Mechanistic study of hydrothermally aged Cu/SSZ-13 catalysts for ammonia-SCR

•Increasing ageing temperatures up to 800°C cause no significant change in the location of Cu ions.•Gradual dealumination occurred over all ageing temperatures between 700 and 850°C.•At 700–800°C, loss of crystallinity became significant and copper sites became more reducible.•Low-temperature NH3 oxidation takes place on sites in 6MRs.•High-temperature NH3 oxidation takes place on more than one site.