Tungsten trioxide nanobelts are one-dimensional tungsten oxide nano structural materials, with high specific surface area and vertical axial size, etc., thus to show higher sensitivity and selectivity and lower working temperature in the field of gas sensor, and has bright future in the applications of high performance NOx gas sensor. Tungsten trioxide (WO₃) is an n-type semiconductor transition metal oxides, because of its special properties to be widely applied in electrochromism, photochromism, gas sensor, photocatalyst and other fields; As a kind of superior performance, low cost of gas sensitive material, it has good sensitivity to NOx, SO₂ and NH₃, CO and other gases, and therefore is considered to be one of the most development prospect of gas sensitive materials. 

 

The preparation steps of accurate orientation tungsten trioxide nanobelts NOx gas sensor are as follows: 

1. Prepare tungsten hexachloride solution, and adjust the molar concentration to 0.003~0.012M; 

(2) Generate accurate orientation of tungsten trioxide nanowires by hydrothermal synthesis method, and carry out centrifugal separation, repeated washing by deionized water and ethanol, drying; 

3. Ultrasonic mixing tungsten trioxide nanowires with anhydrous ethanol and terpineol to prepare sensitive material slurry; 

4. Using the spin coating, printing or pulling method to coat sensitive slurry onto the molybdenum interdigital electrodes coated of aluminium oxide substrate, placed at room temperature for half an hour, and then carry out heat treatment to finally get accurate orientation tungsten trioxide nanobelts NOx gas sensor; while The process of heat treatment conditions are temperature of 400~600°C, sintering in a program sintering furnace by a certain heating rate, the time is 1~2 hours.

 

Study has indicated that this kind of accurate orientation tungsten trioxide nanobelts NOx gas sensor has greatly improved sensitivity, and show beneficial effects of high sensitivity and selectivity, low working temperature, low power consumption in detecting low concentration NOx.