The remarkable performance of a single iridium atom supported on hematite for methane activation: a density functional theory study.

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-Fe 2 O 3 (110) surface and M/α-Fe 2 O 3 (110) surfaces (M = Ag, Ir, Cu, or Co) using the density-functional theory (DFT) + U method. Our study shows that the Ir/α-Fe 2 O 3 (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 CH⋯O and agostic interactions between CH 4 and the Ir/α-Fe 2 O 3 (110) surface. To further modify the reactivity of the Ir/α-Fe 2 O 3 (110) surface towards methane activation, we conducted a study of the effect of oxygen vacancy (O V ) on C-H activation and CH 4 dehydrogenation. In the comparison of pristine α-Fe 2 O 3 (110), Ir/α-Fe 2 O 3 (110), and Ir/α-Fe 2 O 3 (110)-O V surfaces, the Ir/α-Fe 2 O 3 (110)-O V surface is the best in terms of CH 4 adsorption energy and C-H bond elongation, whereas the Ir/α-Fe 2 O 3 (110) surface catalyst has the lowest C-H bond activation barrier for the CH 4 molecule. The calculations indicate that the Ir/α-Fe 2 O 3 (110)-O V surface could be a candidate catalyst for CH 4 dehydrogenation reactions.