Multi sites vs single site for catalytic combustion of methane over Co3O4(110): A first-principles kinetic Monte Carlo study

Abstract

AbstractSingle-atom catalysts have been applied in many processes recently. The difference of their kinetic behavior compared to the traditional heterogeneous catalysts has not been extensively discussed yet. Herein a complete catalytic cycle of CH4 combustion assuming to be confined at isolated single sites of the Co3O4(110) surface is computationally compared with that on multi sites. The macroscopic kinetic behaviors of CH4 combustion on Co3O4(110) is systematically and quantitatively compared between those on the single site and multi sites utilizing kinetic Monte Carlo simulations upon the energetic information from the PBE + <I>U</I> calculation and statistic mechanics. The key factors governing the kinetics of CH4 combustion are disclosed for both the catalytic cycles respectively following the single-site and multi-site mechanisms. It is found that cooperation of multi active sites can promote the activity of complete CH4 combustions substantially in comparison to separated single-site catalyst whereas the confinement of active sites could regulate the selectivity of CH4 oxidation. The quantitative understanding of catalytic mechanism paves the way to improve the activity and selectivity for CH4 oxidation.