Selective catalytic reduction of NO by propane on copper containing alumina pillared alpha-zirconium phosphates

Copper containing alumina pillared cr-zirconium phosphates with different c opper loadings, where copper was incorporated by ion exchange and by impreg nation, have been synthesized and characterized by using techniques such as XPS: UV-VIS spectroscopy, H-2-TPR and NO-TPD. The catalytic activity of th e synthesized materials in the selective catalytic reduction of NO using pr opane as a reducing agent in the presence of oxygen at 623-823 K has been e valuated. In the exchanged sample, copper is mainly present as isolated Cu2 + species, whereas the impregnated materials show copper to be present as s mall CuO clusters (not detectable by XRD) and a fraction as spinel-like str uctures within the alumina pillars. NO-TPD displayed a stronger interaction of NO molecules with the copper exchanged materials, because N2O and O-2 a re detected at temperatures higher than 773 K. Under the selected experimen tal conditions, the most active catalyst in the SCR of NO is the copper exc hanged catalyst, attaining conversions of NO close to 30% at 823 K. Moreove r, the competitiveness factor is high and the TOF number is 1.57x10(-4) mol ecules(NO) per second at(Cu) for the copper exchanged catalyst, this being comparable to that obtained with a Cu-ZSM-5 used as a reference. (C) 2001 E lsevier Science B.V. All rights reserved.