Changing active sites in Cu-CHA catalysts: deNOx selectivity as a function of the preparation method

► Changing copper environment and NH3-SCR activity in Cu-CHA samples as a function of preparation technique. ► Conventional wet ion exchange (WIE) and one-pot synthesis gives very-active catalysts for SCR of NO. ► Location of isolated copper in the vicinity of d6r sub-unit appears crucial to high-activity. ► CVD-IE produces secondary phase of Cu-aluminate which produces undesired N2O.