CN103713016B - Palladium doping stannic oxide enveloped carbon nanometer tube and its preparation method and application - Google Patents
Palladium doping stannic oxide enveloped carbon nanometer tube and its preparation method and application Download PDFInfo
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- CN103713016B CN103713016B CN201310737096.5A CN201310737096A CN103713016B CN 103713016 B CN103713016 B CN 103713016B CN 201310737096 A CN201310737096 A CN 201310737096A CN 103713016 B CN103713016 B CN 103713016B
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Abstract
The invention discloses a kind of palladium doping stannic oxide enveloped carbon nanometer tube utilizing sol-gal process to prepare。Structure is the surface that the tin ash crystal (Pd/SnO2) doped with palladium is coated on CNT。Adopt following steps preparation: by CNT ultrasonic disperse in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, it is subsequently adding chlorine palladium acid sodium solution to be uniformly mixed, regulate pH value to 7-9,30-200 DEG C preserves 0.2-36h and obtains milk white gel, washs, calcines the prepared palladium doping stannic oxide enveloped carbon nanometer tube of 1-36h at 200-700 DEG C after drying。Air-sensitive performance and the reduction of the large increase tin dioxide gas sensor that adulterates of noble metal and CNT respond and recovery time, and make optimum operating temperature move to low temperature。
Description
Technical field
The invention belongs to field of inorganic materials, relate to a kind of palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO utilizing sol-gal process to prepare2/ CNT)。
Background technology
Metal-oxide semiconductor (MOS) gas sensor is widely used in the gas detecting such as explosive, poisonous, environmental hazard。At present, modal metal-oxide sensitive material has ZnO, SnO2、Fe2O3、TiO2Deng, wherein SnO2It is the most extensive that system is applied to gas sensor。Tin ash based powders and thin-film material have many kinds of preparation methods, such as powder sintering, chemical vapour deposition technique, spray pyrolysis method, sol-gel method, radio-frequency magnetron sputter method, pulsed laser deposition, having compared other Technology, adopting sol-gel method to prepare tin ash sill has many advantages, thus apply ratio is wide。Its main advantage has: cost of manufacture is cheap, and instrument and equipment is simple, it is possible to prepare material at a lower temperature, moreover it is possible to control the form of thin film, and most important advantage is to adopt sol-gel method to carry out doping to be easier。At present, substantial amounts of research shows, the three big principal elements affecting oxide-semiconductor sensor are as follows: effectiveness (namely the microstructure of gas sensing thin film controls) (3) function of receptors (i.e. load receptor, for instance noble metal or metal-oxide) of sensing capabilities (2) gas sensing thin film of (1) crystalline metal oxide。About reports such as the sensing capabilities of crystalline metal oxide, Xu, the response time of sensor can along with SnO2The reduction of crystallite dimension shorten rapidly。Recently, Yamazoe etc. propose theoretical model and the formula of crystalline semiconductor depletion layer。For the effectiveness of gas sensing thin film, it is by experiment or theory all detected the gas sensing thin film microstructure important function to gas sensor。Sakai etc. pass through to SnO2In colloidal sol, interpolation Polyethylene Glycol (PEG) forms net and knits structure to control SnO2The microstructure of thin film。As for function of receptors, it is commonly known that carried metal and metal-oxide can improve oxide semiconductor gas sensor to the sensitivity of gas and selectivity。Particularly Pd and PdO load is at SnO2Research many especially, be primarily due to them to SnO2There is electricity and the sensitization of chemistry。
SnO2Being a kind of common Semiconductor gas sensors material, a lot of gases are had response, but air-sensitive performance is relatively low, and generally can be only achieved optimum operating temperature more than 350 DEG C, the response-recovery time is longer。Therefore preparing high air-sensitive property can be most important with the gas sensitive of short response-recovery time。
Summary of the invention
One's duty goal of the invention is in that to overcome existing SnO2The defect of gas sensor, it is provided that a kind of to CO and H2Response recovers gas sensor material fast, highly sensitive, still further provides its preparation method and methods for using them。
For reaching above-mentioned purpose, adopt technical scheme as follows:
A kind of palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO2/ CNT), structure is the tin ash crystal (Pd/SnO doped with palladium2) it is coated on the surface of CNT。
By such scheme, described palladium doping stannic oxide enveloped carbon nanometer tube adopts following steps preparation:
By CNT ultrasonic disperse in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, it is subsequently adding chlorine palladium acid sodium solution to be uniformly mixed, regulate pH value to 7-9,30-200 DEG C preserves 0.2-36h and obtains milk white gel, washs, calcines the prepared palladium doping stannic oxide enveloped carbon nanometer tube of 1-36h at 200-700 DEG C after drying。
By such scheme, in described palladium doping stannic oxide enveloped carbon nanometer tube, the doping of palladium is at 1-20wt%。
By such scheme, described CNT is the CNT through obtaining at 50-200 DEG C of condensing reflux 4-24h acidification。
The preparation method of palladium doping stannic oxide enveloped carbon nanometer tube, comprises the following steps:
By CNT ultrasonic disperse in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, it is subsequently adding chlorine palladium acid sodium solution to be uniformly mixed, regulate pH value to 7-9,30-200 DEG C preserves 0.2-36h and obtains milk white gel, washs, calcines the prepared palladium doping stannic oxide enveloped carbon nanometer tube of 1-36h at 200-700 DEG C after drying。
By such scheme, in the preparation method of described palladium doping stannic oxide enveloped carbon nanometer tube in palladium doping stannic oxide enveloped carbon nanometer tube the doping of palladium at 1-20wt%。
By such scheme, in the preparation method of described palladium doping stannic oxide enveloped carbon nanometer tube, CNT is the CNT through obtaining at 50-200 DEG C of condensing reflux 4-24h acidification。
Described palladium doping stannic oxide enveloped carbon nanometer tube is as the application of gas sensitive。
Described palladium doping stannic oxide enveloped carbon nanometer tube is as the gas sensor of gas sensitive。
The invention provides a kind of based on palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO2/ CNT) novel air-sensitive material gas sensor and preparation method, this gas sensor preparation method is simple, easily realize, and owing to air-sensitive performance and the reduction of noble metal and the large increase tin dioxide gas sensor that adulterates of CNT respond and recovery time, and optimum operating temperature is made to move to low temperature。CO the best sensing capabilities is more than 50, and to the response of CO be 2s recovery time, optimum operating temperature is 150 DEG C, to H2Best sensing capabilities is more than 30, to H2Response and recovery time respectively 3s and 5s, optimum operating temperature is 200 DEG C。It is superior to industrial gases sensor properties。It is hopeful to be applied to CO and H2In detection。
Beneficial effects of the present invention:
Highly sensitive, the sensitivity of business application reaches 4 and can apply；
Response recovery time is fast, and Figaro company of Japan process gas sensor response time is all at more than 10s, and this material can foreshorten to 2-5s；
Temperature is low, pure SnO2Optimum temperature is more than 350 DEG C, and the optimum temperature of this material is 150-200 DEG C。
Accompanying drawing explanation
Fig. 1:: embodiment 1 prepares Pd/SnO2The X diffraction pattern of/CNT；
Figure: 2: embodiment 1 prepares Pd/SnO2The EDS figure of/CNT；
Fig. 3: embodiment 2 prepares Pd/SnO2To the sensitivity relation of variable concentrations CO and response-recovery figure at/CNT gas sensitive 150 DEG C；
Fig. 4: embodiment 2 prepares Pd/SnO2To variable concentrations H at/CNT gas sensitive 200 DEG C2Sensitivity relation and response-recovery figure。
Detailed description of the invention
Following example explain the technology contents of the present invention further, but not as the restriction to technical solution of the present invention。
Palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO2/ CNT), structure is the tin ash crystal (Pd/SnO doped with palladium2) it is coated on the surface of CNT。
Palladium doping stannic oxide enveloped carbon nanometer tube adopts sol-gal process preparation, and detailed process is as follows:
By CNT ultrasonic disperse in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, it is subsequently adding chlorine palladium acid sodium solution to be uniformly mixed, regulate pH value to 7-9,30-200 DEG C preserves 0.2-36h, obtain milky colloidal sol, wash, calcine the prepared palladium doping stannic oxide enveloped carbon nanometer tube of 1-36h at 200-700 DEG C after drying。
In palladium doping stannic oxide enveloped carbon nanometer tube, the doping of palladium calculates that to control the effect when 0-20wt% scope is as gas sensitive better in parts by weight。
Before preparation, CNT has good effect through 50-200 DEG C of condensing reflux 4-24h acidification。
Palladium doping stannic oxide enveloped carbon nanometer tube is as the application of gas sensitive。When experiment finds palladium doping stannic oxide enveloped carbon nanometer tube as the use of gas sensitive, CNT can stop metal-oxide to be reunited, improves sensitivity and the shortening response-recovery time of gas sensor, has unexpected good result。
Based on the palladium doping stannic oxide enveloped carbon nanometer tube gas sensor as gas sensitive。The doping large increase of noble metal and the CNT air-sensitive performance of tin dioxide gas sensor, CO the best sensing capabilities is more than 50, and to the response of CO be 2s recovery time, optimum operating temperature is 150 DEG C, to H2Best sensing capabilities is more than 30, to H2Response and recovery time respectively 3s and 5s, optimum operating temperature is 200 DEG C。It is superior to industrial gases sensor properties, is expected at CO and H2Detection uses in a large number。
Embodiment 1
By CNT ultrasonic disperse 20min in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, after be added thereto to chlorine palladium acid sodium solution (mol ratio of Pd/Sn be 1%,), regulating pH value to 8, at 60-90 DEG C, magnetic agitation 6h obtains milky colloidal sol, washing, dry, calcining be incubated 24h and can be prepared by palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO at 200 DEG C2/ CNT)。
Take a certain amount of Pd/SnO2/ CNT is placed in agate mortar, add appropriate deionized water grind to form all with fine and smooth slurry, then it is coated onto the gold that alchlor is substrate and inserts on finger electrode, the coated sensing layer preparing gas sensor is about 100um, dry in the shade after being painted with, be then placed in air-sensitive tester, be assembled into a complete loops, form a complete gas sensing device, to the aging 24h of electric current。Test its air-sensitive performance and show that the sensitivity when 150 DEG C of the CO to 500ppm has reached 63。
Shown in reference Fig. 1, the present embodiment gained Pd/SnO2The X diffraction pattern of/CNT。SnO from figure226.60, 33.90, 37.90, 51.80, 54.80, 57.80, 61.90, 64.70, 71.30With 78.70(JPCDSfileNo.41-1445) all occurring in that diffraction maximum, this belongs to tetragonal crystal system rutile SnO2Characteristic diffraction peak。But the characteristic diffraction peak not having Pd occurs, it is primarily due to that the doping of Pd is less and Pd is highly dispersed at SnO2On surface。Shown in reference Fig. 2, Pd/SnO2The EDS figure of/CNTs, owing to the doping of Pd is less and is highly dispersed at SnO2Surface, cannot detect the feature diffraction of Pd with XRD, but it can be seen that the characteristic peak of Pd in the EDS figure from Fig. 2, it was shown that Pd has successfully been entrained in SnO2Surface。
Embodiment 2
By CNT ultrasonic disperse 20min in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, after be added thereto to chlorine palladium acid sodium solution (mol ratio of Pd/Sn be 3%,), regulating pH value to 8, at 60-90 DEG C, magnetic agitation 6h obtains milky colloidal sol, washing, dry, calcining be incubated 24h and can prepare palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO at 200 DEG C2/ CNT)。
Take a certain amount of Pd/SnO2/ CNT is placed in agate mortar, add appropriate deionized water grind to form all with fine and smooth slurry, then it is coated onto the gold that alchlor is substrate and inserts on finger electrode, the coated sensing layer preparing gas sensor is about 100um, dries in the shade after being painted with, and is then placed in air-sensitive tester, it is assembled into a complete loops, form a complete gas sensing device, to the aging 24h of electric current, standby。
Performance test is with reference to Pd/SnO shown in Fig. 32To the sensitivity relation of variable concentrations CO and response-recovery figure at/CNT gas sensitive 150 DEG C, the sensitivity that can obtain CO becomes big along with the increase of concentration, Pd/SnO2The recovery time of CO is foreshortened to 2s by/CNT gas sensitive。With reference to Pd/SnO shown in Fig. 32To variable concentrations H at/CNT gas sensitive 200 DEG C2Sensitivity relation and response-recovery figure, H can be obtained2Sensitivity become big along with the increase of concentration, Pd/SnO2/ CNT gas sensitive is to H2Recovery time foreshorten to 5s。
Embodiment 3
By CNT ultrasonic disperse 20min in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, after be added thereto to chlorine palladium acid sodium solution (Pd account for Pd/SnO2/ CNT mass fraction is 1wt%), regulate pH value to 7, obtain milky colloidal sol at 30 DEG C of magnetic agitation 36h, washing, dry, calcining be incubated 1h and can prepare palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO at 700 DEG C2/ CNT)。
Embodiment 4
By CNT ultrasonic disperse 20min in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, after be added thereto to chlorine palladium acid sodium solution (Pd account for Pd/SnO2/ CNT mass fraction is 20wt%), regulate pH value to 9, obtain milky colloidal sol at 200 DEG C of magnetic agitation 0.2h, washing, dry, calcining be incubated 36h and can prepare palladium doping stannic oxide enveloped carbon nanometer tube (Pd/SnO at 200 DEG C2/ CNT)。
Claims (5)
1. the palladium doping stannic oxide enveloped carbon nanometer tube for gas sensitive, it is characterised in that form is the surface that the tin ash crystal doped with palladium is coated on CNT；Palladium doping in tin ash crystal is at 1-20wt%；
Described palladium doping stannic oxide enveloped carbon nanometer tube is adopted and is prepared with the following method:
By CNT ultrasonic disperse in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, it is subsequently adding chlorine palladium acid sodium solution to be uniformly mixed, regulate pH value to 7-9,30-200 DEG C preserves 0.2-36h and obtains milk white gel, washs, calcines the prepared palladium doping stannic oxide enveloped carbon nanometer tube of 1-36h at 200-700 DEG C after drying。
2. palladium doping stannic oxide enveloped carbon nanometer tube as claimed in claim 1, it is characterised in that described CNT is the CNT through obtaining at 50-200 DEG C of condensing reflux 4-24h acidification。
3. the preparation method for the palladium doping stannic oxide enveloped carbon nanometer tube of gas sensitive, it is characterised in that comprise the following steps:
By CNT ultrasonic disperse in ultra-pure water, add stannic chloride pentahydrate presoma ultrasonic disperse again, it is subsequently adding chlorine palladium acid sodium solution to be uniformly mixed, regulate pH value to 7-9,30-200 DEG C preserves 0.2-36h and obtains milk white gel, washs, calcines the prepared palladium doping stannic oxide enveloped carbon nanometer tube of 1-36h at 200-700 DEG C after drying；Wherein palladium doping in tin ash crystal is at 1-20wt%。
4. the preparation method of palladium doping stannic oxide enveloped carbon nanometer tube as claimed in claim 3, it is characterised in that in the preparation method of described palladium doping stannic oxide enveloped carbon nanometer tube, CNT is the CNT through obtaining at 50-200 DEG C of condensing reflux 4-24h acidification。
5. palladium doping stannic oxide enveloped carbon nanometer tube described in claim 1 is as the gas sensor of gas sensitive。
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| CN104386739B (en) * | 2014-10-11 | 2016-02-24 | 武汉工程大学 | Tubular structure PdO/SnO 2nano composite air-sensitive material and its preparation method and application |
| CN104483351B (en) * | 2014-11-27 | 2017-05-03 | 武汉工程大学 | Palladium-doped hollow porous stannic oxide microcubes as well as preparation method and application thereof |
| CN105259211A (en) * | 2015-10-13 | 2016-01-20 | 武汉工程大学 | Gas-sensor nanometer sensitive material, slurry with gas-sensor nanometer sensitive material, preparing method of gas-sensor nanometer sensitive material, preparing method of slurry and application of gas-sensor nanometer sensitive material |
| CN105338799B (en) * | 2015-12-03 | 2018-05-29 | 安徽理工大学 | With the nanocomposite of magnetic metal doping multi-walled carbon nanotube/stannic oxide |
| CN109270127A (en) * | 2018-09-27 | 2019-01-25 | 北京镭硼科技有限责任公司 | A kind of planar semiconductor gas sensor chip and preparation method thereof |
| CN110395714B (en) * | 2019-08-23 | 2022-08-05 | 南京智融纳米新材料科技有限公司 | Antimony doped SnO 2 Preparation method of @ carbon nanotube composite electrothermal film |
| CN112924498B (en) * | 2021-01-22 | 2022-04-01 | 华中科技大学 | Palladium monoatomic modified tin oxide composite material and preparation method and application thereof |
| CN114622244B (en) * | 2022-03-15 | 2023-06-20 | 南京师范大学 | Ru-SnO 2 Hydrogen evolution reaction catalyst and preparation method thereof |
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