1. The preparation method of the hydrogen sensitive element is characterized by at least comprising the following steps:

(1) cleaning and drying the glass substrate for later use;

(2) coating polytetrafluoroethylene on a glass substrate to form the glass substrate with a polytetrafluoroethylene film;

(3) dripping a polyelectrolyte diallyl solution on the surface of the polytetrafluoroethylene film, standing, and washing the glass substrate with the polytetrafluoroethylene film;

(4) dripping the polystyrene disc particle suspension liquid on the surface of the polytetrafluoroethylene film at intervals, and flushing and blow-drying the glass substrate with the polytetrafluoroethylene film after standing;

(5) evaporating and preparing a chromium film on the surface of the glass substrate with the polytetrafluoroethylene film by using evaporation equipment, stripping the polystyrene particles and part of the chromium film above the polystyrene particles, wherein holes are formed on the polytetrafluoroethylene film and the chromium film due to stripping of the polystyrene particles;

(6) carrying out oxygen plasma treatment on the glass substrate with the polytetrafluoroethylene film, and etching the holes until the polytetrafluoroethylene film below the holes is etched;

(7) depositing metal gold and palladium in the holes;

(8) removing the polytetrafluoroethylene film and the chromium film;

(9) annealing the glass substrate, wherein the metal palladium and the gold are infinitely mutually dissolved under the action of high temperature to form a continuous solid solution, namely palladium-gold alloy;

(10) and sequentially coating polytetrafluoroethylene and polymethyl methacrylate on the glass substrate.

2. The method for preparing the hydrogen sensor according to claim 1, wherein the glass substrate in step (1) is a block of 1cm by 1cm, and the cleaning and blow-drying step comprises: and sequentially putting the glass substrate into acetone, isopropanol and deionized water for ultrasonic cleaning, wherein the ultrasonic time is 10-20 min, and then drying the glass substrate by using nitrogen.

3. The method for preparing a hydrogen sensor according to claim 1, wherein the coating process in the step (2) is: spin coating the polytetrafluoroethylene polymer on the glass substrate at the speed of 2000rpm by using a spin coater, wherein the coating time is 20-40 s, and the thickness of the polytetrafluoroethylene film is 260-300 nm; after the glass substrate with the polytetrafluoroethylene film is formed, placing the glass substrate with the polytetrafluoroethylene film on a hot plate at 160-180 ℃ for baking for 8-12 min; and carrying out oxygen plasma treatment on the glass substrate with the polytetrafluoroethylene film for 4-6 s by using a plasma surface treatment instrument.

4. The method for preparing the hydrogen sensor according to claim 1, wherein the standing time in the step (3) is 30-50 s, and the washing step is: and washing the glass substrate with the polytetrafluoroethylene film by using deionized water.

5. The preparation method of the hydrogen sensor according to claim 1, wherein the standing time in the step (4) is 2-4 min, and the rinsing and drying step comprises: and washing the glass substrate with the polytetrafluoroethylene film by using deionized water, and then blowing the glass substrate with the polytetrafluoroethylene film by using nitrogen until the surface is dried.

6. The method for preparing the hydrogen sensor according to claim 1, wherein the thickness of the chromium film in the step (5) is 13-17 nm; the time for the oxygen plasma treatment in the step (6) is 4-6 min; the mass of the gold and the mass of the palladium in the step (7) are the same.

7. The method for preparing a hydrogen sensor according to claim 1, wherein the step of removing the polytetrafluoroethylene film and the chromium film in step (8) is: putting the glass substrate with the chromium film and the polytetrafluoroethylene film into acetone, wherein the polytetrafluoroethylene film can be dissolved in the acetone, and the chromium film falls off along with the dissolution of the polytetrafluoroethylene film; after removing the polytetrafluoroethylene film and the chromium film, putting the glass substrate into isopropanol for soaking, and then drying the glass substrate by using nitrogen.

8. The method for preparing a hydrogen sensor according to claim 1, wherein the annealing step in step (9) is: the glass substrate was placed in an annealing furnace and annealed at a temperature of 500 c for 24 hours using argon gas.

9. The method of claim 1 for making a hydrogen sensorThe method is characterized in that the smearing step in the step (10) is as follows: using a base pressure of 10^-7mbar, deposition pressure 5X 10^-3Preparing a polytetrafluoroethylene film on a glass substrate by a radio frequency magnetron sputtering system with mbar, spinning and coating polymethyl methacrylate on the polytetrafluoroethylene film at the speed of 2000rpm for 20-40 s to form a polymethyl methacrylate film, and soft-drying and heating the glass substrate with the polytetrafluoroethylene film and the polymethyl methacrylate film on a hot plate at the temperature of 160-180 ℃ for 4-6 min.

10. A hydrogen sensor according to claim 1, wherein: the hydrogen sensor is prepared by the method of any one of claims 1 to 9, wherein palladium-gold alloy nanoparticles are uniformly distributed on a glass substrate of the hydrogen sensor, the palladium-gold alloy nanoparticles are disc-shaped, and a polytetrafluoroethylene film and a polymethyl methacrylate film are sequentially arranged on the glass substrate and the palladium-gold alloy nanoparticles.

Background

In the modern times, fossil fuel energy is in short supply and the products thereof can have bad influence on the environment, hydrogen is used as clean and sustainable energy and gradually occupies an increasingly heavier proportion in a plurality of energy sources, but the combustible concentration range of the hydrogen is 4-96 percent, and the hydrogen is extremely combustible gas. There are significant safety concerns in hydrogen energy storage systems, vehicles, electrical appliances, and the entire infrastructure involving hydrogen, and leakage problems must be detected early in the event.

The hydrogen sensitive element of the existing hydrogen sensor is formed by plating a palladium film on the fiber core of an optical fiber, palladium has better sensitivity and selectivity to hydrogen, reversible phase change from metal to metal hydride can be realized, hydrogen is monitored by observing the change of the hydrogen sensitive element, but trace amounts of CO and NO₂The existing hydrogen sensor detects hydrogen inaccurately, and simultaneously has the problems of low hydrogen response speed, easy hydrogen embrittlement and the like at room temperature.

Disclosure of Invention

In order to solve the prior art, the invention provides a hydrogen sensitive element and a preparation method thereof.

The technical scheme for realizing the aim of the invention is that the preparation method of the hydrogen sensitive element at least comprises the following steps:

(1) cleaning and drying the glass substrate for later use;

(2) coating polytetrafluoroethylene on a glass substrate to form the glass substrate with a polytetrafluoroethylene film;

(3) dripping a polyelectrolyte diallyl solution on the surface of the polytetrafluoroethylene film, standing, and washing the glass substrate with the polytetrafluoroethylene film;

(4) dripping the polystyrene disc particle suspension liquid on the surface of the polytetrafluoroethylene film at intervals, and flushing and blow-drying the glass substrate with the polytetrafluoroethylene film after standing;

(5) evaporating and preparing a chromium film on the surface of the glass substrate with the polytetrafluoroethylene film by using evaporation equipment, stripping the polystyrene particles and part of the chromium film above the polystyrene particles, wherein holes are formed on the polytetrafluoroethylene film and the chromium film due to stripping of the polystyrene particles;

(6) carrying out oxygen plasma treatment on the glass substrate with the polytetrafluoroethylene film, and etching the holes until the polytetrafluoroethylene film below the holes is etched;

(7) depositing gold and palladium in the hole;

(8) removing the polytetrafluoroethylene film and the chromium film;

(9) annealing the glass substrate, wherein palladium and gold are infinitely mutually dissolved under the action of high temperature to form a continuous solid solution, namely palladium-gold alloy;

(10) and sequentially coating polytetrafluoroethylene and polymethyl methacrylate on the glass substrate.

The technical scheme is further improved as follows: the glass substrate in the step (1) is in a block shape of 1cm by 1cm, and the cleaning and blow-drying steps are as follows: and sequentially putting the glass substrate into acetone, isopropanol and deionized water for ultrasonic cleaning, wherein the ultrasonic time is 10-20 min, and then blowing the glass substrate by using nitrogen.

And the coating process in the step (2) is as follows: spin coating the polytetrafluoroethylene polymer on a glass substrate at a speed of 2000rpm by using a spin coater, wherein the coating time is 20-40 s, and the thickness of the polytetrafluoroethylene film is 260-300 nm; after the glass substrate with the polytetrafluoroethylene film is formed, placing the glass substrate with the polytetrafluoroethylene film on a hot plate at 160-180 ℃ for baking for 8-12 min; and performing oxygen plasma treatment on the glass substrate with the polytetrafluoroethylene film for 4-6 seconds by using a plasma surface treatment instrument.

And the standing time in the step (3) is 30-50 s, and the washing step is as follows: and washing the glass substrate with the polytetrafluoroethylene film by using deionized water.

And the standing time in the step (4) is 2-4 min, and the washing and drying steps are as follows: and washing the glass substrate with the polytetrafluoroethylene film by using deionized water, and then blowing the glass substrate with the polytetrafluoroethylene film by using nitrogen until the surface is dried.

And the thickness of the chromium film in the step (5) is 13-17 nm; the time of the oxygen plasma treatment in the step (6) is 4-6 min; the mass of the gold and the mass of the palladium in the step (7) are the same.

And the step of removing the polytetrafluoroethylene film and the chromium film in the step (8) comprises the following steps: putting the glass substrate with the chromium film and the polytetrafluoroethylene film into acetone, wherein the polytetrafluoroethylene film can be dissolved in the acetone, and the chromium film falls off along with the dissolution of the polytetrafluoroethylene film; after removing the polytetrafluoroethylene film and the chromium film, putting the glass substrate into isopropanol for soaking, and then blowing the glass substrate by using nitrogen.

And the annealing step in the step (9) is as follows: the glass substrate was placed in an annealing furnace and annealed at a temperature of 500 c for 24 hours using argon gas.

And the smearing step in the step (10) is as follows: using a base pressure of 10^-7mbar, deposition pressure 5X 10^-3Preparing a polytetrafluoroethylene film on a glass substrate by a radio frequency magnetron sputtering system with mbar, spinning and coating polymethyl methacrylate on the polytetrafluoroethylene film at the speed of 2000rpm for 20-40 s to form a polymethyl methacrylate film, and soft-drying and heating the glass substrate with the polytetrafluoroethylene film and the polymethyl methacrylate film on a hot plate at the temperature of 160-180 ℃ for 4-6 min.

The hydrogen sensitive element is prepared by the method, palladium-gold alloy nano particles are uniformly distributed on a glass substrate in the hydrogen sensitive element, the palladium-gold alloy nano particles are disc-shaped, and a polytetrafluoroethylene film and a polymethyl methacrylate film are sequentially arranged on the glass substrate and the palladium-gold alloy nano particles.

According to the technical scheme, the method comprises the following steps: (1) compared with pure palladium, the palladium-gold alloy can effectively increase the response speed of the palladium membrane and improve the hydrogen embrittlement phenomenon.

(2) The hydrogen sensitive element adopts palladium-gold alloy nano particles, and compared with a palladium membrane used by the existing hydrogen sensor, the mass of the used palladium is far less than that of the palladium membrane used by the existing hydrogen sensor, so that the cost is greatly reduced.

(3) The hydrogen sensitive element comprises the polytetrafluoroethylene film, the polytetrafluoroethylene film has high chemical resistance, hydrophobicity and refractive index, and the signal amplitude can be improved by about two times by adding the polytetrafluoroethylene film.

(4) The hydrogen sensitive element comprises the polymethyl methacrylate film, and the polymethyl methacrylate has the characteristics of good transparency, brightness and heat resistance, toughness, hardness, rigidity and the like, so that the service life of the hydrogen sensitive element can be prolonged.

Drawings

FIG. 1 is a schematic sectional view of a hydrogen sensor according to the present invention;

FIG. 2 is a schematic top sectional view of a hydrogen sensor according to the present invention;

in the figure: 1. a glass substrate; 2. a polytetrafluoroethylene film; 3. a polymethyl methacrylate film; 4. palladium-gold alloy.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and examples, and the present invention is not limited to the following examples.

A preparation method of a hydrogen sensitive element comprises the following steps:

(1) cleaning and drying the glass substrate for later use; the glass substrate is in a block shape of 1cm by 1cm, and the cleaning and blow-drying steps are as follows: and sequentially putting the glass substrate into acetone, isopropanol and deionized water for ultrasonic cleaning, wherein the ultrasonic time is 10-20 min, and then blowing the glass substrate by using nitrogen.

The substrate can also be made of other common polymer flexible materials, such as polymethyl methacrylate (PMMA), polystyrene, Polycarbonate (PC), polyethylene terephthalate (PET), Fluorinated Ethylene Propylene (FEP), and the like.

(2) Coating polytetrafluoroethylene on a glass substrate to form the glass substrate with a polytetrafluoroethylene film; the coating process comprises the following steps: spin coating a polytetrafluoroethylene polymer on a glass substrate at a speed of 2000rpm by using a spin coater, wherein the coating time is 20-40 s, and the thickness of a polytetrafluoroethylene film is 260-300 nm; after the glass substrate with the polytetrafluoroethylene film is formed, placing the glass substrate with the polytetrafluoroethylene film on a hot plate at 160-180 ℃ for baking for 8-12 min; and performing oxygen plasma treatment on the glass substrate with the polytetrafluoroethylene film for 4-6 s by using a plasma surface treatment instrument, wherein the oxygen plasma treatment is used for enhancing the hydrophilicity of the glass substrate with the polytetrafluoroethylene film.

(3) Dripping a polyelectrolyte diallyl solution on the surface of a polytetrafluoroethylene film, and washing a glass substrate with the polytetrafluoroethylene film after standing for 30-50 s; the washing steps are as follows: and washing the glass substrate with the polytetrafluoroethylene film by using deionized water, and forming a positively charged surface layer on the surface of the polytetrafluoroethylene film by using a polyelectrolyte diallyl solution.

(4) Dropping polystyrene disc particle suspension liquid on the surface of the polytetrafluoroethylene film at intervals, washing and drying the glass substrate with the polytetrafluoroethylene film after standing, wherein the standing time is 2-4 min, and the washing and drying steps are as follows: and washing the glass substrate with the polytetrafluoroethylene film by using deionized water, and then blowing the glass substrate with the polytetrafluoroethylene film by using nitrogen until the surface is dried.

The suspension of polystyrene disc particles is negatively charged, and therefore the polystyrene disc particles will adsorb on the surface of the polytetrafluoroethylene film which is positively charged.

(5) Evaporating and preparing a chromium film on the surface of a glass substrate with a polytetrafluoroethylene film by using evaporation equipment, stripping the polystyrene particles and part of the chromium film above the polystyrene particles, wherein holes are formed in the polytetrafluoroethylene film and the chromium film due to stripping of the polystyrene particles, and the thickness of the chromium film is 13-17 nm;

(6) carrying out oxygen plasma treatment on the glass substrate with the polytetrafluoroethylene film, and etching the holes until the polytetrafluoroethylene film below the holes is etched; the time for oxygen plasma treatment is 4-6 min;

(7) depositing metal gold and palladium in the holes; the mass of the gold and the palladium is the same;

(8) removing the polytetrafluoroethylene film and the chromium film; the steps for removing the polytetrafluoroethylene film and the chromium film are as follows: putting the glass substrate with the chromium film and the polytetrafluoroethylene film into acetone, wherein the polytetrafluoroethylene film is dissolved in the acetone, and the chromium film falls off along with the dissolution of the polytetrafluoroethylene film; after removing the polytetrafluoroethylene film and the chromium film, putting the glass substrate into isopropanol for soaking, and then blowing the glass substrate by using nitrogen.

(9) Annealing the glass substrate, wherein the metal palladium and the gold can be dissolved in each other infinitely under the action of high temperature to form a continuous solid solution, namely palladium-gold alloy; the annealing step is as follows: the glass substrate was placed in an annealing furnace and annealed at a temperature of 500 c for 24 hours using argon gas.

(10) Sequentially coating polytetrafluoroethylene and polymethyl methacrylate on a glass substrate; application of the compositionThe method comprises the following steps: using a base pressure of 10^-7mbar, deposition pressure 5X 10^-3Preparing a polytetrafluoroethylene film on a glass substrate by a radio frequency magnetron sputtering system with mbar, spinning and coating polymethyl methacrylate on the polytetrafluoroethylene film at the speed of 2000rpm for 20-40 s to form a polymethyl methacrylate film, and soft-drying and heating the glass substrate with the polytetrafluoroethylene film and the polymethyl methacrylate film on a hot plate at the temperature of 160-180 ℃ for 4-6 min.

A hydrogen sensitive element, the glass substrate 1 is evenly distributed with palladium-gold alloy nanometer particles 4, the palladium-gold alloy nanometer particles are disc-shaped, the glass substrate and the palladium-gold alloy nanometer particles are sequentially provided with a polytetrafluoroethylene film 2 and a polymethyl methacrylate film 3.

The specific surface area of the disc shape is larger than that of the columnar or conical shape with the same volume, so that the detection area of the palladium-gold alloy nano particles and hydrogen is enlarged; meanwhile, compared with the existing hydrogen sensor using a palladium membrane, the mass of the used palladium is far less than that of the existing technology, so that the cost is greatly reduced.

The hydrogen sensitive element comprises the polytetrafluoroethylene film, the polytetrafluoroethylene film has high chemical resistance, hydrophobicity and refractive index, the polytetrafluoroethylene film can reduce the surface activation energy of hydrogen entering and exiting plasma metal nanoparticles, and the polytetrafluoroethylene film can optimize the specific surface area of the nanoparticles, reduce the surface activation energy and inhibit the hysteresis phenomenon, so that the detection limit is improved.