CN103191721A - Method for preparing tungsten trioxide/titanium dioxide nanocomposite with core-shell structure - Google Patents

Abstract

The invention discloses a method for preparing tungsten trioxide/titanium dioxide nanocomposite with a core-shell structure. The method comprises the following processes of: transferring a dextrose water solution to a sealed container, obtaining carbon microspheres by hydrothermal reaction, then dispersing and soaking the carbon microspheres into an ethanol mixed solution of titanium tetrachloride and tungsten hexachloride, separating, cleaning and drying to obtain the carbon microspheres of absorbing titanium ions and tungsten ions, and finally burning the carbon microspheres to obtain the tungsten trioxide/titanium dioxide nanocomposite with the core-shell structure. The method is simple in process, low in synthesis cost, free of poison, and easy for realization of industrial large-scale production; and the obtained tungsten trioxide/titanium dioxide nanocomposite with the core-shell structure is uniform in size and good in dispersibility, and has wide practical application value in the aspect of preparation of a photoelectric material or a photocatalytic material.

Description

The preparation method of tungstic acid/titanium dioxide core-shell structure nanometer composite material

Technical field

The present invention relates to the preparation method of a kind of tungstic acid/titanium dioxide core-shell structure nanometer composite material, belong to the photocatalysis technology field.

Background technology

Advantages such as titanium dioxide is as a kind of conventional semiconductors, and is strong owing to having oxidability, and chemical property is stable, and is cheap, in photocatalysis, fields such as solar cell and lithium battery have broad application prospects.But, the energy gap of titanium dioxide bigger (3.0 ~ 3.2 eV), can only absorb wavelength less than the ultraviolet light of 400 nm, and the recombination rate in light induced electron and hole is higher, make electricity conversion significantly reduce, limited the further application of titanium dioxide at photoelectricity especially photocatalysis field to a great extent.At present, reduce titanium dioxide photoproduction carrier recombination rate, the main path that improves its photocatalysis performance carries out itself and other narrow gap semiconductor compound exactly, obtain the nano particle of nucleocapsid structure, because these two kinds semi-conductive band structure differences, by coupling, then can well realize effectively separating of light induced electron and hole, reduce the carrier recombination rate, improve the catalytic performance of material, the introducing of narrow gap semiconductor simultaneously can reinforcing material to the absorption of visible light, further improve material to the utilization rate of luminous energy, on the other hand, the design of nucleocapsid structure also makes photon progressively to be absorbed through reflection repeatedly at material internal, also has material impact for the raising of material photoelectric properties.Tungstic acid has narrower energy gap (2.6 ~ 2.7 eV), its band structure and titanium dioxide can be realized good coupling, carry out itself and titanium dioxide compound, obtain having the composite of nucleocapsid structure, can obtain than the one-component better photoelectricity of (titanium dioxide or tungstic acid) material or photocatalysis performance.

At present, about the more existing reports of tungstic acid/composite titania material, but the design that relates to the material nucleocapsid structure is arranged seldom, and preparation method's complexity, the condition harshness, cost is higher, obtain composite material powder and be easy to reunite, be difficult to reach requirement of actual application.

Summary of the invention

The object of the present invention is to provide the preparation method of a kind of tungstic acid/titanium dioxide core-shell structure nanometer composite material.This procedure is simple, and is synthetic with low cost, nontoxic, is easy to industrial-scale production, and prepared tungstic acid/titanium dioxide core-shell structure nanometer composite material size is even, favorable dispersibility.

The present invention is realized that by the following technical programs the preparation method of a kind of tungstic acid/titanium dioxide core-shell structure nanometer composite material is characterized in that may further comprise the steps:

1) is that the D/W of 0.1 ~ 2.0 mol/L is transferred in the airtight container with concentration, at 160 ~ 200 ℃ of hydro-thermal reaction 1 ~ 20 h of temperature, through cooling, isolated by filtration, with ethanol and washed with de-ionized water filtrate and drying, obtains carbosphere;

2) carbosphere that step 1) is made is scattered in the alcohol mixed solution of titanium tetrachloride and tungsten hexachloride, wherein the concentration of titanium tetrachloride is 0.1 ~ 2.0 mol/L, the mass fraction of tungsten hexachloride is 0.01 ~ 0.20 mol/L, after soaking 3 ~ 36 h, filter to isolate carbosphere, clean with ethanol, dry then, obtain being adsorbed with the carbosphere of titanium ion and tungsten ion;

3) with step 2) carbosphere that is adsorbed with titanium ion and tungsten ion that makes adds calcining furnace, in air atmosphere, be that 0.5 ~ 5 ℃/min is warming up to 350 ~ 600 ℃ of calcining at constant temperature 2 ~ 24 h with heating rate, obtain tungstic acid/titanium dioxide core-shell structure nanometer composite material.

The invention has the advantages that adopt a kind of process simple, method with low cost has prepared tungstic acid/titanium dioxide core-shell structure nanometer composite material.Pass through the concentration of control glucose solution in the process, and the time of hydro-thermal reaction and temperature can accuracy controlling carbon ball template size, and finally reach adjusting to tungstic acid/titanium dioxide core-shell structure nanometer composite material particle size, also can realize composite shell middle level thickness and the big or small control of nuclear by the concentration that changes titanium tetrachloride and tungsten hexachloride solution simultaneously, thereby at photoelectricity or the photocatalysis performance of adjusted material more, reach the optimization of performance, so this method has wide actual application value at photoelectric material or catalysis material aspect preparing.

Description of drawings

Fig. 1 is the X-ray diffraction spectrogram of the prepared tungstic acid/titanium dioxide core-shell structure nanometer composite material of the embodiment of the invention 1.

Fig. 2 is the transmission electron microscopy pattern photo of the prepared tungstic acid/titanium dioxide core-shell structure nanometer composite material of the embodiment of the invention 1.

Fig. 3 is the distribution map of titanium elements in the individual particle of the prepared tungstic acid/titanium dioxide core-shell structure nanometer composite material of the embodiment of the invention 1.

Fig. 4 is the distribution map of W elements in the individual particle of the prepared tungstic acid/titanium dioxide core-shell structure nanometer composite material of the embodiment of the invention 1.

The specific embodiment

Embodiment 1

1) be that the D/W of 0.1 mol/L is transferred in the airtight container with 48 ml concentration, at 200 ℃ of hydro-thermal reaction 20 h of temperature, cooled and filtered is separated, and uses ethanol and deionized water difference cleaning and filtering thing three times, and at 60 ℃ of drying 6 h, obtain carbosphere.

2) carbosphere that step 1) is made (100 mg) is scattered in the alcohol mixed solution of 4 ml titanium tetrachlorides and tungsten hexachloride, wherein the concentration of titanium tetrachloride is 0.1 mol/L, the concentration of tungsten hexachloride is 0.01 mol/L, after soaking 36 h, isolated by filtration, with ethanol cleaning and filtering thing three times, 60 ℃ of drying 6 h then obtain being adsorbed with the carbosphere of titanium ion and tungsten ion.

3) with step 2) carbosphere that is adsorbed with titanium ion and tungsten ion that makes adds calcining furnace, in air atmosphere, be that 0.5 ℃/min is warming up to 350 ℃ of calcining at constant temperature 24 h with heating rate, obtain tungstic acid/titanium dioxide core-shell structure nanometer composite material and sample is carried out XRD test, transmission electron microscope observing and element distributing and detecting.Fig. 1 is the X-ray diffraction spectrogram of composite, and Fig. 2 is the transmission electron microscopy pattern photo of composite, and Fig. 3 and Fig. 4 are respectively the distribution map of titanium and W elements in the individual particle.

Test result: the X-ray diffraction spectrogram confirms that composite is by titanium dioxide and two kinds of thing phase compositions of tungstic acid, transmission electron microscopy pattern photo confirms to have nucleocapsid structure, and size is even, favorable dispersibility, distribution diagram of element confirms that the composite center is tungstic acid, and shell is titanium dioxide.

Embodiment 2

1) be that the D/W of 0.5 mol/L is transferred in the airtight container with 48 ml concentration, at 180 ℃ of hydro-thermal reaction 10 h of temperature, be cooled to the room temperature isolated by filtration, use ethanol and washed with de-ionized water filtrate three times respectively, and at 60 ℃ of drying 6 h, obtain carbosphere.

2) carbosphere that step 1) is made (400 mg) is scattered in the alcohol mixed solution of 16 ml titanium tetrachlorides and tungsten hexachloride, wherein the concentration of titanium tetrachloride is 1.0 mol/L, the concentration of tungsten hexachloride is 0.04 mol/L, after soaking 24 h, isolated by filtration, with ethanol cleaning and filtering thing three times, then at 60 ℃ of drying 6 h, obtain being adsorbed with the carbosphere of titanium ion and tungsten ion.

3) with step 2) carbosphere that is adsorbed with titanium ion and tungsten ion that makes adds calcining furnace, is that 1 ℃/min is warming up to 450 ℃ of calcining at constant temperature 10 h with heating rate in air atmosphere, obtains tungstic acid/titanium dioxide core-shell structure nanometer composite material.

Embodiment 3

1) be that the D/W of 2.0 mol/L is transferred in the airtight container with 48 ml concentration, at 160 ℃ of hydro-thermal reaction 1 h of temperature, cooled and filtered is separated, and uses ethanol and washed with de-ionized water filtrate three times respectively, and at 60 ℃ of drying 6 h, obtain carbosphere.

2) carbosphere that step 1) is made (200 mg) is scattered in 6 ml titanium tetrachlorides and the tungsten hexachloride alcohol mixed solution, wherein the concentration of titanium tetrachloride is 2.0 mol/L, the concentration of tungsten hexachloride is 0.20 mol/L, after soaking 3 h, isolated by filtration, with ethanol cleaning and filtering thing three times, then at 60 ℃ of drying 6 h, obtain being adsorbed with the carbosphere of titanium ion and tungsten ion.

3) with step 2) carbosphere that is adsorbed with titanium ion and tungsten ion that makes adds calcining furnace, is that 5 ℃/min is warming up to 600 ℃ of calcining at constant temperature 2 h with heating rate in air atmosphere, obtains tungstic acid/titanium dioxide core-shell structure nanometer composite material.

Claims (1)

1. the preparation method of tungstic acid/titanium dioxide core-shell structure nanometer composite material is characterized in that may further comprise the steps:

1) is that the D/W of 0.1 ~ 2.0 mol/L is transferred in the airtight container with concentration, at 160 ~ 200 ℃ of hydro-thermal reaction 1 ~ 20 h of temperature, through cooling, isolated by filtration, with ethanol and washed with de-ionized water filtrate and drying, obtains carbosphere;

2) carbosphere that step 1) is made is scattered in the alcohol mixed solution of titanium tetrachloride and tungsten hexachloride, wherein the concentration of titanium tetrachloride is 0.1 ~ 2.0 mol/L, the mass fraction of tungsten hexachloride is 0.01 ~ 0.20 mol/L, after soaking 3 ~ 36 h, filter to isolate carbosphere, clean with ethanol, dry then, obtain being adsorbed with the carbosphere of titanium ion and tungsten ion;

3) with step 2) carbosphere that is adsorbed with titanium ion and tungsten ion that makes adds calcining furnace, in air atmosphere, be that 0.5 ~ 5 ℃/min is warming up to 350 ~ 600 ℃ of calcining at constant temperature 2 ~ 24 h with heating rate, obtain tungstic acid/titanium dioxide core-shell structure nanometer composite material.

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