Effects of surface wettability on (001)-WO3 and (100)-WSe2 : A spin-polarized DFT-MD study

An extensive understanding of WO3 and WSe2 bulk crystalline structures and explicit solvent effects on (001)-
WO3 and (100)-WSe2 facets are essential for design of efficient (photo) electrocatalysts. The atomistic level
understanding of both WO3 and WSe2 bulk solids and how water solvation processes occur on WO3 and WSe2
facets are nowadays characterized by a noticeable lack of knowledge.

Herein, forefront Density Functional Theory-based molecular dynamics have been conducted for assessing
the role of an explicit water environment in the characterization of solid surfaces. Water at the interface
and H-bonds environment, as well as WO3 and WSe2 surface activity, will be described in terms of surface
wettability and interfacial water dynamics, revealing the relevance of treating explicitly liquid water and its
dynamics in assessing catalytic features. We provide pieces of evidence of the hydrophobic character shown by
(001)-WO3 and (100)-WSe2 facets. A preferential in-plane hydration structure of the first water layer has been
detected at both (001)-WO3 and (100)-WSe2 water interface, in which the electric dipole moment of water
molecules is re-oriented in a sort of 2-dimensional H-bond network. Bulk property calculations of WO3 and
WSe2 are also provided