ZnO nanosheet gas-sensitive material loaded with CuxCey catalyst as well as preparation method and application of ZnO nanosheet gas-sensitive material

Abstract

The invention relates to a CuxCey catalyst-loaded ZnO nanosheet gas-sensitive material as well as a preparation method and application thereof, and belongs to the field of gas sensing. According to the method, potassium hydroxide is used as a solution to provide an alkaline environment, copper nitrate trihydrate and cerium nitrate hexahydrate are used as a Cu source and a Ce source respectively, deionized water is used as a solvent, and the CuxCey catalyst is prepared through the steps of mechanical stirring, microwave-assisted hydrothermal method synthesis, centrifugation, drying and the like. The CuxCey-ZnO nano-sheet is further prepared by using potassium hydroxide as a solution to provide an alkaline environment, using zinc acetate as a Zn source and using a CuxCey catalyst as a dopant through the steps of mechanical stirring, centrifuging, drying and the like by a hydrothermal method. The sensor based on the ZnO nanosheet nano material loaded with the CuxCey catalyst has excellent gas-sensitive performance on acetone, and has the advantages of high response, quick response recovery, low detection limit, good selectivity and ideal stability. The response to 50 ppm acetone is 37, and the high stability is shown in a 30-day irregular gas-sensitive test. The method is simple in preparation process, low in equipment requirement and high in controllable degree, the obtained product is uniform and has excellent gas-sensitive performance, and trace detection of acetone can be achieved.

Description

Technical Field

[0001] This application belongs to the field of gas sensing for gas detection, specifically the loaded Cu x Ce y Catalyst ZnO nanosheet gas-sensitive materials, preparation methods and applications. Background Art

[0002] Volatile organic compounds (VOCs) are harmful indoor pollutants. Acetone, a common VOC, poses multiple potential health risks. Therefore, developing acetone gas sensors with high sensitivity, fast response and recovery times, and low detection limits is crucial for ensuring safety in industrial environments and maintaining health in everyday life. Summary of the Invention

[0003] The embodiment of the present application provides a Cu-loaded x Ce y Catalyst ZnO nanosheet gas-sensitive materials, preparation methods, and applications. x Ce y The sensor based on the catalyst-containing ZnO nanosheets exhibits good gas-sensitive performance for acetone, with high response, fast response recovery, low detection limit, good selectivity, and ideal stability.

[0004] The technical solution of this application is:

[0005] In a first aspect, an embodiment of the present application provides a Cu-loaded x Ce y A method for preparing a ZnO nanosheet sensing material for a catalyst, the method comprising:

[0006] S1 used the hydrothermal method to synthesize Cu(NO3)2·3H2O and Ce(NO3)3·6H2O under the alkaline condition of KOH, and obtained Cu after washing and drying. x Ce y Catalyst, wherein x=0, 0.3, 0.4, 0.5, 0.7, 1, y=1-x, and the molar ratio of Cu(NO3)2·3H2O to Ce(NO3)3·6H2O is selected according to the values ​​of x and y;

[0007] S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O were synthesized in the alkaline condition of potassium hydroxide according to the mass ratio, and the loaded Cu was obtained after washing and drying. x Ce y The mass ratios of the ZnO nanosheets of the catalyst are 0.005, 0.01, 0.015, and 0.02.

[0008] Furthermore, the S1 specifically includes:

[0009] Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in deionized water, and then KOH was added to pH = 10 and stirred with magnetic stirring to obtain a mixture;

[0010] The mixture is transferred into an autoclave and subjected to a hydrothermal treatment at 180-200° C. for 10-12 h to obtain a synthetic compound;

[0011] The synthesized product was washed by alternating centrifugation with deionized water and ethanol, and the obtained solid was dried in a vacuum oven at 80-90 °C for 12-14 h and calcined at 450-550 °C for 4-5 h to obtain Cu x Ce y catalyst.

[0012] Furthermore, the S2 specifically includes:

[0013] Cu x Ce y The catalyst and Zn(CH3COO)2·2H2O were added into deionized water to obtain a mixed solution, which was stirred on a magnetic stirring table;

[0014] Add KOH to deionized water and stir on a magnetic stirring table to obtain a diluted KOH solution;

[0015] Under magnetic stirring, pour the KOH solution into the mixed solution and continue stirring;

[0016] Transfer to a stainless steel autoclave and heat in a constant temperature oven at 180-200°C for 24-26 hours, collect the solid, wash it with deionized water and ethanol alternately by centrifugation, and dry it in air at 80-90°C for 12-14 hours to obtain a dry precursor;

[0017] The dried precursor was annealed in a muffle furnace at 500-550 °C for 2-3 h. When the muffle furnace was naturally cooled to room temperature, z wt% Cu x Ce y -ZnO nanosheets, wherein z=0.5, 1, 1.5, 2.

[0018] In a second aspect, an embodiment of the present application provides a Cu-loaded x Ce y ZnO nanosheet sensing material for catalyst, the material being z wt% Cu x Ce y -ZnO nanosheets, wherein z=0.5, 1, 1.5, 2.

[0019] In a third aspect, the present invention provides a z wt% Cu x Ce y -Application of ZnO nanosheets in acetone detection.

[0020] The beneficial effects of this application include:

[0021] The materials provided in the examples of this application have the following characteristics: (1) high sensitivity and low detection limit (2) ideal repeatability and stability (3) easy preparation and portable use. x Ce y The catalyst greatly improves the gas-sensitive response of the sensor to acetone and optimizes the selectivity to acetone.

[0022] A Cu-loaded x Ce y ZnO nanosheet gas sensing material as catalyst. Cu x Ce y Composite material is a kind of material with high Ce 3+ and Cu 2+ The catalyst with high ion concentration efficiency has strong Cu-Ce interaction. However, the significant Cu-Ce interaction helps to enhance the electron transfer between CuO and CeO2, thereby improving the Cu x Ce y The redox properties of the catalyst. 3+ and Cu 2+ The presence of can promote the generation of oxygen vacancies, thereby increasing the Cu x Ce y The ability of the catalyst surface to chemically adsorb oxygen. x Ce y Catalyst-based ZnO nanosheet gas sensors have great application potential in industrial detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 (a) provided in the embodiment of the present application is Cu x Ce y XRD pattern of the catalyst; (b) Cu x Ce y -XRD pattern of ZnO sample;

[0024] Figure 2 The scanning electron microscope (SEM) images provided in the examples of this application, (a) and (c) are pure ZnO, and (b) and (d) are 1% Cu 0.4 Ce 0.6 -ZnO;

[0025] Figure 3(a) 1% Cu provided in the examples of this application 0.4 Ce 0.6 -Lattice image of ZnO, (b) 1% Cu 0.4 Ce 0.6 -HRTEM image of ZnO, (c) 1% Cu 0.4 Ce 0.6 -TEM image of ZnO and corresponding element mapping image, (d) 1% Cu 0.4 Ce 0.6 -SAED pattern of ZnO, (e) EDS element semi-quantitative analysis of 1% Cu0.4Ce0.6-ZnO;

[0026] Figure 4 The ZnO and 1% Cu provided in the examples of this application 0.4 Ce 0.6 -XPS spectra of ZnO: (a) O 1s, (b) Ce 3d, (c) Cu 2p, (d) Zn 2p and (e) full scan spectrum;

[0027] Figure 5 Typical N2 adsorption-desorption isotherms provided in the examples of this application: (a) pure-ZnO; (b) 1% Cu 0.4 Ce 0.6 -ZnO; the specific surface areas of the two samples were calculated by BET method and were 3.052 cm 2 / g and 4.744cm 2 / g.

[0028] Figure 6 The embodiment of the present application provides (a) based on pure-ZnO, 0.5% Cu 0.4 Ce 0.6 -ZnO, 1% Cu 0.4 Ce 0.6 -ZnO, 1.5% Cu 0.4 Ce 0.6 -ZnO and 2% Cu 0.4 Ce 0.6 -ZnO sensor response to 50ppm acetone at 200-340℃; (b) based on 1% Cu x Ce y Response of the ZnO sensor to 50 ppm acetone at 260 °C. DETAILED DESCRIPTION

[0029] The present application is further described below with reference to the accompanying drawings and schematic diagrams of experimental phenomena.

[0030] Example 1

[0031] This example is a one-step hydrothermal method to prepare uniformly loaded Cu x Ce y ZnO nanosheet nanocomposites as catalysts.

[0032] In this embodiment, the following steps are mainly performed:

[0033] A loaded Cu x Ce y A method for preparing a ZnO nanosheet sensing material for a catalyst, the method comprising:

[0034] S1 Using a hydrothermal method, Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in 30 mL of deionized water, KOH was added to pH = 10, and the mixture was stirred with magnetic stirring for 30 min to obtain a mixture;

[0035] The mixture was transferred into a 50 mL autoclave and subjected to hydrothermal treatment at 180 °C for 12 h;

[0036] Then, the sample was washed several times by alternating centrifugation with deionized water and ethanol to obtain a solid, which was dried in a vacuum oven at 80 °C for 12 h and calcined at 500 °C for 4 h to obtain Cu x Ce y catalyst, wherein x=0, y=1, and the molar ratio of Cu(NO3)2·3H2O to Ce(NO3)3·6H2O is selected according to the values ​​of x and y;

[0037] S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O (zinc acetate hydrate) were synthesized in an alkaline environment with a mass ratio of 0.005. In this embodiment, Cu x Ce y The catalyst and 3mmol zinc acetate hydrate were added to 20ml deionized water and stirred on a magnetic stirring table. 18mmol KOH was added to 20ml deionized water and placed on a magnetic stirring table for stirring. Under magnetic stirring, the KOH solution was quickly poured into the zinc acetate solution and continued to stir for 30min. It was then transferred to a 50ml PTFE-lined stainless steel autoclave and heated in a constant temperature oven at 180°C for 24h. The solid was then collected and the sample was washed several times by alternating centrifugation with deionized water and ethanol, and then dried in air at 80°C for 12 hours. The dried precursor was annealed in a muffle furnace at 500°C for 2h. When the muffle furnace naturally cooled to room temperature, z wt% Cu was obtained. x Ce y -ZnO, z=0.5.

[0038] Example 2

[0039] A loaded Cu x Ce y A method for preparing a ZnO nanosheet sensing material for a catalyst, the method comprising:

[0040] S1 Using a hydrothermal method, Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in 30 mL of deionized water, KOH was added to pH = 10, and the mixture was stirred with magnetic stirring for 30 min to obtain a mixture;

[0041] The mixture was transferred into a 50 mL autoclave and subjected to hydrothermal treatment at 200 °C for 10 h. The sample was then washed several times by alternating centrifugation with deionized water and ethanol to obtain a solid. The solid was dried in a vacuum oven at 90 °C for 12 h and calcined at 500 °C for 5 h to obtain Cu x Ce y Catalyst, where x = 0.3, y = 0.7, according to the values ​​of x and y, select the molar ratio of Cu(NO3)2·3H2O and Ce(NO3)3·6H2O. x Ce y The catalyst is pure CeO;

[0042] S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O (zinc acetate hydrate) were synthesized in an alkaline environment with a mass ratio of 0.005. In this embodiment, Cu x Ce y The catalyst and 3mmol zinc acetate hydrate were added to 20ml deionized water and stirred on a magnetic stirring table. 18mmol KOH was added to 20ml deionized water and placed on a magnetic stirring table for stirring. Under magnetic stirring, the KOH solution was quickly poured into the zinc acetate solution and continued to stir for 30min. It was then transferred to a 50ml PTFE-lined stainless steel autoclave and heated in a constant temperature oven at 180°C for 24h. The solid was then collected and the sample was washed several times by alternating centrifugation with deionized water and ethanol, and then dried in air at 80°C for 12 hours. The dried precursor was annealed in a muffle furnace at 500°C for 2h. When the muffle furnace naturally cooled to room temperature, z wt% Cu was obtained. x Ce y -ZnO, z=0.5.

[0043] Example 3

[0044] A loaded Cu x Ce yA method for preparing a ZnO nanosheet sensing material for a catalyst, the method comprising:

[0045] S1 Using a hydrothermal method, Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in 30 mL of deionized water, KOH was added to pH = 10, and the mixture was stirred with magnetic stirring for 30 min to obtain a mixture;

[0046] The mixture was transferred to a 50 mL autoclave and hydrothermally treated at 190 ° C for 11 h. Then, the sample was washed several times by alternating centrifugation with deionized water and ethanol to obtain a solid. The obtained solid was dried in a vacuum oven at 90 ° C for 12 h and calcined at 550 ° C for 4 h to obtain Cu x Ce y catalyst, wherein x=0.4, y=0.6, and the molar ratio of Cu(NO3)2·3H2O to Ce(NO3)3·6H2O is selected according to the values ​​of x and y;

[0047] S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O (zinc acetate hydrate) were synthesized in an alkaline environment with a mass ratio of 0.01. In this embodiment, Cu x Ce y The catalyst and 3mmol zinc acetate hydrate were added to 20ml deionized water and stirred on a magnetic stirring table. 18mmol KOH was added to 20ml deionized water and placed on a magnetic stirring table for stirring. Under magnetic stirring, the KOH solution was quickly poured into the zinc acetate solution and continued to stir for 30min. It was then transferred to a 50ml PTFE-lined stainless steel autoclave and heated in a constant temperature oven at 200℃ for 26h. The solid was then collected and the sample was washed several times by alternating centrifugation with deionized water and ethanol, and then dried in air at 90℃ for 14 hours. The dried precursor was annealed at 550℃ for 3h in a muffle furnace. When the muffle furnace naturally cooled to room temperature, z wt% Cu was obtained. x Ce y -ZnO, z=1.

[0048] Example 4

[0049] A loaded Cu x Ce y A method for preparing a ZnO nanosheet sensing material for a catalyst, the method comprising:

[0050] S1 Using a hydrothermal method, Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in 30 mL of deionized water, KOH was added to pH = 10, and the mixture was stirred with magnetic stirring for 30 min to obtain a mixture;

[0051] The mixture was transferred into a 50 mL autoclave and subjected to hydrothermal treatment at 200 °C for 12 h. The sample was then washed several times by alternating centrifugation with deionized water and ethanol to obtain a solid. The solid was dried in a vacuum oven at 80 °C for 12 h and calcined at 500 °C for 4 h to obtain Cu x Ce y catalyst, wherein x=0.5, y=0.5, and the molar ratio of Cu(NO3)2·3H2O to Ce(NO3)3·6H2O is selected according to the values ​​of x and y;

[0052] S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O (zinc acetate hydrate) were synthesized in an alkaline environment with a mass ratio of 0.015. In this embodiment, Cu x Ce y The catalyst and 3mmol zinc acetate hydrate were added to 20ml deionized water and stirred on a magnetic stirring table. 18mmol KOH was added to 20ml deionized water and placed on a magnetic stirring table for stirring. Under magnetic stirring, the KOH solution was quickly poured into the zinc acetate solution and continued to stir for 30min. It was then transferred to a 50ml PTFE-lined stainless steel autoclave and heated in a constant temperature oven at 180°C for 24h. The solid was then collected and the sample was washed several times by alternating centrifugation with deionized water and ethanol, and then dried in air at 80°C for 12 hours. The dried precursor was annealed in a muffle furnace at 500°C for 2h. When the muffle furnace naturally cooled to room temperature, z wt% Cu was obtained. x Ce y -ZnO, z=1.5.

[0053] Example 5

[0054] A loaded Cu x Ce y A method for preparing a ZnO nanosheet sensing material for a catalyst, the method comprising:

[0055] S1 Using a hydrothermal method, Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in 30 mL of deionized water, KOH was added to pH = 10, and the mixture was stirred with magnetic stirring for 30 min to obtain a mixture;

[0056] The mixture was transferred into a 50 mL autoclave and subjected to hydrothermal treatment at 180 ° C for 12 h. Then, the sample was washed several times by alternating centrifugation with deionized water and ethanol to obtain a solid. The obtained solid was dried in a vacuum oven at 80 ° C for 12 h and calcined at 500 ° C for 4 h to obtain Cu x Ce y catalyst, wherein x=0.7, y=0.3, and the molar ratio of Cu(NO3)2·3H2O to Ce(NO3)3·6H2O is selected according to the values ​​of x and y;

[0057] S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O (zinc acetate hydrate) were synthesized in an alkaline environment with a mass ratio of 0.02. In this embodiment, Cu x Ce y The catalyst and 3mmol zinc acetate hydrate were added to 20ml deionized water and stirred on a magnetic stirring table. 18mmol KOH was added to 20ml deionized water and placed on a magnetic stirring table for stirring. Under magnetic stirring, the KOH solution was quickly poured into the zinc acetate solution and continued to stir for 30min. It was then transferred to a 50ml PTFE-lined stainless steel autoclave and heated in a constant temperature oven at 180°C for 24h. The solid was then collected and the sample was washed several times by alternating centrifugation with deionized water and ethanol, and then dried in air at 80°C for 12 hours. The dried precursor was annealed in a muffle furnace at 500°C for 2h. When the muffle furnace naturally cooled to room temperature, z wt% Cu was obtained. x Ce y -ZnO, z=2.

[0058] Example 6

[0059] A loaded Cu x Ce y A method for preparing a ZnO nanosheet sensing material for a catalyst, the method comprising:

[0060] S1 Using a hydrothermal method, Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in 30 mL of deionized water, KOH was added to pH = 10, and the mixture was stirred with magnetic stirring for 30 min to obtain a mixture;

[0061] The mixture was transferred into a 50 mL autoclave and subjected to hydrothermal treatment at 180 ° C for 12 h. Then, the sample was washed several times by alternating centrifugation with deionized water and ethanol to obtain a solid. The obtained solid was dried in a vacuum oven at 80 ° C for 12 h and calcined at 500 ° C for 4 h to obtain Cu x Cey catalyst, where x=1, y=0, and the molar ratio of Cu(NO3)2·3H2O to Ce(NO3)3·6H2O is selected according to the values ​​of x and y; at this time, Cu x Ce y The catalyst was pure CuO.

[0062] S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O (zinc acetate hydrate) were synthesized in an alkaline environment with a mass ratio of 0.015. In this embodiment, Cu x Ce y The catalyst and 3mmol zinc acetate hydrate were added to 20ml deionized water and stirred on a magnetic stirring table. 18mmol KOH was added to 20ml deionized water and placed on a magnetic stirring table for stirring. Under magnetic stirring, the KOH solution was quickly poured into the zinc acetate solution and continued to stir for 30min. It was then transferred to a 50ml PTFE-lined stainless steel autoclave and heated in a constant temperature oven at 180°C for 24h. The solid was then collected and the sample was washed several times by alternating centrifugation with deionized water and ethanol, and then dried in air at 80°C for 12 hours. The dried precursor was annealed in a muffle furnace at 500°C for 2h. When the muffle furnace naturally cooled to room temperature, z wt% Cu was obtained. x Ce y -ZnO, z=1.5.

[0063] Figure 1 (a) provided in the embodiment of the present application is Cu x Ce y XRD pattern of the catalyst; (b) Cu x Ce y -XRD pattern of ZnO sample; Figure 1 In (a), it can be clearly seen that the diffraction peaks of all CuxCey samples are sharp and clear without any impurity peaks, indicating that the purity of each sample is high. Figure 1 It can be clearly seen in (b) that there are no additional diffraction peaks except the ZnO peak, indicating that the prepared ZnO and CuxCey-ZnO composites are also pure phases.

[0064] Figure 2 The scanning electron microscope (SEM) images provided in the examples of this application, (a) and (c) are pure ZnO, and (b) and (d) are 1% Cu 0.4 Ce 0.6 -ZnO; Figure 2 (a) and Figure 2In (c), it can be observed that the samples are all in the form of nanosheets and are evenly distributed without agglomeration. Figure 2 (b) shows that the pure-ZnO sample is in the shape of nanosheets with smooth surface. Figure 2 In (d), not only smooth nanosheets are observed, but also clustered particles are adsorbed on the surface of the nanosheets. This is exactly the Cu 0.4 Ce 0.6 The catalyst is attached to the surface of ZnO nanosheets.

[0065] Figure 3 (a) 1% Cu provided in the examples of this application 0.4 Ce 0.6 -Lattice image of ZnO, (b) 1% Cu 0.4 Ce 0.6 -HRTEM image of ZnO, (c) 1% Cu 0.4 Ce 0.6 -TEM image of ZnO and corresponding element mapping image, (d) 1% Cu 0.4 Ce 0.6 -SAED pattern of ZnO, (e) EDS element semi-quantitative analysis of 1% Cu0.4Ce0.6-ZnO; Figure 3 The three lattice fringes with spacing of 0.23nm, 0.26nm and 0.31nm in (a) represent the (111) crystal plane of CuO, the (002) crystal plane of ZnO and the (111) crystal plane of CeO2 respectively. 0.4 Ce 0.6 -ZnO has good crystallinity. Figure 3 (c) shows the distribution of four elements: Zn, O, Cu, and Ce. Zn and O elements are evenly distributed throughout the nanosheet, while Cu and Ce elements are located in the corresponding Figure 3 The spots in (b) are concentrated and distributed in small amounts on the nanosheets, indicating that the spots are Cu x Ce y Catalyst. Figure 3 As shown in (e), through semi-quantitative analysis of element content, the contents of four elements were obtained, which are basically consistent with the doping amount. The above results show that Cu x Ce y The catalyst was successfully incorporated into ZnO and attached to the ZnO surface.

[0066] Figure 4 The ZnO and 1% Cu provided in the examples of this application 0.4 Ce 0.6-XPS spectra of ZnO: (a) O 1s, (b) Ce 3d, (c) Cu 2p, (d) Zn 2p and (e) full scan spectrum; Figure 4 In (e), in addition to the C peak from the atmosphere, 1% Cu 0.4 Ce 0.6 -ZnO peaks related to Zn, O, Cu and Ce. Figure 4 In (a), the O 1s peak can be fitted by three peaks, which are the lattice oxygen (O L ), oxygen vacancies (O V ) and chemically adsorbed oxygen (O C ). Sample 1% Cu 0.4 Ce 0.6 -The proportion of vacant oxygen in ZnO is significantly higher than that in ZnO. The possible reason is that Cu x Ce y The incorporation of catalysts increases the oxygen vacancies of ZnO. Figure 4 The Ce 3d XPS fitting results v2 and u2 shown in (b) represent Ce 3+ ion peaks, and the other labels correspond to Ce 4+ ion peak. The characteristic peak of Cu appears in the Cu 2p 3 / 2 At 933.78eV in the region, Figure 4 (c) in the. Figure 4 The left-hand peak centered at 1021.89 eV in (d) can be classified as Zn 2p 3 / 2 Gaussian function part, while the other peak can be assigned to Zn 2p 1 / 2 Compared with the Zn characteristic peak of pure-ZnO sample, the 1% Cu 0.4 Ce 0.6 -ZnO's Zn characteristic peak shifted slightly to the left, indicating that the electrons in the material were transferred from Cu 0.4 Ce 0.6 The catalyst flows to the ZnO.

[0067] Figure 5 Typical N2 adsorption-desorption isotherms provided in the examples of this application: (a) pure-ZnO; (b) 1% Cu 0.4 Ce 0.6-ZnO; the average pore sizes of the two materials measured using the Barrett-Joyner-Halenda (BJH) method were 2.206 nm and 2.778 nm, respectively. The 1% Cu0.4Ce0.6-ZnO sample has a larger specific surface area, which facilitates the adsorption and diffusion of acetone and oxygen. Furthermore, the pore size of the sensing material influences the permeability of gas molecules during the sensing process. A suitable pore size facilitates the adsorption / desorption of gas molecules and reduces response / recovery time.

[0068] Figure 6 The embodiment of the present application provides (a) based on pure-ZnO, 0.5% Cu 0.4 Ce 0.6 -ZnO, 1% Cu 0.4 Ce 0.6 -ZnO, 1.5% Cu 0.4 Ce 0.6 -ZnO and 2% Cu 0.4 Ce 0.6 -ZnO sensor response to 50ppm acetone at 200-340℃; (b) based on 1% Cu x Ce y Response of the ZnO sensor to 50 ppm acetone at 260 °C. Figure 6 (a) shows the response values ​​of catalysts prepared with different ratios of Cu and Ce at 1wt% doping concentration at 260℃, 1% Cu0Ce1-ZnO, 1% Cu 0.3 Ce 0.7 -ZnO, 1% Cu 0.4 Ce 0.6 -ZnO, 1% Cu 0.5 Ce 0.5 -ZnO, 1% Cu 0.7 Ce 0.3 -ZnO, 1%Cu1Ce0-ZnO samples have sensitivities to 50ppm acetone at 260℃ of 32.2, 34.5, 37, 34.1, 26.6, and 23.5, respectively. It can be seen that Cu:Ce(x:y)=0.4:0.6, which means Cu 0.4 Ce 0.6 The catalyst-doped ZnO sample has the best response. Figure 6 In (b), pure-ZnO, 0.5% Cu 0.4 Ce 0.6 -ZnO, 1% Cu 0.4 Ce 0.6 -ZnO, 1.5% Cu 0.4 Ce 0.6 -ZnO and 2%Cu 0.4 Ce0.6 The response values ​​of the -ZnO samples at 260℃ were 11.0, 19.1, 37.0, 34.4, and 19.1, respectively. 0.4 Ce 0.6 The response value of the -ZnO sample (37.0) is 3.4 times higher than that of the pure-ZnO sample (11.0) at the same temperature. 0.4 Ce 0.6 The addition of catalyst reduces the optimal operating temperature from 300℃ to 260℃. The possible reason is that Cu 0.4 Ce 0.6 Catalysts can significantly reduce the activation energy required for chemical reactions, allowing chemical reactions to maintain higher reaction rates at lower temperatures.

Claims

1. A Cu-loaded x Ce y The method for preparing a ZnO nanosheet sensing material as a catalyst is characterized in that: The method comprises: S1 used the hydrothermal method to synthesize Cu(NO3)2·3H2O and Ce(NO3)3·6H2O under the alkaline condition of KOH, and obtained Cu after washing and drying. x Ce y Catalyst, wherein x=0, 0.3, 0.4, 0.5, 0.7, 1, y=1-x, and the molar ratio of Cu(NO3)2·3H2O to Ce(NO3)3·6H2O is selected according to the values ​​of x and y; S2 uses hydrothermal method to x Ce y The catalyst and Zn(CH3COO)2·2H2O were synthesized in the alkaline condition of potassium hydroxide according to the mass ratio, and the loaded Cu was obtained after washing and drying. x Ce y The mass ratios of the ZnO nanosheets of the catalyst are 0.005, 0.01, 0.015, and 0.

02.

2. The preparation method according to claim 1, characterized in that Said S1 specifically includes: Cu(NO3)2·3H2O and Ce(NO3)3·6H2O were dissolved in deionized water, and then KOH was added to pH = 10 and stirred with magnetic stirring to obtain a mixture; The mixture is transferred into an autoclave and subjected to a hydrothermal treatment at 180-200° C. for 10-12 h to obtain a synthetic compound; The synthesized product was washed by alternating centrifugation with deionized water and ethanol, and the obtained solid was dried in a vacuum oven at 80-90 °C for 12-14 h and calcined at 450-550 °C for 4-5 h to obtain Cu x Ce y catalyst.

3. The preparation method according to claim 1, characterized in that The S2 specifically includes: Cu x Ce y The catalyst and Zn(CH3COO)2·2H2O were added into deionized water to obtain a mixed solution, which was stirred on a magnetic stirring table; Add KOH to deionized water and stir on a magnetic stirring table to obtain a diluted KOH solution; Under magnetic stirring, pour the KOH solution into the mixed solution and continue stirring; Transferring the mixture to a stainless steel autoclave and heating it in a constant temperature oven at 180-200°C for 24-26 hours, collecting the solid, washing it with deionized water and ethanol by alternating centrifugation, and drying it in air at 80-90°C for 12-14 hours to obtain a dry precursor; The dried precursor was annealed in a muffle furnace at 500-550 °C for 2-3 h. When the muffle furnace was naturally cooled to room temperature, z wt% Cu was obtained. x Ce y -ZnO nanosheets, wherein z=0.5, 1, 1.5, 2.

4. A Cu-loaded x Ce y Catalyst ZnO nanosheet sensing material, characterized in that, The material is z wt% Cu x Ce y -ZnO nanosheets, wherein z=0.5, 1, 1.5, 2.

5. The z wt% Cu according to claim 4 x Ce y -Application of ZnO nanosheets in acetone detection.

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