Phenol, phenyl azide, and phenylnitrene are hazardous organic molecules; therefore, the fabrication of sensors or filters with high sorption capabilities for the chemicals is necessary. Considering van der Waals interaction, we perform first-principles density functional theory calculations to investigate the adsorption properties of the hazardous molecules on graphene. For parallel stacking configurations, AB stacking is slightly more favorable than AA stacking for all the adsorbates that we considered. We find that phenyl azide has a higher adsorption energy than phenol. Phenylnitrene forms covalent bonds with graphene in oblique stacking structures, resulting in a bandgap opening in graphene. (C) 2014 Elsevier B.V. All rights reserved.