Researchers at Hyderabad and Jodhpur IITs have developed materials that can be used as sensors to detect hydrogen gas leaks. Since the gas is highly inflammable, the dangers of a leak too are real.

Hydrogen gas leaks, especially in an industrial environment, can lead to major accidents.

Detection of hydrogen gas leaks is considered a difficult task.

‘Hydrogen economy’

The IIT researchers have come up with semiconductor materials that can help in the development of reliable hydrogen gas sensors and lead to quick response capability, both in domestic and industrial environments. Scientists see this development as a step  towards a ‘hydrogen economy’.

A paper, co- authoured by Chandra Shekhar Sharma and Mahesh Kumar, and Vijendra Singh Bhati, Akash Nathani and Adarsh Nigam, has been published in the journal Sensors and Actuators. 

Chandra Shekhar Sharma of IIT Hyderabad said the importance of hydrogen as a primary energy source is growing. However, there are two problems associated with the gas — one is the complicated production issues and the other is the difficulty of detecting the gas.

“We have made progress in solving the second,” he added.

What makes a hydrogen leak dangerous is the low ignition energy of the gas and the explosive range (4-75 per cent).

Human beings  cannot sense hydrogen because it is colourless and odourless and, therefore, tools, especially those with sensors, are a must, said Mahesh Kumar of  IIT Jodhpur.

Types of hydrogen sensors

Many kinds of hydrogen sensors are being studied, including optical, electrochemical and electrical. Electrical sensors, in particular resistive sensors, are the closest to practicality due to their low cost, simple design and good sensitivity.

Nano particles (one hundred thousand times thinner than human hair) of zinc oxide (metal oxide semiconductor) have good hydrogen sensing properties.

The research team has improved the sensitivity of this material even further.

The researchers loaded the zinc oxide nanoparticles onto nanofibres of carbon and found that this results in a sensing response of nearly 74 per cent compared to 44.5 per cent in pure ZnO nanoparticles.

Nanofibres are extremely thin fibres that are bundled to look like cotton candy.

The team spun the nanofibres by a process called electrospinning, in which a polymer solution is electrically charged and ejected through a spinneret under a high-voltage electric field.

In this work, the researchers used a special polymer blend to obtain nanofibres of the polymer, which was then converted to carbon nanofibres by heating. This leads to zinc oxide deposits on the surface of the nanofibres.

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