquid, after stirring 10min, joins NH by bismuth saline solution₄VO₃In solution, after continuously stirred 30min, formed Yellow suspension.According to BiVO₄Account for TiO₂The mass ratio of 25%, is the TiO of 1g by quality₂Add in suspension, Stirring 30min.Suspension is moved in the reactor of 120mL inner liner polytetrafluoroethylene, 1.45atm, 160 DEG C Lower hydro-thermal reaction 24h.After reaction terminates, natural cooling, precipitate deionized water and dehydrated alcohol are cleaned repeatedly, It is dried at 60 DEG C, obtains BiVO₄/TiO₂Composite.By BiVO₄/TiO₂After drying, with 10 DEG C/min liter Temperature, to 500 DEG C, calcines 4h at 500 DEG C, and the light yellow powder material obtained is BiVO₄/TiO₂It is combined and receives Rice rod, can clearly show that BiVO from Fig. 1₄/TiO₂Composite nanorod, it can be seen that at 400-600nm from Fig. 2 BiVO in visible-range₄/TiO₂The intensity of composite nanorod is far longer than TiO₂The intensity of nanometer rods, the most so Just BiVO is substantially increased₄/TiO₂The catalytic efficiency of composite nanorod semiconductor catalyst.

Embodiment 2

Repeat the 1. TiO of embodiment 1₂The preparation of nanometer rods.

②BiVO₄/TiO₂The preparation of composite nanorod:

By 0.18g NH₄VO₃Join in 10.30mL deionized water, form NH₄VO₃Solution, adds in a water bath Hot and continuously stirred；Another by 0.75g Bi (NO₃)₃·5H₂O joins in 10.30mL deionized water, forms bismuth Saline solution, after stirring 10min, joins NH by bismuth saline solution₄VO₃In solution, after continuously stirred 30min, Form yellow suspension.According to BiVO₄Account for TiO₂The mass ratio of 50%, is the TiO of 1g by quality₂Add suspension In, stir 30min.Suspension is moved in the reactor of 120mL inner liner polytetrafluoroethylene, 1.59atm, 200 Hydro-thermal reaction 12h at DEG C.After reaction terminates, natural cooling, by the most clear to precipitate deionized water and dehydrated alcohol Wash, be dried at 60 DEG C, obtain BiVO₄/TiO₂Composite.By BiVO₄/TiO₂After drying, with 10 DEG C/min Being warming up to 500 DEG C, calcine 3h at 500 DEG C, the light yellow powder material obtained is BiVO₄/TiO₂Compound Nanometer rods.

Embodiment 3

Repeat the 1. TiO of embodiment 1₂The preparation of nanometer rods.

②BiVO₄/TiO₂The preparation of composite nanorod

By 0.27g NH₄VO₃Join in 15.43mL deionized water, form NH₄VO₃Solution, adds in a water bath Hot and continuously stirred；Another by 1.12g Bi (NO₃)₃·5H₂O joins in 15.43mL deionized water, forms bismuth Saline solution, after stirring 10min, joins NH by bismuth saline solution₄VO₃In solution, after continuously stirred 30min, Form yellow suspension.According to BiVO₄Account for TiO₂The mass ratio of 75%, is the TiO of 1g by quality₂Add suspension In, stir 30min.Suspension is moved in the reactor of 120mL inner liner polytetrafluoroethylene, 1.32atm, 120 Hydro-thermal reaction 36h at DEG C.After reaction terminates, natural cooling, by the most clear to precipitate deionized water and dehydrated alcohol Wash, be dried at 60 DEG C, obtain BiVO₄/TiO₂Composite.By BiVO₄/TiO₂After drying, with 10 DEG C/min Being warming up to 500 DEG C, calcine 8h at 500 DEG C, the light yellow powder material obtained is BiVO₄/TiO₂Compound Nanometer rods.

Application Contrast on effect example

1, BiVO of the present invention₄/TiO₂The application of composite nanorod:

By the 0.2g BiVO in embodiment 1₄/TiO₂Composite nanorod is ground to 20～60 mesh in agate mortar, grinds By BiVO after mill₄/TiO₂Composite nanorod is laid in reactor.With the nitrogen purging reaction that flow velocity is 70mL/min Device, removes the impurity in reactor, is in stable to reactor, and as the toluene of carrier gas, air is passed into reactor In, flow velocity is 2 μ L/h, and the time of being passed through is 30min, is closed by inlet, outlet after 30min, keeps reactor close Envelope, is placed in reactor dark-state and makes the toluene of gas phase at BiVO₄/TiO₂Composite nanorod solid state surface absorption 1h, opens Open xenon lamp and carry out light-catalyzed reaction, course of reaction samples 1 μ L every 30min in gas outlet, after 6h, closes xenon lamp, Toluene concentration Agilent 7890A gas Chromatographic Determination.

2、TiO₂The application of nanometer rods:

1)TiO₂The preparation of nanometer rods: by 3g TiO₂Powder is dissolved in 10M NaOH 100mL solution, under room temperature Be creamy white after stirring 30min liquid, is transferred in the 120mL autoclave of inner liner polytetrafluoroethylene by this solution, Hydro-thermal reaction 48h at 180 DEG C, naturally cools to room temperature.It is centrifuged and collects bottom white depositions, use 1M successively HNO₃, deionized water, ethanol purge sample, after making solution be neutrality, by sample in 80 DEG C of drying baker be dried After, it is ground to fine particle.

2)TiO₂The application of nanometer rods: by step 1) the 0.2g TiO that obtains₂Nanometer rods is ground in agate mortar 20～60 mesh, by TiO after grinding₂Nanometer rods is laid in reactor.Anti-with the nitrogen purging that flow velocity is 70mL/min Answer device, remove the impurity in reactor, be in reactor stable, air is passed into reaction as the toluene of carrier gas In device, flow velocity is 2 μ L/h, and the time of being passed through is 30min, is closed by inlet, outlet after 30min, keeps reactor Seal, reactor is placed in dark-state and makes the toluene of gas phase at TiO₂Nanometer rods solid state surface absorption 1h, opens xenon lamp and enters Row light-catalyzed reaction, samples 1 μ L every 30min in gas outlet in course of reaction, closes xenon lamp after 6h, and toluene is dense Degree Agilent 7890A gas Chromatographic Determination.

3, the explanation to comparing result: experimental result as shown in Figure 3, BiVO₄/TiO₂Composite nanorod is as catalyst Time, to degrade through 4h, toluene removal rate is 82%, TiO₂When nanometer rods is as catalyst, toluene removal rate is 11%, Therefore, BiVO₄Compound, substantially increase TiO₂Photocatalysis performance.

Claims (4)

1. a BiVO with visible light activity₄/TiO₂Composite nanorod, it is characterised in that: it is by TiO₂Receive Rice rod and BiVO₄The light yellow nanocomposite that 1:0.25 in mass ratio～0.75 obtains through hydro-thermal reaction.

2. the BiVO with visible light activity described in claim 1₄/TiO₂The preparation method of composite nanorod, its It is characterised by:

1) by TiO₂Nanometer rods and BiVO₄1:0.25 in mass ratio～0.75 and water mix in suspension, add water Quality is 43:1 with the mass ratio of BiVO4；

2) suspension of step 1 is moved in the reactor of inner liner polytetrafluoroethylene, 1.32～1.59atm, 120～ Hydro-thermal reaction 12～36h at 200 DEG C, after reaction terminates, natural cooling；

3) precipitate that separating step 2 obtains, cleans repeatedly by precipitate deionized water and dehydrated alcohol, and It is dried at 60 DEG C, obtains amorphous BiVO₄/TiO₂；

4) by dried amorphous BiVO₄/TiO₂It is warming up to 500 DEG C with 10 DEG C/min, calcines at 500 DEG C 3～8h, the light yellow powder material obtained is BiVO₄/TiO₂Composite nanorod.

3. the BiVO with visible light activity described in claim 1₄/TiO₂Composite nanorod, it is characterised in that: This BiVO₄/TiO₂Composite nanorod is as the application of catalyzing and degrading pollutant.

The BiVO with visible light activity the most according to claim 3₄/TiO₂Composite nanorod, its feature exists In: by BiVO₄/TiO₂Composite nanorod puts into reactor, is passed through with flow velocity 20～100ml/min by noble gas Reactor purges to system stability, will enter after pollutant are passed through reactor 10～60min with flow velocity 1～10 μ L/h, Gas outlet is closed, and keeps reactor to seal, reactor is placed in dark-state and makes the pollutant of gas phase at BiVO₄/TiO₂Compound Nanometer rods solid state surface absorption 0.5～3h, opens xenon lamp and carries out light-catalyzed reaction, closes xenon lamp after 4～6h.