Density Functional Theory Calculations on the Interaction of Ethene with the {111} Surface of Platinum (original) (raw)
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Hydrogen storage on platinum decorated graphene: A first-principles study
BIBECHANA, 2014
Adsorption of gaseous/molecular hydrogen on platinum (Pt) decorated and pristine graphene have been studied systematically by using density functional theory (DFT) level of calculations implemented by Quantum ESPRESSO codes. The Perdew-Burke-Ernzerhof (PBE) type generalized gradient approximation (GGA) exchange-correlation functional and London dispersion forces have been incorporated in the DFT-D2 level of algorithm for short and long range electron-electron interactions, respectively. With reference to the binding energy of Pt on different symmetry sites of graphene supercells, the bridge (B) site has been predicted as the best adsorption site. In case of 3×3 supercell of graphene (used for detail calculations), the binding energy has been estimated as 2.02 eV. The band structure and density of states calculations of Pt adatom graphene predict changes in electronic/magnetic properties caused by the atom (Pt). The adatom (Pt) also enhances the binding energy per hydrogen molecule i...
2019
Graphene is an exciting new material with many promising applications. One such application of graphene is gas sensing, when adsorbed with transition metals, notably Palladium. Therefore, it is of paramount importance to have appropriate ab initio calculations to calculate the various properties of graphene under different adsorbates and gasses. The first step in these calculations is to have a functioning base Density Functional Theory (DFT) model of pristine graphene decorated with Palladium. The computational methods described in this paper has yielded results for pristine graphene that have been confirmed many times in previous experimental and theoretical studies. Future work needs to consider different concentrations of H2, Van der Waals correction, band graph calculations, and establishing a standardized set of parameters.
A DFT-D study of hydrogen adsorption on functionalized graphene
RSC Adv., 2015
In this paper, we use density functional theory with dispersion correction functional (DFT-D) as implemented in Vienna Ab Initio Simulation package in order to investigate hydrogen adsorption on graphane (GH) and fluorographene (GF). The adsorption sites at different surface coverage rates were studied to determine the most stable configurations. The comparison between the results obtained using standard pure DFT functionals and dispersion corrected ones; highlight the role of the dispersion effect in the adsorption energies and the orientation of the molecules relative to the surface. The coverage rate is found to increase up to 75% on the two sides, what makes these nanoporous materials, promising candidates for hydrogen storage. Electronic properties such as density of states and band structures were calculated on both GH and GF systems. It is observed that after H 2 adsorption the band gap of GH is only slightly modified, whereas the opposite trend is observed on GF.
Density functional study of adsorption of molecular hydrogen on graphene layers
The Journal of Chemical Physics, 2000
Density functional theory has been used to study the adsorption of molecular H 2 on a graphene layer. Different adsorption sites on top of atoms, bonds and the center of carbon hexagons have been considered and compared. We conclude that the most stable configuration of H 2 is physisorbed above the center of an hexagon. Barriers for classical diffusion are, however, very small.
RSC Adv., 2014
The physisorption of molecular hydrogen onto coronene is studied using a multi-scale theoretical approach with Density Functional Theory (DFT) calculations and Molecular Dynamics (MD) simulations. We consider two different kinds of model conformations for the approach of hydrogen towards the coronene i.e., systematic and random. For the systematic attack of hydrogen over coronene, the resulting potential energy profiles from DFT analysis are further found resembling to the Morse potential, and even to the largely flexible Murrell-Sorbie (M-S) potential. The resulting M-S fitting also shows a zero-point energy correction of ∼ 16-17 %. On the other hand, the potential energies from the random approach has been implemented into the Improved Lennard-Jones (ILJ) force field of DL − POLY package following a prior statistical treatment. The MD simulations have been performed at different temperatures from 10 to 390 K. For the interaction of seven hydrogen molecules with coronene, the DFT method shows an average interaction energy of −3.85 kJ/mol per H 2 , which is standing slightly below the Coupled Cluster value (CCSD(T)) of −4.71 kJ/mol that was calculated for a single molecule in the most favorable situation. Moreover, the MD calculations reveal a mean interaction energy of −3.69 kJ/mol per H 2 (a gross mean E c f g of −25.98 kJ/mol at T = 299.97 K), which is again in good agreement to the aforementioned DFT results, proving the quality of the used approach for the study of van der Waals interactions between hydrogen and graphene. (Spain).
First-principles vdW-DF study on the enhanced hydrogen storage capacity of Pt-adsorbed graphene
Journal of Molecular Modeling, 2014
Ab initio vdW calculations with the DFT level of theory were used to investigate hydrogen (H 2) adsorption on Ptadsorbed graphene (Pt-graphene). We have explored the most energetically favorable sites for single Pt atom adsorption on the graphene surface. The interaction of H 2 with the energetically favorable Pt-graphene system was then investigated. We found that H 2 physisorbs on pristine graphene with a binding energy of −0.05 eV, while the binding energy is enhanced to −1.98 eV when H 2 binds Pt-adsorbed graphene. We also found that up to four H 2 molecules can be adsorbed on the Ptgraphene system with a −0.74 eV/H 2 binding energy. The effect of graphene layer stretching on the Pt-graphene capacity/ability for hydrogen adsorption was evaluated. Our results show that the number of H 2 molecules adsorbed on the Pt-graphene surface rises to six molecules with a binding energy of approximately −0.29 eV/H 2. Our first-principles results reveal that the Young's modulus was slightly decreased for Pt adsorption on the graphene layer. The first-principles calculated Young's modulus for the H 2-adsorbed Pt-graphene system demonstrates that hydrogen adsorption can dramatically increase the Young's modulus of such systems. As a result, hydrogen adsorption on the Pt-graphene system might enhance the substrate strength.
Journal of Applied Physics, 2014
Previous Density Functional Theory (DFT) studies on metal decorated graphene generally use local density approximation (LDA) or generalized gradient approximation (GGA) functionals which can cause inaccuracies in hydrogen binding energies as they neglect van der Waals (vdW) interactions and are difficult to compare due to their widely varying simulation parameters. We investigated the hydrogen binding ability of several metals with a consistent set of simulations using the GGA functional and incorporated vdW forces through the vdW-DF2 functional. Metal adatom anchoring on graphene and hydrogen adsorption ability for both single and double sided decoration were studied for eight metals (Al, Li, Na, Ca, Cu, Ni, Pd, and Pt). It was found that the vdW correction can have a significant impact on both metal and hydrogen binding energies. The vdW-DF2 functional led to stronger metal adatom and hydrogen binding for light metals in comparison to GGA results, while heavier transition metals d...
Pt-decorated graphene as superior media for H2S adsorption: A first-principles study
Applied Surface Science, 2012
The adsorption mechanism of hydrogen sulfide (H 2 S) molecules on pristine and Pt-decorated graphene sheets was studied using density functional theory calculations based on local density approximation and generalized gradient approximation methods. Our calculations show that a Pt-decorated graphene system has much higher binding energy, higher net charge transfer values and shorter connecting distances than pristine graphene due to chemisorption of the H 2 S molecule. Furthermore, the calculated density of states show that orbital hybridization is visible between the H 2 S and Pt-decorated graphene sheets, while there is no evidence for hybridization between the H 2 S molecule and the pristine graphene sheet. Interestingly, we find that up to seven H 2 S molecules can stably bind to a Pt atom on each side of the graphene sheet with desirable binding energy.
2019
We conducted theoretical investigation of the structural and electronic properties of Pt-functionalized graphene and NH-doped Pt-functionalized graphene, which are shown to be efficient materials for hydrogen storage. Nitrene radical dopant was an effective addition required for enhancing the Pt binding on the graphene sheet. We found that up to three H2 molecules could be adsorbed by Pt-functionalized graphene with an average binding energy in the range 3.049−1.731eV eV. The most crucial part of our work is measuring the effect of nitrene radical on Pt-functionalized graphene. Our calculations predicted that the addition of NH radicals on Pt-functionalized graphene enhance the binding of Pt on graphene, which helps also to avoid the desorption of Pt(H2)n (n=1-3) complexes from graphene sheet. Our results also predict Pt-functionalized NH-doped graphene is a potential hydrogen storage medium for on-board applications.