Adsorption of toxic mercury, lead, cadmium, and arsenic ions on black phosphorous nanosheet: first-principles calculations

The applicability of the black phosphorus monolayer (BPML) material to remove cadmium, lead, mercury, and arsenic ions from contaminated environments was evaluated. The coordination of metal ion varied from two to four. Both expanding and contracting distortions were observed. The bandgap of BPML was enlarged by 0.12-1.10eV, with the smallest and largest changes for Pb (II) and Hg (II), respectively. After decoration, all decorated BPML nanosheets kept their p-type semiconducting property. The total density of states (TDOS) plots indicated the marked impact of the adatoms on the Fermi level of BPML. The considerably high adsorption energies followed the sequence of Pb (II) < Cd (II) < Hg (II) << As (III), in full correspondence with the remarkable charge transfers (0.440-1.236e). The localized orbital locator (LOL) profiles revealed the nature of the interactions.