Tungsten Oxide Nanowire Gas Sensing Materials Preparation by Hydrothermal Method

Compared with the traditional tungsten oxide materials, tungsten oxide nanowires have larger specific surface area, which have a wide range of application prospects in gas sensor, electroluminescence, photoluminescence, conductivity electrode and photocatalysis. Especially in the application field of oxide semiconductor gas sensor, tungsten oxide nanowires not only have large specific surface area, but also have larger surface activity and stronger adsorption capacity, which accelerates the reaction with gas, thus greatly improving the sensitivity and further reducing the working temperature of the sensor.

The preparation of tungsten oxide nanowire gas sensing materials by hydrothermal method includes the following steps:

(1) 1.0-1.5g sodium tungstate was dissolved in 24-30ml deionized water and stirred in ice water bath for 1h to form colorless and transparent sodium tungstate solution;

(2) Slowly add 3.5-4ml of 3m / L hydrochloric acid to the solution in (1) and continuously stir for 0.5h, then slowly add 4.6-5ml of 0.3m/l oxalic acid and continue to stir for 0.5h to form pale yellow micelle solution;

(3) Transfer 28-30 ml (2) of micelle solution into a 50 ml reactor, add 25-30 g of potassium sulphate and stir evenly, then heat treat in water at 180 ℃ for 12-144 hours;

(4) Tungsten oxide nanowires were prepared by repeatedly washing the hydrothermal products in (3) with deionized water and anhydrous ethanol and drying them in air at 65 ℃.

2.The tungsten oxide nanowire ammonia sensor is prepared by the following methods:

(1) Preparation of gas sensitive material slurry
Taking the tungsten oxide nanowire as the main material, ethyl cellulose and terpineol as the adhesive, and adding glass material to enhance the adhesion between the sensitive material and the alumina substrate, the sensitive material slurry is prepared by mixing and stirring the above materials evenly.

(2) Element sintering
The slurry in (1) is screen printed on the alumina substrate with silver electrode and lead wire, dried in air at 70 ℃, sintered in a box furnace at 300-500 ℃ for 1-2 hours, and a tungsten oxide nanowire ammonia sensor element is prepared.

(3) Component aging
The ammonia sensor sintered in (2) above is aged at 300 ℃ for 72 hours to be tested.

The preparation method and steps of hydrothermal method are very simple, the process parameters in the preparation process are easy to control, the energy consumption in the whole preparation process is very small, the prepared tungsten oxide nanowires have large specific surface area, and the tungsten oxide ammonia sensitive detector prepared by the nanowires has high sensitivity, good repeatability and high stability for low concentration ammonia gas (1-100ppm).

• < Prev
• Next >