Cu/BEA catalysts for the selective catalytic reduction of engine-out NOx emissions: Experimental and kinetic investigations

Selective catalytic reduction (SCR) technology using NH₃ has shown to be the most promising method in the curbing of NOx and zeolite catalysts impregnated with copper has shown excellent SCR activity below 350 °C. However, most of the investigations are carried out with the artificial mixing combination of exhaust gases. The effect of real-time engine-out exhaust gas on NH₃-SCR activity has been scantily reported. In this paper, Cu/BEA zeolite with varying copper loading from 0.83 to 4.31 wt% has been used and the effect of engine-out exhaust emissions has been investigated. The catalysts were prepared using ion-exchange method and characterized using SEM, XRD, and BET analyses. The highest NOx reduction efficiency of 62.5 % was observed for 1.77 wt% Cu for which the Cu/Al ratio was close to unity. The kinetic modeling of the SCR activity was also carried out to validate the experimental results with an average error of 3.85 %.