CN103769189A

CN103769189A - Preparation method of nano titanium dioxide with exposed carbon-nitrogen-codoped (001) surface

Info

Publication number: CN103769189A
Application number: CN201410022238.4A
Authority: CN
Inventors: 谢吉民; 姜志锋; 刘栋
Original assignee: Jiangsu University
Current assignee: Jiangsu University
Priority date: 2014-01-20
Filing date: 2014-01-20
Publication date: 2014-05-07

Abstract

The invention belongs to the field of photocatalysis and in particular relates to a method for preparing nano titanium dioxide with an exposed carbon-nitrogen-codoped (001) surface. According to the method, pine leaves are taken as carbon-nitrogen sources; hydrofluoric acid is taken as a control agent; and anatase nano titanium dioxide with the exposed carbon-nitrogen-codoped (001) surface is prepared under a hydrothermal condition. An experiment of photo-catalytic degradation of rhodamine B shows that the prepared catalyst is good in photo-catalytic activity; and the performance of the catalyst is better than the performance of the commercial P25. The preparation method is low in preparation cost and simple and effective in preparation process; the prepared catalyst is good in practicability, easy to produce in a large scale, and good in economic and environmental benefits.

Description

Nitrogen co-doped { the preparation method of the nano titanium oxide that 001} face exposes of a kind of carbon

Technical field

The invention belongs to photocatalysis field, be specifically related to one take pine tree leaf as carbon nitrogen source, hydrofluoric acid is controlling agent, prepares the nitrogen co-doped { method of the anatase-type nanometer titanium dioxide that 001} face exposes of carbon under hydrothermal condition.

Background technology

Be accompanied by the quickening of process of industrialization, the excessive exploitation of resource and the expansion of mankind's activity scope, environmental problem becomes the problem of the extensive concern of countries in the world day by day.In industry and the waste water of people's daily life, waste gas, usually contain the organic pollution of a large amount of poisonous difficult degradations.Along with international environment standard-required increasingly stringent, the improvement technology of organic contamination is also rapidly developed, and in recent years as emerging pollution control technology, the application of photocatalysis in environmental protection is subject to people's attention day by day.Titanium dioxide is good, nontoxic, pollution-free as a kind of chemical stability, photochemical catalyst cheaply, is widely used in the fields such as wastewater treatment, becomes the environmental type functional material most with exploitation future.Wherein, { 001} face anatase titanium dioxide nanometer sheet is particularly concerned owing to having in heterogeneous reaction compared with high reactivity in exposure.The band-gap energy (3.0 ~ 3.2eV) of anatase titanium dioxide nanometer sheet needs ultraviolet light to excite, but sunshine medium ultraviolet light only accounts for sub-fraction, so only have very little a part of sunshine to be absorbed by titanium dioxide.From making full use of the viewpoint of sunshine, in the urgent need to a kind of titanium dioxide optical catalyst that visible ray is had to response.Research is found, is had good absorption through the titanium dioxide of nonmetal doping in to visible-range.Study and also show, codope adulterates and compares with single-element, has higher photocatalytic activity.Therefore, find and a kind ofly simple to operate, with low cost prepare carbon nitrogen co-doped { method of the nano titanium oxide that 001} face exposes becomes the main target that the photocatalysis preparation producers pursue.

Summary of the invention

The object of the invention is to provide a kind of take pine tree leaf as carbon nitrogen source, and preparation has the nitrogen co-doped { method of the titanium dioxide nano photocatalysis agent that 001} face exposes of carbon of good photocatalytic activity.

The present invention realizes by following steps:

(1) in proportion pine tree leaf is added in deionized water, then said mixture is transferred in the reactor of 25 mL, hydro-thermal reaction, filters removal of impurity and obtains final nano dot;

(2) by nano dot, butyl titanate (Ti (OBu) ₄) and the mass fraction hydrofluoric acid that is 40%, join in proportion anhydrous acetic acid (HAc) and absolute ethyl alcohol (C ₂h ₅oH), in mixed solution, whole operation is under agitation carried out, then, said mixture is transferred in stainless steel autoclave, carried out hydro-thermal reaction, to be cooled to room temperature, sample cleans with deionized water and absolute ethyl alcohol by the method for centrifugation, vacuum drying 48 h.

In described step (1), the amount ratio of pine tree leaf and deionized water is 2g:10 ~ 15ml.

In described step (1), hydrothermal temperature is 200 ℃ of 160 –, and the time is 3h.

In described step (2), in anhydrous acetic acid and absolute ethyl alcohol mixed solution, the volume ratio of anhydrous acetic acid and absolute ethyl alcohol is 1:1.

In described step (2), the volume ratio of anhydrous acetic acid and absolute ethyl alcohol mixed liquor, positive four butyl esters of metatitanic acid and hydrofluoric acid is 40:7:0.1, and nano dot is less than 1:9 with whole mixed liquor volume ratio.

In described step (2), the temperature of hydro-thermal reaction is 200 ℃ of 180 –, and the time is 24 h.

Nitrogen co-doped { the titanium dioxide NC-TiO that 001} face exposes of prepared carbon ₂, crystallization is complete, and particle diameter is about 30 nm, good dispersion.

Utilize X-ray diffractometer (XRD), transmission electron microscope (TEM), x-ray photoelectron power spectrum (XPS), Full-automatic physical chemisorbed analyzer (BET) isothermal adsorption patterns to survey specific area product is carried out to micromorphology analysis, carry out photocatalytic degradation experiment take rhodamine B solution as target dyestuff, to assess its photocatalytic activity.

The present invention has the following advantages:

(1) this method adopts cheap leaf as carbon nitrogen source first, has raw material cheap and easy to get, prepares the features such as simple.

(2) carbon prepared by the method nitrogen co-doped the titanium dioxide that 001} face exposes, and have particle diameter little, be uniformly dispersed, the advantage such as specific area is large, photocatalysis effect is good.

Accompanying drawing explanation

Fig. 1 is the XRD diffraction spectrogram of prepared sample.

Fig. 2 is the transmission electron microscope photo (TEM) of prepared sample.

Fig. 3 is the XPS figure of prepared sample.

Fig. 4 is nitrogen adsorption desorption figure.

Fig. 5 is the time m-degradation rate graph of a relation of business P25 and prepared sample photocatalytic degradation rhodamine B solution.

The specific embodiment

Below in conjunction with specific embodiment, the invention will be further described.

realexecute example 1

The pine tree leaf of 2g is added in the deionized water of 10 ml, then said mixture is transferred in the reactor of 25 mL, 160 ℃ of hydro-thermal reaction 3 h, filter removal of impurity and obtain final nano dot.

In beaker, add the mixed solution of 40 mL ethanol and glacial acetic acid, under stirring, slowly add 7 mL butyl titanates, and then add 0.1 mL hydrofluoric acid and 2 mL nano dots with microsyringe, after question response thing mixes, reactant liquor is proceeded in water heating kettle, 180 ℃ of reaction 24 h.The product of gained is used respectively to deionized water, absolute ethanol washing, then put into vacuum drying chamber and dry 48 h.

realexecute example 2

The pine tree leaf of 2g is added in the deionized water of 12 ml, then said mixture is transferred in the reactor of 25 mL, 180 ℃ of hydro-thermal reaction 3 h, filter removal of impurity and obtain final nano dot.

In the beaker of 100 mL, add the mixed solution of 40 mL ethanol and glacial acetic acid, under stirring, slowly add 7 mL butyl titanates, and then add 0.1 mL hydrofluoric acid and 3 mL nano dots with microsyringe, after question response thing mixes, reactant liquor is proceeded in water heating kettle to 180 ℃ of reaction 24 h.The product of gained is used respectively to deionized water, absolute ethanol washing, then put into vacuum drying chamber and dry 48 h.

realexecute example 3

The pine tree leaf of 2g is added in the deionized water of 15 ml, then said mixture is transferred in the reactor of 25 mL, 200 ℃ of hydro-thermal reaction 3 h, filter removal of impurity and obtain final nano dot.

In the beaker of 100 mL, add the mixed solution of 40 mL ethanol and glacial acetic acid, under stirring, slowly add 7 mL butyl titanates, and then add 0.1 mL hydrofluoric acid and 5 mL nano dots with microsyringe, after question response thing mixes, reactant liquor is proceeded in water heating kettle to 180 ℃ of reaction 24 h.The product of gained is used respectively to deionized water, absolute ethanol washing, then put into vacuum drying chamber and dry 48 h.

realexecute example 4

In the beaker of 100 mL, add the mixed solution of 40 mL ethanol and glacial acetic acid, under stirring, slowly add 7 mL butyl titanates, and then add 0.1 mL hydrofluoric acid and 3 mL nano dots with microsyringe, after question response thing mixes, reactant liquor is proceeded in water heating kettle to 200 ℃ of reaction 24 h.The product of gained is used respectively to deionized water, absolute ethanol washing, then put into vacuum drying chamber and dry 48 h.

The solution trial of photocatalytic degradation rhodamine B:

(1) compound concentration is the rhodamine B solution of 10 mg/L, and the solution preparing is placed in to dark place.

(2) take catalyst 0.08 g of preparation, be placed in Photoreactor, the rhodamine B solution that adds 80 mL steps (1) to prepare, magnetic agitation 30 min, bubbling, dark reaction 1 h, after catalyst is uniformly dispersed, open water source, light source, carries out photocatalytic degradation experiment.

(3) every 30 min sample once, and sampling amount is 5 ml, with multitube frame autobalance centrifuge centrifugal 3 min, centrifugal after for the measurement of ultraviolet-visible absorbance.

(4) prepared catalyst has excellent photocatalytic activity under visible ray condition as seen from Figure 5, and its performance is much better than P25.

Fig. 1,2,3,4 is respectively embodiment 1 and makes the XRD diffraction spectrogram of sample, transmission electron microscope photo, XPS and nitrogen adsorption desorption figure.

In Fig. 1 XRD spectra, can see that the middle diffraction maximum of publishing picture is anatase titanium dioxide characteristic diffraction peak.

The prepared titanium dioxide of Fig. 2 TEM caption is that { 001} face exposes.

In Fig. 3 XPS spectrum figure, can find out that carbon and nitrogen element have adulterated successfully.

Fig. 4 nitrogen adsorption desorption figure can find out that prepared titanium dioxide has higher specific area, 68.4 m ²/ g.

Claims

Carbon nitrogen co-doped the preparation method of nano titanium oxide that 001} face exposes, is characterized in that: preparation process is as follows:

(1) in proportion pine tree leaf is added in deionized water, then said mixture is transferred in the reactor of 25 mL, hydro-thermal reaction, filters removal of impurity and obtains final nano dot;

(2) hydrofluoric acid that is 40% by nano dot, butyl titanate and mass fraction, join in proportion in the mixed solution of anhydrous acetic acid and absolute ethyl alcohol, whole operation is under agitation carried out, then, said mixture is transferred in stainless steel autoclave, carried out hydro-thermal reaction, to be cooled to room temperature, sample cleans with deionized water and absolute ethyl alcohol by the method for centrifugation, vacuum drying 48 h.
2. nitrogen co-doped { preparation method of nano titanium oxide that 001} face exposes, is characterized in that: in described step (1), the amount ratio of pine tree leaf and deionized water is 2g:10 ~ 15ml a kind of carbon as claimed in claim 1.
3. nitrogen co-doped { preparation method of nano titanium oxide that 001} face exposes, is characterized in that: in described step (1), hydrothermal temperature is 200 ℃ of 160 –, and the time is 3h a kind of carbon as claimed in claim 1.
4. nitrogen co-doped { preparation method of nano titanium oxide that 001} face exposes, is characterized in that: in described step (2), in anhydrous acetic acid and absolute ethyl alcohol mixed solution, the volume ratio of anhydrous acetic acid and absolute ethyl alcohol is 1:1 a kind of carbon as claimed in claim 1.
5. nitrogen co-doped { the preparation method of the nano titanium oxide that 001} face exposes of a kind of carbon as claimed in claim 1, it is characterized in that: in described step (2), the volume ratio of anhydrous acetic acid and absolute ethyl alcohol mixed liquor, positive four butyl esters of metatitanic acid and hydrofluoric acid is 40:7:0.1, and nano dot is less than 1:9 with whole mixed liquor volume ratio.
6. nitrogen co-doped { preparation method of nano titanium oxide that 001} face exposes, is characterized in that: in described step (2), the temperature of hydro-thermal reaction is 200 ℃ of 180 –, and the time is 24 h a kind of carbon as claimed in claim 1.