A van der Waals density functional study of chloroform and other trihalomethanes on graphene.

A computational study of chloroform (CHCl(3)) and other trihalomethanes (THMs) adsorbed on graphene is presented. The study uses the van der Waals density functional method to obtain adsorption energies and adsorption structures for these molecules of environmental concern. In this study, chloroform is found to adsorb with the H atom pointing away from graphene, with adsorption energy 357 meV (34.4 kJ/mol). For the other THMs studied the calculated adsorption energy values vary from 206 meV (19.9 kJ/mol) for fluoroform (CHF(3)) to 404 meV (39.0 kJ/mol) for bromoform (CHBr(3)). The corrugation of graphene as seen by the THMs is small, the difference in adsorption energy along the graphene plane is less than 6 meV for chloroform.