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11/18/2019 HYU News > Academics > 이달의연구자

Title

[Researcher of the Month] Highly Sensitive, Power Efficient H2 and H2S Gas Sensors Adoptable to Mobile Forms

Professor Choa Yong-Ho (Department of Materials Science and Chemical Engineering)

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http://www.hanyang.ac.kr/surl/KAZCB

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Professor Choa Yong-Ho (Department of Materials Science and Chemical Engineering) has written a thesis titled, "Facile tilted sputtering process (TSP) for enhanced H2S gas response over selectively loading Pt nanoparticles on SnO2 thin films," which depicts the development of highly sensitive gas sensors that are driven by ultra low power (ULP). Having began the research with the development of gas sensors of various mechanisms through the syntheses of gas inductors in 2010, it was developed through the Fundamental R&D Program for Core Technology of Materials and the NanoMaterial Technology Development Program hosted by the Ministry of Trade, Industry and Energy, and the National Research Foundation of Korea (NRF). Around 10 patents were registered, and some portion of the technology was transferred to Gastron.
Professor Choa Yong-Ho (Department of Materials Science and Chemical Engineering) anticipates the development of various gas sensors including hydrogen and hydrogen sulfide sensors to apply to real life.

A typical gas sensor has a heater built in in order to increase its sensing capabilities. However, this has resulted in an increase in power consumption that has limited mobile application and the manufacturing of small sized gas sensors. The research team led by Choa developed ultra low power gas sensors driven in room temperature of 25C, which satisfies the rising need of ultra low power, as well as highly sensitive hydrogen (H2) and hydrogen sulfide (H2S) gas sensors.
 
While the use of natural gas is increasing day by day, the current state of homes and industrial settings are increasingly prone to gas explosion and pollution. Methods such as the ability to sense gas leakage, the ability to measure and record gas concentration, the recognition of it, and the ability to control and warn of the various pollutants discharged from combustion apparatus are in dire need as of now -- since it is impossible to detect or distinguish the type of gas or the dangers that they entail through only the human sensory organs.
 
H2S gases are generated as a by-product of a petroleum purification process or in the manufacturing processes of glue, leather, and raw fluorescent material. The gas sensor that detects hydrogen sulfide can stop the interior breathing of cells, paralyze central nerves, and show symptoms of asphyxiation, due to its strong toxicity. Therefore, H2S gas requires successive monitoring in order to achieve local industrial development and to create a safe atmosphere. The international world is responding by actively implementing regulations regarding industrial atmosphere control and pollution emissions.
 
The following images (from left) are an integrated wireless smart sensor module, a gas detection graph, and the sensing graph on a mobile display.
(Photo courtesy of Choa)

In addition, the world is rapidly shifting its focus to hydrogen energy as our interest for low-pollution alternative energy is on the rise, along with the growing concern for environmental pollution and exhaustion of fossil energy. However, hydrogen has drawbacks in itself in that it goes through spontaneous combustion or explosion when combined with oxygen in the air. Until a system is developed, hydrogen fuel can only be widely used when the system promptly detects the leakage of hydrogen and prevents the outflow of it in the first place by devising a safety measure in the production, storage, and usage of hydrogen.
 
Choa’s research team have created a chemical resistance sensor that changes according to gas concentration, as well as a thermochemistry sensor that selectively reacts to target gas to generate heat in the reaction and applies this to the sensing. The thermochemistry sensor has the benefit of minimizing power consumption thanks to its form which signals itself generating voltage.
 
 
 
Kim Hyun-soo    -    soosoupkimmy@hanyang.ac.kr
Photos by Lee Hyeon-seon
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