Nonmetal (B, C, N, O, F) doping regulates the electron distribution of monolayer MoS2 for Hg0 adsorption

Mercury removal is very important to solve environmental pollution problems. However, the elemental mercury (Hg0) is difficult to be removed due to its low solubility, volatility, and closed electron structure of 5d106s2. In this work, using first principles study, the adsorption properties of Hg0 on nonmetal (B, C, N, O, and F) doped monolayer MoS2. The results of adsorption energy show that acceptor (B, C, and N) doped MoS2 has a strong adsorption capacity for Hg0, while the same group (O) and donor (F) doped system has almost no such capacity. Meanwhile, the adsorption strength of Hg0 in acceptor doped system decreases with the increase of valence electrons. In other words, 6 valence electron is the critical value, lower than this value is conducive to Hg0 adsorption, while higher or equal to this value is not conducive to Hg0 adsorption. This is due to the fact that the amount of charge transferred by Hg0 to the dopant atom decreases as the number of valence electrons increases. Therefore, B and C doped MoS2 can be used as a gas scavenger for Hg0 removal.