Ethane (CH3CH3), one of the primary components of shale gas, is an attractive candidate for the production of syngas (CO + H2) and ethylene (CH2CH2) via its oxidative C-C and selective C-H bond cleavage, respectively. Understanding the origin of selective conversion is essential to design a good catalyst for CH3CH3 activations. Herein, we combined density functional theory (DFT) calculations with kinetic Monte Carlo (KMC) simulations to shed light on the mechanisms of the oxidative C-H and C-C bond cleavage of CH3CH3 on the PtNi(111) model surface using CO2 as an oxidant. Our calculations show that PtNi is selective to CO via direct CO2 dissociation and the contribution from CH3CH3 via the C-C bond scission of oxygenated (*C2HyO) intermediates. By comparison the CH2CH2 selectivity via the selective C-H bond scission of *CH3CH3, is much lower. The kinetic analysis suggests that the selectivity of PtNi toward syngas can be enhanced by facilitating the formation of key *C2HyO intermediates; while the selectivity toward CH2CH2 can be promoted mainly by accelerating the C-H bond scission of *CH3CH2 to produce *CH2CH2.

Mechanistic study of oxidative C-H and C-C bond cleavage of ethane

255th National Meeting (2018)

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