Study on Pt/Al-MCM-41 for NO selective reduction by hydrogen

Al species can be introduced to the framework of Si-MCM-41 support by isomorphous substitution or wet impregnation and Brønsted acid sites can be created in Al-MCM-41. Pt catalysts supported on Si-MCM-41 and Al-MCM-41 are studied for the selective catalytic reduction of NO by hydrogen in excess oxygen. The introduction of Al species to MCM-41 at suitable Si/Al ratio shows great promotion effect on H2-SCR over Pt/MCM-41. Pt catalyst supported on Al-MCM-41 prepared by isomorphous substitution with the Si/Al ratio of 10 exhibits the best catalytic performance and ca. 80% NOx conversion as well as ca. 85% N2 selectivity can be achieved at 140 °C at high GHSV of 80,000 h−1. The H2-SCR reaction over Pt/Al-MCM-41, together with Pt/Si-MCM-41, are investigated by means of in situ DRIFT spectra and the existence of Brønsted acid sites in Al-MCM-41 is found to play a decisive role on the H2-SCR reaction pathway.