Appraising Multinuclear Cu Structure Formation in Cu-CHA SCR Catalysts via Low-T Dry CO Oxidation with Modulated NH Solvation.

Cu ions (ZCu (OH) , Z Cu ) are regarded as the NH -SCR (SCR=selective catalytic reduction) active site precursors of Cu-exchanged chabazite (CHA) which is among the best available catalysts for the abatement of NO from Diesel engines. During SCR operation, copper sites undergo reduction (Reduction half-cycle, RHC: Cu →Cu ) and oxidation (Oxidaton half-cycle, OHC: Cu →Cu ) semi cycles, whose associated mechanisms are still debated. We recently proposed CO oxidation to CO as an effective method to probe the formation of multinuclear Cu species as the initial low-T RHC step.