Method for preparing ZnO@ZIF-8 compound, ZnO@ZIF-8 compound and gas sensor

A gas-sensing sensor and compound technology, applied in instruments, scientific instruments, coatings, etc., can solve the problems of poor stability, low sensitivity, easy poisoning, etc., and achieve the effect of improving gas selectivity, stability and service life

Inactive Publication Date: 2019-07-05
CHONGQING UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] Aiming at the problems of low sensitivity, poor stability, and easy poisoning failure, the present invention provides a method for preparing micron-sized capsule-shaped ZnO@ZIF-8 complexes, and the micron-sized capsulated ZnO@ZIF-8 complexes prepared by this method It has the advantages of good selectivity, high stability and anti-poisoning

Method used

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  • Method for preparing ZnO@ZIF-8 compound, ZnO@ZIF-8 compound and gas sensor
  • Method for preparing ZnO@ZIF-8 compound, ZnO@ZIF-8 compound and gas sensor
  • Method for preparing ZnO@ZIF-8 compound, ZnO@ZIF-8 compound and gas sensor

Examples

Experimental program
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Effect test

Embodiment 1

[0031] Example 1: Preparation of ZnO@ZIF-8 complex

[0032] The following chemical reagents used were purchased from the market: zinc acetate dihydrate (ZnAc 2 2H 2 O); zinc nitrate hexahydrate (Zn(NO 3 ) 2 ·6H 2 O); methanol; sodium hydroxide (NaOH); hexamethylenetetramine (HMTA); N,N-dimethylformamide (DMF); 2-methylimidazole; absolute ethanol; deionized water.

[0033] The specific process of preparing ZnO@ZIF-8 complex is as follows.

[0034] First, prepare zinc acetate in methanol and sodium hydroxide in methanol. Weigh 0.24g zinc acetate dihydrate (ZnAc 2 2H 2 (0) and 0.43g sodium hydroxide (NaOH), were dissolved in 10ml of absolute methanol respectively, placed on a magnetic stirrer for magnetic stirring for 10min, then NaOH was slowly poured into the ZnAc 2 2H 2 In the O solution, the final product containing Zn(OH) 2 of the suspension.

[0035] Next, the glass substrate with a size of 2cm×2cm was placed in absolute ethanol and deionized water for 5min, ultr...

Embodiment 2

[0042] Example 2: Gas selectivity of ZnO@ZIF-8 composite

[0043] The final product prepared in Example 1—the ZnO@ZIF-8 complex was used to prepare the sensor.

[0044] Feed 50ppm of CO and H into the sensor respectively 2 、CH 4 、C 2 h 6 、C 2 h 4 、C 2 h 2 Gas, measure its sensitivity value Ra / Rg, where Ra is the resistance before ventilation, and Rg is the resistance after gas is passed).

[0045] The result is as Image 6 shown. As shown in the figure, the ZnO@ZIF-8 complex is 2 especially sensitive, while H 2 It is one of the dissolved fault characteristic gases in power transformer oil, so this ZnO@ZIF-8 composite can be used for the detection of dissolved fault characteristic gases in transformer oil.

Embodiment 3

[0046] Example 3: ZnO@ZIF-8 complex on H 2 sensitive stability

[0047] The intermediate product (i.e., ZnO core) and the final product (i.e., ZnO@ZIF-8 complex) of Example 1 were prepared into sensors respectively, and these two sensors were detected on the gas sensing test platform against 50ppm H 2 Sensitivity value of , detected every 5 days.

[0048] The result is as Figure 7 As shown, the sensor prepared using the ZnO@ZIF-8 composite maintained a good resistance to H over a 30-day test period. 2 Sensitive stability, while the sensor made of pure ZnO material is sensitive to H 2 The sensitivity decreased significantly with the increase of time.

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Abstract

Provided is a method for preparing a ZnO@ZIF-8 compound. The method includes the steps that 1, a zinc acetatemethanol solution and a sodium hydroxidemethanol solution are mixed to obtain suspension liquid containing Zn(OH)2, and then a glass substrate is soaked in the suspension liquid containing Zn(OH)2 for 5 minutes; 2, the soaked glass substrate is taken out and then is subjected to annealing for 30 minutes at 350 DEG C; 3, a zinc nitrateaqueous solution and a hexamethylenetetramineaqueous solution are mixed to form a mixed solution; 4, the glass substrate processed in step 2 and the mixedsolution obtained in steps 3 are placed in a high-pressure reactor and are subjected to hydrothermal reaction at 100 DEG C, so that zinc oxide grows on the glass substrate ; 5, a mixed solution of N,N-dimethylformamide and deionized water is prepared, 2-methylimidazole is added, and the mixture is stirred to be uniform to form a mixed liquid; 6, the glass substrate in step 4 is placed into a linerof the reactor, the mixed liquid obtained in step 5 is poured into the liner, hydrothermal reaction is conducted at 80 DEG C for 3 hours so that ZIF-8 can grow on the surface of zinc oxide, and the ZnO@ZIF-8 compound is obtained.

Description

technical field [0001] The present invention relates to a method for preparing a ZnO@ZIF-8 compound, a ZnO@ZIF-8 compound and a gas sensor, especially a method for preparing a micron-sized capsule-like ZnO@ZIF-8 compound, the ZnO@ZIF-8 compound Object and gas sensors can be used in the field of electrical equipment insulation on-line monitoring and fault diagnosis. Background technique [0002] Metal oxide semiconductor materials have the advantages of being sensitive to a variety of gases, low cost, and fast response, so they have become a research hotspot today. ZnO is one of the most representative metal oxides. Although pure zinc oxide is generally sensitive to a variety of gases, its response value is not high, its selectivity is poor, and its detection limit is low. Modified treatment. [0003] Metal-organic frameworks (MOFs) are a class of crystalline porous materials with a periodic network structure formed by self-assembly of inorganic metal centers (metal ions or...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C03C17/28G01N27/12
CPCC03C17/28C03C2217/29C03C2218/111G01N27/125
Inventor 陈伟根王飞鹏崔芳万福朱承治毛航银黄正勇谭亚雄王有元杜林李剑周湶
Owner CHONGQING UNIV
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