Greatly enhanced adsorption and catalytic activity of Au and Pt clusters on defective graphene

Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore.
The Journal of Chemical Physics (Impact Factor: 2.95). 05/2010; 132(19):194704. DOI: 10.1063/1.3427246
Source: PubMed


We report an investigation on CO oxidation catalyzed by Au(8) or Pt(4) clusters on defective graphene using first-principles approach based on density functional theory. The simplest single-carbon-vacancy defect on graphene was found to play an essential role in the catalyzed chemical reaction of CO oxidation. When supported on a defect-free graphene sheet, the reaction barrier of CO oxidation catalyzed by Au(8) (Pt(4)) clusters was estimated to be around 3.0 eV (0.5 eV), and when adsorbed on defective graphene, the reaction barrier was greatly reduced to around 0.2 eV (0.13 eV).

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Available from: Yuan Ping Feng, Oct 05, 2015
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    • "Changing the structure of carbon matrix may be a convenient solution. For example, carbon nanowalls are proposed to be separate Pt supports for fuel cells [4], and the adsorption and catalytic ability of Pt nanoparticles were found enhanced on defective graphene [5]. Recently, a new carbon allotrope named graphdiyne, which was theoretically predicted more than 20 years ago [6] [7], has been successfully synthesized on the surface of copper via a cross-coupling 0008-6223/Ó 2015 Elsevier Ltd. "
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    ABSTRACT: At present, Pt nanoparticle catalysts in fuel cells suffer from aggregation and loss of chemical activity. In this work, graphdiyne, which has natural porous structure, was proposed as substrate with high adsorption ability to stabilize Pt nanoparticles. Using multiscale calculations by ab initio method and the ReaxFF potential, geometry optimizations, molecular dynamics simulations, Metropolis Monte Carlo simulations and minimum energy paths calculations were performed to investigate the adsorption energy and the rates of desorption and migration of Pt nanoparticles on graphdiyne and graphene. According to the comparison between graphdiyne and graphene, it was found that the high adsorption ability of graphdiyne can avoid Pt nanoparticle migration and aggregation on substrate. Then, simulations indicated the potential catalytic ability of graphdiyne-Pt-nanoparticle system to the oxygen reduction reaction in fuel cells. In summary, graphdiyne should be an excellent material to replace graphite or amorphous carbon matrix for stabilizing Pt nanoparticle catalysts.
    Carbon 05/2015; 86. DOI:10.1016/j.carbon.2015.02.014 · 6.20 Impact Factor
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    • "embedded graphene, which shows that these embedded external elements can convert the inert graphene supports to highly active catalysts. Furthermore, it has been experimentally [49] [50] and theoretically [51] [52] shown that metal subnanoclusters on graphene have very high catalytic activity. Inspired by the above findings, this work has investigated the potential of embedding transition-metals into monolayer MoS 2 as a route for making its basal plane catalytically active, by which we may significantly extend the application of this distinctive 2D material . "
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    ABSTRACT: Based on first-principles calculations, the CO catalytic oxidation on the Fe-embedded monolayer MoS2 (Fe-MoS2) was investigated. It is found that Fe atom can be strongly constrained at the S vacancy of monolayer MoS2 with a high diffusion barrier. The CO oxidation reaction proceeds via a two-step mechanism with the highest energy barrier of 0.51 eV, which is started by the Langmuir–Hinshelwood reaction and ended by the Eley–Rideal reaction. The high catalytic activity of the Fe-MoS2 system may be attributed to the charge transfer and the orbital hybridization between the adsorbates and the Fe atom. This study proposes that embedding transition-metals is a promising way for making the basal plane of monolayer MoS2 catalytically active.
    Applied Surface Science 02/2015; 328. DOI:10.1016/j.apsusc.2014.12.024 · 2.71 Impact Factor
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    ABSTRACT: Adsorption energies and stable configurations of CO on the Pt clusters are investigated using the first-principles density-functional theory method. It is found that the adsorption of CO on the top site of the Pt4 cluster is more stable than that on the bridge site. The atomic charges are unevenly distributed within the charged Pt4 cluster, and the structural positions of the Pt atoms determine their charge states and therefore their activity. A systematic study on the effects of electrons and holes doping in the Pt4 clusters suggest an effective method to prevent the CO poisoning through regulating the total charge in Pt4 clusters. The graphene-based substrate is an ideal catalyst support, which makes the Pt catalyst lose electron and weakens the CO adsorption. The results would be of great importance for designing high active nanoscale Pt catalysts used for fuel cells.
    Journal of Nanoparticle Research 05/2012; 14(5). DOI:10.1007/s11051-012-0844-2 · 2.18 Impact Factor
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