A hydrogen sensor that works at room temperature

July 6, 2018, Delft University of Technology
Credit: Delft University of Technology

Researchers at TU Delft have developed a highly sensitive and versatile hydrogen sensor that works at room temperature. The sensor is made of a thin layer of a material called tungsten trioxide.

Hydrogen has the potential to replace fossil fuels as the most important energy carrier in the near future. It has the highest energy per mass of any fuel and can be produced sustainably. However, it is also flammable, making sensors that can detect it an absolute necessity for the transition to a . Various types of hydrogen sensors already exist, but most of these sensors require high temperatures in order to function. Researchers at TU Delft have now developed a sensor that works at room temperature.

A crystalline material

The new sensor is made of a material called tungsten trioxide. One of the properties of tungsten trioxide is that its contains a lot of open spaces. As a result, the material can easily be doped, which is the practice of changing its electronic properties by introducing other atoms.

"By itself, tungsten trioxide is an insulator," said Giordano Mattoni, the lead author. "But when you dope it, you add electronic charges which turn the material into a different colour and also gradually change it into a metal. We wanted to try to dope thin films of tungsten trioxide with hydrogen gas to see if it could function as a sensor."

It turns out that it can. The researchers first created thin sheets of tungsten trioxide using a method called pulsed laser deposition. That way, they were able to deposit single layers of the material onto a substrate one by one. "Using this method, we created sheets of tungsten trioxide with a thickness of only nine nanometres," said Mattoni.

Room temperature operation

The researchers then put platinum droplets on top of the thin layers of tungsten trioxide. Platinum is well known to function as a catalyst which separates the hydrogen molecules into single hydrogen atoms. These atoms, the researchers observed, could then enter the of trioxide, slowly turning it from an insulator into a metal. "This means that, by measuring the resistance of the material, we can determine the amount of hydrogen present in the environment," Mattoni explained.

What sets this new sensor apart from most other is that it can be used at . "It is also much more sensitive than commercially available products and it can be reused in a matter of minutes," Mattoni added. "Also, by increasing or decreasing the of the sensor, the sensitivity range can be tuned for different applications."

Finally, the thin film nature and the compatibility with current semiconductor technologies allow the sensor to be scaled up towards mass production. Mattoni and TU Delft have filed a patent application for this novel sensing technology.

Explore further: Scientists build hydrogen sensor readable with the naked eye

More information: Giordano Mattoni et al. Single-Crystal Pt-Decorated WO3 Ultrathin Films: A Platform for Sub-ppm Hydrogen Sensing at Room Temperature, ACS Applied Nano Materials (2018). DOI: 10.1021/acsanm.8b00627

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5 comments

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loneislander
not rated yet Jul 06, 2018
Can anyone say what the following clip added to this story: "Hydrogen has the potential to replace fossil fuels as the most important energy carrier in the near future. It has the highest energy per mass of any fuel and can be produced sustainably. However, it is also flammable, making sensors that can detect it an absolute necessity for the transition to a hydrogen economy."?

A room temperature hydrogen sensor is a breakthrough irrespective of there ever going to be, or not be, an hydrogen economy. In particular, because we have to expend so much energy to separate hydrogen which can't be gotten back when we burn it, entropy is a bitch.
betterexists
not rated yet Jul 06, 2018
Can anyone say what the following clip added to this story.

https://phys.org/...ncy.html
carbon_unit
not rated yet Jul 06, 2018
loneislander: An alternate version might change the last sentence to something like
Because hydrogen is a colorless, odorless, tasteless and highly combustible gas which leaks readily due to it small molecular size, hydrogen poses a significant risk of fire/explosion if the plumbing which contains it is less than perfect. If a hydrogen economy comes to pass, there will be great need for inexpensive hydrogen detectors to mitigate this risk.
ZoeBell
Jul 06, 2018
This comment has been removed by a moderator.
holoman
not rated yet Jul 09, 2018
Okay, brain drains !

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