A new concept of combined NH3-CO-SCR system for efficient NO reduction in excess oxygen

A new concept of a novel “dual bed” configuration of NH3 and CO-SCR catalytic system (NH3-CO-SCR), comprising Cu/Beta as top catalyst bed for NH3-SCR and WO3/Ir/SiO2 as bottom catalyst bed for CO-SCR, is described in this article. The combined catalytic system provides high NO reduction efficiency, in a broad temperature range (160–600 °C). The NO conversion over the combined catalytic system reached up to 98% between 280 and 320 °C, as compared to the system using only Cu/Beta or WO3/Ir/SiO2 with sole NH3 or CO as reductant. Furthermore, the combined catalytic system shows high NO reduction efficiency even in the presence of lower concentrations of NH3 and CO. Thus, the potential advantage of this combined system is that it can effectively reduce NO during situations when NH3 and CO concentration is expected to fluctuate in real driving conditions which could potentially lead to NH3 and CO slip issues.