Ni-modified niobium pentoxide gas-sensitive element and preparation method and application thereof
阅读说明：本技术 一种Ni修饰的五氧化二铌气敏元件及其制备方法与应用 (Ni-modified niobium pentoxide gas-sensitive element and preparation method and application thereof ) 是由 戴文新 王笑笑 陈旬 张子重 付贤智 于 2021-01-14 设计创作，主要内容包括：本发明公开了一种Ni修饰的Nb-2O-5气敏元件及其制备方法与应用,其是将洗净的FTO叉指电极片于含Ni(NO-3)-2·6H-2O和铌酸铵草酸盐水合物的混合溶液中进行水热反应后,将表面长有粉末状NiO/Nb-2O-5的FTO叉指电极片取出,经去离子水冲洗、烘干、高温煅烧及还原,制得原位水热生成的Ni-xO/Nb-2O-5气敏元件。本发明所得Ni-xO/Nb-2O-5气敏元件在室温及紫外光条件下对CO-2和H-2均显示出了较佳的响应性能,并具有良好的稳定性和重复性,其简化了气敏元件的制备工艺,在半导体光助气敏传感器制备方面具有较好的应用前景。(The invention discloses Ni modified Nb 2 O 5 The gas sensor is prepared by cleaning FTO interdigital electrode plate containing Ni (NO) 3 ) 2 ·6H 2 Carrying out hydrothermal reaction on the mixed solution of O and ammonium niobate oxalate hydrate, and growing powdered NiO/Nb on the surface 2 O 5 The FTO interdigital electrode plate is taken out, washed by deionized water, dried, calcined at high temperature and reduced to prepare Ni generated by in-situ hydrothermal reaction x O/Nb 2 O 5 A gas sensor. Ni obtained by the invention x O/Nb 2 O 5 Gas sensitive element for CO at room temperature under ultraviolet light condition 2 And H 2 The method has the advantages of good response performance, good stability and repeatability, simplified preparation process of the gas sensitive element, and good application prospect in the preparation of semiconductor photo-assisted gas sensitive sensors.)
1. Ni modified Nb2O5The preparation method of the gas sensor is characterized in that: putting the cleaned FTO interdigital electrode plate on the electrode plate containing Ni(NO3)2·6H2Carrying out hydrothermal reaction on the mixed solution of O and ammonium niobate oxalate hydrate, and growing powdered NiO/Nb on the surface2O5The FTO interdigital electrode plate is taken out, washed by deionized water, dried, calcined at high temperature and reduced to prepare Ni generated by in-situ hydrothermal reactionxO/Nb2O5A gas sensor.
2. The Ni-modified Nb of claim 12O5The preparation method of the gas sensor is characterized in that: the FTO interdigital electrode plate is formed by etching FTO conductive glass with the thickness of 1.5cm multiplied by 1cm to cut off the middle of a conductive surface of the FTO conductive glass with a gap with the width of 0.1mm, and the two ends of the FTO interdigital electrode plate have conductive performance.
3. The Ni-modified Nb of claim 12O5The preparation method of the gas sensor is characterized in that: the molar ratio of Ni to Nb in the mixed solution is 1: 10.
4. The Ni-modified Nb of claim 12O5The preparation method of the gas sensor is characterized in that: the temperature of the hydrothermal reaction is 175 ℃, and the time is 14-16 h.
5. The Ni-modified Nb of claim 12O5The preparation method of the gas sensor is characterized in that: the drying temperature is 50-70 ℃.
6. The Ni-modified Nb of claim 12O5The preparation method of the gas sensor is characterized in that: the high-temperature roasting temperature is 300-500 ℃, and the time is 2 h.
7. The Ni-modified Nb of claim 12O5The preparation method of the gas sensor is characterized in that: the reduction is at 3% H2 + 97% N2At 250 ℃ for 1 hour.
8. A Ni modified Nb made by the method of claim 12O5A gas sensor.
9. The Ni-modified Nb of claim 82O5The application of the gas sensor in the photo-assisted gas sensor is characterized in that: the gas sensitive element is used for treating CO under the conditions of room temperature and ultraviolet light2Or H2Can generate gas-sensitive response and can be used as a light-assisted gas-sensitive element in a light-assisted gas-sensitive sensor.
Technical Field
The invention belongs to the technical field of gas sensors, and particularly relates to NixO/Nb2O5A gas sensor, a preparation method thereof and application thereof in a light-assisted gas sensor.
Background
With the continuous development of industrial production, the problem of atmospheric environmental pollution caused by the continuous development of industrial production is a big problem which needs to be solved by human beings at present. The gas sensor is an effective means for detecting the concentration and components of harmful gases, and can convert the type and concentration information of gases into electric signals, thereby realizing the detection of related gases. The metal oxide semiconductor gas sensor has the advantages of high sensitivity, quick response time and recovery time, low cost, long service life, good stability and the like, and is widely applied to the gas sensor. The semiconductor gas sensor can be divided into N type and P type according to the property of the semiconductor, and the N type semiconductor is SnO2、TiO2NiO, MoO, etc. as P-type semiconductor2、CrO3Etc. mainly for CO, H2、O2、H2S, acetone, NOXAnd detection of gases such as ethanol.
When the semiconductor material is irradiated by light with a certain wavelength, photo-generated electrons are excited to jump from a valence band to a conduction band, so that the conductivity of the semiconductor material is changed, and the gas-sensitive response performance of the semiconductor is improved. Therefore, the preparation of the semiconductor gas sensor with good stability and good photoresponse is a key step. The currently commonly used gas sensor is prepared by taking a gold interdigital electrode plate or an FTO interdigital electrode plate as a substrate and loading a semiconductor material on the surface of the substrate by adopting a drop coating method, a spin coating method, a screen printing method or a template method.
As an N-type semiconductor metal oxide, niobium pentoxide (Nb)2O5) Has excellent lightChemical property, good chemical stability and thermal stability, has wide development prospect in the aspect of gas sensor application, and has been reported to be used for detecting NO and H2And good gas sensitive response is shown. The invention adopts Ni to modify the alloy, thereby further enlarging Nb2O5So that the light absorption range of the light-assisted gas sensitive material is better.
Disclosure of Invention
Aiming at the defects of the existing gas sensor preparation technology, the invention provides Ni modified Nb2O5The method is simple, rapid and easy to implement, and the prepared Ni modified Nb is2O5The gas sensor has stable performance, good repeatability and good application prospect.
In order to achieve the purpose, the invention adopts the following technical scheme:
ni modified Nb2O5The preparation method of the gas sensor comprises the step of putting a cleaned FTO interdigital electrode plate on a Ni (NO) -containing electrode plate3)2·6H2Carrying out hydrothermal reaction on the mixed solution of O and ammonium niobate oxalate hydrate, and growing powdered NiO/Nb on the surface2O5The FTO interdigital electrode plate is taken out, washed by deionized water, dried, calcined at high temperature and reduced to prepare Ni generated by in-situ hydrothermal reactionxO/Nb2O5A gas sensor. The method specifically comprises the following steps:
1) ultrasonically cleaning the FTO interdigital electrode plate by using acetone, ethanol and deionized water respectively, and drying for later use;
2) 0.261 g of Ni (NO) was added to the beaker3)2·6H2O, 2.61 g of ammonium niobate oxalate hydrate and 32.7 mL of deionized water are fully stirred on a magnetic stirrer to be dissolved;
3) adding 7.4 mL of 30 wt% hydrogen peroxide solution into the solution obtained in the step 2), oxidizing, and continuously stirring for 30min to obtain the Ni (NO) containing solution3)2·6H2A mixed solution of O and ammonium niobium oxalate;
4) putting the FTO interdigital electrode plate treated in the step 1) into a high-pressure reaction kettle, enabling the conductive surface to face upwards, adding the mixed solution obtained in the step 3), and carrying out hydrothermal reaction at 175 ℃ for 14-16 h;
5) carrying out the hydrothermal reaction in the step 4) to obtain NiO/Nb powder with long-growing surfaces2O5Taking out the FTO interdigital electrode plate, slightly washing the electrode plate by deionized water, and then putting the electrode plate into an oven at 50-70 ℃ for drying;
6) placing the dried FTO interdigital electrode plate in the step 5) in a muffle furnace, calcining at the high temperature of 300-500 ℃ for 2 hours, and then placing in 3% H2 + 97% N2In the atmosphere of (2), reducing for 1h at 250 ℃ to obtain the NixO/Nb2O5A gas sensor.
The FTO interdigital electrode plate is formed by etching FTO conductive glass with the thickness of 1.5cm multiplied by 1cm to cut off the middle of a conductive surface of the FTO conductive glass with a gap with the width of 0.1mm, and the two ends of the FTO interdigital electrode plate have conductive performance.
Ni produced by the above methodxO/Nb2O5Gas sensitive element for CO at room temperature under ultraviolet light condition2Or H2All have good gas-sensitive response, and can be used as a photo-assisted gas-sensitive element for preparing a gas-sensitive sensor.
The invention has the following effects and advantages:
compared with the traditional preparation method of the semiconductor gas sensor, the method prepares Ni in situ by one step through hydrothermal reactionxO/Nb2O5Gas sensor, its preparation method is simple, and the obtained NixO/Nb2O5Gas sensitive element for CO under ultraviolet light and room temperature2And H2The gas has good gas-sensitive response, shows good stability and repeatability, and provides a new idea for the preparation and research of the room-temperature photo-assisted gas-sensitive sensor.
Drawings
FIG. 1 shows Ni obtained in example 1xO/Nb2O5XRD spectrum of the powder.
FIG. 2 is pure Nb2O5Powder (a) and Ni obtained in example 1xO/Nb2O5DRS profile of powder (b).
FIG. 3 shows Ni obtained in example 1xO/Nb2O5TEM image of the powder.
FIG. 4 shows Ni obtained in example 1xO/Nb2O5Gas sensitive element for CO at room temperature in nitrogen2The ultraviolet light assisted gas sensitive response performance measurement result.
FIG. 5 shows Ni obtained in example 1xO/Nb2O5Gas sensor for H at room temperature in nitrogen2The ultraviolet light assisted gas sensitive response performance measurement result.
FIG. 6 shows Ni obtained in example 1xO/Nb2O5Gas sensor (a) and pure Nb without Ni2O5Gas sensor (b) for CO at room temperature in nitrogen2The ultraviolet light helps the gas response performance contrast result.
Detailed Description
In order to make the present invention more comprehensible, the technical solutions of the present invention are further described below with reference to specific embodiments, but the present invention is not limited thereto.
The FTO interdigital electrode plate is formed by etching FTO conductive glass with the thickness of 1.5cm multiplied by 1cm to cut off the middle of a conductive surface of the FTO conductive glass with a gap with the width of 0.1mm, and the two ends of the FTO interdigital electrode plate have conductive performance.
EXAMPLE in situ hydrothermal preparation of NiXO/Nb2O5Gas sensor
1) Ultrasonically cleaning the FTO interdigital electrode plate by using acetone, ethanol and deionized water respectively, and drying at 80 ℃ for later use;
2) 0.261 g of Ni (NO) was added to the beaker3)2·6H2O, 2.61 g of ammonium niobate oxalate hydrate and 32.7 mL of deionized water are fully stirred on a magnetic stirrer to be dissolved;
3) adding 7.4 mL of 30 wt% hydrogen peroxide solution into the solution obtained in the step 2), and continuously stirring for 30min to obtain the solution containing Ni (NO)3)2·6H2A mixed solution of O and ammonium niobium oxalate;
4) putting the FTO interdigital electrode plate treated in the step 1) into a high-pressure reaction kettle, enabling the conductive surface to be upward, adding the mixed solution obtained in the step 3), and carrying out hydrothermal reaction at 175 ℃ for 15 hours;
5) carrying out the hydrothermal reaction in the step 4) to obtain NiO/Nb powder with long-growing surfaces2O5Taking out the FTO interdigital electrode plate, slightly washing the electrode plate by deionized water, and then putting the electrode plate into a 60 ℃ drying oven for drying;
6) placing the dried FTO interdigital electrode plate in the step 5) in a muffle furnace, calcining at the high temperature of 400 ℃ for 2 hours (the heating rate is 2 ℃/min), and then placing in 3% H2 + 97% N2In the atmosphere of (2), reducing for 1h at 250 ℃ to obtain NixO/Nb2O5A gas sensor.
Comparative example in-situ hydrothermal method for preparing pure Nb2O5Gas sensor
1) Ultrasonically cleaning the FTO interdigital electrode plate by using acetone, ethanol and deionized water respectively, and drying at 80 ℃ for later use;
2) adding 2.61 g of ammonium niobate oxalate hydrate and 32.7 mL of deionized water into a beaker, and fully stirring on a magnetic stirrer to dissolve the ammonium niobate oxalate hydrate;
3) adding 7.4 mL of 30 wt% hydrogen peroxide solution into the solution obtained in the step 2), and continuously stirring for 30min to obtain a solution of ammonium niobium oxalate;
4) putting the FTO interdigital electrode plate treated in the step 1) into a high-pressure reaction kettle, enabling the conductive surface to be upward, adding the solution obtained in the step 3), and carrying out hydrothermal reaction at 175 ℃ for 15 hours;
5) carrying out hydrothermal reaction in the step 4) to obtain Nb powder with long powder on the surface2O5Taking out the FTO interdigital electrode plate, slightly washing the electrode plate by deionized water, and then putting the electrode plate into a 60 ℃ drying oven for drying;
6) placing the dried FTO interdigital electrode plate in the step 5) in a muffle furnace, calcining at the high temperature of 400 ℃ for 2 hours (the heating rate is 2 ℃/min), and then placing in 3% H2 + 97% N2In the atmosphere of (1), reducing for 1h at 250 ℃ to obtain Nb2O5A gas sensor.
FIG. 1 shows the obtained NixO/Nb2O5XRD spectrum of the powder. By entering FIG. 1 with standard card PDF #28-0317 and standard card PDF #47-1049The hexagonal phase Nb can be found by line comparison2O5Corresponding characteristic peak of NiO in face-centered cubic phase illustrates NixO/Nb2O5The successful preparation.
FIG. 2 is pure Nb2O5Powder (a) and Ni obtainedxO/Nb2O5DRS profile of powder (b). As can be seen from FIG. 2, the Ni-modified Nb2O5The absorption band edge of (A) is slightly red-shifted, demonstrating that it can enlarge Nb2O5Light absorption range of (1).
FIG. 3 shows the obtained NixO/Nb2O5TEM image of the powder. As can be seen from the figure, Ni was producedxO/Nb2O5The shape of the coexisting particles and nano-rods.
1. Measurement of gas sensitivity
Ni prepared in examplexO/Nb2O5The gas sensor carries out response test in a JF02E type gas-sensitive test system (Kunming noble research King-Kong science and technology company), and specifically, Ni is usedxO/Nb2O5The gas sensor was placed in a 100mL stainless steel sealed gas cell (with a quartz window) and light was supplied from four 365nm UV fluorescent lamps (4W, Philips TL/05). With high purity N2And (3) as background gas, introducing gas to be detected into the gas chamber, and controlling the total flow to be 250 mL/min. The response of the material to gas is represented by the change in resistance, with an operating voltage of 5V. The material is charged into a gas chamber and is first heated to 250 ℃ and then treated with H2Pretreatment for 1h, then in N2And purging in the atmosphere for 30min to remove water and other gases adsorbed on the surface, and cooling to room temperature to switch the gas to be tested for testing.
According to this method, Ni obtained in example 1 was evaluatedxO/Nb2O5Gas sensor to CO2And H2The photo-assisted gas sensitivity of the alloy is improved, and Nb prepared in the comparative example is tested as a comparison2O5Gas sensor to CO2The results are shown in fig. 4-6, respectively.
As can be seen from FIGS. 4 and 5, Ni produced hydrothermally in situxO/Nb2O5Gas sensitive element for CO in ambient temperature ultraviolet light and nitrogen background gas2Gas and H2The gas has good gas-sensitive response, and can keep good stability and repeatability in a cycle test.
As can be seen from FIG. 6, NixO/Nb2O5Gas sensitive element for CO in ambient temperature ultraviolet light and nitrogen background gas2The gas-sensitive response of the alloy is superior to that of pure Nb2O5Gas sensors, which demonstrate Ni produced by in situ hydrothermal methodxO/Nb2O5The material is feasible as the ultraviolet light assisted gas sensitive material at room temperature, the preparation method is simple, the preparation process of the traditional gas sensitive element is simplified, the application in the preparation aspect of the light assisted gas sensitive sensor is facilitated, and a new thought and direction are provided for the preparation of other gas sensitive materials.
2. Sample pairs of different Ni contents to CO2Gas sensitive response value comparison of
Ni with different Ni contents was prepared by the same method as in examplexO/Nb2O5Gas sensors and comparison of different gas sensors for CO in accordance with the above method2The results are shown in Table 1.
TABLE 1 gas sensor for different Ni contents in light to CO2Response value of gas
As can be seen from the results in Table 1, the gas sensor is sensitive to CO with increasing Ni content2Response value (R) of0/R) was gradually increased to a maximum at a Ni/Nb molar ratio of 1: 10.
The above description is only a preferred embodiment of the present invention, and all equivalent changes and modifications made in accordance with the claims of the present invention should be covered by the present invention.