Co-catalytic effect of Al-Cr pillared montmorillonite as a new SCR catalytic support

Abstract

BACKGROUND It is of great interest to use pillared clay (PILC) as a cheap support for a selective catalytic reduction (SCR) catalyst. Al-Cr pillared clay (AlCr-PILC) has high thermal stability due to the introduction of polycations of Al. As a support, AlCr-PILC may show a co-catalytic effect in SCR processes because chromium oxide itself is an active SCR catalyst. The aim of this work is to investigate the potential of AlCr-PILC as a new low temperature SCR catalyst support. RESULTS A series of AlCr-PILC with Al:Cr molar ratio varying from 0:4 to 4:0 were successfully synthesized to support manganese and cerium active phase. MnCe/AlCr(2:2)-PILC exhibited the highest NOx conversion close to 100% at 200–300 °C, and more than 90% N2 selectively over a wide temperature window of 140–300 °C. The catalytic activity of MnCe/AlCr-PILC in terms of both NOx conversion and N2 selectivity is much higher than those of MnCe/Al-PILC, MnCe/Cr-PILC, AlCr-PILC, and the simple mixed MnCeAlCr, indicating the co-catalytic effect of AlCr-PILC support. CONCLUSION AlCr-PILC is a very promising low-temperature SCR catalyst support. The XRD, XPS, and H2-TPR measurements prove that the co-catalytic effect of AlCr-PILC occurred via the strong interaction between MnCe and the AlCr-PILC support. © 2016 Society of Chemical Industry