Charge inhomogeneity of graphene on SiO2: dispersion-corrected density functional theory study on the effect of reactive surface sites

RSC Advances ◽  
2014 ◽  
Vol 4 (70) ◽  
pp. 37236-37243 ◽  
Author(s):  
Jinhee Lee ◽  
Nodo Lee ◽  
Yves Lansac ◽  
Yun Hee Jang
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Study ◽  
Surface Species ◽  
Functional Theory ◽  
Surface Sites ◽  
Reactive Surface

Reactive surface species present on SiO2 in a mixture with inert ones is one likely origin of charge puddles observed in supported graphenes.

scholarly journals Pd Single-Atom Sites on the Surface of PdAu Nanoparticles: A DFT-Based Topological Search for Suitable Compositions

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 122
Author(s):  
Mikhail Mamatkulov ◽  
Ilya V. Yudanov ◽  
Andrey V. Bukhtiyarov ◽  
Konstantin M. Neyman
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Single Atom ◽  
Content Increase ◽  
Atomic Shell ◽  
Surface Species ◽  
Functional Theory ◽  
Topological Approach ◽  
Surface Sites ◽  
Pdau Nanoparticles

Structure of model bimetallic PdAu nanoparticles is analyzed aiming to find Pd:Au ratios optimal for existence of Pd1 single-atom surface sites inside outer Au atomic shell. The analysis is performed using density-functional theory (DFT) calculations and topological approach based on DFT-parameterized topological energy expression. The number of the surface Pd1 sites in the absence of adsorbates is calculated as a function of Pd concentration inside the particles. At low Pd contents none of the Pd atoms emerge on the surface in the lowest-energy chemical orderings. However, surface Pd1 sites become stable, when Pd content inside a Pd-Au particle reaches ca. 60%. Further Pd content increase up to almost pure Pd core is accompanied by increased concentration of surface Pd atoms, mostly as Pd1 sites, although larger Pd ensembles as dimers and linear trimers are formed as well. Analysis of the chemical orderings inside PdAu nanoparticles at different Pd contents revealed that enrichment of the subsurface shell by Pd with predominant occupation of its edge positions precedes emergence of Pd surface species.

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