Understanding deactivation and reactivation of oxidation catalysts in hydrogen combustion engines

This research investigates the deactivation phenomena of oxidation catalysts in exhaust gas aftertreatment systems of hydrogen internal combustion engines ( H 2 -ICEs). The study observes an unexpected catalyst deactivation during extended cold start operation, which is partially reversible through lambda variation and increased exhaust temperatures. Light-off tests on a synthetic gas bench (SGB) reproduce these deactivation effects during the absence of carbon-based and nitrogen oxide emissions, showing that preconditioning with nitrogen oxide (NO) can aid partial reactivation. Additionally, conditioning at higher temperatures effectively prevents significant deactivation. The findings suggest that state-of-the-art oxidation catalysts from diesel engines are applicable for H 2 -ICEs if suitable engine operating modes are employed to mitigate catalyst deactivation .