Chemisorption of Hydroxide on 2D Materials from DFT Calculations: Graphene versus Hexagonal Boron Nitride.
Recent nanofluidic experiments revealed strongly different surface charge measurements for boron-nitride (BN) and graphitic nanotubes when in contact with saline and alkaline water (Nature 2013, 494, 455-458; Phys. Rev. Lett. 2016, 116, 154501). These observations contrast with the similar reactivity of a graphene layer and its BN counterpart, using density functional theory (DFT) framework, for intact and dissociative adsorption of gaseous water molecules. Here we investigate, by DFT in implicit water, single and multiple adsorption of anionic hydroxide on single layers. A differential adsorption strength is found in vacuum for the first ionic adsorption on the two materials-chemisorbed on BN while physisorbed on graphene. The effect of implicit solvation reduces all adsorption values, resulting in a favorable (nonfavorable) adsorption on BN (graphene). We also calculate a pKa≃ 6 for BN in water, in good agreement with experiments. Comparatively, the unfavorable results for graphene in water echo the weaker surface charge measurements but point to an alternative scenario.
École Normale Supérieure-PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France.
Benoit
B
Grosjean
École Normale Supérieure-PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France.
Clarisse
C
Pean
École Normale Supérieure-PSL Research University , Laboratoire de Physique Statistique, UMR 8550, 24, rue Lhomond, 75005 Paris, France.
Alessandro
A
Siria
École Normale Supérieure-PSL Research University , Laboratoire de Physique Statistique, UMR 8550, 24, rue Lhomond, 75005 Paris, France.
Lydéric
L
Bocquet
École Normale Supérieure-PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France.
Rodolphe
R
Vuilleumier
École Normale Supérieure-PSL Research University , Département de Chimie, Sorbonne Universités - UPMC Univ Paris 06, CNRS UMR 8640 PASTEUR, 24, rue Lhomond, 75005 Paris, France.
Marie-Laure
ML
Bocquet