RESUMO
Methane is the major component of natural gas, and it significantly contributes to global warming. In this study, we investigated methane activation on the α-Fe2O3(110) surface and M/α-Fe2O3(110) surfaces (M = Ag, Ir, Cu, or Co) using the density-functional theory (DFT) + U method. Our study shows that the Ir/α-Fe2O3(110) surface is a more effective catalyst for C-H bond activation than other catalyst surfaces. We have applied electron density difference (EDD), density of states (DOS), and Bader charge calculations to confirm the cooperative CHâ¯O and agostic interactions between CH4 and the Ir/α-Fe2O3(110) surface. To further modify the reactivity of the Ir/α-Fe2O3(110) surface towards methane activation, we conducted a study of the effect of oxygen vacancy (OV) on C-H activation and CH4 dehydrogenation. In the comparison of pristine α-Fe2O3(110), Ir/α-Fe2O3(110), and Ir/α-Fe2O3(110)-OV surfaces, the Ir/α-Fe2O3(110)-OV surface is the best in terms of CH4 adsorption energy and C-H bond elongation, whereas the Ir/α-Fe2O3(110) surface catalyst has the lowest C-H bond activation barrier for the CH4 molecule. The calculations indicate that the Ir/α-Fe2O3(110)-OV surface could be a candidate catalyst for CH4 dehydrogenation reactions.
