Formation of C1 oxygenates by Activation of Methane on B, N Co-Doped Graphene Surface Decorated by Oxygen Pre-Covered Ir13 Cluster: A First Principles Study.

The environmentally friendly conversion of methane to value-added chemicals is studied by ab-initio calculations. We focus on the adsorption and dehydrogenation of methane were investigated on Ir13 cluster supported by boron nitrogen co-doped graphene (BNG). We show that the BNG-Ir13 cluster with low oxygen coverage exhibits more negative adsorption energy of methane (-0.44 eV) and lower activation energy barrier for its dissociation (1.24 eV for the second dehydrogenation step) compared to the cluster with high oxygen coverage. Next, assuming abundant CH3 and CH2 species due to a proper temperature control preventing further dehydrogenation, we study competitive C-O coupling reactions leading to the formation of value-added chemicals. The activation energy barriers for the formation of methanol and formaldehyde are on BNG-Ir13 are once again lower at a lower oxygen coverage. Furthermore, we study hydrogen recombination and confirm that H2 molecules can be formed on these surfaces. Based on these findings, the low-oxygen-coverage BNG-Ir13 cluster emerges as a promising catalyst for the selective conversion of methane to methanol and formaldehyde, as well as for hydrogen production.