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

Copper containing alumina pillared cr-zirconium phosphates with different copper loadings, where copper was incorporated by ion exchange and by impregnation, have been synthesized and characterized by using techniques such as XPS: UV-VIS spectroscopy, H-2-TPR and NO-TPD. The catalytic activity of the synthesized materials in the selective catalytic reduction of NO using propane as a reducing agent in the presence of oxygen at 623-823 K has been evaluated. In the exchanged sample, copper is mainly present as isolated Cu2+ species, whereas the impregnated materials show copper to be present as small CuO clusters (not detectable by XRD) and a fraction as spinel-like structures within the alumina pillars. NO-TPD displayed a stronger interaction of NO molecules with the copper exchanged materials, because N2O and O-2 are detected at temperatures higher than 773 K. Under the selected experimental conditions, the most active catalyst in the SCR of NO is the copper exchanged catalyst, attaining conversions of NO close to 30% at 823 K. Moreover, the competitiveness factor is high and the TOF number is 1.57x10(-4) molecules(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 Elsevier Science B.V. All rights reserved.