“Listening” for hydrogen may be the key to detection at any temperature

As hydrogen becomes an increasingly promising renewable energy alternative to fossil fuels, the demand for accurate hydrogen sensors also increases. Traditional sensors use hydrogen-sensitive materials that rely on the sorption of hydrogen molecules. However, these sensors become less effective over time and do not perform in low temperatures.

The emerging field of acoustic topological materials offers a solution. These materials use periodic structures to control the topological features of sound as it moves through space. Duan et al. designed a first-of-its-kind acoustic topological sensor for hydrogen detection that can work at any temperature.

“Due to its colorlessness, odorlessness, flammability, and explosibility, hydrogen sensors are required in various fields in which hydrogen is used,” said author Li Fan. “This could be as an energy source, in batteries, or hydrogen-driving vehicles, for example.”

The authors’ sensor combines two different types of 3D-printed phononic crystals, aligned to produce the desired acoustic topological features at the interface between them.

“When a mixed gas with different hydrogen concentrations is input into the sensor, the density and specific heat, and thus the sound velocity, of the mixed gas are related to the concentration of hydrogen. Because the frequency of the interface state is influenced by the sound velocity in the sensor, we can detect the concentration of hydrogen by measuring the interface state,” said Fan.

The sensor listens as the sound topology shifts and infers the hydrogen content from the change. The same principles of applied acoustic topology can utilized to detect other gases.

Source: “A low-temperature hydrogen sensor based on an acoustic topological material,” by Zhen-dong Duan, Zi-Jian Zhou, Shu Zhu, Wen-Qing Diao, Zheng Liu, Li Fan, Shu-Yi Zhang, Li-Ping Cheng, Xiao-Dong Xu, Applied Physics Letters (2023). The article can be accessed at https://doi.org/10.1063/5.0162618 .