Strain induced variation of PFOS adsorption on pristine and defected phosphorene: A DFT study

Adsorption of per- and polyfluoroalkyl substances (PFAS) such as perfluorooctane sulfonate (PFOS), is a key issue in the environmental area now but not yet fully understood. As a monolayer adsorbent, phosphorene has attracted a body of research interests. Defects and strain are reported to be important for its electronic structure regulations. In this work, we use the density functional theory (DFT) calculations to explore the adsorption of PFOS on the pristine, the Stone-Wales defected (SW), the single vacancy defected (SV) and the double vacancy defected phosphorenes (DV), respectively. Moreover, the effects of the strain of phosphorene along both a- and b-directions (two directions of a monolayer) on the PFOS adsorption are systematically investigated by analyzing the adsorption energy (E_ads), electron transferring and the partial density of states. Finally, the synergistic effects of SV defects and tensile strain of phosphorene towards the enhancement of PFOS adsorption is proposed.