Ethane oxidative dehydrogenation mechanism on MoO₃ (010) surface: A first-principle study using on-site Coulomb correction

We applied the PBE+U method to investigate the mechanism of ethane oxidative dehydrogenation reaction (ODH) on the MoO3(010) surface. Our systematic study shows that ethylene generation is energetically a favorable pathway from the horizontal C2H6 adsorption. The vertical adsorption of C2H6 leads to the aldehyde generation along the a-oxidative dehydrogenation pathway (alpha-ODH). However, along the beta-ODH pathway, the ethylene oxide formation is identified as the final product but may transform to produce ethylene from the CH2CH2O intermediate. The formation energy of oxygen vacancy (delta E-f(v)) of all types of oxygen atoms of the MoO3(010) surface are characterized with the on-site Coulomb correction, being reasonably consistent with the HSE results. The U correction leads to the mismatching between the d(z)(2) orbital of Mo and p(z) orbitals of the terminal oxygen and consequently weakens the Mo-O chemical bond. Therefore, the weakened Mo-O chemical bond can increase the possibility of forming the oxygenated species, such as aldehyde and ethylene oxide.