A theoretical simulation on the catalytic oxidation of CO on Pt/graphene

Abstract

The catalytic oxidation of CO on Pt/X-graphene (X = “pri” for pristine- or “SV” for defective-graphene with a single vacancy) is investigated using the first-principles method based on density functional theory. In contrast to a Pt atom on pristine graphene, a vacancy defect in graphene strongly stabilizes a single Pt adatom and makes the Pt adatom more positively charged, which helps to weaken the CO adsorption and facilitates the O₂ adsorption, thus enhancing the activity for CO oxidation and alleviating the CO poisoning of the platinum catalysts. The CO oxidation reaction on Pt/SV-graphene has a low energy barrier (0.58 eV) by the Langmuir–Hinshelwood (LH) reaction (CO + O₂ → OOCO → CO₂ + O_ads) which is followed by the Eley–Rideal (ER) reaction with an energy barrier of 0.59 eV (CO + O_ads → CO₂). The results validate the reactivity of catalysts on the atomic-scale and initiate a clue for fabricating carbon-based catalysts with low cost and high activity.