Active site characterization of CuSCR catalysts under H2-ICE exhaust gas conditions

Hydrogen engines (H2-ICEs) can be a bridge technology for reducing carbon emissions until fuel cells and battery systems reach full commercial readiness. Because they share similar components to diesel, allowing the use of existing components and infrastructure, making them easier to scale. At the same time, H2-ICEs can deliver diesel-like performance, durability, and reliability while maintaining the advantage of fast refueling. Lean-burn H2-ICE offers enhanced thermal efficiency while minimizing engine-out NOx emissions. One of the main challenges under lean-burn H2-ICE operation is the significant drop in turbo-out temperatures combined with higher water content and the possible presence of unburned hydrogen in the exhaust. This study examines the impact of excess water and residual hydrogen on Cu-SCR durability, active site chemistry, and stability for the case with and without an upstream oxidation catalyst, through aging tests at 450 °C and 550 °C. Changes in Cu redox cycles were assessed through site quantification using CO titration techniques to determine the influence of excess H2O and H2 on catalyst performance and aging.