New smart sensor can detect hazardous gases like explosive hydrogen & toxic nitrogen dioxide
New smart sensor can detect hazardous gases like explosive hydrogen & toxic nitrogen dioxide
A low -power, miniaturised technology could now detect leakage of traces of explosive hydrogen during its use as clean fuel as well as very small amounts of toxic nitrogen dioxide that many be emitted from burning of fossil fuels in gas stoves and kerosene heaters.
Hydrogen is emerging as a clean energy source with applications in fuel cells, transportation, and industry. However, it is also highly flammable and explosive even at low concentrations. Detecting hydrogen gas leaks reliably—especially at room temperature—is critical for ensuring safety in storage, transportation, and usage.
Traditional gas sensors often require high operating temperatures and consume significant energy, making them unsuitable for portable or on-chip applications. Therefore, there exists an urgent need for miniature, low-power, room-temperature hydrogen sensors that are sensitive, selective, and scalable.
Researchers at the School of Physics, IISER Thiruvananthapuram have been on the lookout for a sensor that could detect hydrogen at room temperature, even in trace quantities. The Project was supported by the Nano mission program of the Department of Science and Technology (DST).
Fig: Dr. Vinayak Kamble with a miniaturised sensor device chip made in the lab.
Their breakthrough came from interfaces formed on to one dimensional nickel oxide (NiO nanostructures like suspended nanobeams and nanowires functionalised with materials like nickel metal nanoparticles and/or Zinc oxide (ZnO) nanoparticles. Conventionally, NiO is a p-type semiconductor whereas ZnO is n-type.
When these materials are layered together into core-shell like nanostructures the boundary—the so-called pn junction (between NiO-ZnO) at the at the nanoscale, became exquisitely sensitive to changes in the environment.
A whiff of hydrogen, made the electrical conduction through the material change dramatically. The team consisting of Dr. Vinayak B Kamble, Associate Professor, IISER Thiruvananthapuram, Dr. Kusuma Urs MB, PhD student IISER Thiruvananthapuram Prof. Navakanta Bhat, Professor, CeNSE, IISc Bangalore and Mr. Krutikesh Sahu, CeNSE, IISc Bangalore pushed the idea further. They sculpted suspended nanobeams of nickel and nickel oxide with surgical precision using semiconductor fabrication tools. They also explored a more affordable route — growing ZnO/NiO junctions with simple solution methods. In both cases, it resulted in highly selective hydrogen detection at room temperature, with performance that left conventional sensors in the dust.
The series of studies published in Sensors and Actuators B and ACS Applied Electronic Materials journal and Small, addresses the need for fast, reliable, and energy-efficient gas sensors for strategic sectors such as clean energy, aerospace, and environmental monitoring. With the upcoming Internet of Things (IoT) technologies, sensors are not only used for safety and preventive measures but also used to have energy savvy environment for precise control of atmosphere.
Most commonly used hydrogen sensors currently are made of an expensive metal called Palladium (Pd) that has high affinity for hydrogen. However, it suffers from the problems like poor sensors signal recovery and use of Pd increases the cost of production. While Nickel belongs to the same chemical group in periodic table, thus has very similar chemical properties but price is 1/10th of Pd.
The developed sensors can help real-time hydrogen leak detection in fuel stations, vehicles, and industrial plants can prevent accidents and save lives, monitor volatile organic compounds (VOCs) in polluted urban environments, enable safer deployment of hydrogen as a clean energy source, aiding India’s green transition goals and being lightweight can be used in defence and aerospace.
With scalable fabrication already demonstrated, the research opens the door for a new generation of compact, efficient, and smart gas sensors that could become standard components in various safety and monitoring systems across industries.
Subsequent to this, the group has followed up the work using an oxide semiconductor array made up of NiO, CuO and ZnO based sensors to generate a dataset for AI assisted sensors development last year and currently it is advanced to ultra-low power and self-powered gas sensor devices made of atomically thin materials based heterostructure fabricated by CMOS compatible methods that are selective to either hydrogen in one case and toxic Nitrogen dioxide (NO2) in the other case, just by tailoring the deposition conditions.