(Left) The conceptual drawing of the heater-integrated coplanar hydrogen sensor structure. The palladium nanowire is stably suspended in air, even with its thickness of 20 nm. (Right) A performance graph of the hydrogen sensor operating within 0.6 seconds for hydrogen at a concentration of 0.1 to 4%. Credit: ACS Nano (2023). DOI: 10.1021/acsnano.3c06806
As the diffusion of eco-friendly hydrogen cars increases, the importance of hydrogen sensors also increases. In particular, developing technology to detect hydrogen leaks within a second remains a difficult task. As a result, the development of the world’s first hydrogen sensor meeting the U.S. Department of Energy’s performance standards has become a hot topic.
A KAIST team led by Dr. Min-Seung Jo from Professor Jun-Bo Yoon’s team at the Department of Electrical and Electronics Engineering successfully achieved all of its desired performance indicators, meeting globally recognized standards through collaboration with the electromagnetic energetic materials research team. at the Basic Materials Research Center of Hyundai Motor Company and Professor Min-Ho Seo of Pusan National University.
On January 10, the research group announced that the world’s first hydrogen sensor with a speed of less than 0.6 seconds had been developed.
To ensure faster and more stable hydrogen sensing technology than existing commercialized hydrogen sensors, the KAIST team began developing a next-generation hydrogen sensor in 2021 in collaboration with Hyundai Motor Company. They succeeded after two years of development. The research is published in ACS Nano.
Existing research on hydrogen sensors has mainly focused on sensing materials, such as catalytic treatments or palladium (Pd) alloy materials, which are widely used in hydrogen sensors. Although these studies showed excellent performance with some performance indicators, they did not achieve all desired performance indicators and commercialization was limited due to the difficulty of batch processing.
Electron microscopy of the hydrogen sensor integrated into the coplanar heater. (Left) photo of the entire device. (Top right) Pd nanowire suspended in air. (Bottom right) Cross section of a Pd nanowire. Credit: ACS Nano (2023). DOI: 10.1021/acsnano.3c06806
To overcome this problem, the research team developed a sensor that meets all performance indicators by combining independent micro/nanostructure design and processing technology based on pure palladium materials.
Furthermore, considering future mass production, pure metallic materials with fewer material restrictions were used instead of synthetic materials, and a next-generation hydrogen sensor was developed that could be mass-produced on the basis of a semiconductor batch process.
The developed device is a differential coplanar device in which the heating and sensing materials are integrated side by side on the same plane to overcome the uneven temperature distribution of existing gas sensors, in which the heater, insulating layer and Detection materials are stacked vertically.
Palladium nanomaterial, which is a sensing material, has a completely buoyant structure and is exposed to air from below, thereby maximizing the reaction area with gas to ensure rapid reaction speed. Additionally, the palladium sensing material operates at a uniform temperature throughout the area. The research team was able to ensure fast operating speed, broad detection concentration, and insensitivity to temperature and humidity by precisely controlling the temperature-sensitive detection performance.
The team packaged the fabricated device with a Bluetooth module to create an integrated system that wirelessly detects hydrogen leaks within a second. Unlike existing high-performance optical hydrogen sensors, this one is highly portable and can be used in various applications using hydrogen energy.
(Left) Real-time hydrogen detection results using the hydrogen sensor integrated with the integrated coplanar heater and embedded in a wireless communication and mobile phone application. (Middle) Controls the LED flashing cycle based on the hydrogen concentration level. (Right) Results of confirming 1-second detection performance in a real-time hydrogen leak demonstration. Credit: ACS Nano (2023). DOI: 10.1021/acsnano.3c06806
Dr. Min-Seung Jo, who led the research, said: “The results of this research are of significant value because not only do they operate at high speeds by surpassing the performance limits of existing hydrogen sensors, but they also guarantee the necessary reliability and stability. for real-world use and can be used in various places such as automobiles, hydrogen charging stations and homes.
He also revealed his future plans, saying: “Through the commercialization of this hydrogen sensor technology, I would like to help advance the safe and environmentally friendly use of hydrogen energy. »
The research team is currently working with Hyundai Motor Company to fabricate the device at wafer scale and then mount it on a vehicle module to further verify the sensing performance and durability.
More information:
Min-Seung Jo et al, Ultrafast (∼0.6 s), robust and highly linear hydrogen detection up to 10% using fully suspended pure Pd nanowires, ACS Nano (2023). DOI: 10.1021/acsnano.3c06806
Provided by Korea Advanced Institute of Science and Technology (KAIST)
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