Hydrocarbon selective catalytic reduction of NO over Cu/Fe-pillared clays: Diffuse reflectance infrared spectroscopy studies

The selective catalytic reduction (SCR) of NO was investigated by in situ diffuse reflectance infrared spectroscopy (DRIFTS) over catalysts based on iron-pillared clays (Fe-PILC) ion exchanged with copper. It was studied the influence of either total amount of metal or copper distribution as Cu2+ and CuO on the surface, with the aim to give a general idea of the reaction mechanism for this kind of catalysts. It was noted that the reaction intermediates were nitrates, nitrites, acetate, and CxHyOzN species. At low temperatures, bands corresponding to the vibration of CC and COO− groups were observed for those samples with CuO in their structure, confirming that its presence improves the NO yield to N2.

It was studied the influence of copper distribution as Cu2+ and CuO on the surface of a Fe-PILC, with the aim to give a general idea of the reaction mechanism.Figure optionsDownload high-quality image (40 K)Download as PowerPoint slideResearch highlights▶ The first step for C3H6–SCR over Cu–Fe-PILC is NO oxidation. ▶ The second step is propene adsorption on active sites. ▶ The third step is propene oxidation, promoted by CuO aggregates, to CxHyOz. ▶ Next, CxHyOz reacts with NOx to yield acetates or CxHyOzN compounds. ▶ Finally, the later species form N2, CO2 and H2O as final products.