OXIDATION OF Cu-SSZ-13 AND ACTIVE SITE CHARACTERIZATION FOR METHANE CONVERSION

摘要

The oxidation/reduction mechanisms of Cu exchanged SSZ-13 zeolite has been of great interest to understand reactions such as methane conversion to methanol or selective catalytic reduction of NOx. The dioxygen treatment of copper containing zeolites at temperatures in the range of 300 - 450 °C is known to result in extraframework oxygen - copper bond formation which can activate methane at 150 - 200 °C. We recently observed methanol production on Cu-SSZ-13 with yields as high as 31 μmol methanol/g_(zeolite) at a temperature of 200 °C. The state of the copper ions after O2 treatment of Cu-SSZ-13 zeolite has been investigated using in-situ synchrotron XRD, ex-situ Raman, ex-situ UV-vis experiments and thermogravimetric analysis (TGA) to elucidate the structure and composition of the active site for methanol formation.