Computational insights into interactions between Hg species and α-Fe2O3 (0 0 1)

First-principle calculations based on Density Functional Theory were performed to investigate the binding mechanisms of mercury species on α-Fe₂O₃ (0 0 1) surface. This is crucial in demonstrating the contribution of α-Fe₂O₃ existing in fly ash for mercury removal. It has been determined that Hg⁰ is adsorbed on the α-Fe₂O₃ (0 0 1) surface with physisorption mechanism. The oxidized forms of HgCl and HgCl₂ can be adsorbed on α-Fe₂O₃ (0 0 1) dissociatively or non-dissociatively. In the case of dissociative adsorption, a close examination of the energy diagram indicates that HgCl may be favorable for the adsorption of Cl and desorption of Hg. The dissociation of HgCl₂ with the binding of Cl and HgCl on the surface is possibly the dominant interaction pathway.