First-principles study of CH4 adsorption on transition metal doped phosphorene with Stone-Wales defects

Abstract

Based on density functional theory, the geometric, electrical, and magnetic properties of CH4 adsorption are determined on pristine, Stone-Wales (SW) defected, and transition metal (TM; Mn, Fe, Co, Ni) -doped phosphorene. The results show that doping with transition metals can enrich the magnetic behavior of P, and allow the SW-defected phosphorene (SWP) to exhibit a direct band gap. The adsorption mechanism of CH4 molecule on pristine and SWP is physisorption, which exhibits small adsorption energies and large interaction distances. After doping with TM, the CH4 adsorption mechanism transforms to chemisorption. Interestingly, the CH4 system adsorbed on the Ni-doped SWP exhibits half-metal properties. The recovery time of doping systems is very short due to the small adsorption energy. Compared with the SW-defected phosphorene, the band gap values of Mn, Fe, and Co doped systems decrease after adsorption, which can be used as a signal to detect CH4 gas. Furthermore, due to its highest adsorption energy and charge transfer, Co-doped SWP is more appropriate to be used as a multi-time reusable gas sensor material to detect CH4 gas.