Study of Vacancies and Pd Atom Decoration on the Electronic Properties of Bilayer Graphene

Abstract

We have investigated the scenario of graphene when irradiated with high energetic protons and subsequently decorated with Pd atoms on one of the layers. Theoretical analyses were performed on graphene 2L (two layers) with vacancies (carbon 3 and 13) (sample A), graphene 2L with vacancies and the two carbon atoms intercalated in between the two carbon layers (sample B), graphene 2L with the vacancies intercalated and subsequently with two Pd atoms on one of the layers, the top layer (called surface) (sample C), and, last but not least, graphene 2L with vacancies intercalated and decorated with six Pd atoms on the surface (sample D). For the four cases enunciated, energy bands were performed which provided information about the semimetallic behavior, showing more semi-metallic character for the first case, while less metallic behavior occurs for the second and third one. Moreover, sample D showed a mini gap (between the conduction and valence bands) of the order of 0.02 eV and manifest semiconductor behavior. Total and projected density of states were performed in order to provide information about the contributions from each selected atom to the total DOS in the vicinity of the Fermi level in order to analyze the effect on the electronic behavior. Pd d orbitals contribute with ∼6% to the total DOS, while graphene (carbon atoms) p orbitals contribute with ∼5%. Furthermore, a strong hybridization is manifest between these two multiple degenerate orbitals.In addition, Crystal Orbital Overlap Population (COOP) between metal (M-M) contributions were calculated in order to inquire the existence (or absence) of magnetic instabilities. Pd atoms showed an itinerant ferromagnetic behavior which induces it to the graphene 2L samples.

Graphene‐Based Materials: Synthesis, Characterization, Properties, and Applications

“…The attractive properties of graphene and its derivatives have made them ideal templates for the synthesis of metal nanoparticles (NPs), such as Au,81, 87, 118, 334–359 Ag,81, 360–362 Pd,165, 334, 341, 349, 363–368 Pt,118, 334, 369 Ni,370 and Cu 341. Dependent on the type of the anchored NPs, the graphene–metal NP composites have been applied in a broad range of areas, such as surface‐enhanced Raman scattering (SERS),81, 337 catalysis,349, 363 and electrochemical sensing 119, 348, 371–373.…”

Catalysis performance comparison for electrochemical reduction of CO2 on Pd–Cu/graphene catalyst

“…[20][21][22][23] As a 2D monolayer of sp 2 -hybridized carbon atoms, graphene has excellent electrical conductivity, 24,25 large special surface area and high chemical stability, which would help promote electron transfer and improve reaction kinetics on noble metal nanoparticles. [26][27][28] Furthermore, the reactive groups such as hydroxyl and carboxyl on graphene surface will provide coordination sites for the metal loaded. 29 And the carbon vacancies in graphene can be used as anchoring points for the growth of metal nanoparticles.…”

“…[24][25][26] Consequently, graphene has been widely used to support metal nanoparticles to prepare catalyst. [27][28][29][30][31] In this paper, metal/graphene (Pd/graphene, Cu/graphene, Pd-Cu/graphene) catalysts were prepared and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) technologies. The reduction performance of CO 2 was investigated by electrochemistry tests to select stable and efficient metal/graphene catalyst.…”