阅读说明：本技术 一种检测超低浓度甲醛的弱碱性氧化铟的制备方法及其产品与应用 (Preparation method of alkalescent indium oxide for detecting ultralow-concentration formaldehyde, product and application thereof ) 是由 崔大祥 王敬锋 于 2021-07-20 设计创作，主要内容包括：本发明提供了一种检测超低浓度甲醛的弱碱性氧化铟的制备方法及其产品与应用,采用静电纺丝法,将稀土金属掺杂在氧化铟材料中,制备出稀土改性的氧化铟纳米纤维。由于稀土的掺杂,在改变氧化铟能级的情况下,能够使氧化铟材料表面性显示出弱碱性,因而具备高灵敏的甲醛响应。该方法制备出的材料可应用于ppb级别的甲醛的检测,对超低浓度在50 ppm的甲醛仍具有较强的响应。本发明所制备的气敏材料无毒无害,有望进行放大化生产。(The invention provides a preparation method of alkalescent indium oxide for detecting ultralow-concentration formaldehyde, and a product and application thereof. Due to the doping of the rare earth, the surface property of the indium oxide material can show weak alkalinity under the condition of changing the energy level of the indium oxide, so that the indium oxide material has high-sensitivity formaldehyde response. The material prepared by the method can be applied to detection of ppb-level formaldehyde and still has strong response to ultralow-concentration formaldehyde of 50 ppm. The gas-sensitive material prepared by the invention is non-toxic and harmless, and is expected to be produced in an enlarged way.)

1. A preparation method of alkalescent indium oxide for detecting ultralow-concentration formaldehyde is characterized in that rare earth metal is doped in an indium oxide material by adopting an electrostatic spinning method to prepare rare earth modified alkalescent indium oxide nanofiber, and comprises the following steps:

step one, preparing a rare earth/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring; then adding 0.1-0.5 g of rare earth nitrate precursor into the solution, and continuously stirring until a uniform and transparent rare earth/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

the preparation method comprises the steps of adopting a copper foil as a substrate to receive a rare earth/indium nitrate nanofiber membrane, and preparing a nano multilayer fiber membrane by utilizing an electrostatic spinning technology, wherein the temperature of a rare earth/indium nitrate electrostatic spinning solution is kept at 35 +/-5 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1-2 mL/h, and the receiving distance is 20 cm; the spinning voltage is controlled to be 10-30 kV, a layer of nanofiber film is covered on the surface of the copper foil during electrostatic spinning to form Re-In₂O₃The nanofiber membrane product is then placed onDrying in an oven at 70 ℃ for 12 hours to remove the excess organic solvent on the surface;

third step, Re-In₂O₃Calcining the nano gas-sensitive fiber:

Re-In is added₂O₃The nanofiber membrane is taken off from the copper foil and is put into a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber is naturally cooled to the room temperature, the faint yellow rare earth modified alkalescent indium oxide nanofiber is collected and recorded as Re-In₂O₃And (3) nano fibers.

2. The method for preparing weakly alkaline indium oxide for detecting low-concentration formaldehyde according to claim 1, wherein the rare earth material is rare earth metal of Y, La, Nd, Ho or Tm.

3. The method for preparing weakly basic indium oxide for detecting low-concentration formaldehyde according to claim 1 or 2, comprising the steps of:

step one, preparing a rare earth yttrium/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, and simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring at room temperature; then adding a rare earth yttrium nitrate precursor with the mass of 0.2g into the solution, and continuing stirring until a uniform and transparent yttrium/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

the preparation method comprises the steps of adopting a copper foil as a substrate to receive a rare earth/indium nitrate nanofiber membrane, and preparing a nano multilayer fiber membrane by utilizing an electrostatic spinning technology, wherein the temperature of a rare earth/indium nitrate electrostatic spinning solution is kept at about 35 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1mL/h, and the receiving distance is 20 cm; the spinning voltage is controlled to be 20 kV, and a layer of nanofiber film is covered on the surface of the copper foil to form Re-In while electrostatic spinning is carried out₂O₃A nanofiber membrane product, followed by drying the nanofiber membrane in an oven at 70 ℃ for 12 hours;

third, Y-In₂O₃Calcining the nano gas-sensitive fiber:

reacting Y-In₂O₃The nanofiber membrane is taken off from the copper foil and is put into a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber membrane is naturally cooled to the room temperature, a light yellow rare earth yttrium modified alkalescent indium oxide nanofiber sample is collected and is marked as Y-In₂O₃。

4. The method for preparing weakly basic indium oxide for detecting low-concentration formaldehyde according to claim 1 or 2, comprising the steps of: firstly, preparing a rare earth neodymium/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, and simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring at room temperature; then adding 0.2g of hydrated neodymium nitrate precursor into the solution, and continuing stirring until uniform and transparent neodymium/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

copper foil is used as a substrate to receive a neodymium/indium nitrate nanofiber membrane, the preparation of a nano multilayer fiber membrane is carried out by utilizing an electrostatic spinning technology, the temperature of neodymium/indium nitrate electrostatic spinning solution is kept at about 35 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1mL/h, and the receiving distance is 20 cm; the spinning voltage is controlled to be 20 kV, and a layer of nanofiber film is covered on the surface of the copper foil to form Nd-In while electrostatic spinning is carried out₂O₃A nanofiber membrane product, followed by drying the nanofiber membrane in an oven at 70 ℃ for 12 hours;

third, Nd-In₂O₃Calcining the nano gas-sensitive fiber:

Nd-In₂O₃The nanofiber membrane is taken off from the copper foil and placed In a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber membrane is naturally cooled to the room temperature, a light yellow rare earth neodymium modified alkalescent indium oxide nanofiber sample is collected and recorded as Nd-In₂O₃。

5. The method for preparing weakly basic indium oxide for detecting low-concentration formaldehyde according to claim 1 or 2, comprising the steps of: firstly, preparing a rare earth lanthanum/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, and simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring at room temperature; then adding 0.2g of hydrated lanthanum nitrate precursor into the solution, and continuing stirring until a uniform and transparent lanthanum/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

copper foil is used as a substrate to receive the lanthanum/indium nitrate nanofiber membrane, the electrostatic spinning technology is utilized to prepare a nano multilayer fiber membrane, the temperature of lanthanum/indium nitrate electrostatic spinning solution is kept at about 35 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1mL/h, and the receiving distance is 15 cm; the spinning voltage is controlled to be 30 kV, and a layer of nanofiber film is covered on the surface of the copper foil to form La-In while electrostatic spinning is carried out₂O₃A nanofiber membrane product, followed by drying the nanofiber membrane in an oven at 70 ℃ for 12 hours;

third, La-In₂O₃Calcining the nano gas-sensitive fiber:

La-In is added₂O₃The nanofiber membrane is taken off from the copper foil and placed In a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber membrane is naturally cooled to the room temperature, a light yellow rare earth lanthanum modified alkalescent indium oxide nanofiber sample is collected and recorded as La-In₂O₃。

6. Weakly basic indium oxide, characterised in that it is obtained by a process according to any one of claims 1 to 5.

7. Use of the weakly basic indium oxide according to claim 6 for the detection of ultra low concentrations of formaldehyde.

Technical Field

The invention relates to the technical field of indium oxide material preparation, in particular to a preparation method of alkalescent indium oxide for detecting ultralow-concentration formaldehyde, a product and application thereof, and a preparation method and application of an ultralow-concentration formaldehyde-oriented gas sensor indium oxide material.

Background

With the development of economy and the improvement of the living standard of people, building decoration materials made of various raw materials are introduced into families, and the chemical substance formaldehyde is generally accepted to cause indoor air pollution. Indoor formaldehyde is mainly derived from building materials, furniture, artificial boards, various adhesive coatings, synthetic textiles, and the like. Formaldehyde is a highly toxic substanceThe formaldehyde is the second highest on the priority control list of toxic chemicals in China, is determined to be carcinogenic and teratogenic by the world health organization, is a well-known allergic reaction source and is one of potential strong mutagens. In view of the problem of formaldehyde pollution, it is important to develop a rapid, sensitive and economical formaldehyde detection method. Classical semiconductor sensor materials, e.g. WO₃ZnO and SnO₂ And the like, although capable of responding to formaldehyde, it is difficult to satisfy the demand of a low concentration detection formaldehyde sensor.

Indium (In), located In the fifth periodic group IIIA of the periodic Table of the elements, has generally a valence of +1 and +3, with In being the predominant species₂O₃。In₂O₃The wide-band-gap n-type semiconductor oxide has high electron mobility and obvious response to formaldehyde molecules with certain concentration. In can be further improved by means of noble metal modification, doping of metal ions, compounding of various oxides and the like₂O₃The sensing performance of the sensor can achieve the aim of detecting formaldehyde with high sensitivity under low concentration. Chen et al Applied materials in ACS&Interfaces (2017, 9, 4692-4700) reported In₂O₃Ga is doped in, Ga is synthesized_xIn_2-xO₃A porous fibrous solid solution. By adjusting the Ga/In atomic ratio, the crystal phase, the nano structure and the band gap can be changed, so that the gas sensing performance is further optimized, and the high-efficiency detection of the formaldehyde gas is realized. Wang et al reported that Co-doped In was prepared by hydrothermal method In ACS Sensors (2018, 3, 468-475)₂O₃The nanorods, Co doped with increased oxygen vacancies and surface adsorbed oxygen, In₂O₃The response performance of the nano-rod to formaldehyde gas is improved by more than 20 times. These studies show that the responsiveness of formaldehyde molecules can be enhanced by changing the band structure of the indium oxide material.

Disclosure of Invention

The invention aims to provide a preparation method of alkalescent indium oxide for detecting ultralow-concentration formaldehyde.

Yet another object of the present invention is to: provides a weakly alkaline indium oxide product for detecting ultralow-concentration formaldehyde, which is prepared by the method.

Yet another object of the present invention is to: provides an application of the product.

The purpose of the invention is realized by the following scheme: a preparation method of alkalescent indium oxide for detecting ultralow-concentration formaldehyde adopts an electrostatic spinning method to dope rare earth metal in an indium oxide material to prepare rare earth modified alkalescent indium oxide nanofiber, and comprises the following steps:

step one, preparing a rare earth/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring; then adding 0.1-0.5 g of rare earth nitrate precursor into the solution, and continuously stirring until a uniform and transparent rare earth/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

the preparation method comprises the steps of adopting a copper foil as a substrate to receive a rare earth/indium nitrate nanofiber membrane, and preparing a nano multilayer fiber membrane by utilizing an electrostatic spinning technology, wherein the temperature of a rare earth/indium nitrate electrostatic spinning solution is kept at 35 +/-5 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1-2 mL/h, and the receiving distance is 20 cm; the spinning voltage is controlled to be 10-30 kV, a layer of nanofiber film is covered on the surface of the copper foil during electrostatic spinning to form Re-In₂O₃The nanofiber membrane product was then dried in an oven at 70 ℃ for 12 hours to remove excess organic solvent from the surface;

third step, Re-In₂O₃Calcining the nano gas-sensitive fiber:

Re-In is added₂O₃The nanofiber membrane is taken off from the copper foil and is put into a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber is naturally cooled to the room temperature, the faint yellow rare earth modified alkalescent indium oxide nanofiber is collected and recorded as Re-In₂O₃And (3) nano fibers.

The rare earth material is Y, La, Nd, Ho and Tm rare earth metal.

The spinning speed in the preferred electrostatic spinning technology is controlled to be 0.1-1 mL/h.

The invention provides weakly alkaline indium oxide for detecting ultralow-concentration formaldehyde, which is prepared according to any one of the methods.

The invention provides an application of weakly alkaline indium oxide in detecting ultralow-concentration formaldehyde.

Preparing and testing the gas sensor:

preparing a gas sensor: preparing the gas sensor by adopting an indirectly heated gas sensor method, mixing a sample with ethanol, and grinding the mixture into slurry in agate; then, the slurry is evenly coated on an alumina ceramic tube, 2 Au electrodes are connected on the tube, each electrode is provided with 2 Pt leads, and after drying at room temperature, a Ni-Cr heating wire is introduced into the ceramic tube and is used for controlling the working temperature. And finally welding two ends of 4 Pt leads and Ni-Cr heating wires on six columns of the device base to prepare the gas sensor, wherein the sensor is aged for 24 hours at the temperature of 160 ℃ in the air in order to improve the stability of the gas sensor.

Performance testing of the gas sensor: the sensing performance of the gas is tested by adopting a CGS-8 gas sensing and measuring system. For an n-type semiconductor sensor, the response value is defined as S = R_a/R_gThe response or recovery time of the sensor is defined as the time required for the resistance of the target gas to change by 90% during adsorption or desorption.

The research team continuously explores and discovers in the process of summarizing previous results that the change of the energy band structure of the gas sensitive material can be used for cooperatively regulating and controlling the alkalinity of the surface of the material, so that the aim of detecting formaldehyde with high sensitivity can be fulfilled. When the target gas is acidic and the oxide surface is basic, different reactions may occur with the target gas formaldehyde molecules. Therefore, adjusting the energy level structure and surface properties of the metal oxide semiconductor is an effective strategy to achieve good gas sensing performance. Since formaldehyde is an acidic compound (pKa of formaldehyde is 13.27) and rare earth is a basic metal material, rare earth is doped with In₂O₃After the material is prepared, the alkalinity of the surface of the material can be changed, so that the response performance of the gas sensitive material is greatly improved.

Based on the research thought, the invention aims to provide a preparation method of weakly alkaline indium oxide for detecting ultralow-concentration formaldehyde, and a product and application thereof. The gas sensor material prepared by the invention has low price and high responsiveness to ultralow-concentration formaldehyde, and can be used for detecting ppb-level formaldehyde; and the preparation method is simple, nontoxic and harmless, and is suitable for large-scale production.

And doping rare earth metal into the indium oxide material by adopting an electrostatic spinning method to prepare the rare earth modified indium oxide nanofiber. Due to the doping of the rare earth, the surface property of the indium oxide material can show weak alkalinity under the condition of changing the energy level of the indium oxide, so that the indium oxide material has high-sensitivity formaldehyde response. The material prepared by the method can be applied to detection of ppb-level formaldehyde and still has strong response to ultralow-concentration formaldehyde of 50 ppm.

Drawings

FIG. 1 shows Y-In obtained In example 1₂O₃SEM electron microscope spectrogram of the nano gas-sensitive fiber.

Detailed Description

The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

Example 1:

a weakly alkaline indium oxide for detecting ultralow-concentration formaldehyde is prepared by doping rare earth metal in an indium oxide material by an electrostatic spinning method to prepare rare earth modified indium oxide nanofiber, and is prepared by the following steps:

step one, preparing a rare earth yttrium/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, and simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring at room temperature; then adding a rare earth yttrium nitrate precursor with the mass of 0.2g into the solution, and continuing stirring until a uniform and transparent yttrium/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

the preparation method comprises the steps of adopting a copper foil as a substrate to receive a rare earth/indium nitrate nanofiber membrane, and preparing a nano multilayer fiber membrane by utilizing an electrostatic spinning technology, wherein the temperature of a rare earth/indium nitrate electrostatic spinning solution is kept at about 35 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1mL/h, and the receiving distance is 20 cm; the spinning voltage is controlled to be 20 kV, and a layer of nanofiber film is covered on the surface of the copper foil to form Re-In while electrostatic spinning is carried out₂O₃Drying the nanofiber membrane product in an oven at 70 ℃ for 12 hours to remove the organic solvent such as organic DMF (dimethyl formamide) on the surface;

third, Y-In₂O₃Calcining the nano gas-sensitive fiber:

reacting Y-In₂O₃The nanofiber membrane is taken off from the copper foil and is put into a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber membrane is naturally cooled to the room temperature, a light yellow rare earth yttrium modified alkalescent indium oxide nanofiber sample is collected and is marked as Y-In₂O₃And (3) nano fibers.

The resulting Y-In₂O₃The SEM spectrogram of the nano gas-sensitive fiber is shown in figure 1, and SEM photographs show that the appearance of a sample is one-dimensional nano fiber, the diameter of the sample is 100-200 nm, and the length of the sample is hundreds of microns. The special two-dimensional radial nano structure promotes the formaldehyde molecules to move directionally on the surface of the formaldehyde molecules, and provides structural guarantee for the detection and response of the high-sensitivity formaldehyde molecules.

The sample of this example is used for detecting formaldehyde with ultra-low concentration, which is shown in table one in the application example. The lower limit of the concentration of formaldehyde is 50 ppm.

Example 2:

the weakly basic indium oxide for detecting ultralow-concentration formaldehyde is prepared by the following steps similar to the steps in example 1:

firstly, preparing a rare earth neodymium/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, and simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring at room temperature; then adding 0.2g of hydrated neodymium nitrate precursor into the solution, and continuing stirring until uniform and transparent neodymium/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

copper foil is used as a substrate to receive a neodymium/indium nitrate nanofiber membrane, the preparation of a nano multilayer fiber membrane is carried out by utilizing an electrostatic spinning technology, the temperature of neodymium/indium nitrate electrostatic spinning solution is kept at about 35 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1mL/h, and the receiving distance is 20 cm; the spinning voltage is controlled to be 20 kV, and a layer of nanofiber film is covered on the surface of the copper foil to form Nd-In while electrostatic spinning is carried out₂O₃Drying the nanofiber membrane product in an oven at 70 ℃ for 12 hours to remove the organic solvent such as organic DMF (dimethyl formamide) on the surface;

third, Nd-In₂O₃Calcining the nano gas-sensitive fiber:

Nd-In₂O₃The nanofiber membrane is taken off from the copper foil and placed In a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber membrane is naturally cooled to the room temperature, a light yellow rare earth neodymium modified alkalescent indium oxide nanofiber sample is collected and recorded as Nd-In₂O₃And (3) nano fibers.

The sample of this example is used for detecting formaldehyde with ultra-low concentration, which is shown in table one in the application example. The lower limit of the concentration of formaldehyde is 100 ppm.

Example 3:

the weakly basic indium oxide for detecting ultralow-concentration formaldehyde is prepared by the following steps similar to the steps in example 1:

firstly, preparing a rare earth lanthanum/indium nitrate electrostatic spinning solution:

adding 10.0 g of indium nitrate hydrate into 100 g of absolute ethyl alcohol, and simultaneously adding 25 g of N, N-Dimethylformamide (DMF), and magnetically stirring at room temperature; then adding 0.2g of hydrated lanthanum nitrate precursor into the solution, and continuing stirring until a uniform and transparent lanthanum/indium nitrate electrostatic spinning solution is formed;

step two, preparing a multilayer nanofiber membrane by electrostatic spinning:

copper foil is used as a substrate to receive the lanthanum/indium nitrate nanofiber membrane, the electrostatic spinning technology is utilized to prepare a nano multilayer fiber membrane, the temperature of lanthanum/indium nitrate electrostatic spinning solution is kept at about 35 ℃, the indoor air humidity is kept at 40%, the spinning speed is 0.1mL/h, and the receiving distance is 15 cm; the spinning voltage is controlled to be 30 kV, and a layer of nanofiber film is covered on the surface of the copper foil to form La-In while electrostatic spinning is carried out₂O₃Drying the nanofiber membrane product in an oven at 70 ℃ for 12 hours to remove the organic solvent such as organic DMF (dimethyl formamide) on the surface;

third, La-In₂O₃Calcining the nano gas-sensitive fiber:

La-In is added₂O₃The nanofiber membrane is taken off from the copper foil and placed In a crucible, the crucible is calcined In a muffle furnace at the temperature of 650 ℃ for 4 hours, the heating rate is 3 ℃/min, after the nanofiber membrane is naturally cooled to the room temperature, a light yellow rare earth lanthanum modified alkalescent indium oxide nanofiber sample is collected and recorded as La-In₂O₃And (3) nano fibers.

The sample of this example is used for detecting formaldehyde with ultra-low concentration, which is shown in table one in the application example. The lower limit of the concentration of formaldehyde is 100 ppm.

Application example

Preparing a gas sensor: preparing the gas sensor by adopting an indirectly heated gas sensor method, mixing the samples of the examples 1 to 3 with ethanol respectively, and grinding the mixture into slurry in agate; and then uniformly coating the slurry on an alumina ceramic tube, wherein the tube is connected with 2 Au electrodes, each electrode is provided with 2 Pt leads, after drying at room temperature, a Ni-Cr heating wire is introduced into the ceramic tube for controlling the working temperature, and finally, the two ends of the 4 Pt leads and the Ni-Cr heating wire are welded on six columns of a device base to prepare the gas sensor, and in order to improve the stability of the gas sensor, the gas sensor is aged for 24 hours at the temperature of 160 ℃ in the air.

The research finds that the rare earth is modified by Y, Nd and La, and is alkalineModified Re-In₂O₃The materials all showed good formaldehyde response characteristics. Wherein, Y-In₂O₃The lower limit of the detected formaldehyde concentration reaches 50 ppm. Therefore, the sensor material is suitable for detecting low-concentration formaldehyde, and the detection performance of the related formaldehyde sensor is as follows:

the above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.