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Researchers develop highly sensitive Hydrogen sensors

Date: 26 August 2019 Tags: Nanotechnology

Issue

 

A sensor that can detect hydrogen gas even when present at extremely low concentration of 1 part per million (ppm) has been developed by researchers at the Indian Institute of Technology (IIT) Jodhpur in collaboration with IIT Hyderabad.

 

Background

 

A hydrogen sensor is a gas detector that detects the presence of hydrogen. They contain micro-fabricated point-contact hydrogen sensors and are used to locate hydrogen leaks. They are considered low-cost, compact, durable, and easy to maintain as compared to conventional gas detecting instruments.

 

Details

  • The developed sensor has 30% sensitivity to detect hydrogen at 1 ppm concentration and as high as 74% sensitivity when the concentration of the gas is 100 ppm. It takes about 25 seconds to detect hydrogen.

  • Carbon nanofibres with minute pores are decorated on the zinc oxide semiconductor. The carbon nanofibres increase adsorption of oxygen on the surface of the semiconductor. More oxygen adsorbed would mean the number of electrons available for conduction is reduced leading to increased resistance.

  • Hydrogen reacts with the adsorbed oxygen (to produce water molecule) thereby making more electrons available for current conduction..

  • In the presence of hydrogen the resistance reduces drastically leading to more current flow, thus suggesting hydrogen gas leakage. When hydrogen is removed, the resistance goes back to the initial state.

  • The researchers are able to activate the chemical reaction at a relatively lower temperature as carbon nanofibres are used. The nanomaterial increases the surface area and acts as a catalyst to reduce the activation energy.

Importance of discovery

  • Hydrogen gas is a pollution-free, renewable source of energy and is seen as a fuel of choice in the future. However, hydrogen is highly explosive and flammable in nature.

  • It is a small molecule and can readily mix with air but detecting hydrogen gas leakage become quite difficult particularly as it is colourless and tasteless.

  • A sensor that can detect hydrogen even when present at very low concentration becomes essential. And this is where the current work becomes important.