Design of Single-Atom Catalysts for Hg0 Oxidation Using H2o2

Abstract

Hg0 removal is the most difficult part in mercury purification due to its insolubility in water and strong volatility. Catalytic oxidation is the main method for Hg0 removal. O2 and hydrogen halides (HCl and H2S) are common oxidants for catalytic Hg0 oxidation. However, previous studies showed that current catalytic oxidation routes have sluggish kinetics and may cause secondary pollution. Herein, we propose a new pathway for catalytic Hg0 oxidation on the surface of single-atom catalysts (SACs) using the green oxidant H2O2. Some potential catalysts were screened by analysing the adsorption and activation mechanism of H2O2 on the surface of SACs. Spin-polarized density functional theory calculations with van der Waals corrections (DFT-D3) revealed that Zn1-N4-C has the lowest rate-determining step barrier (0.35 eV) among the analyzed systems. This study proposes a promising pathway for a kinetically facile catalytic Hg0 oxidation, providing a new option for effective Hg0 removal.

Keywords: single-atom catalysts, hydrogen peroxide, dissociative adsorption, mercury oxidation