CN103588245A

CN103588245A - Preparation method for hollow carbon/titanium dioxide composite nano material

Info

Publication number: CN103588245A
Application number: CN201310554834.2A
Authority: CN
Inventors: 张海娇; 焦正; 郭敬新; 胡乐; 缪彧; 徐慧娟
Original assignee: University of Shanghai for Science and Technology
Current assignee: University of Shanghai for Science and Technology
Priority date: 2013-11-11
Filing date: 2013-11-11
Publication date: 2014-02-19
Anticipated expiration: 2033-11-11
Also published as: CN103588245B

Abstract

The invention relates to a preparation method of hollow carbon/titanium dioxide composite nanometer material. The present invention adopts the method of in-situ etching, using titanium tetrafluoride (TiF ₄ ) as the titanium source, the mixed solution of ethanol/water as the solvent, and carbon-coated silicon dioxide as the hard template, through the hydrolysis of the titanium source, the While _TiO2 was generated on the surface of the carbon shell, the by-product HF generated during the reaction was used to effectively remove the silica template, thereby preparing a carbon/titania composite nanomaterial with a hollow feature and uniform morphology. This method can not only prepare hollow carbon/titanium dioxide composite nanomaterials with good crystallization and excellent performance, but also make full use of the by-product HF, which not only saves costs, improves efficiency, but also effectively avoids environmental pollution.

Description

The preparation method of hollow carbon/titanium dioxide composite nano material

Technical field

The present invention relates to a kind of preparation method of hollow carbon/titanium dioxide composite nano material.

Background technology

Nano-TiO ₂because of it, there is the outstanding advantages such as wide material sources, with low cost, Stability Analysis of Structures and excellent performance, and standby being popular, be in recent years semiconductor material for one of environmental protection and energy technology field most study, new and high technology material most with prospects.However, TiO ₂itself still comes with some shortcomings: the one, and greater band gap, thus low to sunlight utilization ratio, catalyzed reaction efficiency is not high, limited its application, the 2nd, the easy complex light in electron hole, spectral absorption narrow range, in use easy inactivation.In order further to improve its effective rate of utilization, expand its range of application, people have attempted multiple method of modifying, wherein to TiO ₂comparatively pay close attention to the compound research of other materials, this is mainly because the abundant combining nano TiO of matrix material ₂and the advantage of carrier, thereby form, have complementary advantages, its performance of more effective raising and efficiency.Wherein, take matrix material that carbon nanomaterial prepared as carrier receives much concern because of its unique advantage.Practice shows, carbon/TiO ₂composite nano materials has following outstanding advantages: (1) carbon nanomaterial has high specific surface area conventionally, can effectively strengthen the contact area between substrate molecule and catalyzer, thereby improves reaction efficiency; (2) carbon nanomaterial has good electroconductibility, can improve the ability that electronics transmits, and makes up pure phase TiO ₂deficiency; (3) supporting role of carbon skeleton, makes the TiO of its load ₂have stable structure more, thereby increased stability and the returnability in reaction process.

At present, what the preparation of hollow carbon/titanium dioxide nano material mainly adopted is the method for hard template method and high temperature pyrolysis carbon matrix precursor, but conventional hard template method must be used strong acid or highly basic to remove template, cost but also complex operation have so not only been increased, waste time and energy, be unfavorable for very much environmental protection; And the method for high temperature pyrolysis has increased again a large amount of energy consumptions virtually.

Summary of the invention

The object of the invention is to overcome some problems that exist in prior art, a kind of preparation method of hollow carbon/titanium dioxide composite nano material is provided, present method can obtain pattern homogeneous, hollow carbon/titanic oxide nano compound material of well-crystallized.

For achieving the above object, the following technical scheme of a kind of employing of the present invention:

A preparation method for hollow carbon/titanium dioxide composite nano material, is characterized in that the concrete steps of the method are:

A. the coated silica nano material of carbon is added deionized water in, being mixed with concentration is the uniform dispersion A of 0.008-0.012 g/ mL;

B. by titanium tetrafluoride (TiF ₄) put into ethanol, being mixed with concentration is 0.1-0.5 mmol/mL uniform dispersion B;

Under the condition stirring, step b gained dispersion liquid B is dropwise slowly splashed in step a gained dispersion liquid A, under 60～180 ℃ of conditions, react 4-12 h; After having reacted, product is through centrifugal, washing, oven dry; Finally roasting 3 h under tube furnace 400-600 ℃ inert atmosphere, obtain hollow carbon/titanium dioxide composite nano material.

Compared with prior art, the technology of the present invention has following remarkable advantage:

The present invention be take titanium tetrafluoride in the process of ，Tai source, titanium source hydrolysis, and the by product hydrofluoric acid (HF) that utilizes its hydrolysis to produce successfully removes silicon oxide template, adopts the mixed solvent of ethanol and water simultaneously, can effectively suppress TiF ₄hydrolysis rate, thereby the titanium dioxide that makes to produce is grown in the surface of carbon shell more equably.And TiF ₄the by product HF that hydrolysis produces, just in time can remove the silicon-dioxide in template, thereby forms hollow structure, finally forms hollow carbon/titanium dioxide composite nano material of pattern homogeneous, well-crystallized.The method of this original position etching has not only obtained the hollow carbon/titanium dioxide composite nano material of excellent performance, the more important thing is and by product HF can be made full use of, and has not only saved cost, has improved efficiency, has effectively avoided especially environmental pollution.The inventive method technique is simple, and mild condition had both avoided removing in traditional technology the loaded down with trivial details of hard template, had realized again economical reaction.

Accompanying drawing explanation

Fig. 1 is the XRD spectra of gained hollow carbon/titanium dioxide composite nano material in the embodiment of the present invention 1.

Fig. 2 is the TEM photo of gained hollow carbon/titanium dioxide composite nano material in the embodiment of the present invention 1.

Fig. 3 is the SEM photo of gained hollow carbon/titanium dioxide composite nano material in the embodiment of the present invention 1.

Embodiment

the silica nano material that carbon is coated prepare reference: Antonio B. Fuertes, et al., chem. Commun., 2012,48,6124-6126.Concrete steps are:

A. the mixture (volume ratio of second alcohol and water is 2:1) that measures 40 mL ethanol (ethanol) and deionized water, adds 1.3 mL ammoniacal liquor (NH ₃h ₂o), mix, stir 0.5 h at 30 ℃; Measure 1.4 mL tetraethyl orthosilicates (TEOS) and join in above-mentioned solution, after mixing, then take 0.2 g Resorcinol with electronic balance, after adding and making to dissolve completely, then to add concentration be 37 wt% 0.3 mL formaldehyde solutions, continues reaction 24 h;

B. above-mentioned mixing solutions is packed in the band teflon-lined autoclave of 100 mL, at 110 ℃, react 24 h; After having reacted, product is taken out from reactor, through steps such as centrifugal, the washing of routine, oven dry, obtain the present invention and prepare the coated silica nano material of needed template-carbon;

Embodiment mono-:

A. with electronic balance, accurately take the coated silica nano material of carbon of the upper step preparation of 0.1 g, join in 10 mL deionized waters, ultrasonic make dispersed;

B. with electronic balance, accurately take 2.5 mmol titanium tetrafluoride (TiF ₄) put into 10 mL ethanol, ultrasonic, after being uniformly dispersed, under the condition stirring, dropwise slowly splash in step suspension liquid, drip off rear to be mixed even, mixed solution is all packed in the band teflon-lined autoclave of 100 mL, under 180 ℃ of conditions, react 6 h;

C. after having reacted, product is taken out from reactor, through centrifugal, washing, oven dry, nitrogen, protect under environment the steps such as roasting, obtain hollow carbon/composite titania material prepared by the present invention.

Prepared sample is carried out to physical property sign, and its partial results as shown in drawings.Resulting materials is hollow structure, and the particle on surface is piled up in surface with sheet, and pattern homogeneous, and its particle diameter is in 150 nm left and right, and the platy shaped particle on surface is about 25 nm.

Embodiment bis-:

With electronic balance, accurately take 2.5 mmol titanium tetrafluoride (TiF ₄) put into 10 mL deionized waters, ultrasonic, after being uniformly dispersed, under the condition stirring, dropwise slowly splash in step suspension liquid, drip off rear to be mixed even, mixed solution is all packed in the band teflon-lined autoclave of 100 mL, under 180 ℃ of conditions, react 6 h.

Acquired results and embodiment 1 have bigger difference, and difference is the TiO obtaining ₂for particle is larger, and shape is inhomogeneous, can not be coated on equably on the surface of template.

Embodiment tri-:

With electronic balance, accurately take 2.5 mmol titanium tetrafluoride (TiF ₄) put into 10 mL deionized waters, ultrasonic, after being uniformly dispersed, under the condition stirring, dropwise slowly splash in step suspension liquid, drip off rear to be mixed even, mixed solution is all packed in the band teflon-lined autoclave of 100 mL, under 60 ℃ of conditions, react 12 h.

Acquired results and embodiment 1 have bigger difference, and difference is that, under cold condition, silica template can not effectively be removed, and major part also all maintains the original state, surface TiO ₂still for platy shaped particle is piled up.

Referring to accompanying drawing, Fig. 1 is the XRD spectra of the embodiment of the present invention 1 gained hollow carbon/titanium dioxide composite nano material.XRD analysis: carry out on Japanese RigaKu D/max-2550 type X-ray diffractometer; Adopt CuK α diffraction.Known from Fig. 1, gained TiO of the present invention ₂nano material has typically anatase structured, consistent with standard spectrogram (PDF No:21-1272), has no other assorted peak, proves that it is pure crystal phase structure.

Referring to accompanying drawing, Fig. 2 is transmission electron microscope (TEM) picture of the embodiment of the present invention 1 gained hollow carbon/titanium dioxide composite nano material.Tem analysis: adopt the JEOL-200CX of Jeol Ltd. type transmission electron microscope observation material pattern.From TEM picture, can find out, hollow carbon/titanic oxide nano compound material pattern homogeneous prepared by the present invention, inner for diameter is about the cavity of 100 nm, the particle on surface exists with the form of sheet accumulation, its particle diameter is about 150 nm, and the maximum particle diameter of surperficial sheet is about 25 nm.

Referring to accompanying drawing, Fig. 3 is scanning electronic microscope (SEM) picture of the embodiment of the present invention 1 gained hollow carbon/titanium dioxide composite nano material.Sem analysis: adopt the JSM-6700F of Jeol Ltd. sem observation material pattern.Therefrom can find out, hollow carbon/titanic oxide nano compound material prepared by the present invention has uniform ball-like structure, from fragmentation particle can see obvious cavity structure, consistent with the result of TEM.

Claims

1. a preparation method of hollow carbon/titanium dioxide composite nanomaterial is characterized in that the concrete steps of the method are:

a. Add carbon-coated silica nanomaterials to deionized water to prepare a uniform dispersion A with a concentration of 0.008-0.012 g/mL;

b. Put titanium tetrafluoride (TiF ₄ ) into ethanol to prepare a uniform dispersion B with a concentration of 0.1-0.5 mmol/mL;

c. Under the condition of stirring, slowly drop the dispersion liquid B obtained in step b into the dispersion liquid A obtained in step a, and react at 60-180 °C for 4-12 h; after the reaction is completed, the product is centrifuged, Washing and drying; finally, roasting for 3 h in an inert atmosphere at 400-600 °C in a muffle furnace to obtain a hollow carbon/titanium dioxide composite nanomaterial.