A reactive molecular dynamics simulation study of methane oxidation assisted by platinum/graphene-based catalysts

Abstract

Platinum-decorated functionalized graphene sheet (Pt@FGS) is a promising nanoparticle additive for catalytic fuel combustion. In this study, four cases involving pure methane oxidation and methane oxidation in the presence of various Pt/graphene-based nanoparticle catalysts are investigated using the reactive force field molecular dynamics (ReaxFF MD) simulations to reveal catalytic mechanisms and kinetics of methane oxidation. The results demonstrate that Pt@FGS is the most effective catalyst among all the nanoparticle candidates involved in this research. Compared with pure methane oxidation, the combination of Pt and FGS in the Pt@FGS reaction improves the catalytic activity by dramatically lowering the activation energy by approximately 73%. Additionally, the catalytic methane oxidation is initiated by the cleavage of CH bond and the production of hydroxyl. The observed H transfer process suggests that enhanced dehydrogenation of Pt@FGS and interatomic exchanges activate the catalytic cycle and dominate the catalytic process. Moreover, FGS can be further oxidized mostly at the edge of the sheet to increase the functionality. In summary, this research sheds light on the catalytic mechanisms for enhanced fuel combustion in the presence of Pt@FGS.