Tungsten Oxide Hydrogen Sensor

In industrial production, hydrogen, as a non-polluting green energy, has attracted wide attention. However, hydrogen is volatile, low ignition point, colorless and tasteless. It is a very dangerous flammable gas when it encounters open fire when its concentration in air is 4-75%. Therefore, the monitoring technology and research of gas sensitive materials for hydrogen play an important role in ensuring personal and property safety.

At present, metal oxides such as SnO₂, ZnO, Ti₂ and WO₃ are mainly used as sensitive materials for resistive semiconductor hydrogen sensors. Hydrogen sensor can detect the change of resistance value of sensitive material by semiconductor metal oxide to get the concentration of hydrogen. Tungsten oxide is a kind of N-type semiconductor material with excellent gas sensitivity. Therefore, some scholars use tungsten oxide to prepare hydrogen sensor. The process includes:

(1)The tungsten powder 20 is laid on the surface of the heating element; the substrate 10 is inverted on the surface of the tungsten powder 20. The substrate 10 can be made of high temperature resistant insulating materials such as quartz or ceramics. Before preparation, the substrate is first cut into a certain size (such as 3mm *15mm), then cleaned by ultrasonic cleaning solution such as alcohol and deionized water for 10 minutes, and then dried.

(2)Tungsten oxide nanowires 21 are grown on the substrate 10 by heating and holding in an aerobic environment, and tungsten powder 20 is attached to its surface, as shown in the figure.

(3)Substrate 10 was added at vacuum of 5 Pa, oxygen flow rate of 2.5 SCCM and argon flow rate of 200 sccm. The tungsten powder can be grown into tungsten oxide nano-flower structure by heating and heat preservation.

(4)Substrate is annealed by heating, and noble metal 30 is doped on tungsten oxide nanoflower structure 22 to obtain hydrogen sensor sensitive material, noble metal is one of platinum, gold, palladium, nickel and silver.

(4) The tungsten oxide nanoflower hydrogen sensor was fabricated by fabricating electrode 40 at both ends of the hydrogen sensor sensitive material and packaging the lead wire. The sensitive material of tungsten oxide hydrogen sensor prepared by the above process has nanostructure with definite morphology, large specific surface area, low cost and high sensitivity to hydrogen at lower temperature.

The sensitive material of tungsten oxide hydrogen sensor prepared by the above process has nanostructure with definite morphology, large specific surface area, low cost and high sensitivity to hydrogen at lower temperature.

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