Adsorption of water molecules on pristine and defective NiPX$_3$ (X: S, Se) monolayers

TL;DR

This study provides a theoretical analysis of water molecule adsorption on pristine and defective NiPX$_3$ monolayers, revealing physisorption as the dominant interaction with implications for water splitting applications.

Contribution

It offers the first detailed theoretical description of water adsorption on NiPX$_3$ monolayers, including defect effects, establishing a foundation for future water/MPX$_3$ studies.

Findings

Water physisorption energies do not exceed -650 meV.

Dissociative water adsorption is energetically unfavorable.

Defects do not significantly alter the physisorption nature.

Abstract

Layered transition metal trichalcogenides MPX$_3$ (M: transition metal; X: S, Se) demonstrate a wide spectrum of properties and are widely proposed as effective materials for the water splitting reactions. Among these materials, NiPX$_3$ are the most promising ones due to the match their electronic structures for the oxygen and hydrogen evolution reactions. Here, we present first steps of a detailed theoretical description on the adsorption of water molecules on pristine and defected (chalcogen vacancies) surfaces of NiPX$_3$ and show that in all cases a physisorption takes the place with adsorption energies do not exceeding $-650$\,meV and water dissociative adsorption is unfavourable. This work provides a general description for water molecules interaction with MPX$_3$ and can serve as a basis for further studies on more complicated water/MPX$_3$ reactions.