Modeling of laser-pulse induced water decomposition on two-dimensional materials by simulations based on time-dependent density functional theory

摘要

We use time-dependent density functional theory to study laser-pulse induced decomposition of H_2O molecules above the two-dimensional (2D) materials graphene, hexagonal boron nitride, and graphitic carbon nitride. We examine femtosecond-laser pulses with a full width at half maximum of 10 or 20 fs for laser-field intensity and wavelengths of 800 or 400 nm by varying the intensity of the laser field from 5 to 9 V/A, with the corresponding range of fluence per pulse up to 10.7 J/cm~2. For a H_2O molecule above the graphitic sheets, the threshold for laser-field H_2O decomposition is reduced by more than 20% compared with that of an isolated H_2O molecule. We also show that hole doping enhances the water adsorption energy above graphene. The present results indicate that the graphitic materials should support laser-induced chemistry and that other 2D materials that can enhance laser-induced H_2O decomposition should be investigated.