Silver-modified micron tubular indium oxide nitrogen dioxide gas-sensitive material and preparation method thereof

[0027] Example 1

[0028] A method of preparing a tubular indium oxide modified nitrogen dioxide sensitive material silver microns:

[0029] (1) 0.179g 1,4- terephthalic acid was dissolved in 60mL N, N- dimethylformamide (DMF) and stirred until the solution became clear, and then added 0.383g of indium nitrate hydrate (In (NO 3 ) 3 · 3h 2O) dispersion, ultrasonic until dissolved. The above solution was transferred to the autoclave, and the autoclave was placed in an oven at 100 deg.] C synthesis reaction heat 4h, centrifuged, washed and dried in the precursor 24h 80 deg.] C to obtain a tubular indium microns.

[0030] The tubular microns of indium oxide prepared in (2) in step (1) to give the precursor was heated to 450 deg.] C at a heating rate of 5 ℃ / min, and calcined 4h, to give a tubular indium microns.

[0031] (3) Weigh 80mg step (2) (0.288 mmol) of indium oxide prepared tubular microns dispersed in 100mL of silver nitrate (silver nitrate concentration of 0.5mmol / L) concentration of 1.5mL of sodium citrate (sodium citrate of 30mmol / L) mixed solution, stirred for 30min until fully dissolved to obtain a solution a, then solution a was added dropwise 6mL temperature of 0 ℃ sodium borohydride (concentration of sodium borohydride was 10mmol / L) was continuously stirred after 5min, the reaction was allowed to stand 2h, to give a dark brown suspension was then centrifuged and washed three times with deionized water and ethanol, and dried at 80 deg.] C 24h to give a silver indium oxide-modified tubular microns dioxide sensitive material. This XRD pattern of the tubular microns indium oxide modified nitrogen dioxide sensitive material silver obtained in Preparation Example See figure 1;From figure 1 As can be seen in the XRD patterns of the samples prepared using the present invention 2θ = 21.4 °, 30.6 °, 35.5 °, 37.8 °, 51.0 °, 60.5 ° and a diffraction peak corresponding to international standard diffraction data card (In 2 O 3 ) JPCDS No.06-0416 consistent, 2θ = 38.2 ° and 44.3 ° and a diffraction peak corresponding to international standard diffraction data card (Ag) JPCDS No.87-0597 match, and no other hetero peaks, indicating successful silver in the load 2 O 3 surface.

[0032] This SEM view of a tubular indium silver microns dioxide sensitive material obtained in Example MODIFIED see figure 2;From figure 2 As can be seen in samples prepared using the present invention, a length of 6 ~ 7μm hexagonal tubular stacked together.

[0033] The tubular micron silver indium oxide modified nitrogen dioxide gas-sensitive material obtained in Preparation Example of the present embodiment of the gas sensing different concentrations of nitrogen dioxide gas, see graph in response image 3 ,From image 3 As can be seen in NO 2 Concentration increases the sensitivity of the silver modified microns tubular indium oxide sensor gradually increases, and when concentrations as low as 0.5ppm, the sensitivity was 6.5, showing good NO 2 Gas sensing performance.

[0034] Preparation of silver modified embodiment of the present loading of the tubular indium microns nitrogen dioxide gas sensing material of silver was 6.3%.

[0035] Example 2

[0036] (1) terephthalic acid was dissolved 0.45g 1,4- 80mL N, N- dimethylformamide (DMF) and stirred until the solution became clear, then adding 0.96g of indium nitrate hydrate (In (NO 3 ) 3 · 3h 2 O) dispersion, ultrasonic until dissolved. The above solution was transferred to the autoclave, and the autoclave was placed in an oven at 100 deg.] C synthesis reaction heat 14H, centrifuged, washed and dried in the precursor 24h 80 deg.] C to obtain a tubular indium microns.

[0037] (2) Preparation of step (1) obtained indium oxide precursor tubular microns at a ramp rate 2 ℃ / min heating to 475 ℃, calcined 5h, to obtain a tubular indium microns.

[0038] (3) Weigh 80mg step (2) of indium oxide prepared tubular microns dispersed in 90mL of silver nitrate (silver nitrate concentration of 0.5mmol / L) 2mL with sodium citrate (sodium citrate concentration of 30mmol / L) the mixed solution was stirred for 30min until fully dissolved to obtain a solution a, then solution a was added dropwise 5.7mL temperature of 0 ℃ sodium borohydride (concentration of sodium borohydride was 10mmol / L) was continuously stirred 5min, static the reaction set 2h, to give a dark brown suspension was then centrifuged and washed three times with deionized water and ethanol, and dried at 80 deg.] C 24h to give a silver indium oxide modified nitrogen dioxide microns tubular gas-sensitive material, silver loading is 5.7%.

[0039] Example 3

[0040] (1) terephthalic acid was dissolved 0.21g 1,4- 70mL N, N- dimethylformamide (DMF) and stirred until the solution became clear, then adding 0.45g of indium nitrate hydrate (In (NO 3 ) 3 · 3h 2 O) dispersion, ultrasonic until dissolved. The above solution was transferred to the autoclave, and the autoclave was placed in an oven at 90 deg.] C synthesis reaction heat 24h, centrifuged, washed and dried in the precursor 24h 80 deg.] C to obtain a tubular indium microns.

[0041] (2) Preparation of step (1) obtained in the tubular indium oxide precursor was heated to 500 microns deg.] C at a heating rate of 4 ℃ / min, and calcined 4h, to give a tubular indium microns.

[0042] (3) Weigh 80mg step (2) obtained in Preparation microns tubular indium oxide dispersed in 70mL of silver nitrate (silver nitrate concentration of 0.5mmol / L) and 1.5mL of sodium citrate (sodium citrate concentration of 30mmol / L ) of the mixed solution was stirred for 30min until fully dissolved to obtain a solution a, then solution a was added dropwise 4.7mL temperature sodium borohydride (sodium borohydride concentration is 10mmol / L) was continuously stirred 0 ℃ after 5min, the reaction was allowed to stand 2h, to give a dark brown suspension was then centrifuged and washed three times with deionized water and ethanol, and dried at 80 deg.] C 24h to give a silver indium oxide modified nitrogen dioxide microns tubular gas-sensitive material, the silver loading 4.5%.