Cu ion-exchanged titanium pillared clays (Cu-TiPILCs) were studied as catalysts for selective catalytic reduction (SCR) of NO by propylene. The results showed that the catalysts were porous materials with copper species located in the interlayer. The catalytic activity of Cu-TiPILCs was found to depend on the calcination temperature of the TiPILC and the amount of copper loading. The optimum copper loading was about 6 wt %, which gave the higher activity at low temperatures. The effect of both ceria and silver as promoters on the activity and hydrothermal stability of Cu-TiPILCs for SCR of NO with C3H6 under oxidizing and wet conditions was investigated. The addition of silver resulted in a small shift of the maximum of NO conversion toward higher temperatures. However, the addition of ceria as a cocation to Cu-TiPILC catalysts lightly decreased the reversible inhibition by water occurring under catalytic conditions in a temperature range between 200 and 275 degreesC. Ceria species have the ability to suppress the agglomeration of Cu2+ species and stabilize the catalyst when water is present in the feed stream. It was verified that a small amount of ceria (similar to1 wt %) can provide the maximum promotion effect.