Ethylene Epoxidation Catalyzed by a Cu38 Nanoparticle: A Computational Study

The reaction mechanisms of ethylene epoxidation on a Cu-38 nanoparticle have been investigated by the first-principles calculations. The adsorption of C2H4 and O-2 as well as the coadsorption of O-2-C2H4 were also examined. Our results show that C2H4 and O-2 are likely to adsorb on the top (T) and hollow (H) sites with adsorption energies of -0.51 and -2.19 eV, respectively. The climbing image nudged elastic band method was carried out to illustrate the potential energy profile of the ethylene oxidation reaction. Both epoxide and acetaldehyde are formed by the Langmuir-Hinshelwood mechanism. The overall reaction for the formation of epoxide is predicted to be exothermic by 3.20-3.56 eV whereas it is exothermic by 3.83-4.31 eV for the formation of acetaldehyde. The Cu-38 nanoparticle exhibits higher catalytic properties and selectivity for the epoxide formation than the Au-38 nanoparticle.