Preparation method of efficient gas sensor for confinement isolated platinum atoms based on porous tin dioxide nanorod

Abstract

The invention discloses a preparation method of a high-efficiency gas sensor for confinement isolated platinum atoms based on porous SnO2 nanorods, isolated Pt atoms are precisely deposited in SnO2 pore channels through an ALD technology, and the working temperature (190 DEG C) of the sensor is remarkably reduced by utilizing a confinement effect and a monatomic catalysis synergistic effect, so that the gas sensor has high sensitivity and high sensitivity. The sensitivity (Ra / Rg = 6.33 at5ppm) to acetone, the response speed (9 seconds) and the stability (the attenuation rate is 2.8% in 28 days) are improved. The sensor has wide application prospects in the fields of medical diagnosis, environmental monitoring and the like.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor gas sensor material technology, specifically relating to a gas sensor and its fabrication method that confines isolated platinum (Pt) atoms within porous SnO2 nanorods using atomic layer deposition (ALD) technology. This sensor exhibits low operating temperature, high sensitivity, and rapid response and recovery characteristics, making it suitable for the efficient detection of acetone gas. Background Technology

[0002] Metal-oxide-semiconductor (MOS) gas sensors are widely used for the detection of volatile organic compounds (VOCs) due to their advantages such as low cost, high sensitivity, and ease of integration. SnO2, as a typical n-type semiconductor, is a common sensing material, but it suffers from problems such as high operating temperature, poor selectivity, and insufficient sensitivity. In existing technologies, performance can be improved by doping with noble metals (such as Pt and Pd) or constructing porous structures, but traditional methods tend to lead to noble metal agglomeration, reducing atom utilization and resulting in poor stability. Furthermore, the confinement effect and stability of single-atom catalysts still face challenges.

[0003] This invention optimizes the porous nanostructure of SnO2 and combines it with ALD technology to precisely deposit isolated Pt atoms, thereby enhancing acetone adsorption through confinement effect and reducing reaction activation energy, thus significantly improving the overall performance of the sensor. Summary of the Invention

[0004] The purpose of this invention is to provide a method for fabricating a highly efficient gas sensor based on porous SnO2 nanorods that confine isolated platinum atoms. By employing atomic layer deposition (ALD) technology, atomically dispersed Pt species are precisely confined within the inner surface of SnO2 channels, successfully solving the technical challenges of low Pt dispersion and poor thermal stability in traditional methods. This material exhibits a response value of 6.33 (R0) to 5 ppm acetone at 190°C. a / R g The detection limit is as low as 19 ppb, the response / recovery time is shortened to 9s / 20s, and the performance degradation is less than 3% after 28 days. Its overall performance is significantly better than that of existing technologies.

[0005] A method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods for confining isolated platinum atoms is characterized by confining isolated Pt atoms within the channels of the SnO2 nanorods using ALD technology, specifically including the following steps:

[0006] Step 1: Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor.

[0007] Step 2: Porous SnO2 nanorods were prepared by calcination at 500 degrees Celsius using Sn-based metal-organic frameworks (Sn-MOF) as precursors.

[0008] Step 3: Using ALD technology, Pt atoms are deposited on the surface of SnO2 nanorods to form a structure in which isolated Pt sites are confined within SnO2 channels.

[0009] Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

[0010] Furthermore, in step 1, the feeding ratio of terephthalic acid and SnCl2·2H2O is 1:1, 3:1, and 4:1.

[0011] Furthermore, in step 2, the temperature for calcining Sn-MOF in air is set to 500 degrees Celsius and 600 degrees Celsius.

[0012] Furthermore, in step 3, an Au source or a Pd source is used as the precursor.

[0013] Furthermore, in step 4, an ethanol-dispersible material is used for coating.

[0014] Beneficial effects:

[0015] 1. This invention achieves a reduction in the operating temperature of acetone gas by the SnO2 gas sensor;

[0016] 2. This invention improves the sensitivity of the SnO2 gas sensor to acetone gas;

[0017] 3. This invention improves the response recovery speed of the SnO2 gas sensor to acetone gas;

[0018] 4. This invention enhances the stability of the SnO2 gas sensor. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the synthesis route of SnO2 nanorods and the ALD deposition of Pt.

[0020] Figure 2 This is a schematic diagram of the TEM, HRTEM, and elemental distribution of SnO2-Pt2.

[0021] Figure 3 The L3-edge XANES and EXAFS spectra of Pt demonstrate the coordination structure of isolated Pt atoms.

[0022] Figure 4 This is a diagram comparing sensor performance, including optimal operating temperature, selectivity, and long-term stability. Detailed Implementation

[0023] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0024] Example 1

[0025] This embodiment provides a method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods that confine isolated platinum atoms, specifically including the following steps:

[0026] Step 1. Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor.

[0027] Step 2: Calcine the Sn-MOF precursor obtained in Step 1 at 550℃ for 2 hours to obtain porous SnO2 nanorods.

[0028] Step 3: Using an ALD device, with Pt source and O3 as precursors, two cycles of Pt atoms are deposited on the SnO2 surface to obtain SnO2-Pt2;

[0029] Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

[0030] Example 2

[0031] This embodiment provides a method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods that confine isolated gold atoms, specifically including the following steps:

[0032] Step 1. Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor.

[0033] Step 2: Calcine the Sn-MOF precursor obtained in Step 1 at 550℃ for 2 hours to obtain porous SnO2 nanorods.

[0034] Step 3: Using an ALD device, with Au source and O3 as precursors, two cycles of Pt atoms are deposited on the SnO2 surface to obtain SnO2-Pt2;

[0035] Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

[0036] Example 3

[0037] This embodiment provides a method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods that confine isolated palladium atoms, specifically including the following steps:

[0038] Step 1. Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor.

[0039] Step 2: Calcine the Sn-MOF precursor obtained in Step 1 at 550℃ for 2 hours to obtain porous SnO2 nanorods.

[0040] Step 3: Using an ALD device, with Pd source and O3 as precursors, two cycles of Pt atoms are deposited on the SnO2 surface to obtain SnO2-Pt2;

[0041] Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

[0042] like Figure 1 The diagram shows the synthesis route of SnO2-Pt2 prepared in Example 1 above.

[0043] like Figure 2 The images shown are TEM, HRTEM and elemental analysis diagrams of SnO2-Pt2 prepared in Example 1 above. It can be seen that Pt elements are uniformly distributed on the SnO2 surface.

[0044] like Figure 3 The images show the Pt L3-edge XANES and EXAFS spectra, which show that Pt is confined in a monodisperse form within the porous SnO2 channels.

[0045] like Figure 4 For sensor performance comparison, including optimal operating temperature, selectivity, and long-term stability, it can be seen that the optimal operating temperature of the SnO2-Pt2 sensor decreases from 275℃ for pure SnO2 to 190℃, and the response value (R) to 5ppm acetone... a / R g The detection limit was improved from 2.63 to 6.33, the detection limit was reduced to 19 ppb, the response time was reduced from 23 seconds to 9 seconds, the recovery time was reduced from 31 seconds to 20 seconds, and the response value decreased by only 2.8% within 28 days.

[0046] In summary, these three examples aim to illustrate that highly efficient gas sensors can be fabricated by confining isolated noble metal atoms such as Pt, Au, and Pd on the surface of porous SnO2 nanorods using atomic layer deposition (ALD) technology. Based on the performance data from Example 1, it is inferred that this modified sensor, compared to a pure SnO2 sensor, exhibits significant improvements in optimal operating temperature, response value, detection limit, response time, recovery time, and long-term stability. This demonstrates the regulatory effect of different isolated noble metal atom modifications on the performance of porous SnO2 nanorod-based gas sensors.

[0047] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms, characterized in that, The isolated Pt atoms are confined within the channels of SnO2 nanorods using ALD technology, specifically including the following steps: Step 1: Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor; Step 2: Porous SnO2 nanorods were prepared by calcination at 500 degrees Celsius using Sn-based metal-organic frameworks (Sn-MOF) as precursors. Step 3: Using ALD technology, Pt atoms are deposited on the surface of SnO2 nanorods to form a structure in which isolated Pt sites are confined within SnO2 channels; Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

2. The method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms according to claim 1, characterized in that, In step 1, the feeding ratio of terephthalic acid and SnCl2·2H2O is 1:1, 3:1 and 4:

1.

3. The method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms according to claim 1, characterized in that, In step 2, the temperature for calcining Sn-MOF in air is set to 500 degrees Celsius and 600 degrees Celsius.

4. The method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms according to claim 1, characterized in that, In step 3, an Au source or a Pd source is used as a precursor.

5. The method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms according to claim 1, characterized in that, In step 4, an ethanol-dispersible material is used for coating.

6. The method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms according to claim 1, characterized in that, Specifically, the steps include the following: Step 1. Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor. Step 2: Calcine the Sn-MOF precursor obtained in Step 1 at 550℃ for 2 hours to obtain porous SnO2 nanorods. Step 3: Using an ALD device, with Pt source and O3 as precursors, two cycles of Pt atoms are deposited on the SnO2 surface to obtain SnO2-Pt2; Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

7. The method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms according to claim 1, characterized in that, A method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated gold atoms includes the following steps: Step 1. Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor. Step 2: Calcine the Sn-MOF precursor obtained in Step 1 at 550℃ for 2 hours to obtain porous SnO2 nanorods. Step 3: Using an ALD device, with Au source and O3 as precursors, two cycles of Pt atoms are deposited on the SnO2 surface to obtain SnO2-Pt2; Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

8. The method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated platinum atoms according to claim 1, characterized in that, A method for fabricating a high-efficiency gas sensor based on porous SnO2 nanorods confining isolated palladium atoms includes the following steps: Step 1. Terephthalic acid and SnCl2·2H2O were mixed in a 2:1 ratio and heated in a water bath at 60°C to obtain the Sn-MOF precursor. Step 2: Calcine the Sn-MOF precursor obtained in Step 1 at 550℃ for 2 hours to obtain porous SnO2 nanorods. Step 3: Using an ALD device, with Pd source and O3 as precursors, two cycles of Pt atoms are deposited on the SnO2 surface to obtain SnO2-Pt2; Step 4: Coat the SnO2-Pt composite material onto the interdigital electrodes of the microelectromechanical system (MEMS) chip to construct the sensor.

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