Charge transfer driven interaction of CH4, CO2 and NH3 with TiS2 monolayer: Influence of vacancy defect

Abstract

In this work we have investigated the dissociation of hydrogen rich CH4 and NH3 molecules along with CO2 on the surface of pristine and various defect induced TiS2 monolayer. The aim is to see whether the monolayer surfaces are able to produce H2 by decomposing the feedstock adsorbates and also to examine whether it can be a sorbent for CO2. We have tried to explore a monolayer surface which can simultaneously act as a catalyst to dissociate CH4, as well as to adsorb CO2 which is the only harmful by-product in steam reforming method for hydrogen production from CH4. The hydrogen generation has been predicted from the nature of gas adsorption, and the adsorption energies have been estimated to see whether it falls under chemisorption or physisorption range. Both S and Ti vacancy defects have been studied and the first-principles electronic structure calculation helps to envisage the charge redistribution of the three adsorbates on both pristine and defective TiS2 surfaces.