CN108169292B - LaFeO co-modified by Au and Cl3Ethanol-based gas sensor and preparation method thereof - Google Patents
LaFeO co-modified by Au and Cl3Ethanol-based gas sensor and preparation method thereof Download PDFInfo
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- 229910017771 LaFeO Inorganic materials 0.000 title claims abstract description 52
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N EtOH Substances CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 100
- 239000011858 nanopowder Substances 0.000 claims abstract description 41
- 229910002321 LaFeO3 Inorganic materials 0.000 claims abstract description 30
- 229910052737 gold Inorganic materials 0.000 claims abstract description 23
- 239000000919 ceramic Substances 0.000 claims abstract description 19
- 239000007864 aqueous solution Substances 0.000 claims abstract description 11
- 239000000243 solution Substances 0.000 claims abstract description 8
- 238000003980 solgel method Methods 0.000 claims abstract description 6
- 239000010931 gold Substances 0.000 claims description 38
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims description 15
- 229910004042 HAuCl4 Inorganic materials 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 7
- 229910052760 oxygen Inorganic materials 0.000 claims description 7
- 230000032683 aging Effects 0.000 claims description 6
- 238000000137 annealing Methods 0.000 claims description 6
- 238000010438 heat treatment Methods 0.000 claims description 6
- 150000002500 ions Chemical class 0.000 claims description 6
- 239000002243 precursor Substances 0.000 claims description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 6
- 239000002105 nanoparticle Substances 0.000 claims description 5
- 239000008118 PEG 6000 Substances 0.000 claims description 4
- 229920002584 Polyethylene Glycol 6000 Polymers 0.000 claims description 4
- 239000002202 Polyethylene glycol Substances 0.000 claims description 4
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 229920001223 polyethylene glycol Polymers 0.000 claims description 4
- 238000003756 stirring Methods 0.000 claims description 4
- 229910018487 Ni—Cr Inorganic materials 0.000 claims description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 3
- WUOACPNHFRMFPN-UHFFFAOYSA-N alpha-terpineol Chemical compound CC1=CCC(C(C)(C)O)CC1 WUOACPNHFRMFPN-UHFFFAOYSA-N 0.000 claims description 3
- 239000008367 deionised water Substances 0.000 claims description 3
- 229910021641 deionized water Inorganic materials 0.000 claims description 3
- SQIFACVGCPWBQZ-UHFFFAOYSA-N delta-terpineol Natural products CC(C)(O)C1CCC(=C)CC1 SQIFACVGCPWBQZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000003365 glass fiber Substances 0.000 claims description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 claims description 3
- 238000000227 grinding Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- 239000004570 mortar (masonry) Substances 0.000 claims description 3
- 229940116411 terpineol Drugs 0.000 claims description 3
- 150000001768 cations Chemical class 0.000 claims description 2
- 239000007789 gas Substances 0.000 abstract description 106
- 230000004044 response Effects 0.000 abstract description 34
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 abstract description 9
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 abstract description 6
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 abstract description 6
- 230000008859 change Effects 0.000 abstract description 4
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 abstract description 3
- 239000001569 carbon dioxide Substances 0.000 abstract description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 abstract description 3
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 abstract description 3
- 239000000126 substance Substances 0.000 description 18
- 239000000843 powder Substances 0.000 description 9
- 238000001514 detection method Methods 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 230000009286 beneficial effect Effects 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 230000036541 health Effects 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 2
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 235000011837 pasties Nutrition 0.000 description 1
- 238000002186 photoelectron spectrum Methods 0.000 description 1
- 206010036067 polydipsia Diseases 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 235000014101 wine Nutrition 0.000 description 1
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- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
- G01N27/127—Composition of the body, e.g. the composition of its sensitive layer comprising nanoparticles
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Abstract
The invention belongs to the technical field of gas sensor preparation, and provides Au and Cl co-modified LaFeO3Ethanol-based gas sensor and preparation method thereof, LaFeO3HAuCl with the mass fraction of 1 percent and the mass ratio of 1:100 are added into the solution4Preparation of LaFeO jointly modified by Au and Cl by aqueous solution and sol-gel method3Preparing the nano powder into the gas sensor element with the indirectly heated ceramic tube structure. The optimal working temperature of the prepared gas sensor element on ethanol is 128 ℃; the gas response to 100ppm ethanol at the optimal working temperature is 47.7, and the gas response has no great change after 96 hours and good stability; the response to 100ppm DMF, dichloromethane, normal hexane, carbon dioxide and hydrogen gas is below 23.3, and the selectivity is good; the gas response to 20ppm ethanol reaches 19.5, and the gas response to low-concentration ethanol gas is very high.
Description
Technical Field
The invention belongs to the technical field of gas sensor preparation, and particularly relates to Au and Cl co-modified LaFeO3Alcohol-based gas sensor and preparation method thereof, LaFeO modified by Au and Cl together3The nanometer powder is a working substance, and the LaFeO is obviously improved under the conditions of ensuring lower working temperature, higher selectivity and stability3The gas response of the ethanol-based gas sensor element, wherein the gas response is defined as the ratio of the resistance of the sensor element in the gas environment to be measured to the resistance in dry air.
Background
With the development of modern society, people pay more and more attention to health and safety questionsThe problem is that ethanol is a main component of various wines, and simultaneously is a combustible gas, and the ethanol gas sensor has great health and potential safety hazards in excessive drinking, drunk driving and ethanol leakage, so that the ethanol gas sensor with high sensitivity, high selectivity, stability and reliability has important significance on human health and life safety. Currently, doped semiconductor oxides SnO2、ZnO、TiO2、Fe2O3、V2O5And the like are widely applied to the detection of the ethanol gas, and the detection of the ethanol gas is realized by measuring the change of the resistance by using the principle that oxygen adsorbed on the surface of the semiconductor oxide reacts with the detected ethanol gas to change the resistance of the semiconductor material. However, the ethanol gas sensor generally has the problems of higher working temperature, lower gas response, longer response recovery time, poorer selectivity and the like, and is not beneficial to the development of the gas-sensitive sensing technology.
Perovskite type oxide LaFeO3Is a p-type semiconductor, and the resistance increases when exposed to a reducing gas such as ethanol. Recently, LaFeO is used3Research on the basic ethanol gas sensor elements has received much attention because of the high stability of such sensors. However, based on previous research work by researchers we found that: LaFeO3The resistance is very large, which is not beneficial to practical application, and LaFeO3The optimal working temperature of the ethanol-based gas sensor element is still higher, generally higher than 200 ℃, which is not beneficial to the research of low-power consumption devices; the gas response to ethanol gas at the optimum operating temperature is not sufficiently high, and particularly the response to ethanol gas at low concentrations is yet to be improved. The existing method mainly provides more hole carriers through the position of substituting trivalent La by doping bivalent elements such as Ca, Sr, Ba, Pb and the like or the position of substituting trivalent Fe by doping elements such as Co, Mg, Ni and the like, thereby reducing the resistance of the material and improving the gas-sensitive property of the material, but LaFeO is used at present3The gas response and selectivity of ethanol-based gas sensor elements remains to be improved.
Disclosure of Invention
The invention provides Au and Cl co-modified LaFeO3Ethanol-based gas sensorAnd a preparation method thereof, provides LaFeO jointly modified by Au and Cl3The nanometer powder is a working substance, and the LaFeO is obviously improved under the conditions of ensuring lower working temperature, higher selectivity and stability3The gas response of the ethanol-based gas sensor element, wherein the gas response is defined as the ratio of the resistance of the sensor element in the gas environment to be measured to the resistance in dry air.
The invention is realized by the following technical scheme:
LaFeO co-modified by Au and Cl3Alcohol-based gas sensors in LaFeO3Adding LaFeO into the solution31% of HAuCl in a mass ratio of 1:1004Preparing Au and Cl co-modified LaFeO by using aqueous solution and sol-gel method3And preparing the nano powder into the indirectly heated ceramic tube structure gas sensor element.
The preparation method comprises the following steps:
（1）LaFeO3preparing nano powder: la (NO) of equal stoichiometric ratio3)3·6H2O and Fe (NO)3)3·9H2Dissolving O in deionized water; adding citric acid according to the molar ratio of the sum of the cations to the citric acid of 1:2, and preparing 1mol of LaFeO3Adding 10g of polyethylene glycol PEG-6000 into the nano powder, and adding the polyethylene glycol PEG-6000 into the nano powder according to the proportion of LaFeO3HAuCl with the mass fraction of 1 percent is added into the mixture with the mass ratio of 1:1004Placing the aqueous solution in a water bath kettle at 70-80 ℃ to be stirred to form sol, and continuously stirring the sol to a xerogel state; heating the xerogel in a crucible at the temperature of 380-3Nano powder;
(2) preparing a gas sensor element with an indirectly heated ceramic tube structure: LaFeO modified by 0.1 +/-0.05 gAu and Cl3Placing the nanometer powder in agate mortar, adding 0.025 + -0.005 g glass fiber, adding 0.2-0.3ml terpineol dropwise, grinding together to paste, and making into the final product with two annular gold electrodes and four Pt conductorsUniformly coating a layer of paste on the outer surface of the ceramic tube core, putting the ceramic tube core into a muffle furnace, and annealing for 2 hours at the temperature of 190-; and (3) passing an Ni-Cr heating wire with the resistance of about 35 +/-2 omega through the ceramic tube and the four electrode leads to be welded on the sensor base together, installing an outer cover lantern ring, and aging for 24 hours under the current of 120 mA by using an aging table to prepare the indirectly heated gas sensor element.
The thickness of the paste coated in the step (2) is 35-45 um. The LaFeO modified by the Au and the Cl together3The nano powder is single-phase nano-grade particles with an orthogonal structure, and the particle size is 20-80 nm; au and Cl ions are distributed on the surface of the nano-particles. Prepared LaFeO co-modified by Au and Cl3The ethanol-based gas sensor element has an operating temperature for ethanol of 128 deg.c.
In the invention, HAuCl is added into precursor solution4，HAuCl4Can provide Au and Cl ions simultaneously, so that the finally obtained LaFeO3The surface of the nano powder is modified by Au and Cl ions. HAuCl with the mass fraction of 1 percent is added into the precursor solution4Aqueous solution of 1% by weight of HAuCl4The choice of aqueous solution allows for better dispersion of the Au and Cl ions in the precursor.
According to HAuCl4With LaFeO3HAuCl with the mass fraction of 1 percent is added into the mixture with the mass ratio of 1:1004The mass ratio of the aqueous solution is selected to ensure that the obtained nano powder still maintains LaFeO3Orthogonal structure, and simultaneously improves the finally obtained LaFeO3The surface of the nano powder has the capability of adsorbing oxygen. Sintering the powder at 590-610 ℃ for 2 h, wherein the combination of temperature and time ensures the obtained LaFeO3The powder is single-phase nano-particles with an orthogonal structure, and Au and Cl ions are distributed on the surfaces of the nano-particles.
After a layer of gas-sensitive material is coated, the gas-sensitive element is placed in a muffle furnace and annealed for 2 hours at the temperature of 190-210 ℃, and the combination of the annealing temperature and the annealing time can enable the gas-sensitive element to have better gas-sensitive performance compared with the combination of other temperatures and times.
LaFeO jointly modified by Au and Cl3The optimal working temperature of the gas sensor element taking nano powder as working substance to ethanol is 128 DEG C(ii) a The gas response to 100ppm ethanol at the optimal working temperature is 47.7, and the gas response is not changed too much after 96 hours, so that the stability is good; under the optimal working temperature, the response to gases such as 100ppm DMF, dichloromethane, normal hexane, carbon dioxide, hydrogen and the like is 23.3 or less, and the selectivity is good; the gas response to 20ppm ethanol can reach 19.5 at the optimal working temperature, and the gas response to low-concentration ethanol gas is still high.
The invention has the beneficial effects that: the invention relates to LaFeO3The improvement of the working substance of the ethanol-based gas sensor element has obvious originality, and the preparation of LaFeO by using a sol-gel method is firstly proposed3In the process of nano powder, proper amount of HAuCl is added into precursor4Selecting proper annealing conditions for the aqueous solution to obtain LaFeO modified by Au and Cl together3The nano powder increases the oxygen adsorption capacity of the surface of the nano powder, and obviously improves LaFeO under the conditions of ensuring lower working temperature, higher selectivity and stability3The gas response of the ethanol gas sensor element is constructed by the base indirectly heated ceramic tube. The sol-gel method is adopted, nitrate is used as a raw material, and the method has the advantages of low cost, environmental friendliness, simple process, convenience in operation and the like.
Drawings
FIG. 1 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3X-ray diffraction pattern of the nano powder; FIG. 2 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3Transmission electron microscope atlas of the nanometer powder; FIG. 3 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3The X photoelectron energy spectrum of the nano powder body sensitive to the surface; FIG. 4 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3Nano powder and no HAuCl4The obtained LaFeO3The powder is a working substance and the gas response of the gas sensor element to 100ppm ethanol gas at different temperatures; FIG. 5 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3Nano powder and no HAuCl4The obtained LaFeO3The powder is a working substance and the gas sensor element responds to ethanol gas with different concentrations at 128 ℃; FIG. 6 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3Nano powder and no HAuCl4The obtained LaFeO3The powder is a working substance and the gas sensor element responds to 100ppm of different gases at 128 ℃; FIG. 7 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3The nano powder is a dynamic response curve of a working substance gas sensor element to 100ppm ethanol gas at 128 ℃; FIG. 8 is the addition of 1wt% HAuCl prepared in example 14The LaFeO is obtained3The nano powder is the change of gas response of a working substance gas sensor element to 100ppm ethanol gas at 128 ℃ along with time.
Detailed Description
All the raw materials of the present invention are commercially available chemical pure reagents, and the present invention will be further described in detail with reference to specific examples.
Example 1: LaFeO co-modified by Au and Cl3Alcohol-based gas sensors in LaFeO3Adding LaFeO into the solution31% of HAuCl in a mass ratio of 1:1004Preparing Au and Cl co-modified LaFeO by using aqueous solution and sol-gel method3And preparing the nano powder into the indirectly heated ceramic tube structure gas sensor element.
The preparation method comprises the following steps:
（1）LaFeO3preparing nano powder: accurately weigh 0.02mol of La (NO)3)3· 6H2O and Fe (NO)3)3·9H2Dissolving O in deionized water; adding 0.08mol of citric acid and 2g of polyethylene glycol PEG-6000, and adding 4.85ml of HAuCl with the mass fraction of 1%4Placing the aqueous solution in a water bath kettle at 70-80 ℃ to be stirred to form sol, and continuously stirring the sol to a xerogel state; heating the xerogel in a crucible at the temperature of 380-LaFeO (LaFeO)3Nano powder;
(2) preparing a gas sensor element with an indirectly heated ceramic tube structure: placing 0.1 + -0.05 g of the nano powder into an agate mortar, adding 0.025 + -0.005 g of glass fiber, adding 0.2-0.3ml of terpineol by using a rubber dropper, and grinding together to be pasty. Uniformly coating a layer of gas-sensitive material on the outer surface of a ceramic tube core with two annular gold electrodes and four Pt leads by using a coating pen, wherein the thickness is 35-45 mu m, putting the ceramic tube core into a muffle furnace, and annealing the ceramic tube core for 2 hours at the temperature of 190-; and (3) passing an Ni-Cr heating wire with the resistance of about 35 +/-2 omega through the ceramic tube and the four electrode leads to be welded on the sensor base together, installing an outer cover lantern ring, and aging for 24 hours under the current of 120 mA by using an aging table to prepare the indirectly heated gas sensor element.
The obtained LaFeO jointly modified by Au and Cl3The X-ray diffraction pattern of the nano powder is shown in figure 1, and the result shows that the obtained LaFeO3The single-phase particles with the orthogonal structure show that the LaFeO is not damaged by Au and Cl ions3The crystal mechanism of (1). The transmission electron micrograph is shown in FIG. 2, and the result shows that the particle size ranges from 20 to 80 nm. According to the obtained LaFeO jointly modified by Au and Cl3An X photoelectron spectrum 3 of the nano powder sensitive to the surface shows that the Au and Cl elements do exist on the surface of the particle except La, Fe, O and C.
Detecting the prepared LaFeO jointly modified by Au and Cl3The gas sensor element using nano powder as the working substance has a gas response to 100ppm of ethanol gas at different temperatures, and the result is shown in fig. 4, and it can be seen from fig. 4 that: LaFeO modified by Au and Cl together3The optimal working temperature of the gas sensor element taking nano powder as working substance to ethanol is 128 ℃, and the gas response is far higher than that of unmodified LaFeO3The gas sensor element with the nano powder as the working substance has gas response at the same temperature, and the LaFeO is obviously improved by the material obtained by the invention3Gas sensitivity of the ethanol-based gas sensor element.
Detecting the prepared LaFeO jointly modified by Au and Cl3The gas sensor element with nano powder as working substance responds to the gas of ethanol gas with different concentrations at the optimal working temperature, and the detection result is shown inFig. 5 shows that, from fig. 5: the gas response to 20ppm ethanol can reach 19.5 at the optimal working temperature, and the gas response to low-concentration ethanol gas is still high and is also higher than that of unmodified LaFeO3The nano powder is the detection result of the working substance gas sensor element.
Detecting the prepared LaFeO jointly modified by Au and Cl3The gas sensor element with nano powder as the working substance responds to 100ppm of different gases at the optimal working temperature, the detection result is shown in figure 6, and the results can be obtained as follows: the response to gases of 100ppm DMF, dichloromethane, normal hexane, carbon dioxide, hydrogen and the like at the optimal working temperature is 23.3 or below, and the selectivity is good.
Detecting the prepared LaFeO jointly modified by Au and Cl3The gas response of the gas sensor element with the nano powder as the working substance to 100ppm ethanol at the optimal working temperature changes along with the time, and the detection result is shown in figure 8, which can be obtained from the following figure: the gas response to 100ppm ethanol at the optimal working temperature is 47.7, and the gas response is still not changed too much after 96 hours, so that the gas response has good stability.
The invention adopts a static gas distribution method to measure LaFeO jointly modified by Au and Cl3The gas sensor element with the nano powder as the working substance has the gas-sensitive property on ethanol gas, and the gas response of the gas sensor element is defined as the ratio of the resistance Rg of the element in the gas to be detected and the resistance Ra of the element in dry air.
Claims (5)
1. LaFeO co-modified by Au and Cl3The ethanol-based gas sensor is characterized in that: adding 1% HAuCl4 aqueous solution into LaFeO3 precursor solution according to the mass ratio of 1:100 of HAuCl4 to LaFeO 3; preparation of LaFeO jointly modified by Au and Cl by using sol-gel method3And preparing the nano powder into the indirectly heated ceramic tube structure gas sensor element.
2. An Au and Cl co-modified LaFeO according to claim 13The ethanol-based gas sensor is characterized in that: the preparation method comprises the following steps:
（1）LaFeO3preparing nano powder: la (NO) of equal stoichiometric ratio3)3·6H2O and Fe (NO)3)3·9H2Dissolving O in deionized water; adding citric acid according to the molar ratio of the sum of the cations to the citric acid of 1:2, and preparing 1mol of LaFeO3Adding 10g of polyethylene glycol PEG-6000 into the nano powder, adding 1% HAuCl4 aqueous solution into LaFeO3 precursor solution according to the mass ratio of 1:100 of HAuCl4 to LaFeO3, placing the solution into a 70-80 ℃ water bath kettle, stirring to form sol, and continuing stirring to a dry gel state; heating the xerogel in a crucible at the temperature of 380-3Nano powder;
(2) preparing a gas sensor element with an indirectly heated ceramic tube structure: LaFeO modified by 0.1 +/-0.05 gAu and Cl3Placing the nano powder in an agate mortar, adding 0.025 +/-0.005 g of glass fiber, dripping 0.2-0.3ml of terpineol, grinding the mixture into paste, uniformly coating a layer of paste on the outer surface of a ceramic tube core with two annular gold electrodes and four Pt leads, placing the ceramic tube core in a muffle furnace, and annealing for 2 hours at the temperature of 190 plus one material at 210 ℃; and (3) passing an Ni-Cr heating wire with the resistance of about 35 +/-2 omega through the ceramic tube and the four electrode leads to be welded on the sensor base together, installing an outer cover lantern ring, and aging for 24 hours under the current of 120 mA by using an aging table to prepare the gas sensor element with the indirectly heated ceramic tube structure.
3. An Au and Cl co-modified LaFeO according to claim 23The ethanol-based gas sensor is characterized in that: the thickness of the paste coated in the step (2) is 35-45 μm.
4. An Au and Cl co-modified LaFeO according to claim 23The ethanol-based gas sensor is characterized in that: the LaFeO modified by the Au and the Cl together3The nano powder is single-phase nano particles with an orthogonal structureParticle size is 20 to 80 nm; au and Cl ions are distributed on the surface of the nano-particles.
5. An Au and Cl co-modified LaFeO according to claim 23The ethanol-based gas sensor is characterized in that: prepared LaFeO co-modified by Au and Cl3The ethanol-based gas sensor element has an operating temperature for ethanol of 128 deg.c.
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| CN101982234A (en) * | 2010-09-16 | 2011-03-02 | 中国石油天然气集团公司 | Three-dimensionally ordered macroporous gold-loaded catalyst with composite oxide as carrier and for catalytic combustion |
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101982234A (en) * | 2010-09-16 | 2011-03-02 | 中国石油天然气集团公司 | Three-dimensionally ordered macroporous gold-loaded catalyst with composite oxide as carrier and for catalytic combustion |
Non-Patent Citations (2)
| Title |
|---|
| 《Enhanced Ethanol Sensing Performance of Au and Cl Comodified LaFeO3 Nanoparticles》;Ensi Cao et al.;《ACS Applied Nano Materials》;20190215(第2期);第1541-1551页 * |
| 《Toward the Design of a Hierarchical Perovskite Support: Ultra-Sintering-Resistant Gold Nanocatalysts for CO Oxidation》;Chengcheng Tian et al.;《ACS Catalysis》;20170410(第7期);第3388-3393页 * |
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