XAFS Study of Cu_I-Y and Cu_II-Y Interacting with CO and NO

Abstract
We report a study of the local copper environment in Cu^I-Y prepared by gas phase reaction of H-Y with CuCl and in Cu^II-Y prepared by conventional ion exchange with aqueous cupric salt. For the Cu^I-Y sample, the effect of the interaction with CO and NO will also been reported. XANES, UV-Vis and IR (NO dosed at 77 K) techniques prove that the copper species in the prepared samples have the desired oxidation state. Reduction of Cu^I-Y with CO leads to the formation of small copper clusters well identified by EXAFS, XANES and UV-Vis spectroscopies, while interaction with NO partially oxydate Cu^I to Cu^II. For both as prepared Cu^I-Y and Cu^II-Y samples EXAFS does not observe first shell Cu-Cu bond lengths, so excluding the presence of "so called" Cu-dimers in zeolites prepared following our methods.