Density functional study of Hg adsorption mechanisms on α-Fe2O3 with H2S

Abstract

First-principle calculations based on the density functional theory are performed to clarify the Hg0 adsorption reaction mechanism on an α-Fe2O3 surface with H2S in coal-utilizing facilities. Theoretical calculations based on the various adsorption mechanisms of H2S and Hg0 on α-Fe2O3 are performed to investigate a realistic reaction pathway. The results demonstrate that the Eley–Rideal mechanism with Hg0 adsorption on H2S/α-Fe2O3 surface is the most suitable reaction process, whereas the Mars–Maessen, Langmuir–Hinshelwood, and Eley–Rideal mechanisms with H2S adsorption on Hg0/α-Fe2O3 surface are not possible in real reaction mechanisms. In addition, the potential energy diagram of H2S dissociation on α-Fe2O3 surface is provided.