Insights into the Adsorption, Alloy Formation, and Poisoning Effects of Hg on Monometallic and Bimetallic Adsorbents.

The removal of elemental mercury (Hg) from coal-derived syngas at high temperatures is desired to improve the thermal efficiency of the coal-to-chemical processes. First-principles density functional theory (DFT) calculations for Hg adsorption are performed using different exchange correlation functionals (PBE, optPBE-vdW, and optB88-vdW). Gibbs free energy (Δ) calculations are further performed to evaluate the feasibility of Hg adsorption on various exposed planes of metal nanoparticles and to obtain bimetallic compositions for Hg removal at various temperatures.