First-principles study of oxidation state and coordination of Cu-Dimers in Cu-SSZ-13 during methane-to-methanol reaction conditions

Direct methane-to-methanol conversion is a dream reaction which presently can be realized via a three-step cycle over copper-exchanged zeolites; an activation phase, a reaction phase, and finally an extraction phase. Here we use ab initio molecular dynamics and first-principles thermodynamics to examine oxidation state and coordination of Cu-dimers in Cu-SSZ-13 under relevant experimental conditions. A multitude of Cu2(HxOy) clusters are exergonic at room temperature. However, at the relevant reaction conditions only Cu2O and Cu2(OH) remain as thermodynamically stable structures for the activation and extraction phase, respectively