Characterizing the Exchange Sites in Cu-SSZ-13 and Cu-SAPO-34 during the Selective Catalytic Reduction of NO_x with NH3: A Detailed Study from First Principles

摘要

Nitrogen oxides (NOx) are one of the main air pollutants present in the exhaust from diesel engines, which are popular for vehicle transportation due to their efficiency and durability [1]. However, NOx emission control is a challenge in these "lean-burn" engines [2]. As is well known, the selective catalytic reduction (SCR) of NOx with NH3 is a reaction between the NO, NO2, and O2 oxidants and the NH3 reductant to form N2 and H2O. Copperexchanged small-pore zeolites, such as Cu-SSZ-13 and Cu-SAPO-34, display excellent catalytic activity and hydrothermal stability in SCR of NOx, as has been shown in a number of recent studies [3, 4]. 6 membered rings, 4 membered rings and 8 membered rings build these zeolites, as shown in Figure 1.