Promoting ethylene epoxidation on gold nanoclusters: self and CO induced O2 activation

Abstract

We have investigated the epoxidation of ethylene heterogeneously catalyzed by small gold nanoclusters based on density functional theory calculations. A promising trimolecular Langmuir–Hinshelwood mechanism via co-adsorbed ethylene- and CO-assisted reaction is addressed which provides significant insights into the fundamental catalytic mechanism for ethylene oxidation on small Au nanoclusters. O₂ activation is found to be a key step for accelerating ethylene oxidation. Especially, the coadsorbed neighboring CO is found to be more robust for promoting the activation of the O–O bond, resulting in the formation of epoxide and CO₂ due to the barrierless process. The new CO-promoted oxidation mechanism has also been clarified by the ab initio MD simulations.