Influence of the Operating Parameters on the Selective Catalytic Reduction of NO with Hydrocarbons Using Cu-Ion-Exchanged Titanium-Pillared Interlayer Clays (Ti-PILCs)

Recently, the suitability of titanium-pillared clays as catalyst supports has been explored, because of their interesting physical properties. In this work, we have studied the influence of the operating parameters on the selective catalytic reduction of NO by propylene over a characterized Cu-ionexchanged titanium-pillared interlayer clays (Ti-PILCs). NO reduction was favored by a C3H6 concentration increase when the combustion of this hydrocarbon was complete. NO reduction was observed to be promoted by a small amount of oxygen when the oxygen concentration was less than that required for complete C3H6 combustion (critical oxygen concentration). For oxygen concentrations higher than this critical value, the effect of oxygen concentration was different, depending on the reaction temperature, compared to that corresponding to the maximum NO conversion. Two different rate-limiting steps exist in the SCR-NO, when Cu-Ti-PILCs are used as catalysts, depending on the reaction temperature: surface reaction control at low temperatures and external mass-transfer control at high temperatures.