Tungsten Trioxide Film---Hydrogen Sensor

According to some reports, Delft University of Technology has invented a new type of hydrogen sensor which is made of tungsten trioxide film and combined with the high resistance and the ability to use platinum catalyst to sense the hydrogen. It can sense a hydrogen concentration of 1 pppm at near room temperature.

 When the hydrogen concentration exceeds 100 pppm, the reaction time is less than 1 second.

Hydrogen is one of the potential alternatives for fossil fuels. Due to its high flammability, we need to develop hydrogen sensor if we want to develop the hydrogen energy economy. However, hydrogen sensors still have a big problem in temperature control. The sensor can only work at high temperatures. Besides, the sensitivity is low and the reaction time is slow.

The biggest difference between new hydrogen sensor developed by Delft University of Technology and other sensors is that the new hydrogen can be used at room temperature.

Firstly, researchers adopt the method of pulsed laser deposition to deposit on the substrate layer by layer. It can produce the tungsten trioxide film which is only 9nm thick. Then the platinum is dropped on top of the tungsten trioxide film, which acts as a catalyst to separate the hydrogen molecules into a single hydrogen atom. The atom enters into the crystal lattice of the tungsten trioxide, and slowly converts it from an insulator to a metal.

The tungsten trioxide film is exposed to different conditions, such as normal air, mixed hydrogen environment and vacuum. The experiment result shows that the resistance and sample color of the tungsten trioxide film change when they are exposed to hydrogen. But they will return to the initial state in normal air.

Because this tungsten trioxide film is compatible with current semiconductor technology, the new hydrogen sensor has the potential for mass production. The research team at Delft University of Technology is preparing to apply for a patent for this technology.

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