Oxygen Atom Function: The Case of Methane Oxidation Mechanism to Synthesis Gas over a Pd Cluster

Abstract

A dimer model Pd 2 was established to study the adsorption of CH x (x = 1-4) and CH 4 dehydrogenation, as well as syngas formation using density functional theory (DFT) at the atomic level. Meanwhile, insight into understanding the role of the oxygen atom on the partial oxidation of methane (POM) was also calculated based on a trimer model of Pd 2 O. For the adsorption of CH x , results showed that the presence of an oxygen atom was a disadvantage to the adsorption of CH x (x = 1-3) species. For CH 4 dissociation, the process of CH 2 →CH + H was found to be the rate-limiting step (RSD) on both Pd 2 and Pd 2 O. H 2 was formed by the reaction of CH 2 + 2H→CH 2 + H 2 . For CO formation, it was primarily formed in the process of CH + O→CHO→CO + H on both the Pd 2 and the Pd 2 O catalyst. Thermodynamic and kinetic calculations revealed that formation and maintainance of the oxygen atom on the Pd surface could promote a POM reaction to achieve high H 2 and CO yield and selectivity. Our study provides a helpful understanding of the effect of an adsorbed oxygen atom on a POM reaction with a Pd catalyst.

Partial Oxidation of Methane to Methanol by Using Molecular O2 on Pd2+ Catalyst: An Insight from Theory

“…[28][29][30][31] A comparative study has been performed by Lang et al on free Au and Pd dimer cations for methane activation and catalytic ethylene formation. [32] Methane activation mechanism was studied by Meng et al [33] with Pd 2 dimer in an unsupported format indicating its catalytic efficacy towards methane conversion. Pd 2 decorated graphene [34] is also used for methane gas detection due to the strong interaction of Pd 2 with graphene.…”

“…on free Au and Pd dimer cations for methane activation and catalytic ethylene formation [32] . Methane activation mechanism was studied by Meng et al [33] . with Pd 2 dimer in an unsupported format indicating its catalytic efficacy towards methane conversion.…”