Effect of Heat Treatment on the Formation of Copper Active Centers Obtained by the Interaction of Copper Chloride with H-Mordenite

Abstract

The effect of temperature conditions on the formation of copper active sites obtained by solid state ion exchange between copper chloride and H-mordenite zeolite using X-ray absorption spectroscopy in near-threshold (XANES) and extended (EXAFS) spectral regions behind the copper K-edge measured in in-situ conditions of the reaction at temperatures varying from room temperature to 400°C. The analysis of the spectra performed using direct calculations of CuK-XANES and taking into account anharmonic corrections for CuK-EXAFS fitting enables us to establish that there is no ion exchange up to 200°C and copper remains in the CuCl state. An increase in the temperature higher 200°C leads to the incorporation of copper atoms to the zeolite framework.