CN105651844A - Bi2S3-based ammonia gas sensor and preparation method thereof - Google Patents

Abstract

The present invention discloses a Bi2S3-based ammonia gas sensor and a preparation method thereof. The sensor comprises an insulating substrate, a pair of metal electrodes arranged on the insulating substrate, metal leading-out conducting wires, and a gas sensitive material layer sprayed on the metal electrode, wherein the gas sensitive material layer comprises Bi2S3 nanoparticles and a binder polyvinyl alcohol, and the Bi2S3 nanoparticles are prepared through a reaction of a bismuth nitrate aqueous solution and hydrogen sulfide gas or a sodium sulfide aqueous solution in the presence of ultrasonic waves. According to the present invention, the sensor has good selectivity for ammonia, is free of sintering, can work at a room temperature, and can be used for determination of ammonia gas within a percentage concentration range and automatic control of the ammonia related production process.

Description

A kind of Bi2S3Base ammonia gas sensor and preparation method thereof

Technical field

Bi provided by the invention₂S₃Base ammonia gas sensor, relates to sensor field, in particular it relates to one is based on a nanometer Bi₂S₃Ammonia gas sensor and preparation method thereof.

Background technology

Gas sensor is widely used in the aspects such as poisonous and Combustible Gas Leak warning, environment protection and monitoring. Currently used various gas sensors are broadly divided into by gas-sensitive property: five classes such as semi-conductor type, electrochemistry type, solid electrolyte type, catalytic combustion type, photochemistry type, wherein, semiconductor gas sensor is the element adopting metal-oxide or metal semiconductor oxide material to make, produce surface adsorption or reaction with gas when interacting, cause with carrier moving be feature electrical conductivity or C-V characteristic or surface potential change. Its changing value is relevant to the concentration of tested gas. For improving selectivity and the sensitivity of gas sensor, in metal-oxide, often add noble metal as catalyst. This kind of device fabrication is simple, cost is low. But operating temperature is high, its measurement is affected relatively larger by environment.

Ammonia is a kind of unpleasant toxic gas, and oral cavity and respiratory tract to humans and animals have stronger zest and corrosivity, high concentration ammonia even can causing death, even if the health of humans and animals also can be caused serious harm by the ammonia of low concentration in environment. Therefore, how quickly ammonia in detection environment, the data foundation providing necessary of administering for air ambient has very important realistic meaning.

But, ammonia is also important industrial chemicals, intermediate and product, and its volume of production occupies very big ratio in chemical industry. With scientific research, the requirement of material and product purity is more and more higher along with producing, it is necessary to produce high-quality chemical products. This is accomplished by production process is carried out very accurate automatically controlling. To relate to ammonia Chemical Manufacture implement automatically control it is crucial that develop and ammonia in raw material or product had ammonia gas sensor highly sensitive, that selectivity is good. Ammonia concentration change transitions in raw material or product can be the signal of telecommunication by this sensor, flows to control equipment, thus realizing automatically controlling to relating to ammonia Chemical Manufacture. Owing to the ammonia concentration in Chemical Manufacture is higher, mostly at concentration range, accordingly, it would be desirable to a kind of gas sensor that this concentration range ammonia can be produced response. At present, this class ammonia gas sensor extremely lacks.

Summary of the invention

Present invention aims to the deficiencies in the prior art, it is provided that a kind of based on a nanometer Bi₂S₃Ammonia gas sensor and preparation method thereof.

Provided by the present invention nanometer of Bi₂S₃Ammonia gas sensor is drawn wire and nanometer Bi by insulating substrate, pair of metal electrodes, metal successively₂S₃Material layer forms, wherein nanometer Bi₂S₃Material layer includes polyvinyl alcohol adhesive.

Described insulating substrate includes aluminum oxide ceramic substrate, SiO 2-ceramic substrate, glass substrate, bakelite substrate/or bakelite substrate.

Described metal electrode is that the distance between two electrodes is 1mm by Pt metal and any one made interdigital electrode of Au.

Described metal lead-outs is made up of any one of Pt metal and Au.

Described nanometer of Bi₂S₃The diameter of nano particles of material layer is 20-160nm; Nanometer Bi₂S₃The thickness of material layer is 5-50 ��m.

Described nanometer of Bi₂S₃The detailed preparation method of ammonia gas sensor, including below step.

1) Bi is prepared₂S₃Nanoparticle, under the ultrasound wave of 40KHz, by Bi (NO₃)₃Aqueous solution and H₂S gas or Na₂Any one reaction of S solution, reaction temperature is room temperature to 50 DEG C of scopes, Bi (NO₃)₃With sulfide mol ratio be 1:1, reaction end is centrifugally separating to obtain brownish black precipitation, with distilled water wash, dry obtains Bi₂S₃Nanoparticle.

2) Bi prepared by step 1)₂S₃Nanoparticle and 0.1% polyvinyl alcohol, grind 2 hours, after dilution, make slurry.

3) Au slurry or Pt slurry are coated on insulating substrate and make interdigital electrode, after drying, weld metal lead-outs.

4) by step 2) the slurry electronic spray gun spraying to metal electrode prepared prepares into a nanometer Bi with on substrate₂S₃Material layer, then dries and obtains sensor element.

Beneficial effect: provided by the invention nanometer of Bi₂S₃Ammonia gas sensor has responsiveness height, and selectivity is good, and response and recovery are fast, makes simple, it is not necessary to sintering, works under room temperature, and consume energy the low advantage low with cost.

Accompanying drawing explanation

Fig. 1 is the Bi of embodiment 1 preparation₂S₃Nanoparticle stereoscan photograph.

Fig. 2 is nanometer Bi of embodiment 1 preparation₂S₃The responsiveness of ammonia gas sensor is with ammonia concentration change curve.

Detailed description of the invention

Below by specific embodiment, the present invention is described in further detail, but the invention is not limited in this.

Embodiment one.

1) Bi (NO of 9.7 grams (0.02 moles) is weighed₃)₃��5H₂O, puts in 300mL beaker, adds 20 milliliters of dilute nitric acid dissolutions, is then diluted to 100 milliliters. Bi (the NO that will have dissolved₃)₃Solution heats to 50 DEG C in ultrasonic thermostatic water bath pot, and ultrasonic frequency is adjusted to 40kHz, by the Na of concentration 0.3 mol/L under stirring₂S solution 100 milliliters is added dropwise to Bi (NO₃)₃In solution, Bi (NO₃)₃With Na₂The mol ratio of S is 2:3. Now, there is a large amount of brownish black Bi₂S₃Precipitation generates, and after question response, is cooled to room temperature, sucking filtration, with distilled water wash three times, the Bi that will obtain₂S₃Baking oven put into by solid, dries four hours at 150 DEG C.

2) Bi prepared by step 1)₂S₃Nanoparticle and 0.1% polyvinyl alcohol, grind 2 hours, after dilution, make slurry.

3) take aluminum oxide ceramic substrate, put into the sodium hydroxide solution that concentration is 6 mol/L and boil 20 minutes, take out after cooling, with distilled water flushing three times, be placed in baking oven and dry. Au slurry is coated on cleaned Al 2 O ceramic substrate and makes interdigital electrode, dries, then the Pt wire bond of diameter 0.1mm is received on electrode as lead-out wire.

4) by step 2) the electronic spray gun spraying of slurry prepared prepares into, on Au electrode and aluminum oxide ceramic substrate, nanometer Bi that thickness is 5 ��m₂S₃Material layer, then obtains sensor element 120 DEG C of drying.

Embodiment two.

1) Bi (NO of 9.7 grams (0.02 moles) is weighed₃)₃��5H₂O, puts in 300mL beaker, adds 20 milliliters of dilute nitric acid dissolutions, is then diluted to 100 milliliters. Bi (the NO that will have dissolved₃)₃Solution is placed in ultrasonic thermostatic water bath pot, and ultrasonic frequency is adjusted to 40kHz, by the Na of concentration 0.3 mol/L under room temperature condition₂S solution 100 milliliters is added dropwise to Bi (NO₃)₃In solution, Bi (NO₃)₃With Na₂The mol ratio of S is 2:3. Now, there is a large amount of brownish black Bi₂S₃Precipitation generates, and after question response, is cooled to room temperature, sucking filtration, with distilled water wash three times, the Bi that will obtain₂S₃Baking oven put into by solid, dries four hours at 150 DEG C.

2) Bi prepared by step 1)₂S₃Nanoparticle and 0.1% polyvinyl alcohol, grind 2 hours, after dilution, make slurry.

3) take glass substrate, put into the sodium hydroxide solution that concentration is 6 mol/L and boil 20 minutes, take out after cooling, with distilled water flushing three times, be placed in baking oven and dry. Pt slurry is coated on cleaned glass substrate and makes interdigital electrode, dries, then the Pt wire bond of diameter 0.1mm is received on electrode as lead-out wire.

4) by step 2) the electronic spray gun spraying of slurry prepared prepares into, on Pt electrode and glass substrate, the Bi that thickness is 20 ��m nanometers₂S₃Material layer, then obtains sensor element 120 DEG C of drying.

Embodiment three.

1) Bi (NO of 9.7 grams (0.02 moles) is weighed₃)₃��5H₂O, puts in 300mL ground flask, adds 20 milliliters of dilute nitric acid dissolutions, is then diluted to 100 milliliters. Cover with, after the ground glass stopper of DLC, will be equipped with Bi (NO₃)₃The flask of solution moves in ultrasonic thermostatic water bath pot and heats to 50 DEG C, and ultrasonic frequency is adjusted to 40kHz. By flask conduit and equipped with H₂The steel cylinder of S gas connects, by 0.03 mole of H₂S gas slowly is passed into Bi (NO₃)₃In solution, Bi (NO₃)₃With H₂The mol ratio of S is 2:3, and tail gas imports in the sodium hydroxide solution (concentration is 6 mol/L) being contained in another container so that it is be predominantly absorbed. Course of reaction has a large amount of brownish black Bi₂S₃Precipitation generates, and after question response, is cooled to room temperature, sucking filtration, with distilled water wash three times, the Bi that will obtain₂S₃Baking oven put into by solid, dries four hours at 150 DEG C.

2) Bi prepared by step 1)₂S₃Nanoparticle and 0.1% polyvinyl alcohol, grind 2 hours, after dilution, make slurry.

3) take silicon dioxide substrates, put into the sodium hydroxide solution that concentration is 6 mol/L and boil 20 minutes, take out after cooling, with distilled water flushing three times, be placed in baking oven and dry. Au slurry is coated on cleaned glass substrate and makes interdigital electrode, dries, then the Au wire bond of diameter 0.1mm is received on electrode as lead-out wire.

4) by step 2) the electronic spray gun spraying of slurry prepared prepares into, in Au electrode and silicon dioxide substrates, nanometer Bi that thickness is 35 ��m₂S₃Material layer, then obtains sensor element 120 DEG C of drying.

Embodiment four.

1) Bi (NO of 9.7 grams (0.02 moles) is weighed₃)₃��5H₂O, puts in 300mL ground flask, adds 20 milliliters of dilute nitric acid dissolutions, is then diluted to 100 milliliters. Cover with, after the ground glass stopper of DLC, will be equipped with Bi (NO₃)₃The flask of solution moves in ultrasonic thermostatic water bath pot, and ultrasonic frequency is adjusted to 40kHz. By flask conduit and equipped with H₂The steel cylinder of S gas connects, by 0.03 mole of H under room temperature₂S gas slowly is passed into Bi (NO₃)₃In solution, Bi (NO₃)₃With H₂The mol ratio of S is 2:3.Tail gas imports in the sodium hydroxide solution (concentration is 6 mol/L) being contained in another container so that it is be predominantly absorbed. Reaction has a large amount of brownish black Bi₂S₃Precipitation generates, and after question response, is cooled to room temperature, sucking filtration, with distilled water wash three times, the Bi that will obtain₂S₃Baking oven put into by solid, dries four hours at 150 DEG C.

2) Bi prepared by step 1)₂S₃Nanoparticle and 0.1% polyvinyl alcohol, grind 2 hours, after dilution, make slurry.

3) take aluminum oxide ceramic substrate, put into the sodium hydroxide solution that concentration is 6 mol/L and boil 20 minutes, take out after cooling, with distilled water flushing three times, be placed in baking oven and dry. Au slurry is coated on cleaned aluminum oxide ceramic substrate and makes interdigital electrode, dries, then the Pt wire bond of diameter 0.1mm is received on electrode as lead-out wire.

4) by step 2) the electronic spray gun spraying of slurry prepared prepares into, on Au electrode and substrate, the Bi that thickness is 50 ��m nanometers₂S₃Material layer, then obtains sensor element 120 DEG C of drying.

Claims (6)

1. a Bi₂S₃Base ammonia gas sensor, it is characterised in that: drawn wire and nanometer Bi by insulating substrate, pair of metal electrodes, metal successively₂S₃Material layer forms, wherein nanometer Bi₂S₃Material layer includes a kind of polyvinyl alcohol adhesive.

2. the ammonia gas sensor described in claim 1, it is characterised in that: described insulating substrate includes aluminum oxide ceramic substrate, SiO 2-ceramic substrate, glass substrate, bakelite substrate/or bakelite substrate.

3. the ammonia gas sensor described in claim 1, it is characterised in that: described metal electrode is by Pt metal and any one interdigital electrode made of Au, and the distance between two electrodes is 1mm.

4. the ammonia gas sensor described in claim 1, it is characterised in that: described metal lead-outs is made up of any one of Pt metal and Au.

5. the ammonia gas sensor described in claim 1, it is characterised in that: described nanometer of Bi₂S₃The diameter of nano particles of material layer is 20-160nm; Described nanometer of Bi₂S₃The thickness of material layer is 5-50 ��m.

6. the method for ammonia gas sensor according to any one of preparation claim 1-5, including below step:

1) Bi is prepared₂S₃Nanoparticle, under the ultrasound wave of 40KHz, by Bi (NO₃)₃Aqueous solution reacts with sulfide precipitation agent, and described precipitant is H₂S gas and Na₂Any one of S solution, reaction temperature is room temperature to 50 DEG C of scopes, Bi (NO₃)₃With sulfide mol ratio be that 2:3, reaction terminates, sucking filtration, obtains brownish black precipitation, with distilled water wash, dry obtains Bi₂S₃Nanoparticle;

2) Bi prepared by step 1)₂S₃Nanoparticle mixes with binding agent, grinds 2 hours, makes slurry after dilution;

3) Au slurry or Pt slurry are coated on insulating substrate, after drying, weld metal lead-outs;

4) by step 2) the slurry electronic spray gun spraying to metal electrode prepared prepares into a nanometer Bi with on substrate₂S₃Material layer, then dries and obtains sensor element.