Influence of Support Effects on CO Oxidation Kinetics on CO-Saturated Graphene-Supported Pt₁₃Nanoclusters

Abstract

We investigate support effects on the CO oxidation reaction on graphene−supported Pt 13 nanoclusters using first-principles density functional theory calculations. As CO adsorption on Pt 13 clusters is found to be substantially stronger than O adsorption, we focus on understanding CO oxidation kinetics on CO-saturated Pt nanoclusters. For this high CO coverage regime, the relevant kinetic mechanism is shown to proceed via a CO*-assisted activation of the O 2 molecule, resulting in the formation of an O*−O−C*−O transition state that eventually forms a CO 2 molecule and a chemisorbed O* species. By sampling this particular reaction pathway at various surface sites on unsupported Pt 13 nanoclusters as well as clusters bound at support point defects (vacancies/ divacancies) in graphene, we show that strong support−cluster interactions substantially reduce the CO oxidation reaction barrier, on average, by about 0.5 eV. Our results suggest that defect engineering of carbon supports could serve to enhance the catalytic activity of ultrasmall Pt nanoclusters, opening up another dimension for rational design of catalytic materials.

Remarkable enhancement of the specific activities of Pt catalysts to methanol oxidation through tuning the surface properties of supporting materials by fast microwave treatments

“…The above XPS results display that the content of carbonyl and carboxyl groups in Pt-RGO/PF-5 is highest among the three catalysts. Furthermore, the researches [7,10,11] indicate that the hydroxyl/phenolic groups and surface defects, besides as the preferred positions for Pt nucleation and distribution, may help to remove CO from Pt surface also. In Pt-RGO/PF-5, the existence of certain amount of sp 3 defects and enriched hydroxyl/phenolic groups is confirmed by the XPS data in Fig.…”

“…Meanwhile, the DFT simulations demonstrate that the bonding energy of Pt on the surface of oxygen-doped graphene is much higher than that on the undoped surface, which suggests the durability of Pt catalyst will be strengthened greatly on oxygen-doped graphene [9]. Some other theoretical studies also imply that the CO tolerance of Pt clusters can be possibly boosted through engineering the interaction between the Pt clusters and the specific defects on the graphene substrate [10,11].…”

A DFT study on the possibility of using a single Cu atom incorporated nitrogen‐doped graphene as a promising and highly active catalyst for oxidation of CO

“…. To further increase the catalytic performance and reduce activation energies, great progress has been also made by turning to “single atom catalysts” (SACs) by downsizing the catalyst to the atomic scale . However, the main problem is that these noble metal‐based catalysts are costly and usually need high temperature for efficient operation, which restrict their mass production.…”

Graphene-Based Heterogeneous Catalysis: Role of Graphene

“…In comparison, without the monovacancy in graphene, O2 does not adsorb on the Au clusters on pristine graphene, and thus the reactivity of the Au clusters supported on defective graphene was concluded to be defect-induced. Consequently, Ramasubramaniam and co-workers studied various Pt nanoclusters on graphene, with various defects giving similar conclusions with regard to CO oxidation reaction [46][47][48]. The enhanced adsorption of the nanoclusters due to the strong hybridization of the adsorbates with the dangling bonds of neighboring carbon atoms in the vicinity of the vacancy also holds for other nanoclusters, such as Fe13 [49], Al13 [49], Nin (n = 1-6) [50] and Con (n = 2, 4, 6) [51].…”