Structural characterization of adsorbed dinitrogen on copper-ion-exchanged mordenite through xafs measurements

X-ray absorption spectroscopy has been used to elucidate the structure of copper-ion-exchanged mordenite in the calcined state. Information about the chemical state and the local structural geometry of the exchanged copper ion has been elucidated by studing the XANES and EX AFS spectroscopy. These findings show spectral features which would be assigned to Cu(OH)2-like species at 298 K, to OuO phase at 473 K, and to Cu(I) species at 673 K. Cu(I) species is present in an amorphous-like or micro cry stalline structure. It is found that N2 molecules are adsorbed strongly on Cu(I) species and give a strong absorption band at 2299 cm"1 in infrared spectroscopy. The analysis of the EX AFS for the adsorbed N2 is performed, and demonstrates that this state is a bent type.