CN109701534B

CN109701534B - Copper-doped TiO with extremely low band gap2Method for preparing nanoparticles

Info

Publication number: CN109701534B
Application number: CN201811571308.6A
Authority: CN
Inventors: 严继康; 陈俊宇; 刘明; 姜贵民; 甘国友; 杜景红; 张家敏; 易健宏
Original assignee: Kunming University of Science and Technology
Current assignee: Kunming University of Science and Technology
Priority date: 2018-12-21
Filing date: 2018-12-21
Publication date: 2021-08-10
Anticipated expiration: 2038-12-21
Also published as: CN109701534A

Abstract

The invention discloses copper-doped TiO with extremely low band gap₂Method for producing nanoparticles, CuCl₂•2H₂Putting O into water to obtain solution A; under the condition of magnetic stirring, dropwise adding titanium tetra-n-butoxide into the solution A, and continuously stirring after dropwise adding is finished to obtain solution B; dropwise adding nitric acid into the solution B, and continuously stirring to obtain solution C after dropwise adding; drying the solution C, and then keeping the temperature at 420-460 ℃ for 1-2 h to obtain copper-doped TiO with extremely low band gap₂A nanoparticle; the copper-doped TiO prepared by the invention₂The nano particles have good photocatalytic activity and have important application value in the aspect of environmental protection such as pollutant degradation.

Description

Copper-doped TiO with extremely low band gap2Method for preparing nanoparticles

Technical Field

The invention relates to copper-doped TiO with extremely low band gap₂A preparation method of nano particles belongs to the field of spectroscopy.

Background

Due to TiO₂Has the advantages of good commercial performance, optical and electronic performance, chemical stability, low toxicity and the like, and is widely researched as a heterogeneous catalyst or a semiconductor. To widen TiO₂In the field of application in these fields, doping modification is one of the most important means. For example, the following elements are used for photocatalyst applicationsDoping elements: fe, Cr, C, N, Bi. In the field of spectroscopic applications, doped with TiO₂In the research on the application of semiconductors in dye-sensitized solar cells, Ni, V, Yb, and the like are used as doping elements. Wherein, Cu doping is commonly applied in different applications, and the preparation method is divided into three types: (1) TiO produced industrially₂Synthesizing titanium dioxide by an immersion method, (2) obtaining TiO by a precursor containing Cu element₂(3) A sol-gel preparation method. For various experiments Cu-TiO₂The sample, in some cases the band gap energy, is given. For example, a wet dipping method is used, the band gap energy value is higher and is between 2.40eV and 2.83eV, the Cu doping amount is between 2 percent and 10 percent, and the copper-doped TiO with low band gap energy value is prepared₂It has not been reported.

Disclosure of Invention

The invention provides copper-doped TiO with extremely low band gap₂The preparation method of the nano-particles specifically comprises the following steps:

(1) 2-8 g of CuCl₂•2H₂Putting O into 100mL of water with the temperature of 2-5 ℃ to obtain solution A;

(2) under the condition of magnetic stirring, dropwise adding 45-50 mL of titanium tetra-n-butoxide into the solution A in the step (1), and continuously stirring for 30-40 min after dropwise adding is finished to obtain a solution B;

(3) dropwise adding 4-6 mL of nitric acid into the solution B in the step (2), and continuously stirring for 30-40 min after dropwise adding is finished to obtain solution C;

(4) drying the liquid C obtained in the step (3) by using a vacuum rotary sucker at 50-60 ℃, and then heating to 90-100 ℃ for drying until the moisture is completely eliminated;

(5) preserving the heat of the product obtained in the step (4) at the temperature of 420-460 ℃ for 1-2 h to obtain copper-doped TiO with extremely low band gap₂And (3) nanoparticles.

The rotating speed of the magnetic stirring in the step (2) is 1400-1600 rpm.

And (3) dropwise adding titanium tetra-n-butoxide at the speed of 0.3-0.6 mL/s in the step (2).

The mass fraction of the nitric acid in the step (3) is 60-70%, and the dripping speed of the nitric acid is 0.1-0.2 mL/s.

The inventionPrepared copper doped TiO₂The nano-particles have extremely low band gap energy and visible light absorptivity compared with TiO not doped with copper before₂The absorption rate of a sample is improved by 3% -5%, and the copper-doped TiO₂The method has important application value in environmental protection aspects such as sample pollutant degradation.

Drawings

FIG. 1 shows the copper-doped TiO prepared in example 1₂A TEM image of (a);

FIG. 2 shows crystalline TiO₂And the copper-doped TiO prepared in examples 1 to 3₂XRD pattern (the curves in the figure are from top to bottom undoped TiO respectively₂And copper-doped TiO prepared in example 1, example 2 and example 3₂）；

FIG. 3 shows crystalline TiO₂And the copper-doped TiO prepared in examples 1 to 3₂Raman spectrum (the curves in the figure are from top to bottom undoped TiO respectively₂And copper-doped TiO prepared in example 1, example 2 and example 3₂）；

FIG. 4 shows crystalline TiO₂And the copper-doped TiO prepared in examples 1 to 3₂The energy band spectra of (a), (b), (c) and (d) are respectively undoped TiO₂Copper-doped TiO prepared in examples 1, 2 and 3₂）；

FIG. 5 shows amorphous TiO₂Crystalline TiO₂And the copper-doped TiO prepared in example 3₂And degrading methyl orange by visible light.

Detailed Description

The present invention will be further described in detail with reference to the drawings and specific examples.

Example 1

Copper-doped TiO with extremely low band gap₂The preparation method of the nano-particles specifically comprises the following steps:

(1) 2g of CuCl₂•2H₂Putting O into 100mL of water with the temperature of 2 ℃ to obtain solution A;

(2) under the condition of magnetic stirring, dropwise adding 45mL of titanium tetra-n-butoxide into the solution A in the step (1) at a speed of 0.3mL/s, and continuously stirring for 30min after dropwise adding is finished to obtain a solution B, wherein the rotation speed of the magnetic stirring is 1400 rpm;

(3) dropwise adding 4mL of nitric acid into the solution B in the step (2), wherein the mass fraction of the nitric acid is 60%, the dropwise adding speed of the nitric acid is 0.1mL/s, and continuously stirring for 30min after the dropwise adding is finished to obtain a solution C;

(4) drying the liquid C obtained in the step (3) by using a vacuum rotary sucker at 50 ℃, and then continuously heating the liquid C on the vacuum rotary sucker to 90 ℃ for drying until the moisture is completely eliminated;

(5) preserving the heat of the product obtained in the step (4) at 420 ℃ for 1.5h to obtain copper-doped TiO with extremely low band gap₂And (3) nanoparticles.

FIG. 1 shows the preparation of copper-doped TiO according to this example₂From the TEM images, it can be seen that only a single type of nanocrystal particle is present, indicating that no other nanoparticles are present.

Example 2

(1) 5g of CuCl₂•2H₂Putting O into 100mL of water at 4 ℃ to obtain solution A;

(2) under the condition of magnetic stirring, dropwise adding 48mL of titanium tetra-n-butoxide into the solution A in the step (1), and continuing stirring for 35min after dropwise adding is finished, wherein the dropwise adding speed of the titanium tetra-n-butoxide is 0.5mL/s, so as to obtain a solution B, and the magnetic stirring rotating speed is 1500 rpm;

(3) dropwise adding 5mL of nitric acid into the solution B in the step (2), wherein the mass fraction of the nitric acid is 65%, the dropwise adding speed of the nitric acid is 0.15mL/s, and continuously stirring for 35min after the dropwise adding is finished to obtain a solution C;

(4) drying the C liquid obtained in the step (3) by using a vacuum rotary sucker at 55 ℃, and then continuously heating the C liquid on the vacuum rotary sucker to 95 ℃ for drying until the moisture is completely eliminated;

(5) preserving the heat of the product obtained in the step (4) at 450 ℃ for 1.2h to obtain copper-doped TiO with extremely low band gap₂And (3) nanoparticles.

Example 3

Copper-doped TiO with extremely low band gap₂NanoparticlesThe preparation method specifically comprises the following steps:

(1) 8g of CuCl₂•2H₂Putting O into 100mL of water with the temperature of 5 ℃ to obtain solution A;

(2) under the condition of magnetic stirring, dropwise adding 50mL of titanium tetra-n-butoxide into the solution A in the step (1), and continuing stirring for 40min after dropwise adding is finished, wherein the dropwise adding speed of the titanium tetra-n-butoxide is 0.6mL/s, so as to obtain a solution B, and the magnetic stirring rotating speed is 1600 rpm;

(3) dropwise adding 6mL of nitric acid into the solution B in the step (2), wherein the mass fraction of the nitric acid is 70%, the dropwise adding speed of the nitric acid is 0.2mL/s, and continuously stirring for 40min after the dropwise adding is finished to obtain a solution C;

(4) drying the C liquid obtained in the step (3) by using a vacuum rotary sucker at 60 ℃, and then continuously heating the C liquid on the vacuum rotary sucker to 100 ℃ for drying until the moisture is completely eliminated;

(5) keeping the temperature of the product obtained in the step (4) at 460 ℃ for 1h to obtain copper-doped TiO with extremely low band gap₂And (3) nanoparticles.

FIG. 2 shows crystalline TiO₂And the copper-doped TiO prepared in examples 1 to 3₂XRD pattern (the curves in the pattern are respectively undoped TiO from top to bottom in sequence₂And copper-doped TiO prepared in example 1, example 2 and example 3₂) (ii) a In the figure 2θ= 25.28 ℃ and 2θ=27.42 ℃ for anatase phase (101) and rutile phase (110) respectively, as can be seen in all copper doped TiO₂In the sample (2), only TiO was found₂In addition, XRD did not show the formation of any other phase, and it could be concluded that Cu is present²⁺Uniform dispersion in anatase crystals due to similar ionic radii of copper and Ti (R)_Cu=0.72Å；R_Ti=0.68 a), there is a certain possibility that copper binds to O at interstitial positions, which creates tension in the anatase structure resulting in a blue shift of the diffraction peak on the (101) crystal plane.

FIG. 3 shows crystalline TiO₂And the copper-doped TiO prepared in examples 1 to 3₂The Raman spectrum (the curves in the figure are respectively undoped TiO from top to bottom in turn₂And prepared in example 1, example 2, example 3Copper doped TiO₂) (ii) a From the figure, anatase TiO can be seen₂Vibration modes with six raman activities: a. the_1g(519cm^-1)， 2B _1g(399cm^-1And 519cm^-1)，3Eg(144cm^-1，197cm^-1，639 cm^-1) In the map, we can observe TiO₂Has a diffraction peak at 445cm^-1Of rutile structureEgThe diffraction peak of the mode is 446.5cm^-1Copper doping produces TiO₂Structural distortions which may lead to changes in the raman spectrum are observedEg 144cm^-1The wave number of (2) is in an ascending trend, andEg639cm^-1shows a decreasing trend in wave number, indicating that Cu replaces Ti to increase oxygen vacancies and defects.

FIG. 4 shows crystalline TiO₂And the copper-doped TiO prepared in examples 1 to 3₂The energy band spectra of (a), (b), (c) and (d) are respectively undoped TiO₂Copper-doped TiO prepared in examples 1, 2 and 3₂) (ii) a From the figure, it can be seen that the TiO is not doped₂Has a band gap value of 2.91eV, and the copper-doped TiO prepared in example 1₂Has a band gap value of 2.11eV, and the copper-doped TiO prepared in example 2₂Has a band gap value of 1.71eV, and the copper-doped TiO prepared in example 3₂The band gap energy of (A) is 1.6 eV.

FIG. 5 shows amorphous TiO₂Crystalline TiO₂And the copper-doped TiO prepared in example 3₂Degrading methyl orange by visible light;

from the figure, it can be seen that the TiO doped with copper₂Has better degradation effect than crystalline TiO₂More preferably amorphous TiO₂It can be seen that Cu doping increases TiO₂Efficiency of photodegradation of methyl orange.

Claims

1. Copper-doped TiO with extremely low band gap₂The preparation method of the nano-particles is characterized by comprising the following steps:

(1) 8g of CuCl₂•2H₂O is put into 100mL of water with the temperature of 5 DEG CTo obtain solution A;