Competition between Pauli Exclusion and H-Bonding: H₂O and NH₃ on Silicene

Abstract

We demonstrate that the competition between Pauli exclusion and H-bonding dominates the adsorption of H 2 O on silicene through first-principles calculations. It explains the bewildering problem that isolated H 2 O is inert on silicene while isolated NH 3 tends to chemisorption. Moreover, Pauli exclusion can be overcome by the synergetic effect of Si•••O dative bonding and intermolecular H-bonding. As a result, H 2 O molecules are readily to chemisorb in clusters. It is expected that the competition is in general polar molecule adsorption on silicene and, thus, crucial for the adsorption mechanism.

Strain Effect on the Dissociation of Water Molecules on Silicene: Density Functional Theory Study

“…Based on the DFT-D calculations with consideration of van der Waals forces through the Grimme scheme and eq , the obtained E ad values are listed in Table . Based on our calculations, the favorable adsorption site of the H 2 O is at the hollow site with an adsorption energy E ad = −0.19 eV, as shown in Figure a, which is similar to that in ref . To study the effect of the simulation cell size on the results, we also performed calculations with H 2 O adsorbed on the hollow site using a 5 × 5 supercell and found adsorption energy E ad = −0.19 eV, which is the same as the result obtained with the 4 × 4 supercell, indicating that the 4 × 4 supercell is large enough for this simulation.…”

“…37 Motivated by this fact, the band gap and conductivity of silicene are also expected to be tuned by dissociative adsorption of H 2 O molecules. However, H 2 O molecules are inert 38−41 to the silicene due to the Pauli exclusion effect, 38 materials. 42−49 It is reported that strain can enhance the binding energy and charge transfer between water and the substrate on an in-plane graphene/silicene heterostructure.…”

“…Motivated by this fact, the band gap and conductivity of silicene are also expected to be tuned by dissociative adsorption of H 2 O molecules. However, H 2 O molecules are inert − to the silicene due to the Pauli exclusion effect, and the dissociation of water molecule on silicene is difficult. The possibility of the dissociation of molecules can be evaluated by the energy barrier, where reducing the energy barrier would facilitate the dissociative reactions.…”

Adsorption of Actinide (U–Pu) Complexes on the Silicene and Germanene Surface: A Theoretical Study

“…Recent years have also witnessed a strong interest in the 2D material of the next element in the group, germanene, which is made up of a single layer of germanium atoms. , C, Si, and Ge have a lot of similarities due to the presence of the same valence electron configurations 2s 2 2p 2 , 3s 2 3p 2 , and 4s 2 4p 2 , respectively. Moreover, the high compatibility of silicene to Si-based nanotechnology and its outstanding inherited properties from graphene make it highly interesting. − …”