The mechanism of carcinogenic heavy metal adsorption on a new monolayer AlP5

A new monolayer AlP5 is proposed for the detection of carcinogenic heavy metals such as As, Hg and Cd in water. Based on the first-principles calculations, AlP5 is predicted to be dynamically, mechanically, and thermody-namically stable. AlP5 is a quasi-direct semiconductor with an indirect/direct band gap of 0.92/0.95 eV, and strain and layer stacking order can be used to tune its band gap. The electronic properties of AlP5 adsorbed by heavy metals in vacuum and water environments are analyzed to investigate the sensing behaviors. The results indicate that the presence of H2O molecules increases the adsorption energy of As, Hg and Cd on the surface of AlP5. The adsorption capacity of AlP5 for heavy metals in vacuum and water environments is As > Cd > Hg. The significant changes in band structure, charge transfer and density of states (DOS) indicate that AlP5 exhibits strong interactions for As, Cd and Hg. Therefore, the monolayer AlP5 is suitable for detecting and adsorbing heavy metals As, Cd and Hg.