A study conducted by Masashi Harada et al. has been published in Chemical Engineering Journal.
The performance of fuel cells is governed by the behavior of water generated during operation. In recent years, catalyst layers using mesoporous carbon (a carbon material with nanometer-sized pores) have been developed to control internal water behavior. However, it has been difficult to capture the distribution of water within the catalyst layer—particularly within the mesopores—at the nanoscale during operation.
In this study, we employed small-angle neutron scattering (SANS) to directly observe the state of water within the mesopores under operating conditions while varying humidity and current. By controlling the contrast between carbon and water in neutron scattering through adjustment of the hydrogen isotope ratio in the humidified gas, we demonstrated that three states of water in the pores—“adsorption,” “condensation,” and “evaporation”—can be distinguished. Furthermore, we revealed that water behavior varies not only with humidity and current but also with the position along the gas flow path. These findings are expected to contribute to the development of future high-performance fuel cells.
Title : Water Generation in the Mesoporous Catalyst Layers of Automotive Fuel Cells: Insights from Operando Small-Angle Neutron Scattering
Authors: Harada, M., Hasegawa, N., Kato, A., Higuchi, Y., Kato, S., Song, F., Iwase, H., Takata, S.
Journal Name: Chemical Engineering Journal
Published: December 1, 2025
https://doi.org/10.1016/j.cej.2025.170753