CN104098124A

CN104098124A - Preparation method of SnO2 nanotube and application thereof to gas sensor

Info

Publication number: CN104098124A
Application number: CN201310118280.1A
Authority: CN
Inventors: 张军; 郭静; 曹丙强
Original assignee: University of Jinan
Current assignee: University of Jinan
Priority date: 2013-04-08
Filing date: 2013-04-08
Publication date: 2014-10-15

Abstract

The application of the invention relates to a preparation method of a SnO2 nanotube and application thereof to gas sensors. The SnO2 nanotube provided by the invention employs a sacrificial template method for preparation, and uses cheap and easily available KMnO4, MnSO4.H2O, SnCl2.2H2O and deionized water. First, a hydrothermal reaction is employed for the preparation of a MnO2 nanorod sacrificial template, and then a redox reaction is carried out to obtain a Sn(OH)x precursor, which is then roasted to obtain the SnO2 nanotube. Under acidic conditions, MnO2 with oxidizability and Sn<2+> with reducibility generate a redox reaction, so that MnO2 is reduced to Mn<2+>, Sn<2+> is oxidized into Sn<4+>, which is at the same time hydrolyzed on the nanorod template surface to generate Sn(OH)x. The sacrificial template method provided by the invention has simple steps, eliminates the post treatment process of template, and does not pollute or destruct the composition and structure of the SnO2 nanotube; and the SnO2 nanotube material has unique hollow structure and large surface to volume ratio, shows good response-recovery speed and high sensitivity to alcohol, and is a promising gas sensitive material.

Description

A kind of SnO 2the preparation method of nanotube and gas sensor application

Technical field

The present invention relates to gas sensor and air-sensitive material technology field, relate in particular to a kind of SnO ₂the preparation method of nanotube and gas sensor application.

Background technology

SnO ₂be a kind of typical N-shaped metal-oxide semiconductor (MOS), there is unique physics and chemistry characteristic, be widely used in the fields such as transparency electrode, catalyzer, gas sensor.At gas sensor field, SnO- ₂to study the most extensive a kind of gas sensitive, have abundant raw material, preparation easily, the feature such as excellent in stability, surface-sensitive characteristic be good.Adopt SnO- ₂the gas sensor of preparing as active material has the advantages such as manufacture craft is simple, price is low, good stability.The development of nano material, for exploitation high-performance gas sensitive provides important thinking.The structure of nano material has material impact to its performance.By various chemical preparation means, people can synthesize the material with various special nanostructures, such as nanoparticle, nanometer rod, nano wire, nanotube and nanometer sheet etc.Wherein, nano tube structure has that large surface volume ratio, inner hollow, space are abundant, the structurally ordered features such as electronic conduction that are beneficial to, and is the very potential gas sensitive of one.

The preparation of metal oxide nanotubes material adopts template more, as porous anodic aluminium oxide (AAO).But this kind of method carried out post-processed to template because of needs, thereby make that synthesis step is loaded down with trivial details, cost is high, template is difficult for complete Ex-all, tubular structure is vulnerable to destroy, thereby has greatly limited SnO ₂synthetic and the application of nano-tube material.Therefore, from the angle of scientific research and practical application, develop a kind of step preparation method simple, with low cost, for exploitation SnO ₂the application performance of nanotube is significant.

Summary of the invention

The object of the invention is to for above-mentioned technical Analysis, provide that a kind of step is simple, reaction conditions is gentle, be easy to control product S nO ₂the sacrifice method for preparing template of nanotube pattern, and use it for making gas sensor, there is potential using value.

Technical scheme of the present invention:

A kind of SnO ₂the preparation method of nanotube, the starting raw material that it is characterized in that described preparation method is KMnO cheap and easy to get ₄, MnSO ₄h ₂o, SnCl ₂2H ₂o and deionized water, adopt hydro-thermal reaction, normal temperature oxidation reduction reaction, and through centrifugal, washing, the processing such as oven dry and roasting, first prepare MnO ₂nanometer rod is sacrificed template, due to MnO ₂there is oxidisability, Sn ²⁺have reductibility, under acidic conditions, can there is redox reaction, MnO in the two ₂be reduced into Mn ²⁺, Sn ²⁺be oxidized to Sn ⁴⁺, generate Sn (OH) in the hydrolysis of nanometer rod template surface simultaneously _x, after roasting, be transformed into SnO ₂.Prepared SnO ₂nanotube is assembled by nanoparticle, and the length of nanotube is 0.5～2 μ m.

Described SnO ₂nanotube preparation method, comprises the following steps:

(1) MnO ₂nanometer rod is sacrificed template preparation

By 0.63g KMnO ₄with 0.25g MnSO ₄h ₂o is dissolved in 40mL deionized water,, transfers in 50 mL hydrothermal reaction kettles to dissolving completely through magnetic agitation.By hydrothermal reaction kettle isothermal reaction 12h at 160 DEG C, take out reactor and be cooled to room temperature, by whizzer collecting reaction product, after washing, 80 DEG C are dried, and obtain brown MnO ₂nanometer rod;

(2) SnO ₂nanotube preparation

By the prepared MnO of 60mg step (1) ₂nanometer rod is scattered in 35mL deionized water, to being uniformly dispersed, weighs 0.25g SnCl through magnetic agitation ₂2H ₂o joins in above-mentioned mixed solution, continues to stir reaction 48h.By whizzer collecting reaction product, after washing, 80 DEG C are dried, and by products therefrom roasting 1h at 500 DEG C, obtain canescence SnO ₂nanotube.

The described SnO that utilizes ₂nanotube making gas sensor step is as follows:

By SnO ₂nanotube adds water and makes slurry, is coated on alumina ceramic tube, has two gold electrodes and four platinum wires on alumina ceramic tube, Guan Zhongwei nickel-chromium heater strip.Vitrified pipe is welded on six leg bases, makes gas sensor.Adopt HW-60A air-sensitive tester, the gas sensitization characteristic of testing sensor, probe temperature is 300 DEG C, and test gas is ethanol, and atmospheric moisture is 35%.

Advantage of the present invention and positively effect are as follows:

(1) MnO of the present invention ₂nanometer rod is sacrificed template synthesis SnO ₂nanotube, based on chemistry redox reaction principle.MnO ₂nanometer rod is served as the growth templates of nanotube, meanwhile, and because reduction causes MnO ₂nanometer rod is constantly dissolved, and has finally removed the post-processed step of template from.This sacrifice template step is simple, and template can become deliquescent Mn ²⁺remove completely, do not need post-processed, can be to SnO ₂the composition and structure of nano-tube material pollutes and destroys;

(2) SnO that prepared by the present invention ₂nano-tube material is because its unique hollow structure and larger surface volume ratio, be conducive to infiltration and the diffusion of gas in gas sensitive inside, the gas sensor of preparing as active material shows good response-recovery speed, higher sensitivity, circulation ratio and stability to ethanol, thereby has broad application prospects.

Brief description of the drawings

Fig. 1 is MnO ₂nanometer rod is sacrificed the SEM picture of template.

Fig. 2 is SnO ₂the SEM picture of nanotube.

Fig. 3 is SnO ₂the XRD figure case of nanotube.

Fig. 4 is SnO ₂the response-recovery performance of nanotube gas sensor to different concentration ethanol.

Fig. 5 is SnO ₂the sensitivity of nanotube gas sensor to different concentration ethanol.

Embodiment

Embodiment:

The present invention is with KMnO ₄, MnSO ₄h ₂o, SnCl ₂2H ₂o is raw material, taking water as solvent, first prepares MnO ₂nanometer rod is sacrificed template, then prepares SnO by redox reaction ₂nanotube, below by embodiment, the present invention will be further described:

(1) by 0.63g KMnO ₄with 0.25g MnSO ₄h ₂o is dissolved in 40mL deionized water,, transfers in 50 mL hydrothermal reaction kettles to dissolving completely through magnetic agitation.By hydrothermal reaction kettle insulation reaction 12h at 160 DEG C, take out reactor and be cooled to room temperature, by whizzer collecting reaction product, after washing, 80 DEG C are dried, and obtain brown MnO ₂nanometer rod;

(2) by 60mg MnO ₂nanometer rod is scattered in 35mL deionized water, to being uniformly dispersed, weighs 0.25g SnCl through magnetic agitation ₂2H ₂o joins in above-mentioned mixed solution, continues to stir reaction 48h.By whizzer collecting reaction product, after washing, 80 DEG C are dried, and by products therefrom roasting 1h at 500 DEG C, obtain canescence SnO ₂nanotube.

SnO ₂the structural characterization of nanotube and air-sensitive property detection:

(1) instrument that the observation of the pattern of material adopts is scanning electron microscope Quanta FEG 250.Figure 1 shows that MnO ₂nanometer rod, visible MnO from scheming ₂the well-regulated one dimension of nanometer rod tool mechanism, length is several microns, diameter is tens nanometers.Figure 2 shows that SnO ₂nanotube, nanotube surface is more coarse, and can differentiate nanotube is to have nanoparticle to form, and length is 0.5-1 micron, and diameter is tens nanometers.From the illustration of Fig. 2, can obviously see the beginning of nanotube;

(2) test of the crystalline structure of material adopts Rigaku D/max-2500 type powder x-ray diffraction.Figure 3 shows that SnO ₂the X-ray diffraction pattern of nanotube, diffraction peak and standard card JCPDS No.41-1445 match, and illustrate that this nano-tube material is the SnO of tetragonal system ₂;

(3) adopt HW-60A type air-sensitive tester, tested SnO ₂the gas sensor that nanotube is made detects performance to the air-sensitive of ethanol, and probe temperature is 300 DEG C, and gas concentration is 5,20,50,100 and 200ppm.SnO shown in Fig. 4 ₂the response-recovery curve of nanotube to different concentration ethanol gas, sensor has response-recovery speed fast to ethanol as seen from the figure, and the ethanol of different concns is had to good resolving power.Figure 5 shows that SnO ₂nanotube is to different concentration ethanol gas sensitivity, and visible light transducer sensitivity increases along with the increase of concentration.And having lower detectivity, is 2.1 to the sensitivity of 5ppm ethanol.

Claims

1. a SnO ₂nanotube, is characterized in that: there is the structure of hollow, and larger surface volume ratio, length is 0.5～2 μ m, tube wall is made up of nanoparticle, has abundant pore texture between particle.

2. a SnO as claimed in claim 1 ₂the preparation method of nanotube, is characterized in that: adopt KMnO ₄, MnSO ₄h ₂o, SnCl ₂2H ₂o is as starting raw material, and deionized water is solvent, prepares MnO by hydro-thermal reaction ₂nanometer rod, as sacrificing template, in acidic solution, with the Sn with reductibility ²⁺there is redox reaction, MnO ₂be reduced into Mn ²⁺, Sn ²⁺be oxidized to Sn ⁴⁺, generate Sn (OH) in the hydrolysis of nanometer rod template surface simultaneously _x, obtain SnO by roasting ₂nanotube.

3. SnO according to claim 2 ₂the preparation method of nanotube, is characterized in that: described KMnO ₄, MnSO ₄h ₂o and go from

The mass ratio of sub-water is 60-65:23-26:400, and hydrothermal temperature is 160 DEG C, and the reaction times is 12h.

4. SnO according to claim 2 ₂the preparation method of nanotube, is characterized in that: described MnO ₂nanometer rod template and SnCl ₂2H ₂o

Mass ratio be 6:25.

5. SnO according to claim 2 ₂the preparation method of nanotube, is characterized in that: described maturing temperature is 500 DEG C.