Methane conversion into C2 hydrocarbons promoted by N2 over MoP (001) surface: A DFT investigation

Herein, DFT calculations were employed to investigate direct CH4 catalytic conversion over MoP (001) surface. On the surface, CH4 decomposes completely with H-2 formation, while C-2 hydrocarbon formation is unlikely. Fortunately, N-2 introduction would promote direct CH4 conversion into C-2 hydrocarbons. N-2* prefers to dissociate into two N* on the surface and complete CH4 decomposition is little influenced. While H-2 formation is suppressed and a portion of H* adatoms are abstracted by N* resulting in NH3. Two C* intermediates from CH4 decomposition combine into C-2* cluster with 1.35eV barrier. The two C of C-2* capture H alternatively producing C2H4 and C2H6 finally. The rate-determining step with 1.78eV barrier happens in NH3 formation. Moreover, desorption of products is favorable, and separation of C-2 hydrocarbons and NH3 is ease to achieve.