نتایج جستجو برای: isolated adsorption site
تعداد نتایج: 720852 فیلتر نتایج به سال:
Plane-wave pseudopotential Density Functional Theory (OFT) periodic slab calculations were performed usingthe giteralized gradient approximation (GHA) to investigate the adsorption of nitric oxide(NO) on the (I II)surface of Cu. Copper rface was stimulated using th P 'odic Slab Method consisting of Five atomic Layers.Four different adsorption saes (Atop. Bridge, RCP Hollow, and FCC Hollow) were...
Molecular hydrogen and oxygen adsorptions on a (6, 6) armchair silicon nanotube have been studied by optimizing the distances of the admolecules from both inside and outside the tube. Full geometry and spin optimizations have been performed without any symmetry constraints with an all electron 3-21G* basis set and the B3LYP functional. The molecule is originally placed perpendicular or parallel...
The stability and reactivity of the hematite, Fe2O3(0001) surface are studied by density functional theory including an on-site Coulomb term (DFT+U). Even under oxygen rich conditions, the metal-terminated surface is shown to be stable. On this surface termination, the isolated water molecule forms a heterolytically dissociated structure with the OH- group attached to a surface Fe3+ ion and the...
Metathesis of propene to ethene and 2-butenes was studied over a series of MoOx/SBA-15 catalysts (molybdenum oxide supported on mesoporous silica SBA-15; Mo loading 2.1~13.3 wt%, apparent Mo surface density 0.2~2.5 nm). The catalysts have been prepared by an ion exchange technique. Nitrogen adsorption, HMAS-NMR, Raman, and FTIR spectroscopies were applied to characterize the catalysts. Adsorpti...
A catalytic site typically consists of one or more atoms of a catalyst surface that arrange into a configuration offering a specific electronic structure for adsorbing or dissociating reactant molecules. The catalytic activity of adjacent bimetallic sites of metallic nanoparticles has been studied previously. An isolated bimetallic site supported on a non-metallic surface could exhibit a distin...
it seems using the maxwell-stefan (m-s) diffusion model in combination with the vacancy solutiontheory (vst) and the single-component adsorption data provides a superior, qualitative, andquantitative prediction of diffusion in zeolites. in the m-s formulation, thermodynamic factor (г) isan essential parameter which must be estimated by an adsorption isotherm. researchers usually utilizethe simp...
The adsorption ability of activated carbon, chitosan, and chitosan/activated carbon composite for cadmium separation from aqueous solution was analyzed via statistical physical modeling. The equilibrium data were analyzed by Langmuir, Hill, double layer model, and the multi-layer model with saturation isotherm models. Results showed that the multi-layer model with saturation could well describe...
ABSTRACT The main objective of this work is to investigate the adsorption of Pyrrole 2-carboxylic acid (PCA) from O, N and C sites on the surface of pristine and Ni doped B12N12 nano cage by using density functional theory (DFT). The results of adsorption energy indicate that the adsorption of PCA on the surface of B12N12 and NiB11N12 is exoth...
we have studied the adsorption processes of h2 on the v (100) surface of vanadium using self consistent field theory.dissociative adsorptions of h2 are significantly favored compared to molecular adsorptions. there is a significant charge transfer from the first layer of the vanadium surface to the hydrogen atoms. three possible adsorption sites, top, bridge and center site, were considered in ...
The adsorption of hydrogen sulfide molecule on undoped and N-doped TiO2/Au nanocomposites was investigated by density functional theory (DFT) calculations. The results showed that the adsorption energies of H2S on the nanocomposites follow the order of 2N doped (Ti site)>N-doped (Ti site)>Undoped (Ti site). The structural properties including bond lengths, angles<span id="...
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