CN107831194A - A kind of nano line cluster WO sensitive to ammonia3‑W18O49Hetero-junction thin-film - Google Patents
A kind of nano line cluster WO sensitive to ammonia3‑W18O49Hetero-junction thin-film Download PDFInfo
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Abstract
It can be used for detecting NH the invention provides one kind3Nano line cluster WO3‑W18O49The preparation method of hetero-junction thin-film, belong to gas sensor technology field.We mix tungsten hexachloride with isopropanol, and nano line cluster WO is prepared for by solvent-thermal method3‑W18O49Hetero-junctions powder, then thin-film device is prepared into by being coated with method, then carry out air-sensitive test.In the range of measured temperature (100 300 DEG C), the sample is at 250 DEG C to 500ppm NH3Response be up to 23.3, response/recovery time is 13 seconds/49 seconds.In addition, nano line cluster WO3‑W18O49The NH of the also detectable concentration of hetero-junction thin-film3(2 1000ppm), and to NH3With higher selectivity and stability.This colorimetric sensor films preparation method is simple, and cost of material is low, material membrane excellent performance, favorable repeatability, has good application value and prospect.
Description
Technical field
The invention belongs to gas sensor technology field, and in particular to a kind of nano line cluster WO3-W18O49Hetero-junction thin-film
Prepare and its air-sensitive performance of ammonia is studied.
Background technology
In recent years, due to possessing wide material sources, component height adjustable, chemical property stabilization, conductance under suitable pH value
The features such as property is good, oxygen defect is more, tungsten oxide material (WOx-3) gradually receive significant attention.In WOx-3In material, Lacking oxygen is shallow
Alms giver, conductance, the density of donors of material are effectively improved, enhances material for gaseous (such as NH3, CO2, NO2) absorption, therefore,
WOx-3Material is tempting in detection of gas field prospect.W18O49(WO2.72) it is a kind of more representational WOx-3Material, due to
W18O49Energy gap it is narrower, another aspect W18O49It is WOx-3Material (WO2.625-WO3) in a kind of material of oxygen defect content highest
Material, these properties cause W18O49Material is applied more broadly in detection of gas.
However, undeniable is intrinsic W18O49Sensitivity is relatively low, limits its answering in terms of high sensitivity detection
With.So far, in order to improve W18O49The sensitivity of based sensor, researcher have done repeatedly substantial amounts of trial, concluded
Mainly to there is three kinds:1) element doping, the W adulterated such as Ti-18O49(Sens.Actuators B:Chem.,2012,162,
244) W that is, 2) noble metal decorated, being modified such as Pt-18O49(Sens.Actuators B:Chem., 2011,153,354), 3) shape
Into hetero-junctions, such as W18O49@CuO core@shells nanometer rods (J.Alloys Compd., 2016,673,364), W18O49/TiO2Hetero-junctions
Nano wire (Sens.Actuators B:Chem.,2017,240,477).Wherein, air-sensitive performance is improved by constructing hetero-junctions
It is most widely used.But, it is worth mentioning at this point that the method for preparing hetero-junctions at present is required for multistep to synthesize.It is often necessary to first
Synthesize the first component, then mixed again with the second component, or the presoma of two components need to be constantly mixed to uniform, it is all so
Class method not only complex steps, thereby increases and it is possible to introduce potential pollution.Therefore, how to realize that one-step method is to prepare heterojunction material
Researcher is firstly the need of solving the problems, such as at present.
In the present invention, we are with tungsten hexachloride (WCl6) it is tungsten source, using isopropanol as solvent, prepared using solvent-thermal method
Nano line cluster WO3-W18O49Hetero-junctions powder, in order to carry out performance comparison, we are with WCl6For tungsten source, using normal propyl alcohol to be molten
Agent, a nanometer spindle W is equally prepared for using solvent-thermal method18O49Powder.Then WO is prepared for respectively using being coated with method3-W18O49
Hetero-junction thin-film and W18O49Thin-film device is simultaneously used for NH3Detection.Nano line cluster WO3-W18O49Heterojunction material preparation method
Simply, cost of material is low, favorable repeatability, compared to pure W18O49, based on nano line cluster WO3-W18O49The sensor pair of hetero-junctions
NH3Air-sensitive performance have greatly improved, thus there is good application value and prospect.
The content of the invention
It is an object of the invention to provide one kind to detect NH3Hetero-junction thin-film preparation method.Prepared by solvent-thermal method
Nano line cluster WO3-W18O49Hetero-junctions powder, then it is prepared into film by being coated with method.The preparation method have cost it is cheap, operation
Simply, the features such as convenient and swift, prepared product air-sensitive performance is excellent.
Below with WCl6Exemplified by briefly explain the present invention implementation process.Nano line cluster is prepared using solvent-thermal method first
WO3-W18O49Hetero-junctions powder, the appropriate powder and methanol are well mixed rear overhang and are coated in interdigital electrode, after waiting film to dry
It is placed in Muffle furnace, is taken out after being handled 2 hours at 100 DEG C, obtains testing substrate.Nano line cluster WO3-W18O49It is heterogeneous
Knot film can be realized by step in detail below:
(1) by a certain amount of WCl6Appropriate isopropanol is dissolved in, is persistently stirred 30 minutes at room temperature;
(2) above-mentioned solution is poured into and hydro-thermal reaction is carried out in stainless steel cauldron, hydrothermal condition is 200 DEG C, 24 hours;
(3) product of hydro-thermal reaction is cooled down at room temperature, then carried out repeatedly with deionized water and absolute ethyl alcohol respectively
Centrifuge washing, by the sample after centrifugation, 60 DEG C of dryings in vacuum drying chamber, obtain WO3-W18O49Powder;
(4) take appropriate above-mentioned powder to be dissolved in methanol solvate and ultrasound 2 hours, be then printed on being coated with instrument and solution is coated with
On the potsherd of platinum electrode, after waiting film to be completely dried, it is placed in Muffle furnace 2 hours, in-furnace temperature is arranged to 100 DEG C, most
After obtain test substrate.
Nano line cluster WO can be obtained by said process3-W18O49Hetero-junction thin-film, changing isopropanol into normal propyl alcohol can make
Obtain nanometer spindle W18O49Film.100 DEG C, 150 DEG C, 200 DEG C, 250 DEG C, 300 DEG C of conditions of work are contrasted, find WO3-W18O49
Material is at 250 DEG C to 500ppm NH3Sensitivity highest, and W18O49Material is at 200 DEG C to 500ppm NH3It is sensitive
Spend highest.At 250 DEG C, WO3-W18O49And W18O49Material is to 500ppm NH3Response/recovery time be more or less the same, be respectively
13 seconds/49 seconds and 9 seconds/29 seconds.Meanwhile by study 250 DEG C at two kinds of materials to various concentrations NH3The sound of (2-1000ppm)
Should, find for WO3-W18O49, with NH3The increase of concentration, sensor is to NH3Sensitivity increase, in surveyed concentration range
Do not occur saturation inside.And for W18O49, surveying high concentration NH3When sensitivity start saturation.In addition, it was found that WO3-
W18O49To NH3Selectivity it is higher, and stability is preferable.
Nano line cluster WO provided by the present invention3-W18O49The preparation method of hetero-junction thin-film, it can be achieved to NH3Gao Ling
Quick detection.This method is prepared simply, and cost of material is low, favorable repeatability, has good application value and prospect.
Brief description of the drawings
Fig. 1 is WO3-W18O49The preparation flow figure of hetero-junction thin-film device.
Fig. 2 (a)-(b) is respectively W under different temperatures18O49And WO3-W18O49Resistance with 500ppm NH3Break-make gas changes
Curve map, Fig. 2 (c) are two kinds of materials to 500ppm NH3Sensitivity vary with temperature curve map, Fig. 2 (d) is two at 250 DEG C
The resistance of kind material is with 500ppm NH3Break-make gas change curve.
Fig. 3 (a) is W18O49And WO3-W18O49Resistance with various concentrations NH3(illustration is two kinds to break-make gas change curve
The resistance of material is with 2ppm NH3Break-make gas change curve), Fig. 3 (b) is the sensitivity of corresponding two kinds of materials with NH3Concentration
(illustration is the sensitivity of two kinds of materials with NH to change curve3The partial enlarged drawing of concentration curve).
Under the conditions of Fig. 4 (a) is 250 DEG C, WO3-W18O49To NH3Selectivity test figure, Fig. 4 (b) is WO3-W18O49It is right
200ppm NH3Stability test figure.
Embodiment
It is described in detail the present invention with reference to the accompanying drawings and examples.
Embodiment 1, by 0.297 gram of WCl650 milliliters of isopropanols are dissolved in, are persistently stirred 30 minutes at room temperature.Then will be above-mentioned
Solution pours into and hydro-thermal reaction is carried out in stainless steel cauldron, and hydrothermal condition is 200 DEG C, 24 hours.The product of hydro-thermal reaction is existed
Cool down at room temperature, then carry out 3 centrifuge washings with deionized water and absolute ethyl alcohol respectively, the sample after centrifugation is done in vacuum
60 DEG C of dryings, obtain WO in dry case3-W18O49Powder.Take 0.05 gram of powder to be dissolved in 2 ml methanol solvents and carry out 2 hours
Ultrasound, then solution is coated with the potsherd for being printed on platinum electrode with being coated with instrument, after waiting film to be completely dried, is placed on Muffle
2 hours in stove, in-furnace temperature is arranged to 100 DEG C, finally obtains test substrate, preparation flow figure such as Fig. 1 institutes of the thin-film device
Show.
Fig. 2 (a)-(b) is respectively W at 100-300 DEG C18O49And WO3-W18O49Resistance with 500ppm NH3Break-make gas becomes
Change curve map.For W18O49, there is an abnormal phenomena, i.e., in 250 DEG C and 300 DEG C, with NH3Be continually fed into, material
The resistance of material increases after falling before, as shown in Fig. 2 (a) dotted line circle mark.For two kinds of materials, when test temperature is relatively low
When (100 DEG C, 150 DEG C), material can not recover within the defined time, (the T when test temperature is higher>150 DEG C), material is last
Aerial steadying resistance is higher than ground state resistance, as shown in Fig. 2 (a)-(b).
Transducer sensitivity computational methods:S=Ra/Rg.Wherein, RaFor the resistance of sensor in air atmosphere, RgTo pass
Resistance of the sensor under specific ammonia density.The response time of sensor is defined as:From when being contacted with certain density tested gas
Start, the time required to 90% that stable state resistance under this concentration is reached to resistance;Recovery time is defined as:From with certain density quilt
When surveying gas disengaging, recover to change 90% required time of resistance to resistance.Fig. 2 (c) is two kinds of materials to 500ppm
NH3Sensitivity vary with temperature curve map, WO3-W18O49Material is at 250 DEG C to NH3Sensitivity highest, be 23.3, and
W18O49Material is at 200 DEG C to NH3Sensitivity highest, be 7.77.Fig. 2 (d) be 250 DEG C at two kinds of materials resistance with
500ppm NH3Break-make gas change curve.Understand WO3-W18O49And W18O49Material is to 500ppm NH3Response/recovery time
It is more or less the same, respectively 13 seconds/49 seconds and 9 seconds/29 seconds.
Fig. 3 (a) is W18O49And WO3-W18O49Resistance with various concentrations NH3Break-make gas change curve, illustration are two kinds
The resistance value of material is with 2ppm NH3Break-make gas change curve.As seen from the figure, WO3-W18O49Even if material is to low concentration
NH3Also there is higher response (WO3-W18O49To 2ppm NH3Sensitivity be 2.26, and W18O49To 2ppm NH3Sensitivity only
For 1.48).Fig. 3 (b) is two kinds of corresponding sensitivity of material with NH3Concentration curve figure, illustration are the sensitive of two kinds of materials
Degree is with NH3The partial enlarged drawing of change in concentration.As seen from the figure, with NH3The increase of concentration, WO3-W18O49Sensor is to NH3Spirit
, there is not saturation in surveyed concentration range in sensitivity increase, and for W18O49, surveying high concentration NH3When sensitivity start saturation.
Meanwhile we have studied WO3-W18O49To NH3Selectivity, interference gas include carbon dioxide, hydrogen, methane and
Ethanol, all gas concentration are 500ppm, as shown in Fig. 4 (a), it is known that WO3-W18O49To NH3Selectivity it is higher.Finally I
Have studied WO3-W18O49To 200ppm NH3Stability, we are using a week as the cycle, to WO3-W18O49Intermittence is surveyed
Try 7 times, the stability of material has been evaluated with this, as shown in Fig. 4 (b).From result, measured in different time points sensitive
Spend essentially identical, therefore WO3-W18O49To NH3Stability it is preferable.
Claims (1)
- A kind of 1. nano line cluster WO sensitive to ammonia3-W18O49Hetero-junction thin-film and preparation method thereof, its preparation process include:(1) by a certain amount of WCl6Appropriate isopropanol is dissolved in, is persistently stirred 30 minutes at room temperature;(2) above-mentioned solution is poured into and hydro-thermal reaction is carried out in stainless steel cauldron, hydrothermal condition is 200 DEG C, 24 hours;(3) product of hydro-thermal reaction is cooled down at room temperature, then repeatedly centrifuged with deionized water and absolute ethyl alcohol respectively Washing, by the sample after centrifugation, 60 DEG C of dryings in vacuum drying chamber, obtain WO3-W18O49Powder;(4) take appropriate above-mentioned powder to be dissolved in methanol solvate and ultrasound 2 hours, be then printed on platinum electricity with being coated with instrument and solution is coated with On the potsherd of pole, after waiting film to be completely dried, it is placed in Muffle furnace 2 hours, in-furnace temperature is arranged to 100 DEG C, finally To test substrate.
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CN110743535A (en) * | 2019-11-28 | 2020-02-04 | 湖南大学 | Tungsten oxide homojunction composite photocatalyst and preparation method and application thereof |
CN111957276A (en) * | 2020-07-14 | 2020-11-20 | 华中科技大学 | Gas sensitive material parallel automatic synthesis device based on solvothermal method |
CN115128134A (en) * | 2022-06-21 | 2022-09-30 | 武汉铂纳智感科技有限公司 | Gas sensor based on optical excitation, preparation method and application |
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Cited By (6)
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CN115128134A (en) * | 2022-06-21 | 2022-09-30 | 武汉铂纳智感科技有限公司 | Gas sensor based on optical excitation, preparation method and application |
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